The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/net/zlib.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*
    2  * This file is derived from various .h and .c files from the zlib-1.0.4
    3  * distribution by Jean-loup Gailly and Mark Adler, with some additions
    4  * by Paul Mackerras to aid in implementing Deflate compression and
    5  * decompression for PPP packets.  See zlib.h for conditions of
    6  * distribution and use.
    7  *
    8  * Changes that have been made include:
    9  * - added Z_PACKET_FLUSH (see zlib.h for details)
   10  * - added inflateIncomp and deflateOutputPending
   11  * - allow strm->next_out to be NULL, meaning discard the output
   12  *
   13  * $FreeBSD: src/sys/net/zlib.c,v 1.18.2.1 2005/01/31 23:26:23 imp Exp $
   14  */
   15 
   16 /* 
   17  *  ==FILEVERSION 971210==
   18  *
   19  * This marker is used by the Linux installation script to determine
   20  * whether an up-to-date version of this file is already installed.
   21  */
   22 
   23 #define NO_DUMMY_DECL
   24 #define NO_ZCFUNCS
   25 #define MY_ZCALLOC
   26 
   27 #if defined(__FreeBSD__) && defined(_KERNEL)
   28 #define inflate inflate_ppp     /* FreeBSD already has an inflate :-( */
   29 #endif
   30 
   31 
   32 /* +++ zutil.h */
   33 /*-
   34  * zutil.h -- internal interface and configuration of the compression library
   35  * Copyright (C) 1995-1996 Jean-loup Gailly.
   36  * For conditions of distribution and use, see copyright notice in zlib.h
   37  */
   38 
   39 /* WARNING: this file should *not* be used by applications. It is
   40    part of the implementation of the compression library and is
   41    subject to change. Applications should only use zlib.h.
   42  */
   43 
   44 /* From: zutil.h,v 1.16 1996/07/24 13:41:13 me Exp $ */
   45 
   46 #ifndef _Z_UTIL_H
   47 #define _Z_UTIL_H
   48 
   49 #ifdef _KERNEL
   50 #include <net/zlib.h>
   51 #else
   52 #include "zlib.h"
   53 #endif
   54 
   55 #ifdef _KERNEL
   56 /* Assume this is a *BSD or SVR4 kernel */
   57 #include <sys/types.h>
   58 #include <sys/time.h>
   59 #include <sys/systm.h>
   60 #include <sys/param.h>
   61 #include <sys/kernel.h>
   62 #include <sys/module.h>
   63 #  define HAVE_MEMCPY
   64 
   65 #else
   66 #if defined(__KERNEL__)
   67 /* Assume this is a Linux kernel */
   68 #include <linux/string.h>
   69 #define HAVE_MEMCPY
   70 
   71 #else /* not kernel */
   72 
   73 #if defined(MSDOS)||defined(VMS)||defined(CRAY)||defined(WIN32)||defined(RISCOS)
   74 #   include <stddef.h>
   75 #   include <errno.h>
   76 #else
   77     extern int errno;
   78 #endif
   79 #ifdef STDC
   80 #  include <string.h>
   81 #  include <stdlib.h>
   82 #endif
   83 #endif /* __KERNEL__ */
   84 #endif /* _KERNEL */
   85 
   86 #ifndef local
   87 #  define local static
   88 #endif
   89 /* compile with -Dlocal if your debugger can't find static symbols */
   90 
   91 typedef unsigned char  uch;
   92 typedef uch FAR uchf;
   93 typedef unsigned short ush;
   94 typedef ush FAR ushf;
   95 typedef unsigned long  ulg;
   96 
   97 extern const char *z_errmsg[10]; /* indexed by 2-zlib_error */
   98 /* (size given to avoid silly warnings with Visual C++) */
   99 
  100 #define ERR_MSG(err) z_errmsg[Z_NEED_DICT-(err)]
  101 
  102 #define ERR_RETURN(strm,err) \
  103   return (strm->msg = (const char*)ERR_MSG(err), (err))
  104 /* To be used only when the state is known to be valid */
  105 
  106         /* common constants */
  107 
  108 #ifndef DEF_WBITS
  109 #  define DEF_WBITS MAX_WBITS
  110 #endif
  111 /* default windowBits for decompression. MAX_WBITS is for compression only */
  112 
  113 #if MAX_MEM_LEVEL >= 8
  114 #  define DEF_MEM_LEVEL 8
  115 #else
  116 #  define DEF_MEM_LEVEL  MAX_MEM_LEVEL
  117 #endif
  118 /* default memLevel */
  119 
  120 #define STORED_BLOCK 0
  121 #define STATIC_TREES 1
  122 #define DYN_TREES    2
  123 /* The three kinds of block type */
  124 
  125 #define MIN_MATCH  3
  126 #define MAX_MATCH  258
  127 /* The minimum and maximum match lengths */
  128 
  129 #define PRESET_DICT 0x20 /* preset dictionary flag in zlib header */
  130 
  131         /* target dependencies */
  132 
  133 #ifdef MSDOS
  134 #  define OS_CODE  0x00
  135 #  ifdef __TURBOC__
  136 #    include <alloc.h>
  137 #  else /* MSC or DJGPP */
  138 #    include <malloc.h>
  139 #  endif
  140 #endif
  141 
  142 #ifdef OS2
  143 #  define OS_CODE  0x06
  144 #endif
  145 
  146 #ifdef WIN32 /* Window 95 & Windows NT */
  147 #  define OS_CODE  0x0b
  148 #endif
  149 
  150 #if defined(VAXC) || defined(VMS)
  151 #  define OS_CODE  0x02
  152 #  define FOPEN(name, mode) \
  153      fopen((name), (mode), "mbc=60", "ctx=stm", "rfm=fix", "mrs=512")
  154 #endif
  155 
  156 #ifdef AMIGA
  157 #  define OS_CODE  0x01
  158 #endif
  159 
  160 #if defined(ATARI) || defined(atarist)
  161 #  define OS_CODE  0x05
  162 #endif
  163 
  164 #ifdef MACOS
  165 #  define OS_CODE  0x07
  166 #endif
  167 
  168 #ifdef __50SERIES /* Prime/PRIMOS */
  169 #  define OS_CODE  0x0F
  170 #endif
  171 
  172 #ifdef TOPS20
  173 #  define OS_CODE  0x0a
  174 #endif
  175 
  176 #if defined(_BEOS_) || defined(RISCOS)
  177 #  define fdopen(fd,mode) NULL /* No fdopen() */
  178 #endif
  179 
  180         /* Common defaults */
  181 
  182 #ifndef OS_CODE
  183 #  define OS_CODE  0x03  /* assume Unix */
  184 #endif
  185 
  186 #ifndef FOPEN
  187 #  define FOPEN(name, mode) fopen((name), (mode))
  188 #endif
  189 
  190          /* functions */
  191 
  192 #ifdef HAVE_STRERROR
  193    extern char *strerror OF((int));
  194 #  define zstrerror(errnum) strerror(errnum)
  195 #else
  196 #  define zstrerror(errnum) ""
  197 #endif
  198 
  199 #if defined(pyr)
  200 #  define NO_MEMCPY
  201 #endif
  202 #if (defined(M_I86SM) || defined(M_I86MM)) && !defined(_MSC_VER)
  203  /* Use our own functions for small and medium model with MSC <= 5.0.
  204   * You may have to use the same strategy for Borland C (untested).
  205   */
  206 #  define NO_MEMCPY
  207 #endif
  208 #if defined(STDC) && !defined(HAVE_MEMCPY) && !defined(NO_MEMCPY)
  209 #  define HAVE_MEMCPY
  210 #endif
  211 #ifdef HAVE_MEMCPY
  212 #  ifdef SMALL_MEDIUM /* MSDOS small or medium model */
  213 #    define zmemcpy _fmemcpy
  214 #    define zmemcmp _fmemcmp
  215 #    define zmemzero(dest, len) _fmemset(dest, 0, len)
  216 #  else
  217 #    define zmemcpy memcpy
  218 #    define zmemcmp memcmp
  219 #    define zmemzero(dest, len) memset(dest, 0, len)
  220 #  endif
  221 #else
  222    extern void zmemcpy  OF((Bytef* dest, Bytef* source, uInt len));
  223    extern int  zmemcmp  OF((Bytef* s1,   Bytef* s2, uInt len));
  224    extern void zmemzero OF((Bytef* dest, uInt len));
  225 #endif
  226 
  227 /* Diagnostic functions */
  228 #ifdef DEBUG_ZLIB
  229 #  include <stdio.h>
  230 #  ifndef verbose
  231 #    define verbose 0
  232 #  endif
  233    extern void z_error    OF((char *m));
  234 #  define Assert(cond,msg) {if(!(cond)) z_error(msg);}
  235 #  define Trace(x) fprintf x
  236 #  define Tracev(x) {if (verbose) fprintf x ;}
  237 #  define Tracevv(x) {if (verbose>1) fprintf x ;}
  238 #  define Tracec(c,x) {if (verbose && (c)) fprintf x ;}
  239 #  define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}
  240 #else
  241 #  define Assert(cond,msg)
  242 #  define Trace(x)
  243 #  define Tracev(x)
  244 #  define Tracevv(x)
  245 #  define Tracec(c,x)
  246 #  define Tracecv(c,x)
  247 #endif
  248 
  249 
  250 typedef uLong (*check_func) OF((uLong check, const Bytef *buf, uInt len));
  251 
  252 voidpf zcalloc OF((voidpf opaque, unsigned items, unsigned size));
  253 void   zcfree  OF((voidpf opaque, voidpf ptr));
  254 
  255 #define ZALLOC(strm, items, size) \
  256            (*((strm)->zalloc))((strm)->opaque, (items), (size))
  257 #define ZFREE(strm, addr)  (*((strm)->zfree))((strm)->opaque, (voidpf)(addr))
  258 #define TRY_FREE(s, p) {if (p) ZFREE(s, p);}
  259 
  260 #endif /* _Z_UTIL_H */
  261 /* --- zutil.h */
  262 
  263 /* +++ deflate.h */
  264 /* deflate.h -- internal compression state
  265  * Copyright (C) 1995-1996 Jean-loup Gailly
  266  * For conditions of distribution and use, see copyright notice in zlib.h 
  267  */
  268 
  269 /* WARNING: this file should *not* be used by applications. It is
  270    part of the implementation of the compression library and is
  271    subject to change. Applications should only use zlib.h.
  272  */
  273 
  274 /* From: deflate.h,v 1.10 1996/07/02 12:41:00 me Exp $ */
  275 
  276 #ifndef _DEFLATE_H
  277 #define _DEFLATE_H
  278 
  279 /* #include "zutil.h" */
  280 
  281 /* ===========================================================================
  282  * Internal compression state.
  283  */
  284 
  285 #define LENGTH_CODES 29
  286 /* number of length codes, not counting the special END_BLOCK code */
  287 
  288 #define LITERALS  256
  289 /* number of literal bytes 0..255 */
  290 
  291 #define L_CODES (LITERALS+1+LENGTH_CODES)
  292 /* number of Literal or Length codes, including the END_BLOCK code */
  293 
  294 #define D_CODES   30
  295 /* number of distance codes */
  296 
  297 #define BL_CODES  19
  298 /* number of codes used to transfer the bit lengths */
  299 
  300 #define HEAP_SIZE (2*L_CODES+1)
  301 /* maximum heap size */
  302 
  303 #define MAX_BITS 15
  304 /* All codes must not exceed MAX_BITS bits */
  305 
  306 #define INIT_STATE    42
  307 #define BUSY_STATE   113
  308 #define FINISH_STATE 666
  309 /* Stream status */
  310 
  311 
  312 /* Data structure describing a single value and its code string. */
  313 typedef struct ct_data_s {
  314     union {
  315         ush  freq;       /* frequency count */
  316         ush  code;       /* bit string */
  317     } fc;
  318     union {
  319         ush  dad;        /* father node in Huffman tree */
  320         ush  len;        /* length of bit string */
  321     } dl;
  322 } FAR ct_data;
  323 
  324 #define Freq fc.freq
  325 #define Code fc.code
  326 #define Dad  dl.dad
  327 #define Len  dl.len
  328 
  329 typedef struct static_tree_desc_s  static_tree_desc;
  330 
  331 typedef struct tree_desc_s {
  332     ct_data *dyn_tree;           /* the dynamic tree */
  333     int     max_code;            /* largest code with non zero frequency */
  334     static_tree_desc *stat_desc; /* the corresponding static tree */
  335 } FAR tree_desc;
  336 
  337 typedef ush Pos;
  338 typedef Pos FAR Posf;
  339 typedef unsigned IPos;
  340 
  341 /* A Pos is an index in the character window. We use short instead of int to
  342  * save space in the various tables. IPos is used only for parameter passing.
  343  */
  344 
  345 typedef struct deflate_state {
  346     z_streamp strm;      /* pointer back to this zlib stream */
  347     int   status;        /* as the name implies */
  348     Bytef *pending_buf;  /* output still pending */
  349     ulg   pending_buf_size; /* size of pending_buf */
  350     Bytef *pending_out;  /* next pending byte to output to the stream */
  351     int   pending;       /* nb of bytes in the pending buffer */
  352     int   noheader;      /* suppress zlib header and adler32 */
  353     Byte  data_type;     /* UNKNOWN, BINARY or ASCII */
  354     Byte  method;        /* STORED (for zip only) or DEFLATED */
  355     int   last_flush;    /* value of flush param for previous deflate call */
  356 
  357                 /* used by deflate.c: */
  358 
  359     uInt  w_size;        /* LZ77 window size (32K by default) */
  360     uInt  w_bits;        /* log2(w_size)  (8..16) */
  361     uInt  w_mask;        /* w_size - 1 */
  362 
  363     Bytef *window;
  364     /* Sliding window. Input bytes are read into the second half of the window,
  365      * and move to the first half later to keep a dictionary of at least wSize
  366      * bytes. With this organization, matches are limited to a distance of
  367      * wSize-MAX_MATCH bytes, but this ensures that IO is always
  368      * performed with a length multiple of the block size. Also, it limits
  369      * the window size to 64K, which is quite useful on MSDOS.
  370      * To do: use the user input buffer as sliding window.
  371      */
  372 
  373     ulg window_size;
  374     /* Actual size of window: 2*wSize, except when the user input buffer
  375      * is directly used as sliding window.
  376      */
  377 
  378     Posf *prev;
  379     /* Link to older string with same hash index. To limit the size of this
  380      * array to 64K, this link is maintained only for the last 32K strings.
  381      * An index in this array is thus a window index modulo 32K.
  382      */
  383 
  384     Posf *head; /* Heads of the hash chains or NIL. */
  385 
  386     uInt  ins_h;          /* hash index of string to be inserted */
  387     uInt  hash_size;      /* number of elements in hash table */
  388     uInt  hash_bits;      /* log2(hash_size) */
  389     uInt  hash_mask;      /* hash_size-1 */
  390 
  391     uInt  hash_shift;
  392     /* Number of bits by which ins_h must be shifted at each input
  393      * step. It must be such that after MIN_MATCH steps, the oldest
  394      * byte no longer takes part in the hash key, that is:
  395      *   hash_shift * MIN_MATCH >= hash_bits
  396      */
  397 
  398     long block_start;
  399     /* Window position at the beginning of the current output block. Gets
  400      * negative when the window is moved backwards.
  401      */
  402 
  403     uInt match_length;           /* length of best match */
  404     IPos prev_match;             /* previous match */
  405     int match_available;         /* set if previous match exists */
  406     uInt strstart;               /* start of string to insert */
  407     uInt match_start;            /* start of matching string */
  408     uInt lookahead;              /* number of valid bytes ahead in window */
  409 
  410     uInt prev_length;
  411     /* Length of the best match at previous step. Matches not greater than this
  412      * are discarded. This is used in the lazy match evaluation.
  413      */
  414 
  415     uInt max_chain_length;
  416     /* To speed up deflation, hash chains are never searched beyond this
  417      * length.  A higher limit improves compression ratio but degrades the
  418      * speed.
  419      */
  420 
  421     uInt max_lazy_match;
  422     /* Attempt to find a better match only when the current match is strictly
  423      * smaller than this value. This mechanism is used only for compression
  424      * levels >= 4.
  425      */
  426 #   define max_insert_length  max_lazy_match
  427     /* Insert new strings in the hash table only if the match length is not
  428      * greater than this length. This saves time but degrades compression.
  429      * max_insert_length is used only for compression levels <= 3.
  430      */
  431 
  432     int level;    /* compression level (1..9) */
  433     int strategy; /* favor or force Huffman coding*/
  434 
  435     uInt good_match;
  436     /* Use a faster search when the previous match is longer than this */
  437 
  438     int nice_match; /* Stop searching when current match exceeds this */
  439 
  440                 /* used by trees.c: */
  441     /* Didn't use ct_data typedef below to supress compiler warning */
  442     struct ct_data_s dyn_ltree[HEAP_SIZE];   /* literal and length tree */
  443     struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
  444     struct ct_data_s bl_tree[2*BL_CODES+1];  /* Huffman tree for bit lengths */
  445 
  446     struct tree_desc_s l_desc;               /* desc. for literal tree */
  447     struct tree_desc_s d_desc;               /* desc. for distance tree */
  448     struct tree_desc_s bl_desc;              /* desc. for bit length tree */
  449 
  450     ush bl_count[MAX_BITS+1];
  451     /* number of codes at each bit length for an optimal tree */
  452 
  453     int heap[2*L_CODES+1];      /* heap used to build the Huffman trees */
  454     int heap_len;               /* number of elements in the heap */
  455     int heap_max;               /* element of largest frequency */
  456     /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
  457      * The same heap array is used to build all trees.
  458      */
  459 
  460     uch depth[2*L_CODES+1];
  461     /* Depth of each subtree used as tie breaker for trees of equal frequency
  462      */
  463 
  464     uchf *l_buf;          /* buffer for literals or lengths */
  465 
  466     uInt  lit_bufsize;
  467     /* Size of match buffer for literals/lengths.  There are 4 reasons for
  468      * limiting lit_bufsize to 64K:
  469      *   - frequencies can be kept in 16 bit counters
  470      *   - if compression is not successful for the first block, all input
  471      *     data is still in the window so we can still emit a stored block even
  472      *     when input comes from standard input.  (This can also be done for
  473      *     all blocks if lit_bufsize is not greater than 32K.)
  474      *   - if compression is not successful for a file smaller than 64K, we can
  475      *     even emit a stored file instead of a stored block (saving 5 bytes).
  476      *     This is applicable only for zip (not gzip or zlib).
  477      *   - creating new Huffman trees less frequently may not provide fast
  478      *     adaptation to changes in the input data statistics. (Take for
  479      *     example a binary file with poorly compressible code followed by
  480      *     a highly compressible string table.) Smaller buffer sizes give
  481      *     fast adaptation but have of course the overhead of transmitting
  482      *     trees more frequently.
  483      *   - I can't count above 4
  484      */
  485 
  486     uInt last_lit;      /* running index in l_buf */
  487 
  488     ushf *d_buf;
  489     /* Buffer for distances. To simplify the code, d_buf and l_buf have
  490      * the same number of elements. To use different lengths, an extra flag
  491      * array would be necessary.
  492      */
  493 
  494     ulg opt_len;        /* bit length of current block with optimal trees */
  495     ulg static_len;     /* bit length of current block with static trees */
  496     ulg compressed_len; /* total bit length of compressed file */
  497     uInt matches;       /* number of string matches in current block */
  498     int last_eob_len;   /* bit length of EOB code for last block */
  499 
  500 #ifdef DEBUG_ZLIB
  501     ulg bits_sent;      /* bit length of the compressed data */
  502 #endif
  503 
  504     ush bi_buf;
  505     /* Output buffer. bits are inserted starting at the bottom (least
  506      * significant bits).
  507      */
  508     int bi_valid;
  509     /* Number of valid bits in bi_buf.  All bits above the last valid bit
  510      * are always zero.
  511      */
  512 
  513 } FAR deflate_state;
  514 
  515 /* Output a byte on the stream.
  516  * IN assertion: there is enough room in pending_buf.
  517  */
  518 #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
  519 
  520 
  521 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
  522 /* Minimum amount of lookahead, except at the end of the input file.
  523  * See deflate.c for comments about the MIN_MATCH+1.
  524  */
  525 
  526 #define MAX_DIST(s)  ((s)->w_size-MIN_LOOKAHEAD)
  527 /* In order to simplify the code, particularly on 16 bit machines, match
  528  * distances are limited to MAX_DIST instead of WSIZE.
  529  */
  530 
  531         /* in trees.c */
  532 void _tr_init         OF((deflate_state *s));
  533 int  _tr_tally        OF((deflate_state *s, unsigned dist, unsigned lc));
  534 ulg  _tr_flush_block  OF((deflate_state *s, charf *buf, ulg stored_len,
  535                           int eof));
  536 void _tr_align        OF((deflate_state *s));
  537 void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
  538                           int eof));
  539 void _tr_stored_type_only OF((deflate_state *));
  540 
  541 #endif
  542 /* --- deflate.h */
  543 
  544 /* +++ deflate.c */
  545 /* deflate.c -- compress data using the deflation algorithm
  546  * Copyright (C) 1995-1996 Jean-loup Gailly.
  547  * For conditions of distribution and use, see copyright notice in zlib.h 
  548  */
  549 
  550 /*
  551  *  ALGORITHM
  552  *
  553  *      The "deflation" process depends on being able to identify portions
  554  *      of the input text which are identical to earlier input (within a
  555  *      sliding window trailing behind the input currently being processed).
  556  *
  557  *      The most straightforward technique turns out to be the fastest for
  558  *      most input files: try all possible matches and select the longest.
  559  *      The key feature of this algorithm is that insertions into the string
  560  *      dictionary are very simple and thus fast, and deletions are avoided
  561  *      completely. Insertions are performed at each input character, whereas
  562  *      string matches are performed only when the previous match ends. So it
  563  *      is preferable to spend more time in matches to allow very fast string
  564  *      insertions and avoid deletions. The matching algorithm for small
  565  *      strings is inspired from that of Rabin & Karp. A brute force approach
  566  *      is used to find longer strings when a small match has been found.
  567  *      A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
  568  *      (by Leonid Broukhis).
  569  *         A previous version of this file used a more sophisticated algorithm
  570  *      (by Fiala and Greene) which is guaranteed to run in linear amortized
  571  *      time, but has a larger average cost, uses more memory and is patented.
  572  *      However the F&G algorithm may be faster for some highly redundant
  573  *      files if the parameter max_chain_length (described below) is too large.
  574  *
  575  *  ACKNOWLEDGEMENTS
  576  *
  577  *      The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
  578  *      I found it in 'freeze' written by Leonid Broukhis.
  579  *      Thanks to many people for bug reports and testing.
  580  *
  581  *  REFERENCES
  582  *
  583  *      Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
  584  *      Available in ftp://ds.internic.net/rfc/rfc1951.txt
  585  *
  586  *      A description of the Rabin and Karp algorithm is given in the book
  587  *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
  588  *
  589  *      Fiala,E.R., and Greene,D.H.
  590  *         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
  591  *
  592  */
  593 
  594 /* From: deflate.c,v 1.15 1996/07/24 13:40:58 me Exp $ */
  595 
  596 /* #include "deflate.h" */
  597 
  598 char deflate_copyright[] = " deflate 1.0.4 Copyright 1995-1996 Jean-loup Gailly ";
  599 /*
  600   If you use the zlib library in a product, an acknowledgment is welcome
  601   in the documentation of your product. If for some reason you cannot
  602   include such an acknowledgment, I would appreciate that you keep this
  603   copyright string in the executable of your product.
  604  */
  605 
  606 /* ===========================================================================
  607  *  Function prototypes.
  608  */
  609 typedef enum {
  610     need_more,      /* block not completed, need more input or more output */
  611     block_done,     /* block flush performed */
  612     finish_started, /* finish started, need only more output at next deflate */
  613     finish_done     /* finish done, accept no more input or output */
  614 } block_state;
  615 
  616 typedef block_state (*compress_func) OF((deflate_state *s, int flush));
  617 /* Compression function. Returns the block state after the call. */
  618 
  619 local void fill_window    OF((deflate_state *s));
  620 local block_state deflate_stored OF((deflate_state *s, int flush));
  621 local block_state deflate_fast   OF((deflate_state *s, int flush));
  622 local block_state deflate_slow   OF((deflate_state *s, int flush));
  623 local void lm_init        OF((deflate_state *s));
  624 local void putShortMSB    OF((deflate_state *s, uInt b));
  625 local void flush_pending  OF((z_streamp strm));
  626 local int read_buf        OF((z_streamp strm, charf *buf, unsigned size));
  627 #ifdef ASMV
  628       void match_init OF((void)); /* asm code initialization */
  629       uInt longest_match  OF((deflate_state *s, IPos cur_match));
  630 #else
  631 local uInt longest_match  OF((deflate_state *s, IPos cur_match));
  632 #endif
  633 
  634 #ifdef DEBUG_ZLIB
  635 local  void check_match OF((deflate_state *s, IPos start, IPos match,
  636                             int length));
  637 #endif
  638 
  639 /* ===========================================================================
  640  * Local data
  641  */
  642 
  643 #define NIL 0
  644 /* Tail of hash chains */
  645 
  646 #ifndef TOO_FAR
  647 #  define TOO_FAR 4096
  648 #endif
  649 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
  650 
  651 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
  652 /* Minimum amount of lookahead, except at the end of the input file.
  653  * See deflate.c for comments about the MIN_MATCH+1.
  654  */
  655 
  656 /* Values for max_lazy_match, good_match and max_chain_length, depending on
  657  * the desired pack level (0..9). The values given below have been tuned to
  658  * exclude worst case performance for pathological files. Better values may be
  659  * found for specific files.
  660  */
  661 typedef struct config_s {
  662    ush good_length; /* reduce lazy search above this match length */
  663    ush max_lazy;    /* do not perform lazy search above this match length */
  664    ush nice_length; /* quit search above this match length */
  665    ush max_chain;
  666    compress_func func;
  667 } config;
  668 
  669 local config configuration_table[10] = {
  670 /*      good lazy nice chain */
  671 /* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
  672 /* 1 */ {4,    4,  8,    4, deflate_fast}, /* maximum speed, no lazy matches */
  673 /* 2 */ {4,    5, 16,    8, deflate_fast},
  674 /* 3 */ {4,    6, 32,   32, deflate_fast},
  675 
  676 /* 4 */ {4,    4, 16,   16, deflate_slow},  /* lazy matches */
  677 /* 5 */ {8,   16, 32,   32, deflate_slow},
  678 /* 6 */ {8,   16, 128, 128, deflate_slow},
  679 /* 7 */ {8,   32, 128, 256, deflate_slow},
  680 /* 8 */ {32, 128, 258, 1024, deflate_slow},
  681 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* maximum compression */
  682 
  683 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
  684  * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
  685  * meaning.
  686  */
  687 
  688 #define EQUAL 0
  689 /* result of memcmp for equal strings */
  690 
  691 #ifndef NO_DUMMY_DECL
  692 struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
  693 #endif
  694 
  695 /* ===========================================================================
  696  * Update a hash value with the given input byte
  697  * IN  assertion: all calls to to UPDATE_HASH are made with consecutive
  698  *    input characters, so that a running hash key can be computed from the
  699  *    previous key instead of complete recalculation each time.
  700  */
  701 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
  702 
  703 
  704 /* ===========================================================================
  705  * Insert string str in the dictionary and set match_head to the previous head
  706  * of the hash chain (the most recent string with same hash key). Return
  707  * the previous length of the hash chain.
  708  * IN  assertion: all calls to to INSERT_STRING are made with consecutive
  709  *    input characters and the first MIN_MATCH bytes of str are valid
  710  *    (except for the last MIN_MATCH-1 bytes of the input file).
  711  */
  712 #define INSERT_STRING(s, str, match_head) \
  713    (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
  714     s->prev[(str) & s->w_mask] = match_head = s->head[s->ins_h], \
  715     s->head[s->ins_h] = (Pos)(str))
  716 
  717 /* ===========================================================================
  718  * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
  719  * prev[] will be initialized on the fly.
  720  */
  721 #define CLEAR_HASH(s) \
  722     s->head[s->hash_size-1] = NIL; \
  723     zmemzero((charf *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
  724 
  725 /* ========================================================================= */
  726 int deflateInit_(strm, level, version, stream_size)
  727     z_streamp strm;
  728     int level;
  729     const char *version;
  730     int stream_size;
  731 {
  732     return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
  733                          Z_DEFAULT_STRATEGY, version, stream_size);
  734     /* To do: ignore strm->next_in if we use it as window */
  735 }
  736 
  737 /* ========================================================================= */
  738 int deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
  739                   version, stream_size)
  740     z_streamp strm;
  741     int  level;
  742     int  method;
  743     int  windowBits;
  744     int  memLevel;
  745     int  strategy;
  746     const char *version;
  747     int stream_size;
  748 {
  749     deflate_state *s;
  750     int noheader = 0;
  751     static char* my_version = ZLIB_VERSION;
  752 
  753     ushf *overlay;
  754     /* We overlay pending_buf and d_buf+l_buf. This works since the average
  755      * output size for (length,distance) codes is <= 24 bits.
  756      */
  757 
  758     if (version == Z_NULL || version[0] != my_version[0] ||
  759         stream_size != sizeof(z_stream)) {
  760         return Z_VERSION_ERROR;
  761     }
  762     if (strm == Z_NULL) return Z_STREAM_ERROR;
  763 
  764     strm->msg = Z_NULL;
  765 #ifndef NO_ZCFUNCS
  766     if (strm->zalloc == Z_NULL) {
  767         strm->zalloc = zcalloc;
  768         strm->opaque = (voidpf)0;
  769     }
  770     if (strm->zfree == Z_NULL) strm->zfree = zcfree;
  771 #endif
  772 
  773     if (level == Z_DEFAULT_COMPRESSION) level = 6;
  774 
  775     if (windowBits < 0) { /* undocumented feature: suppress zlib header */
  776         noheader = 1;
  777         windowBits = -windowBits;
  778     }
  779     if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
  780         windowBits < 9 || windowBits > 15 || level < 0 || level > 9 ||
  781         strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
  782         return Z_STREAM_ERROR;
  783     }
  784     s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
  785     if (s == Z_NULL) return Z_MEM_ERROR;
  786     strm->state = (struct internal_state FAR *)s;
  787     s->strm = strm;
  788 
  789     s->noheader = noheader;
  790     s->w_bits = windowBits;
  791     s->w_size = 1 << s->w_bits;
  792     s->w_mask = s->w_size - 1;
  793 
  794     s->hash_bits = memLevel + 7;
  795     s->hash_size = 1 << s->hash_bits;
  796     s->hash_mask = s->hash_size - 1;
  797     s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
  798 
  799     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
  800     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
  801     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
  802 
  803     s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
  804 
  805     overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
  806     s->pending_buf = (uchf *) overlay;
  807     s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
  808 
  809     if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
  810         s->pending_buf == Z_NULL) {
  811         strm->msg = (const char*)ERR_MSG(Z_MEM_ERROR);
  812         deflateEnd (strm);
  813         return Z_MEM_ERROR;
  814     }
  815     s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
  816     s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
  817 
  818     s->level = level;
  819     s->strategy = strategy;
  820     s->method = (Byte)method;
  821 
  822     return deflateReset(strm);
  823 }
  824 
  825 /* ========================================================================= */
  826 int deflateSetDictionary (strm, dictionary, dictLength)
  827     z_streamp strm;
  828     const Bytef *dictionary;
  829     uInt  dictLength;
  830 {
  831     deflate_state *s;
  832     uInt length = dictLength;
  833     uInt n;
  834     IPos hash_head = 0;
  835 
  836     if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL)
  837         return Z_STREAM_ERROR;
  838 
  839     s = (deflate_state *) strm->state;
  840     if (s->status != INIT_STATE) return Z_STREAM_ERROR;
  841 
  842     strm->adler = adler32(strm->adler, dictionary, dictLength);
  843 
  844     if (length < MIN_MATCH) return Z_OK;
  845     if (length > MAX_DIST(s)) {
  846         length = MAX_DIST(s);
  847 #ifndef USE_DICT_HEAD
  848         dictionary += dictLength - length; /* use the tail of the dictionary */
  849 #endif
  850     }
  851     zmemcpy((charf *)s->window, dictionary, length);
  852     s->strstart = length;
  853     s->block_start = (long)length;
  854 
  855     /* Insert all strings in the hash table (except for the last two bytes).
  856      * s->lookahead stays null, so s->ins_h will be recomputed at the next
  857      * call of fill_window.
  858      */
  859     s->ins_h = s->window[0];
  860     UPDATE_HASH(s, s->ins_h, s->window[1]);
  861     for (n = 0; n <= length - MIN_MATCH; n++) {
  862         INSERT_STRING(s, n, hash_head);
  863     }
  864     if (hash_head) hash_head = 0;  /* to make compiler happy */
  865     return Z_OK;
  866 }
  867 
  868 /* ========================================================================= */
  869 int deflateReset (strm)
  870     z_streamp strm;
  871 {
  872     deflate_state *s;
  873     
  874     if (strm == Z_NULL || strm->state == Z_NULL ||
  875         strm->zalloc == Z_NULL || strm->zfree == Z_NULL) return Z_STREAM_ERROR;
  876 
  877     strm->total_in = strm->total_out = 0;
  878     strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
  879     strm->data_type = Z_UNKNOWN;
  880 
  881     s = (deflate_state *)strm->state;
  882     s->pending = 0;
  883     s->pending_out = s->pending_buf;
  884 
  885     if (s->noheader < 0) {
  886         s->noheader = 0; /* was set to -1 by deflate(..., Z_FINISH); */
  887     }
  888     s->status = s->noheader ? BUSY_STATE : INIT_STATE;
  889     strm->adler = 1;
  890     s->last_flush = Z_NO_FLUSH;
  891 
  892     _tr_init(s);
  893     lm_init(s);
  894 
  895     return Z_OK;
  896 }
  897 
  898 /* ========================================================================= */
  899 int deflateParams(strm, level, strategy)
  900     z_streamp strm;
  901     int level;
  902     int strategy;
  903 {
  904     deflate_state *s;
  905     compress_func func;
  906     int err = Z_OK;
  907 
  908     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
  909     s = (deflate_state *) strm->state;
  910 
  911     if (level == Z_DEFAULT_COMPRESSION) {
  912         level = 6;
  913     }
  914     if (level < 0 || level > 9 || strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
  915         return Z_STREAM_ERROR;
  916     }
  917     func = configuration_table[s->level].func;
  918 
  919     if (func != configuration_table[level].func && strm->total_in != 0) {
  920         /* Flush the last buffer: */
  921         err = deflate(strm, Z_PARTIAL_FLUSH);
  922     }
  923     if (s->level != level) {
  924         s->level = level;
  925         s->max_lazy_match   = configuration_table[level].max_lazy;
  926         s->good_match       = configuration_table[level].good_length;
  927         s->nice_match       = configuration_table[level].nice_length;
  928         s->max_chain_length = configuration_table[level].max_chain;
  929     }
  930     s->strategy = strategy;
  931     return err;
  932 }
  933 
  934 /* =========================================================================
  935  * Put a short in the pending buffer. The 16-bit value is put in MSB order.
  936  * IN assertion: the stream state is correct and there is enough room in
  937  * pending_buf.
  938  */
  939 local void putShortMSB (s, b)
  940     deflate_state *s;
  941     uInt b;
  942 {
  943     put_byte(s, (Byte)(b >> 8));
  944     put_byte(s, (Byte)(b & 0xff));
  945 }   
  946 
  947 /* =========================================================================
  948  * Flush as much pending output as possible. All deflate() output goes
  949  * through this function so some applications may wish to modify it
  950  * to avoid allocating a large strm->next_out buffer and copying into it.
  951  * (See also read_buf()).
  952  */
  953 local void flush_pending(strm)
  954     z_streamp strm;
  955 {
  956     deflate_state *s = (deflate_state *) strm->state;
  957     unsigned len = s->pending;
  958 
  959     if (len > strm->avail_out) len = strm->avail_out;
  960     if (len == 0) return;
  961 
  962     if (strm->next_out != Z_NULL) {
  963         zmemcpy(strm->next_out, s->pending_out, len);
  964         strm->next_out += len;
  965     }
  966     s->pending_out += len;
  967     strm->total_out += len;
  968     strm->avail_out  -= len;
  969     s->pending -= len;
  970     if (s->pending == 0) {
  971         s->pending_out = s->pending_buf;
  972     }
  973 }
  974 
  975 /* ========================================================================= */
  976 int deflate (strm, flush)
  977     z_streamp strm;
  978     int flush;
  979 {
  980     int old_flush; /* value of flush param for previous deflate call */
  981     deflate_state *s;
  982 
  983     if (strm == Z_NULL || strm->state == Z_NULL ||
  984         flush > Z_FINISH || flush < 0) {
  985         return Z_STREAM_ERROR;
  986     }
  987     s = (deflate_state *) strm->state;
  988 
  989     if ((strm->next_in == Z_NULL && strm->avail_in != 0) ||
  990         (s->status == FINISH_STATE && flush != Z_FINISH)) {
  991         ERR_RETURN(strm, Z_STREAM_ERROR);
  992     }
  993     if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
  994 
  995     s->strm = strm; /* just in case */
  996     old_flush = s->last_flush;
  997     s->last_flush = flush;
  998 
  999     /* Write the zlib header */
 1000     if (s->status == INIT_STATE) {
 1001 
 1002         uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
 1003         uInt level_flags = (s->level-1) >> 1;
 1004 
 1005         if (level_flags > 3) level_flags = 3;
 1006         header |= (level_flags << 6);
 1007         if (s->strstart != 0) header |= PRESET_DICT;
 1008         header += 31 - (header % 31);
 1009 
 1010         s->status = BUSY_STATE;
 1011         putShortMSB(s, header);
 1012 
 1013         /* Save the adler32 of the preset dictionary: */
 1014         if (s->strstart != 0) {
 1015             putShortMSB(s, (uInt)(strm->adler >> 16));
 1016             putShortMSB(s, (uInt)(strm->adler & 0xffff));
 1017         }
 1018         strm->adler = 1L;
 1019     }
 1020 
 1021     /* Flush as much pending output as possible */
 1022     if (s->pending != 0) {
 1023         flush_pending(strm);
 1024         if (strm->avail_out == 0) {
 1025             /* Since avail_out is 0, deflate will be called again with
 1026              * more output space, but possibly with both pending and
 1027              * avail_in equal to zero. There won't be anything to do,
 1028              * but this is not an error situation so make sure we
 1029              * return OK instead of BUF_ERROR at next call of deflate:
 1030              */
 1031             s->last_flush = -1;
 1032             return Z_OK;
 1033         }
 1034 
 1035     /* Make sure there is something to do and avoid duplicate consecutive
 1036      * flushes. For repeated and useless calls with Z_FINISH, we keep
 1037      * returning Z_STREAM_END instead of Z_BUFF_ERROR.
 1038      */
 1039     } else if (strm->avail_in == 0 && flush <= old_flush &&
 1040                flush != Z_FINISH) {
 1041         ERR_RETURN(strm, Z_BUF_ERROR);
 1042     }
 1043 
 1044     /* User must not provide more input after the first FINISH: */
 1045     if (s->status == FINISH_STATE && strm->avail_in != 0) {
 1046         ERR_RETURN(strm, Z_BUF_ERROR);
 1047     }
 1048 
 1049     /* Start a new block or continue the current one.
 1050      */
 1051     if (strm->avail_in != 0 || s->lookahead != 0 ||
 1052         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
 1053         block_state bstate;
 1054 
 1055         bstate = (*(configuration_table[s->level].func))(s, flush);
 1056 
 1057         if (bstate == finish_started || bstate == finish_done) {
 1058             s->status = FINISH_STATE;
 1059         }
 1060         if (bstate == need_more || bstate == finish_started) {
 1061             if (strm->avail_out == 0) {
 1062                 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
 1063             }
 1064             return Z_OK;
 1065             /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
 1066              * of deflate should use the same flush parameter to make sure
 1067              * that the flush is complete. So we don't have to output an
 1068              * empty block here, this will be done at next call. This also
 1069              * ensures that for a very small output buffer, we emit at most
 1070              * one empty block.
 1071              */
 1072         }
 1073         if (bstate == block_done) {
 1074             if (flush == Z_PARTIAL_FLUSH) {
 1075                 _tr_align(s);
 1076             } else if (flush == Z_PACKET_FLUSH) {
 1077                 /* Output just the 3-bit `stored' block type value,
 1078                    but not a zero length. */
 1079                 _tr_stored_type_only(s);
 1080             } else { /* FULL_FLUSH or SYNC_FLUSH */
 1081                 _tr_stored_block(s, (char*)0, 0L, 0);
 1082                 /* For a full flush, this empty block will be recognized
 1083                  * as a special marker by inflate_sync().
 1084                  */
 1085                 if (flush == Z_FULL_FLUSH) {
 1086                     CLEAR_HASH(s);             /* forget history */
 1087                 }
 1088             }
 1089             flush_pending(strm);
 1090             if (strm->avail_out == 0) {
 1091               s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
 1092               return Z_OK;
 1093             }
 1094         }
 1095     }
 1096     Assert(strm->avail_out > 0, "bug2");
 1097 
 1098     if (flush != Z_FINISH) return Z_OK;
 1099     if (s->noheader) return Z_STREAM_END;
 1100 
 1101     /* Write the zlib trailer (adler32) */
 1102     putShortMSB(s, (uInt)(strm->adler >> 16));
 1103     putShortMSB(s, (uInt)(strm->adler & 0xffff));
 1104     flush_pending(strm);
 1105     /* If avail_out is zero, the application will call deflate again
 1106      * to flush the rest.
 1107      */
 1108     s->noheader = -1; /* write the trailer only once! */
 1109     return s->pending != 0 ? Z_OK : Z_STREAM_END;
 1110 }
 1111 
 1112 /* ========================================================================= */
 1113 int deflateEnd (strm)
 1114     z_streamp strm;
 1115 {
 1116     int status;
 1117     deflate_state *s;
 1118 
 1119     if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
 1120     s = (deflate_state *) strm->state;
 1121 
 1122     status = s->status;
 1123     if (status != INIT_STATE && status != BUSY_STATE &&
 1124         status != FINISH_STATE) {
 1125       return Z_STREAM_ERROR;
 1126     }
 1127 
 1128     /* Deallocate in reverse order of allocations: */
 1129     TRY_FREE(strm, s->pending_buf);
 1130     TRY_FREE(strm, s->head);
 1131     TRY_FREE(strm, s->prev);
 1132     TRY_FREE(strm, s->window);
 1133 
 1134     ZFREE(strm, s);
 1135     strm->state = Z_NULL;
 1136 
 1137     return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
 1138 }
 1139 
 1140 /* =========================================================================
 1141  * Copy the source state to the destination state.
 1142  */
 1143 int deflateCopy (dest, source)
 1144     z_streamp dest;
 1145     z_streamp source;
 1146 {
 1147     deflate_state *ds;
 1148     deflate_state *ss;
 1149     ushf *overlay;
 1150 
 1151     if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL)
 1152         return Z_STREAM_ERROR;
 1153     ss = (deflate_state *) source->state;
 1154 
 1155     zmemcpy(dest, source, sizeof(*dest));
 1156 
 1157     ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
 1158     if (ds == Z_NULL) return Z_MEM_ERROR;
 1159     dest->state = (struct internal_state FAR *) ds;
 1160     zmemcpy(ds, ss, sizeof(*ds));
 1161     ds->strm = dest;
 1162 
 1163     ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
 1164     ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
 1165     ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
 1166     overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
 1167     ds->pending_buf = (uchf *) overlay;
 1168 
 1169     if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
 1170         ds->pending_buf == Z_NULL) {
 1171         deflateEnd (dest);
 1172         return Z_MEM_ERROR;
 1173     }
 1174     /* ??? following zmemcpy doesn't work for 16-bit MSDOS */
 1175     zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
 1176     zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
 1177     zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
 1178     zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
 1179 
 1180     ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
 1181     ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
 1182     ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
 1183 
 1184     ds->l_desc.dyn_tree = ds->dyn_ltree;
 1185     ds->d_desc.dyn_tree = ds->dyn_dtree;
 1186     ds->bl_desc.dyn_tree = ds->bl_tree;
 1187 
 1188     return Z_OK;
 1189 }
 1190 
 1191 /* ===========================================================================
 1192  * Return the number of bytes of output which are immediately available
 1193  * for output from the decompressor.
 1194  */
 1195 int deflateOutputPending (strm)
 1196     z_streamp strm;
 1197 {
 1198     if (strm == Z_NULL || strm->state == Z_NULL) return 0;
 1199     
 1200     return ((deflate_state *)(strm->state))->pending;
 1201 }
 1202 
 1203 /* ===========================================================================
 1204  * Read a new buffer from the current input stream, update the adler32
 1205  * and total number of bytes read.  All deflate() input goes through
 1206  * this function so some applications may wish to modify it to avoid
 1207  * allocating a large strm->next_in buffer and copying from it.
 1208  * (See also flush_pending()).
 1209  */
 1210 local int read_buf(strm, buf, size)
 1211     z_streamp strm;
 1212     charf *buf;
 1213     unsigned size;
 1214 {
 1215     unsigned len = strm->avail_in;
 1216 
 1217     if (len > size) len = size;
 1218     if (len == 0) return 0;
 1219 
 1220     strm->avail_in  -= len;
 1221 
 1222     if (!((deflate_state *)(strm->state))->noheader) {
 1223         strm->adler = adler32(strm->adler, strm->next_in, len);
 1224     }
 1225     zmemcpy(buf, strm->next_in, len);
 1226     strm->next_in  += len;
 1227     strm->total_in += len;
 1228 
 1229     return (int)len;
 1230 }
 1231 
 1232 /* ===========================================================================
 1233  * Initialize the "longest match" routines for a new zlib stream
 1234  */
 1235 local void lm_init (s)
 1236     deflate_state *s;
 1237 {
 1238     s->window_size = (ulg)2L*s->w_size;
 1239 
 1240     CLEAR_HASH(s);
 1241 
 1242     /* Set the default configuration parameters:
 1243      */
 1244     s->max_lazy_match   = configuration_table[s->level].max_lazy;
 1245     s->good_match       = configuration_table[s->level].good_length;
 1246     s->nice_match       = configuration_table[s->level].nice_length;
 1247     s->max_chain_length = configuration_table[s->level].max_chain;
 1248 
 1249     s->strstart = 0;
 1250     s->block_start = 0L;
 1251     s->lookahead = 0;
 1252     s->match_length = s->prev_length = MIN_MATCH-1;
 1253     s->match_available = 0;
 1254     s->ins_h = 0;
 1255 #ifdef ASMV
 1256     match_init(); /* initialize the asm code */
 1257 #endif
 1258 }
 1259 
 1260 /* ===========================================================================
 1261  * Set match_start to the longest match starting at the given string and
 1262  * return its length. Matches shorter or equal to prev_length are discarded,
 1263  * in which case the result is equal to prev_length and match_start is
 1264  * garbage.
 1265  * IN assertions: cur_match is the head of the hash chain for the current
 1266  *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
 1267  * OUT assertion: the match length is not greater than s->lookahead.
 1268  */
 1269 #ifndef ASMV
 1270 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
 1271  * match.S. The code will be functionally equivalent.
 1272  */
 1273 local uInt longest_match(s, cur_match)
 1274     deflate_state *s;
 1275     IPos cur_match;                             /* current match */
 1276 {
 1277     unsigned chain_length = s->max_chain_length;/* max hash chain length */
 1278     register Bytef *scan = s->window + s->strstart; /* current string */
 1279     register Bytef *match;                       /* matched string */
 1280     register int len;                           /* length of current match */
 1281     int best_len = s->prev_length;              /* best match length so far */
 1282     int nice_match = s->nice_match;             /* stop if match long enough */
 1283     IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
 1284         s->strstart - (IPos)MAX_DIST(s) : NIL;
 1285     /* Stop when cur_match becomes <= limit. To simplify the code,
 1286      * we prevent matches with the string of window index 0.
 1287      */
 1288     Posf *prev = s->prev;
 1289     uInt wmask = s->w_mask;
 1290 
 1291 #ifdef UNALIGNED_OK
 1292     /* Compare two bytes at a time. Note: this is not always beneficial.
 1293      * Try with and without -DUNALIGNED_OK to check.
 1294      */
 1295     register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
 1296     register ush scan_start = *(ushf*)scan;
 1297     register ush scan_end   = *(ushf*)(scan+best_len-1);
 1298 #else
 1299     register Bytef *strend = s->window + s->strstart + MAX_MATCH;
 1300     register Byte scan_end1  = scan[best_len-1];
 1301     register Byte scan_end   = scan[best_len];
 1302 #endif
 1303 
 1304     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
 1305      * It is easy to get rid of this optimization if necessary.
 1306      */
 1307     Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
 1308 
 1309     /* Do not waste too much time if we already have a good match: */
 1310     if (s->prev_length >= s->good_match) {
 1311         chain_length >>= 2;
 1312     }
 1313     /* Do not look for matches beyond the end of the input. This is necessary
 1314      * to make deflate deterministic.
 1315      */
 1316     if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
 1317 
 1318     Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
 1319 
 1320     do {
 1321         Assert(cur_match < s->strstart, "no future");
 1322         match = s->window + cur_match;
 1323 
 1324         /* Skip to next match if the match length cannot increase
 1325          * or if the match length is less than 2:
 1326          */
 1327 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
 1328         /* This code assumes sizeof(unsigned short) == 2. Do not use
 1329          * UNALIGNED_OK if your compiler uses a different size.
 1330          */
 1331         if (*(ushf*)(match+best_len-1) != scan_end ||
 1332             *(ushf*)match != scan_start) continue;
 1333 
 1334         /* It is not necessary to compare scan[2] and match[2] since they are
 1335          * always equal when the other bytes match, given that the hash keys
 1336          * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
 1337          * strstart+3, +5, ... up to strstart+257. We check for insufficient
 1338          * lookahead only every 4th comparison; the 128th check will be made
 1339          * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
 1340          * necessary to put more guard bytes at the end of the window, or
 1341          * to check more often for insufficient lookahead.
 1342          */
 1343         Assert(scan[2] == match[2], "scan[2]?");
 1344         scan++, match++;
 1345         do {
 1346         } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
 1347                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
 1348                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
 1349                  *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
 1350                  scan < strend);
 1351         /* The funny "do {}" generates better code on most compilers */
 1352 
 1353         /* Here, scan <= window+strstart+257 */
 1354         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 1355         if (*scan == *match) scan++;
 1356 
 1357         len = (MAX_MATCH - 1) - (int)(strend-scan);
 1358         scan = strend - (MAX_MATCH-1);
 1359 
 1360 #else /* UNALIGNED_OK */
 1361 
 1362         if (match[best_len]   != scan_end  ||
 1363             match[best_len-1] != scan_end1 ||
 1364             *match            != *scan     ||
 1365             *++match          != scan[1])      continue;
 1366 
 1367         /* The check at best_len-1 can be removed because it will be made
 1368          * again later. (This heuristic is not always a win.)
 1369          * It is not necessary to compare scan[2] and match[2] since they
 1370          * are always equal when the other bytes match, given that
 1371          * the hash keys are equal and that HASH_BITS >= 8.
 1372          */
 1373         scan += 2, match++;
 1374         Assert(*scan == *match, "match[2]?");
 1375 
 1376         /* We check for insufficient lookahead only every 8th comparison;
 1377          * the 256th check will be made at strstart+258.
 1378          */
 1379         do {
 1380         } while (*++scan == *++match && *++scan == *++match &&
 1381                  *++scan == *++match && *++scan == *++match &&
 1382                  *++scan == *++match && *++scan == *++match &&
 1383                  *++scan == *++match && *++scan == *++match &&
 1384                  scan < strend);
 1385 
 1386         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 1387 
 1388         len = MAX_MATCH - (int)(strend - scan);
 1389         scan = strend - MAX_MATCH;
 1390 
 1391 #endif /* UNALIGNED_OK */
 1392 
 1393         if (len > best_len) {
 1394             s->match_start = cur_match;
 1395             best_len = len;
 1396             if (len >= nice_match) break;
 1397 #ifdef UNALIGNED_OK
 1398             scan_end = *(ushf*)(scan+best_len-1);
 1399 #else
 1400             scan_end1  = scan[best_len-1];
 1401             scan_end   = scan[best_len];
 1402 #endif
 1403         }
 1404     } while ((cur_match = prev[cur_match & wmask]) > limit
 1405              && --chain_length != 0);
 1406 
 1407     if ((uInt)best_len <= s->lookahead) return best_len;
 1408     return s->lookahead;
 1409 }
 1410 #endif /* ASMV */
 1411 
 1412 #ifdef DEBUG_ZLIB
 1413 /* ===========================================================================
 1414  * Check that the match at match_start is indeed a match.
 1415  */
 1416 local void check_match(s, start, match, length)
 1417     deflate_state *s;
 1418     IPos start, match;
 1419     int length;
 1420 {
 1421     /* check that the match is indeed a match */
 1422     if (zmemcmp((charf *)s->window + match,
 1423                 (charf *)s->window + start, length) != EQUAL) {
 1424         fprintf(stderr, " start %u, match %u, length %d\n",
 1425                 start, match, length);
 1426         do {
 1427             fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
 1428         } while (--length != 0);
 1429         z_error("invalid match");
 1430     }
 1431     if (z_verbose > 1) {
 1432         fprintf(stderr,"\\[%d,%d]", start-match, length);
 1433         do { putc(s->window[start++], stderr); } while (--length != 0);
 1434     }
 1435 }
 1436 #else
 1437 #  define check_match(s, start, match, length)
 1438 #endif
 1439 
 1440 /* ===========================================================================
 1441  * Fill the window when the lookahead becomes insufficient.
 1442  * Updates strstart and lookahead.
 1443  *
 1444  * IN assertion: lookahead < MIN_LOOKAHEAD
 1445  * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
 1446  *    At least one byte has been read, or avail_in == 0; reads are
 1447  *    performed for at least two bytes (required for the zip translate_eol
 1448  *    option -- not supported here).
 1449  */
 1450 local void fill_window(s)
 1451     deflate_state *s;
 1452 {
 1453     register unsigned n, m;
 1454     register Posf *p;
 1455     unsigned more;    /* Amount of free space at the end of the window. */
 1456     uInt wsize = s->w_size;
 1457 
 1458     do {
 1459         more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
 1460 
 1461         /* Deal with !@#$% 64K limit: */
 1462         if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
 1463             more = wsize;
 1464 
 1465         } else if (more == (unsigned)(-1)) {
 1466             /* Very unlikely, but possible on 16 bit machine if strstart == 0
 1467              * and lookahead == 1 (input done one byte at time)
 1468              */
 1469             more--;
 1470 
 1471         /* If the window is almost full and there is insufficient lookahead,
 1472          * move the upper half to the lower one to make room in the upper half.
 1473          */
 1474         } else if (s->strstart >= wsize+MAX_DIST(s)) {
 1475 
 1476             zmemcpy((charf *)s->window, (charf *)s->window+wsize,
 1477                    (unsigned)wsize);
 1478             s->match_start -= wsize;
 1479             s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
 1480             s->block_start -= (long) wsize;
 1481 
 1482             /* Slide the hash table (could be avoided with 32 bit values
 1483                at the expense of memory usage). We slide even when level == 0
 1484                to keep the hash table consistent if we switch back to level > 0
 1485                later. (Using level 0 permanently is not an optimal usage of
 1486                zlib, so we don't care about this pathological case.)
 1487              */
 1488             n = s->hash_size;
 1489             p = &s->head[n];
 1490             do {
 1491                 m = *--p;
 1492                 *p = (Pos)(m >= wsize ? m-wsize : NIL);
 1493             } while (--n);
 1494 
 1495             n = wsize;
 1496             p = &s->prev[n];
 1497             do {
 1498                 m = *--p;
 1499                 *p = (Pos)(m >= wsize ? m-wsize : NIL);
 1500                 /* If n is not on any hash chain, prev[n] is garbage but
 1501                  * its value will never be used.
 1502                  */
 1503             } while (--n);
 1504             more += wsize;
 1505         }
 1506         if (s->strm->avail_in == 0) return;
 1507 
 1508         /* If there was no sliding:
 1509          *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
 1510          *    more == window_size - lookahead - strstart
 1511          * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
 1512          * => more >= window_size - 2*WSIZE + 2
 1513          * In the BIG_MEM or MMAP case (not yet supported),
 1514          *   window_size == input_size + MIN_LOOKAHEAD  &&
 1515          *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
 1516          * Otherwise, window_size == 2*WSIZE so more >= 2.
 1517          * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
 1518          */
 1519         Assert(more >= 2, "more < 2");
 1520 
 1521         n = read_buf(s->strm, (charf *)s->window + s->strstart + s->lookahead,
 1522                      more);
 1523         s->lookahead += n;
 1524 
 1525         /* Initialize the hash value now that we have some input: */
 1526         if (s->lookahead >= MIN_MATCH) {
 1527             s->ins_h = s->window[s->strstart];
 1528             UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
 1529 #if MIN_MATCH != 3
 1530             Call UPDATE_HASH() MIN_MATCH-3 more times
 1531 #endif
 1532         }
 1533         /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
 1534          * but this is not important since only literal bytes will be emitted.
 1535          */
 1536 
 1537     } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
 1538 }
 1539 
 1540 /* ===========================================================================
 1541  * Flush the current block, with given end-of-file flag.
 1542  * IN assertion: strstart is set to the end of the current match.
 1543  */
 1544 #define FLUSH_BLOCK_ONLY(s, eof) { \
 1545    _tr_flush_block(s, (s->block_start >= 0L ? \
 1546                    (charf *)&s->window[(unsigned)s->block_start] : \
 1547                    (charf *)Z_NULL), \
 1548                 (ulg)((long)s->strstart - s->block_start), \
 1549                 (eof)); \
 1550    s->block_start = s->strstart; \
 1551    flush_pending(s->strm); \
 1552    Tracev((stderr,"[FLUSH]")); \
 1553 }
 1554 
 1555 /* Same but force premature exit if necessary. */
 1556 #define FLUSH_BLOCK(s, eof) { \
 1557    FLUSH_BLOCK_ONLY(s, eof); \
 1558    if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
 1559 }
 1560 
 1561 /* ===========================================================================
 1562  * Copy without compression as much as possible from the input stream, return
 1563  * the current block state.
 1564  * This function does not insert new strings in the dictionary since
 1565  * uncompressible data is probably not useful. This function is used
 1566  * only for the level=0 compression option.
 1567  * NOTE: this function should be optimized to avoid extra copying from
 1568  * window to pending_buf.
 1569  */
 1570 local block_state deflate_stored(s, flush)
 1571     deflate_state *s;
 1572     int flush;
 1573 {
 1574     /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
 1575      * to pending_buf_size, and each stored block has a 5 byte header:
 1576      */
 1577     ulg max_block_size = 0xffff;
 1578     ulg max_start;
 1579 
 1580     if (max_block_size > s->pending_buf_size - 5) {
 1581         max_block_size = s->pending_buf_size - 5;
 1582     }
 1583 
 1584     /* Copy as much as possible from input to output: */
 1585     for (;;) {
 1586         /* Fill the window as much as possible: */
 1587         if (s->lookahead <= 1) {
 1588 
 1589             Assert(s->strstart < s->w_size+MAX_DIST(s) ||
 1590                    s->block_start >= (long)s->w_size, "slide too late");
 1591 
 1592             fill_window(s);
 1593             if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
 1594 
 1595             if (s->lookahead == 0) break; /* flush the current block */
 1596         }
 1597         Assert(s->block_start >= 0L, "block gone");
 1598 
 1599         s->strstart += s->lookahead;
 1600         s->lookahead = 0;
 1601 
 1602         /* Emit a stored block if pending_buf will be full: */
 1603         max_start = s->block_start + max_block_size;
 1604         if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
 1605             /* strstart == 0 is possible when wraparound on 16-bit machine */
 1606             s->lookahead = (uInt)(s->strstart - max_start);
 1607             s->strstart = (uInt)max_start;
 1608             FLUSH_BLOCK(s, 0);
 1609         }
 1610         /* Flush if we may have to slide, otherwise block_start may become
 1611          * negative and the data will be gone:
 1612          */
 1613         if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
 1614             FLUSH_BLOCK(s, 0);
 1615         }
 1616     }
 1617     FLUSH_BLOCK(s, flush == Z_FINISH);
 1618     return flush == Z_FINISH ? finish_done : block_done;
 1619 }
 1620 
 1621 /* ===========================================================================
 1622  * Compress as much as possible from the input stream, return the current
 1623  * block state.
 1624  * This function does not perform lazy evaluation of matches and inserts
 1625  * new strings in the dictionary only for unmatched strings or for short
 1626  * matches. It is used only for the fast compression options.
 1627  */
 1628 local block_state deflate_fast(s, flush)
 1629     deflate_state *s;
 1630     int flush;
 1631 {
 1632     IPos hash_head = NIL; /* head of the hash chain */
 1633     int bflush;           /* set if current block must be flushed */
 1634 
 1635     for (;;) {
 1636         /* Make sure that we always have enough lookahead, except
 1637          * at the end of the input file. We need MAX_MATCH bytes
 1638          * for the next match, plus MIN_MATCH bytes to insert the
 1639          * string following the next match.
 1640          */
 1641         if (s->lookahead < MIN_LOOKAHEAD) {
 1642             fill_window(s);
 1643             if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
 1644                 return need_more;
 1645             }
 1646             if (s->lookahead == 0) break; /* flush the current block */
 1647         }
 1648 
 1649         /* Insert the string window[strstart .. strstart+2] in the
 1650          * dictionary, and set hash_head to the head of the hash chain:
 1651          */
 1652         if (s->lookahead >= MIN_MATCH) {
 1653             INSERT_STRING(s, s->strstart, hash_head);
 1654         }
 1655 
 1656         /* Find the longest match, discarding those <= prev_length.
 1657          * At this point we have always match_length < MIN_MATCH
 1658          */
 1659         if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
 1660             /* To simplify the code, we prevent matches with the string
 1661              * of window index 0 (in particular we have to avoid a match
 1662              * of the string with itself at the start of the input file).
 1663              */
 1664             if (s->strategy != Z_HUFFMAN_ONLY) {
 1665                 s->match_length = longest_match (s, hash_head);
 1666             }
 1667             /* longest_match() sets match_start */
 1668         }
 1669         if (s->match_length >= MIN_MATCH) {
 1670             check_match(s, s->strstart, s->match_start, s->match_length);
 1671 
 1672             bflush = _tr_tally(s, s->strstart - s->match_start,
 1673                                s->match_length - MIN_MATCH);
 1674 
 1675             s->lookahead -= s->match_length;
 1676 
 1677             /* Insert new strings in the hash table only if the match length
 1678              * is not too large. This saves time but degrades compression.
 1679              */
 1680             if (s->match_length <= s->max_insert_length &&
 1681                 s->lookahead >= MIN_MATCH) {
 1682                 s->match_length--; /* string at strstart already in hash table */
 1683                 do {
 1684                     s->strstart++;
 1685                     INSERT_STRING(s, s->strstart, hash_head);
 1686                     /* strstart never exceeds WSIZE-MAX_MATCH, so there are
 1687                      * always MIN_MATCH bytes ahead.
 1688                      */
 1689                 } while (--s->match_length != 0);
 1690                 s->strstart++; 
 1691             } else {
 1692                 s->strstart += s->match_length;
 1693                 s->match_length = 0;
 1694                 s->ins_h = s->window[s->strstart];
 1695                 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
 1696 #if MIN_MATCH != 3
 1697                 Call UPDATE_HASH() MIN_MATCH-3 more times
 1698 #endif
 1699                 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
 1700                  * matter since it will be recomputed at next deflate call.
 1701                  */
 1702             }
 1703         } else {
 1704             /* No match, output a literal byte */
 1705             Tracevv((stderr,"%c", s->window[s->strstart]));
 1706             bflush = _tr_tally (s, 0, s->window[s->strstart]);
 1707             s->lookahead--;
 1708             s->strstart++; 
 1709         }
 1710         if (bflush) FLUSH_BLOCK(s, 0);
 1711     }
 1712     FLUSH_BLOCK(s, flush == Z_FINISH);
 1713     return flush == Z_FINISH ? finish_done : block_done;
 1714 }
 1715 
 1716 /* ===========================================================================
 1717  * Same as above, but achieves better compression. We use a lazy
 1718  * evaluation for matches: a match is finally adopted only if there is
 1719  * no better match at the next window position.
 1720  */
 1721 local block_state deflate_slow(s, flush)
 1722     deflate_state *s;
 1723     int flush;
 1724 {
 1725     IPos hash_head = NIL;    /* head of hash chain */
 1726     int bflush;              /* set if current block must be flushed */
 1727 
 1728     /* Process the input block. */
 1729     for (;;) {
 1730         /* Make sure that we always have enough lookahead, except
 1731          * at the end of the input file. We need MAX_MATCH bytes
 1732          * for the next match, plus MIN_MATCH bytes to insert the
 1733          * string following the next match.
 1734          */
 1735         if (s->lookahead < MIN_LOOKAHEAD) {
 1736             fill_window(s);
 1737             if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
 1738                 return need_more;
 1739             }
 1740             if (s->lookahead == 0) break; /* flush the current block */
 1741         }
 1742 
 1743         /* Insert the string window[strstart .. strstart+2] in the
 1744          * dictionary, and set hash_head to the head of the hash chain:
 1745          */
 1746         if (s->lookahead >= MIN_MATCH) {
 1747             INSERT_STRING(s, s->strstart, hash_head);
 1748         }
 1749 
 1750         /* Find the longest match, discarding those <= prev_length.
 1751          */
 1752         s->prev_length = s->match_length, s->prev_match = s->match_start;
 1753         s->match_length = MIN_MATCH-1;
 1754 
 1755         if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
 1756             s->strstart - hash_head <= MAX_DIST(s)) {
 1757             /* To simplify the code, we prevent matches with the string
 1758              * of window index 0 (in particular we have to avoid a match
 1759              * of the string with itself at the start of the input file).
 1760              */
 1761             if (s->strategy != Z_HUFFMAN_ONLY) {
 1762                 s->match_length = longest_match (s, hash_head);
 1763             }
 1764             /* longest_match() sets match_start */
 1765 
 1766             if (s->match_length <= 5 && (s->strategy == Z_FILTERED ||
 1767                  (s->match_length == MIN_MATCH &&
 1768                   s->strstart - s->match_start > TOO_FAR))) {
 1769 
 1770                 /* If prev_match is also MIN_MATCH, match_start is garbage
 1771                  * but we will ignore the current match anyway.
 1772                  */
 1773                 s->match_length = MIN_MATCH-1;
 1774             }
 1775         }
 1776         /* If there was a match at the previous step and the current
 1777          * match is not better, output the previous match:
 1778          */
 1779         if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
 1780             uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
 1781             /* Do not insert strings in hash table beyond this. */
 1782 
 1783             check_match(s, s->strstart-1, s->prev_match, s->prev_length);
 1784 
 1785             bflush = _tr_tally(s, s->strstart -1 - s->prev_match,
 1786                                s->prev_length - MIN_MATCH);
 1787 
 1788             /* Insert in hash table all strings up to the end of the match.
 1789              * strstart-1 and strstart are already inserted. If there is not
 1790              * enough lookahead, the last two strings are not inserted in
 1791              * the hash table.
 1792              */
 1793             s->lookahead -= s->prev_length-1;
 1794             s->prev_length -= 2;
 1795             do {
 1796                 if (++s->strstart <= max_insert) {
 1797                     INSERT_STRING(s, s->strstart, hash_head);
 1798                 }
 1799             } while (--s->prev_length != 0);
 1800             s->match_available = 0;
 1801             s->match_length = MIN_MATCH-1;
 1802             s->strstart++;
 1803 
 1804             if (bflush) FLUSH_BLOCK(s, 0);
 1805 
 1806         } else if (s->match_available) {
 1807             /* If there was no match at the previous position, output a
 1808              * single literal. If there was a match but the current match
 1809              * is longer, truncate the previous match to a single literal.
 1810              */
 1811             Tracevv((stderr,"%c", s->window[s->strstart-1]));
 1812             if (_tr_tally (s, 0, s->window[s->strstart-1])) {
 1813                 FLUSH_BLOCK_ONLY(s, 0);
 1814             }
 1815             s->strstart++;
 1816             s->lookahead--;
 1817             if (s->strm->avail_out == 0) return need_more;
 1818         } else {
 1819             /* There is no previous match to compare with, wait for
 1820              * the next step to decide.
 1821              */
 1822             s->match_available = 1;
 1823             s->strstart++;
 1824             s->lookahead--;
 1825         }
 1826     }
 1827     Assert (flush != Z_NO_FLUSH, "no flush?");
 1828     if (s->match_available) {
 1829         Tracevv((stderr,"%c", s->window[s->strstart-1]));
 1830         _tr_tally (s, 0, s->window[s->strstart-1]);
 1831         s->match_available = 0;
 1832     }
 1833     FLUSH_BLOCK(s, flush == Z_FINISH);
 1834     return flush == Z_FINISH ? finish_done : block_done;
 1835 }
 1836 /* --- deflate.c */
 1837 
 1838 /* +++ trees.c */
 1839 /* trees.c -- output deflated data using Huffman coding
 1840  * Copyright (C) 1995-1996 Jean-loup Gailly
 1841  * For conditions of distribution and use, see copyright notice in zlib.h 
 1842  */
 1843 
 1844 /*
 1845  *  ALGORITHM
 1846  *
 1847  *      The "deflation" process uses several Huffman trees. The more
 1848  *      common source values are represented by shorter bit sequences.
 1849  *
 1850  *      Each code tree is stored in a compressed form which is itself
 1851  * a Huffman encoding of the lengths of all the code strings (in
 1852  * ascending order by source values).  The actual code strings are
 1853  * reconstructed from the lengths in the inflate process, as described
 1854  * in the deflate specification.
 1855  *
 1856  *  REFERENCES
 1857  *
 1858  *      Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
 1859  *      Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
 1860  *
 1861  *      Storer, James A.
 1862  *          Data Compression:  Methods and Theory, pp. 49-50.
 1863  *          Computer Science Press, 1988.  ISBN 0-7167-8156-5.
 1864  *
 1865  *      Sedgewick, R.
 1866  *          Algorithms, p290.
 1867  *          Addison-Wesley, 1983. ISBN 0-201-06672-6.
 1868  */
 1869 
 1870 /* From: trees.c,v 1.11 1996/07/24 13:41:06 me Exp $ */
 1871 
 1872 /* #include "deflate.h" */
 1873 
 1874 #ifdef DEBUG_ZLIB
 1875 #  include <ctype.h>
 1876 #endif
 1877 
 1878 /* ===========================================================================
 1879  * Constants
 1880  */
 1881 
 1882 #define MAX_BL_BITS 7
 1883 /* Bit length codes must not exceed MAX_BL_BITS bits */
 1884 
 1885 #define END_BLOCK 256
 1886 /* end of block literal code */
 1887 
 1888 #define REP_3_6      16
 1889 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
 1890 
 1891 #define REPZ_3_10    17
 1892 /* repeat a zero length 3-10 times  (3 bits of repeat count) */
 1893 
 1894 #define REPZ_11_138  18
 1895 /* repeat a zero length 11-138 times  (7 bits of repeat count) */
 1896 
 1897 local int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
 1898    = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0};
 1899 
 1900 local int extra_dbits[D_CODES] /* extra bits for each distance code */
 1901    = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};
 1902 
 1903 local int extra_blbits[BL_CODES]/* extra bits for each bit length code */
 1904    = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
 1905 
 1906 local uch bl_order[BL_CODES]
 1907    = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
 1908 /* The lengths of the bit length codes are sent in order of decreasing
 1909  * probability, to avoid transmitting the lengths for unused bit length codes.
 1910  */
 1911 
 1912 #define Buf_size (8 * 2*sizeof(char))
 1913 /* Number of bits used within bi_buf. (bi_buf might be implemented on
 1914  * more than 16 bits on some systems.)
 1915  */
 1916 
 1917 /* ===========================================================================
 1918  * Local data. These are initialized only once.
 1919  */
 1920 
 1921 local ct_data static_ltree[L_CODES+2];
 1922 /* The static literal tree. Since the bit lengths are imposed, there is no
 1923  * need for the L_CODES extra codes used during heap construction. However
 1924  * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
 1925  * below).
 1926  */
 1927 
 1928 local ct_data static_dtree[D_CODES];
 1929 /* The static distance tree. (Actually a trivial tree since all codes use
 1930  * 5 bits.)
 1931  */
 1932 
 1933 local uch dist_code[512];
 1934 /* distance codes. The first 256 values correspond to the distances
 1935  * 3 .. 258, the last 256 values correspond to the top 8 bits of
 1936  * the 15 bit distances.
 1937  */
 1938 
 1939 local uch length_code[MAX_MATCH-MIN_MATCH+1];
 1940 /* length code for each normalized match length (0 == MIN_MATCH) */
 1941 
 1942 local int base_length[LENGTH_CODES];
 1943 /* First normalized length for each code (0 = MIN_MATCH) */
 1944 
 1945 local int base_dist[D_CODES];
 1946 /* First normalized distance for each code (0 = distance of 1) */
 1947 
 1948 struct static_tree_desc_s {
 1949     ct_data *static_tree;        /* static tree or NULL */
 1950     intf    *extra_bits;         /* extra bits for each code or NULL */
 1951     int     extra_base;          /* base index for extra_bits */
 1952     int     elems;               /* max number of elements in the tree */
 1953     int     max_length;          /* max bit length for the codes */
 1954 };
 1955 
 1956 local static_tree_desc  static_l_desc =
 1957 {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
 1958 
 1959 local static_tree_desc  static_d_desc =
 1960 {static_dtree, extra_dbits, 0,          D_CODES, MAX_BITS};
 1961 
 1962 local static_tree_desc  static_bl_desc =
 1963 {(ct_data *)0, extra_blbits, 0,      BL_CODES, MAX_BL_BITS};
 1964 
 1965 /* ===========================================================================
 1966  * Local (static) routines in this file.
 1967  */
 1968 
 1969 local void tr_static_init OF((void));
 1970 local void init_block     OF((deflate_state *s));
 1971 local void pqdownheap     OF((deflate_state *s, ct_data *tree, int k));
 1972 local void gen_bitlen     OF((deflate_state *s, tree_desc *desc));
 1973 local void gen_codes      OF((ct_data *tree, int max_code, ushf *bl_count));
 1974 local void build_tree     OF((deflate_state *s, tree_desc *desc));
 1975 local void scan_tree      OF((deflate_state *s, ct_data *tree, int max_code));
 1976 local void send_tree      OF((deflate_state *s, ct_data *tree, int max_code));
 1977 local int  build_bl_tree  OF((deflate_state *s));
 1978 local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
 1979                               int blcodes));
 1980 local void compress_block OF((deflate_state *s, ct_data *ltree,
 1981                               ct_data *dtree));
 1982 local void set_data_type  OF((deflate_state *s));
 1983 local unsigned bi_reverse OF((unsigned value, int length));
 1984 local void bi_windup      OF((deflate_state *s));
 1985 local void bi_flush       OF((deflate_state *s));
 1986 local void copy_block     OF((deflate_state *s, charf *buf, unsigned len,
 1987                               int header));
 1988 
 1989 #ifndef DEBUG_ZLIB
 1990 #  define send_code(s, c, tree) send_bits(s, tree[(c)].Code, tree[(c)].Len)
 1991    /* Send a code of the given tree. c and tree must not have side effects */
 1992 
 1993 #else /* DEBUG_ZLIB */
 1994 #  define send_code(s, c, tree) \
 1995      { if (verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
 1996        send_bits(s, tree[c].Code, tree[c].Len); }
 1997 #endif
 1998 
 1999 #define d_code(dist) \
 2000    ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
 2001 /* Mapping from a distance to a distance code. dist is the distance - 1 and
 2002  * must not have side effects. dist_code[256] and dist_code[257] are never
 2003  * used.
 2004  */
 2005 
 2006 /* ===========================================================================
 2007  * Output a short LSB first on the stream.
 2008  * IN assertion: there is enough room in pendingBuf.
 2009  */
 2010 #define put_short(s, w) { \
 2011     put_byte(s, (uch)((w) & 0xff)); \
 2012     put_byte(s, (uch)((ush)(w) >> 8)); \
 2013 }
 2014 
 2015 /* ===========================================================================
 2016  * Send a value on a given number of bits.
 2017  * IN assertion: length <= 16 and value fits in length bits.
 2018  */
 2019 #ifdef DEBUG_ZLIB
 2020 local void send_bits      OF((deflate_state *s, int value, int length));
 2021 
 2022 local void send_bits(s, value, length)
 2023     deflate_state *s;
 2024     int value;  /* value to send */
 2025     int length; /* number of bits */
 2026 {
 2027     Tracevv((stderr," l %2d v %4x ", length, value));
 2028     Assert(length > 0 && length <= 15, "invalid length");
 2029     s->bits_sent += (ulg)length;
 2030 
 2031     /* If not enough room in bi_buf, use (valid) bits from bi_buf and
 2032      * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
 2033      * unused bits in value.
 2034      */
 2035     if (s->bi_valid > (int)Buf_size - length) {
 2036         s->bi_buf |= (value << s->bi_valid);
 2037         put_short(s, s->bi_buf);
 2038         s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
 2039         s->bi_valid += length - Buf_size;
 2040     } else {
 2041         s->bi_buf |= value << s->bi_valid;
 2042         s->bi_valid += length;
 2043     }
 2044 }
 2045 #else /* !DEBUG_ZLIB */
 2046 
 2047 #define send_bits(s, value, length) \
 2048 { int len = (length);\
 2049   if ((s)->bi_valid > (int)Buf_size - len) {\
 2050     int val = (value);\
 2051     (s)->bi_buf |= (val << (s)->bi_valid);\
 2052     put_short((s), (s)->bi_buf);\
 2053     (s)->bi_buf = (ush)val >> (Buf_size - (s)->bi_valid);\
 2054     (s)->bi_valid += len - Buf_size;\
 2055   } else {\
 2056     (s)->bi_buf |= (value) << (s)->bi_valid;\
 2057     (s)->bi_valid += len;\
 2058   }\
 2059 }
 2060 #endif /* DEBUG_ZLIB */
 2061 
 2062 /* the arguments must not have side effects */
 2063 
 2064 /* ===========================================================================
 2065  * Initialize the various 'constant' tables. In a multi-threaded environment,
 2066  * this function may be called by two threads concurrently, but this is
 2067  * harmless since both invocations do exactly the same thing.
 2068  */
 2069 local void tr_static_init()
 2070 {
 2071     static int static_init_done = 0;
 2072     int n;        /* iterates over tree elements */
 2073     int bits;     /* bit counter */
 2074     int length;   /* length value */
 2075     int code;     /* code value */
 2076     int dist;     /* distance index */
 2077     ush bl_count[MAX_BITS+1];
 2078     /* number of codes at each bit length for an optimal tree */
 2079 
 2080     if (static_init_done) return;
 2081 
 2082     /* Initialize the mapping length (0..255) -> length code (0..28) */
 2083     length = 0;
 2084     for (code = 0; code < LENGTH_CODES-1; code++) {
 2085         base_length[code] = length;
 2086         for (n = 0; n < (1<<extra_lbits[code]); n++) {
 2087             length_code[length++] = (uch)code;
 2088         }
 2089     }
 2090     Assert (length == 256, "tr_static_init: length != 256");
 2091     /* Note that the length 255 (match length 258) can be represented
 2092      * in two different ways: code 284 + 5 bits or code 285, so we
 2093      * overwrite length_code[255] to use the best encoding:
 2094      */
 2095     length_code[length-1] = (uch)code;
 2096 
 2097     /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
 2098     dist = 0;
 2099     for (code = 0 ; code < 16; code++) {
 2100         base_dist[code] = dist;
 2101         for (n = 0; n < (1<<extra_dbits[code]); n++) {
 2102             dist_code[dist++] = (uch)code;
 2103         }
 2104     }
 2105     Assert (dist == 256, "tr_static_init: dist != 256");
 2106     dist >>= 7; /* from now on, all distances are divided by 128 */
 2107     for ( ; code < D_CODES; code++) {
 2108         base_dist[code] = dist << 7;
 2109         for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
 2110             dist_code[256 + dist++] = (uch)code;
 2111         }
 2112     }
 2113     Assert (dist == 256, "tr_static_init: 256+dist != 512");
 2114 
 2115     /* Construct the codes of the static literal tree */
 2116     for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
 2117     n = 0;
 2118     while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
 2119     while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
 2120     while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
 2121     while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
 2122     /* Codes 286 and 287 do not exist, but we must include them in the
 2123      * tree construction to get a canonical Huffman tree (longest code
 2124      * all ones)
 2125      */
 2126     gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
 2127 
 2128     /* The static distance tree is trivial: */
 2129     for (n = 0; n < D_CODES; n++) {
 2130         static_dtree[n].Len = 5;
 2131         static_dtree[n].Code = bi_reverse((unsigned)n, 5);
 2132     }
 2133     static_init_done = 1;
 2134 }
 2135 
 2136 /* ===========================================================================
 2137  * Initialize the tree data structures for a new zlib stream.
 2138  */
 2139 void _tr_init(s)
 2140     deflate_state *s;
 2141 {
 2142     tr_static_init();
 2143 
 2144     s->compressed_len = 0L;
 2145 
 2146     s->l_desc.dyn_tree = s->dyn_ltree;
 2147     s->l_desc.stat_desc = &static_l_desc;
 2148 
 2149     s->d_desc.dyn_tree = s->dyn_dtree;
 2150     s->d_desc.stat_desc = &static_d_desc;
 2151 
 2152     s->bl_desc.dyn_tree = s->bl_tree;
 2153     s->bl_desc.stat_desc = &static_bl_desc;
 2154 
 2155     s->bi_buf = 0;
 2156     s->bi_valid = 0;
 2157     s->last_eob_len = 8; /* enough lookahead for inflate */
 2158 #ifdef DEBUG_ZLIB
 2159     s->bits_sent = 0L;
 2160 #endif
 2161 
 2162     /* Initialize the first block of the first file: */
 2163     init_block(s);
 2164 }
 2165 
 2166 /* ===========================================================================
 2167  * Initialize a new block.
 2168  */
 2169 local void init_block(s)
 2170     deflate_state *s;
 2171 {
 2172     int n; /* iterates over tree elements */
 2173 
 2174     /* Initialize the trees. */
 2175     for (n = 0; n < L_CODES;  n++) s->dyn_ltree[n].Freq = 0;
 2176     for (n = 0; n < D_CODES;  n++) s->dyn_dtree[n].Freq = 0;
 2177     for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
 2178 
 2179     s->dyn_ltree[END_BLOCK].Freq = 1;
 2180     s->opt_len = s->static_len = 0L;
 2181     s->last_lit = s->matches = 0;
 2182 }
 2183 
 2184 #define SMALLEST 1
 2185 /* Index within the heap array of least frequent node in the Huffman tree */
 2186 
 2187 
 2188 /* ===========================================================================
 2189  * Remove the smallest element from the heap and recreate the heap with
 2190  * one less element. Updates heap and heap_len.
 2191  */
 2192 #define pqremove(s, tree, top) \
 2193 {\
 2194     top = s->heap[SMALLEST]; \
 2195     s->heap[SMALLEST] = s->heap[s->heap_len--]; \
 2196     pqdownheap(s, tree, SMALLEST); \
 2197 }
 2198 
 2199 /* ===========================================================================
 2200  * Compares to subtrees, using the tree depth as tie breaker when
 2201  * the subtrees have equal frequency. This minimizes the worst case length.
 2202  */
 2203 #define smaller(tree, n, m, depth) \
 2204    (tree[n].Freq < tree[m].Freq || \
 2205    (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
 2206 
 2207 /* ===========================================================================
 2208  * Restore the heap property by moving down the tree starting at node k,
 2209  * exchanging a node with the smallest of its two sons if necessary, stopping
 2210  * when the heap property is re-established (each father smaller than its
 2211  * two sons).
 2212  */
 2213 local void pqdownheap(s, tree, k)
 2214     deflate_state *s;
 2215     ct_data *tree;  /* the tree to restore */
 2216     int k;               /* node to move down */
 2217 {
 2218     int v = s->heap[k];
 2219     int j = k << 1;  /* left son of k */
 2220     while (j <= s->heap_len) {
 2221         /* Set j to the smallest of the two sons: */
 2222         if (j < s->heap_len &&
 2223             smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
 2224             j++;
 2225         }
 2226         /* Exit if v is smaller than both sons */
 2227         if (smaller(tree, v, s->heap[j], s->depth)) break;
 2228 
 2229         /* Exchange v with the smallest son */
 2230         s->heap[k] = s->heap[j];  k = j;
 2231 
 2232         /* And continue down the tree, setting j to the left son of k */
 2233         j <<= 1;
 2234     }
 2235     s->heap[k] = v;
 2236 }
 2237 
 2238 /* ===========================================================================
 2239  * Compute the optimal bit lengths for a tree and update the total bit length
 2240  * for the current block.
 2241  * IN assertion: the fields freq and dad are set, heap[heap_max] and
 2242  *    above are the tree nodes sorted by increasing frequency.
 2243  * OUT assertions: the field len is set to the optimal bit length, the
 2244  *     array bl_count contains the frequencies for each bit length.
 2245  *     The length opt_len is updated; static_len is also updated if stree is
 2246  *     not null.
 2247  */
 2248 local void gen_bitlen(s, desc)
 2249     deflate_state *s;
 2250     tree_desc *desc;    /* the tree descriptor */
 2251 {
 2252     ct_data *tree  = desc->dyn_tree;
 2253     int max_code   = desc->max_code;
 2254     ct_data *stree = desc->stat_desc->static_tree;
 2255     intf *extra    = desc->stat_desc->extra_bits;
 2256     int base       = desc->stat_desc->extra_base;
 2257     int max_length = desc->stat_desc->max_length;
 2258     int h;              /* heap index */
 2259     int n, m;           /* iterate over the tree elements */
 2260     int bits;           /* bit length */
 2261     int xbits;          /* extra bits */
 2262     ush f;              /* frequency */
 2263     int overflow = 0;   /* number of elements with bit length too large */
 2264 
 2265     for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
 2266 
 2267     /* In a first pass, compute the optimal bit lengths (which may
 2268      * overflow in the case of the bit length tree).
 2269      */
 2270     tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
 2271 
 2272     for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
 2273         n = s->heap[h];
 2274         bits = tree[tree[n].Dad].Len + 1;
 2275         if (bits > max_length) bits = max_length, overflow++;
 2276         tree[n].Len = (ush)bits;
 2277         /* We overwrite tree[n].Dad which is no longer needed */
 2278 
 2279         if (n > max_code) continue; /* not a leaf node */
 2280 
 2281         s->bl_count[bits]++;
 2282         xbits = 0;
 2283         if (n >= base) xbits = extra[n-base];
 2284         f = tree[n].Freq;
 2285         s->opt_len += (ulg)f * (bits + xbits);
 2286         if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
 2287     }
 2288     if (overflow == 0) return;
 2289 
 2290     Trace((stderr,"\nbit length overflow\n"));
 2291     /* This happens for example on obj2 and pic of the Calgary corpus */
 2292 
 2293     /* Find the first bit length which could increase: */
 2294     do {
 2295         bits = max_length-1;
 2296         while (s->bl_count[bits] == 0) bits--;
 2297         s->bl_count[bits]--;      /* move one leaf down the tree */
 2298         s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
 2299         s->bl_count[max_length]--;
 2300         /* The brother of the overflow item also moves one step up,
 2301          * but this does not affect bl_count[max_length]
 2302          */
 2303         overflow -= 2;
 2304     } while (overflow > 0);
 2305 
 2306     /* Now recompute all bit lengths, scanning in increasing frequency.
 2307      * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
 2308      * lengths instead of fixing only the wrong ones. This idea is taken
 2309      * from 'ar' written by Haruhiko Okumura.)
 2310      */
 2311     for (bits = max_length; bits != 0; bits--) {
 2312         n = s->bl_count[bits];
 2313         while (n != 0) {
 2314             m = s->heap[--h];
 2315             if (m > max_code) continue;
 2316             if (tree[m].Len != (unsigned) bits) {
 2317                 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
 2318                 s->opt_len += ((long)bits - (long)tree[m].Len)
 2319                               *(long)tree[m].Freq;
 2320                 tree[m].Len = (ush)bits;
 2321             }
 2322             n--;
 2323         }
 2324     }
 2325 }
 2326 
 2327 /* ===========================================================================
 2328  * Generate the codes for a given tree and bit counts (which need not be
 2329  * optimal).
 2330  * IN assertion: the array bl_count contains the bit length statistics for
 2331  * the given tree and the field len is set for all tree elements.
 2332  * OUT assertion: the field code is set for all tree elements of non
 2333  *     zero code length.
 2334  */
 2335 local void gen_codes (tree, max_code, bl_count)
 2336     ct_data *tree;             /* the tree to decorate */
 2337     int max_code;              /* largest code with non zero frequency */
 2338     ushf *bl_count;            /* number of codes at each bit length */
 2339 {
 2340     ush next_code[MAX_BITS+1]; /* next code value for each bit length */
 2341     ush code = 0;              /* running code value */
 2342     int bits;                  /* bit index */
 2343     int n;                     /* code index */
 2344 
 2345     /* The distribution counts are first used to generate the code values
 2346      * without bit reversal.
 2347      */
 2348     for (bits = 1; bits <= MAX_BITS; bits++) {
 2349         next_code[bits] = code = (code + bl_count[bits-1]) << 1;
 2350     }
 2351     /* Check that the bit counts in bl_count are consistent. The last code
 2352      * must be all ones.
 2353      */
 2354     Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
 2355             "inconsistent bit counts");
 2356     Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
 2357 
 2358     for (n = 0;  n <= max_code; n++) {
 2359         int len = tree[n].Len;
 2360         if (len == 0) continue;
 2361         /* Now reverse the bits */
 2362         tree[n].Code = bi_reverse(next_code[len]++, len);
 2363 
 2364         Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
 2365              n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
 2366     }
 2367 }
 2368 
 2369 /* ===========================================================================
 2370  * Construct one Huffman tree and assigns the code bit strings and lengths.
 2371  * Update the total bit length for the current block.
 2372  * IN assertion: the field freq is set for all tree elements.
 2373  * OUT assertions: the fields len and code are set to the optimal bit length
 2374  *     and corresponding code. The length opt_len is updated; static_len is
 2375  *     also updated if stree is not null. The field max_code is set.
 2376  */
 2377 local void build_tree(s, desc)
 2378     deflate_state *s;
 2379     tree_desc *desc; /* the tree descriptor */
 2380 {
 2381     ct_data *tree   = desc->dyn_tree;
 2382     ct_data *stree  = desc->stat_desc->static_tree;
 2383     int elems       = desc->stat_desc->elems;
 2384     int n, m;          /* iterate over heap elements */
 2385     int max_code = -1; /* largest code with non zero frequency */
 2386     int node;          /* new node being created */
 2387 
 2388     /* Construct the initial heap, with least frequent element in
 2389      * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
 2390      * heap[0] is not used.
 2391      */
 2392     s->heap_len = 0, s->heap_max = HEAP_SIZE;
 2393 
 2394     for (n = 0; n < elems; n++) {
 2395         if (tree[n].Freq != 0) {
 2396             s->heap[++(s->heap_len)] = max_code = n;
 2397             s->depth[n] = 0;
 2398         } else {
 2399             tree[n].Len = 0;
 2400         }
 2401     }
 2402 
 2403     /* The pkzip format requires that at least one distance code exists,
 2404      * and that at least one bit should be sent even if there is only one
 2405      * possible code. So to avoid special checks later on we force at least
 2406      * two codes of non zero frequency.
 2407      */
 2408     while (s->heap_len < 2) {
 2409         node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
 2410         tree[node].Freq = 1;
 2411         s->depth[node] = 0;
 2412         s->opt_len--; if (stree) s->static_len -= stree[node].Len;
 2413         /* node is 0 or 1 so it does not have extra bits */
 2414     }
 2415     desc->max_code = max_code;
 2416 
 2417     /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
 2418      * establish sub-heaps of increasing lengths:
 2419      */
 2420     for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
 2421 
 2422     /* Construct the Huffman tree by repeatedly combining the least two
 2423      * frequent nodes.
 2424      */
 2425     node = elems;              /* next internal node of the tree */
 2426     do {
 2427         pqremove(s, tree, n);  /* n = node of least frequency */
 2428         m = s->heap[SMALLEST]; /* m = node of next least frequency */
 2429 
 2430         s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
 2431         s->heap[--(s->heap_max)] = m;
 2432 
 2433         /* Create a new node father of n and m */
 2434         tree[node].Freq = tree[n].Freq + tree[m].Freq;
 2435         s->depth[node] = (uch) (MAX(s->depth[n], s->depth[m]) + 1);
 2436         tree[n].Dad = tree[m].Dad = (ush)node;
 2437 #ifdef DUMP_BL_TREE
 2438         if (tree == s->bl_tree) {
 2439             fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
 2440                     node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
 2441         }
 2442 #endif
 2443         /* and insert the new node in the heap */
 2444         s->heap[SMALLEST] = node++;
 2445         pqdownheap(s, tree, SMALLEST);
 2446 
 2447     } while (s->heap_len >= 2);
 2448 
 2449     s->heap[--(s->heap_max)] = s->heap[SMALLEST];
 2450 
 2451     /* At this point, the fields freq and dad are set. We can now
 2452      * generate the bit lengths.
 2453      */
 2454     gen_bitlen(s, (tree_desc *)desc);
 2455 
 2456     /* The field len is now set, we can generate the bit codes */
 2457     gen_codes ((ct_data *)tree, max_code, s->bl_count);
 2458 }
 2459 
 2460 /* ===========================================================================
 2461  * Scan a literal or distance tree to determine the frequencies of the codes
 2462  * in the bit length tree.
 2463  */
 2464 local void scan_tree (s, tree, max_code)
 2465     deflate_state *s;
 2466     ct_data *tree;   /* the tree to be scanned */
 2467     int max_code;    /* and its largest code of non zero frequency */
 2468 {
 2469     int n;                     /* iterates over all tree elements */
 2470     int prevlen = -1;          /* last emitted length */
 2471     int curlen;                /* length of current code */
 2472     int nextlen = tree[0].Len; /* length of next code */
 2473     int count = 0;             /* repeat count of the current code */
 2474     int max_count = 7;         /* max repeat count */
 2475     int min_count = 4;         /* min repeat count */
 2476 
 2477     if (nextlen == 0) max_count = 138, min_count = 3;
 2478     tree[max_code+1].Len = (ush)0xffff; /* guard */
 2479 
 2480     for (n = 0; n <= max_code; n++) {
 2481         curlen = nextlen; nextlen = tree[n+1].Len;
 2482         if (++count < max_count && curlen == nextlen) {
 2483             continue;
 2484         } else if (count < min_count) {
 2485             s->bl_tree[curlen].Freq += count;
 2486         } else if (curlen != 0) {
 2487             if (curlen != prevlen) s->bl_tree[curlen].Freq++;
 2488             s->bl_tree[REP_3_6].Freq++;
 2489         } else if (count <= 10) {
 2490             s->bl_tree[REPZ_3_10].Freq++;
 2491         } else {
 2492             s->bl_tree[REPZ_11_138].Freq++;
 2493         }
 2494         count = 0; prevlen = curlen;
 2495         if (nextlen == 0) {
 2496             max_count = 138, min_count = 3;
 2497         } else if (curlen == nextlen) {
 2498             max_count = 6, min_count = 3;
 2499         } else {
 2500             max_count = 7, min_count = 4;
 2501         }
 2502     }
 2503 }
 2504 
 2505 /* ===========================================================================
 2506  * Send a literal or distance tree in compressed form, using the codes in
 2507  * bl_tree.
 2508  */
 2509 local void send_tree (s, tree, max_code)
 2510     deflate_state *s;
 2511     ct_data *tree; /* the tree to be scanned */
 2512     int max_code;       /* and its largest code of non zero frequency */
 2513 {
 2514     int n;                     /* iterates over all tree elements */
 2515     int prevlen = -1;          /* last emitted length */
 2516     int curlen;                /* length of current code */
 2517     int nextlen = tree[0].Len; /* length of next code */
 2518     int count = 0;             /* repeat count of the current code */
 2519     int max_count = 7;         /* max repeat count */
 2520     int min_count = 4;         /* min repeat count */
 2521 
 2522     /* tree[max_code+1].Len = -1; */  /* guard already set */
 2523     if (nextlen == 0) max_count = 138, min_count = 3;
 2524 
 2525     for (n = 0; n <= max_code; n++) {
 2526         curlen = nextlen; nextlen = tree[n+1].Len;
 2527         if (++count < max_count && curlen == nextlen) {
 2528             continue;
 2529         } else if (count < min_count) {
 2530             do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
 2531 
 2532         } else if (curlen != 0) {
 2533             if (curlen != prevlen) {
 2534                 send_code(s, curlen, s->bl_tree); count--;
 2535             }
 2536             Assert(count >= 3 && count <= 6, " 3_6?");
 2537             send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
 2538 
 2539         } else if (count <= 10) {
 2540             send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
 2541 
 2542         } else {
 2543             send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
 2544         }
 2545         count = 0; prevlen = curlen;
 2546         if (nextlen == 0) {
 2547             max_count = 138, min_count = 3;
 2548         } else if (curlen == nextlen) {
 2549             max_count = 6, min_count = 3;
 2550         } else {
 2551             max_count = 7, min_count = 4;
 2552         }
 2553     }
 2554 }
 2555 
 2556 /* ===========================================================================
 2557  * Construct the Huffman tree for the bit lengths and return the index in
 2558  * bl_order of the last bit length code to send.
 2559  */
 2560 local int build_bl_tree(s)
 2561     deflate_state *s;
 2562 {
 2563     int max_blindex;  /* index of last bit length code of non zero freq */
 2564 
 2565     /* Determine the bit length frequencies for literal and distance trees */
 2566     scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
 2567     scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
 2568 
 2569     /* Build the bit length tree: */
 2570     build_tree(s, (tree_desc *)(&(s->bl_desc)));
 2571     /* opt_len now includes the length of the tree representations, except
 2572      * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
 2573      */
 2574 
 2575     /* Determine the number of bit length codes to send. The pkzip format
 2576      * requires that at least 4 bit length codes be sent. (appnote.txt says
 2577      * 3 but the actual value used is 4.)
 2578      */
 2579     for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
 2580         if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
 2581     }
 2582     /* Update opt_len to include the bit length tree and counts */
 2583     s->opt_len += 3*(max_blindex+1) + 5+5+4;
 2584     Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
 2585             s->opt_len, s->static_len));
 2586 
 2587     return max_blindex;
 2588 }
 2589 
 2590 /* ===========================================================================
 2591  * Send the header for a block using dynamic Huffman trees: the counts, the
 2592  * lengths of the bit length codes, the literal tree and the distance tree.
 2593  * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
 2594  */
 2595 local void send_all_trees(s, lcodes, dcodes, blcodes)
 2596     deflate_state *s;
 2597     int lcodes, dcodes, blcodes; /* number of codes for each tree */
 2598 {
 2599     int rank;                    /* index in bl_order */
 2600 
 2601     Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
 2602     Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
 2603             "too many codes");
 2604     Tracev((stderr, "\nbl counts: "));
 2605     send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
 2606     send_bits(s, dcodes-1,   5);
 2607     send_bits(s, blcodes-4,  4); /* not -3 as stated in appnote.txt */
 2608     for (rank = 0; rank < blcodes; rank++) {
 2609         Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
 2610         send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
 2611     }
 2612     Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
 2613 
 2614     send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
 2615     Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
 2616 
 2617     send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
 2618     Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
 2619 }
 2620 
 2621 /* ===========================================================================
 2622  * Send a stored block
 2623  */
 2624 void _tr_stored_block(s, buf, stored_len, eof)
 2625     deflate_state *s;
 2626     charf *buf;       /* input block */
 2627     ulg stored_len;   /* length of input block */
 2628     int eof;          /* true if this is the last block for a file */
 2629 {
 2630     send_bits(s, (STORED_BLOCK<<1)+eof, 3);  /* send block type */
 2631     s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
 2632     s->compressed_len += (stored_len + 4) << 3;
 2633 
 2634     copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
 2635 }
 2636 
 2637 /* Send just the `stored block' type code without any length bytes or data.
 2638  */
 2639 void _tr_stored_type_only(s)
 2640     deflate_state *s;
 2641 {
 2642     send_bits(s, (STORED_BLOCK << 1), 3);
 2643     bi_windup(s);
 2644     s->compressed_len = (s->compressed_len + 3) & ~7L;
 2645 }
 2646 
 2647 
 2648 /* ===========================================================================
 2649  * Send one empty static block to give enough lookahead for inflate.
 2650  * This takes 10 bits, of which 7 may remain in the bit buffer.
 2651  * The current inflate code requires 9 bits of lookahead. If the
 2652  * last two codes for the previous block (real code plus EOB) were coded
 2653  * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
 2654  * the last real code. In this case we send two empty static blocks instead
 2655  * of one. (There are no problems if the previous block is stored or fixed.)
 2656  * To simplify the code, we assume the worst case of last real code encoded
 2657  * on one bit only.
 2658  */
 2659 void _tr_align(s)
 2660     deflate_state *s;
 2661 {
 2662     send_bits(s, STATIC_TREES<<1, 3);
 2663     send_code(s, END_BLOCK, static_ltree);
 2664     s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
 2665     bi_flush(s);
 2666     /* Of the 10 bits for the empty block, we have already sent
 2667      * (10 - bi_valid) bits. The lookahead for the last real code (before
 2668      * the EOB of the previous block) was thus at least one plus the length
 2669      * of the EOB plus what we have just sent of the empty static block.
 2670      */
 2671     if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
 2672         send_bits(s, STATIC_TREES<<1, 3);
 2673         send_code(s, END_BLOCK, static_ltree);
 2674         s->compressed_len += 10L;
 2675         bi_flush(s);
 2676     }
 2677     s->last_eob_len = 7;
 2678 }
 2679 
 2680 /* ===========================================================================
 2681  * Determine the best encoding for the current block: dynamic trees, static
 2682  * trees or store, and output the encoded block to the zip file. This function
 2683  * returns the total compressed length for the file so far.
 2684  */
 2685 ulg _tr_flush_block(s, buf, stored_len, eof)
 2686     deflate_state *s;
 2687     charf *buf;       /* input block, or NULL if too old */
 2688     ulg stored_len;   /* length of input block */
 2689     int eof;          /* true if this is the last block for a file */
 2690 {
 2691     ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
 2692     int max_blindex = 0;  /* index of last bit length code of non zero freq */
 2693 
 2694     /* Build the Huffman trees unless a stored block is forced */
 2695     if (s->level > 0) {
 2696 
 2697          /* Check if the file is ascii or binary */
 2698         if (s->data_type == Z_UNKNOWN) set_data_type(s);
 2699 
 2700         /* Construct the literal and distance trees */
 2701         build_tree(s, (tree_desc *)(&(s->l_desc)));
 2702         Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
 2703                 s->static_len));
 2704 
 2705         build_tree(s, (tree_desc *)(&(s->d_desc)));
 2706         Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
 2707                 s->static_len));
 2708         /* At this point, opt_len and static_len are the total bit lengths of
 2709          * the compressed block data, excluding the tree representations.
 2710          */
 2711 
 2712         /* Build the bit length tree for the above two trees, and get the index
 2713          * in bl_order of the last bit length code to send.
 2714          */
 2715         max_blindex = build_bl_tree(s);
 2716 
 2717         /* Determine the best encoding. Compute first the block length in bytes*/
 2718         opt_lenb = (s->opt_len+3+7)>>3;
 2719         static_lenb = (s->static_len+3+7)>>3;
 2720 
 2721         Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
 2722                 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
 2723                 s->last_lit));
 2724 
 2725         if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
 2726 
 2727     } else {
 2728         Assert(buf != (char*)0, "lost buf");
 2729         opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
 2730     }
 2731 
 2732     /* If compression failed and this is the first and last block,
 2733      * and if the .zip file can be seeked (to rewrite the local header),
 2734      * the whole file is transformed into a stored file:
 2735      */
 2736 #ifdef STORED_FILE_OK
 2737 #  ifdef FORCE_STORED_FILE
 2738     if (eof && s->compressed_len == 0L) { /* force stored file */
 2739 #  else
 2740     if (stored_len <= opt_lenb && eof && s->compressed_len==0L && seekable()) {
 2741 #  endif
 2742         /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
 2743         if (buf == (charf*)0) error ("block vanished");
 2744 
 2745         copy_block(s, buf, (unsigned)stored_len, 0); /* without header */
 2746         s->compressed_len = stored_len << 3;
 2747         s->method = STORED;
 2748     } else
 2749 #endif /* STORED_FILE_OK */
 2750 
 2751 #ifdef FORCE_STORED
 2752     if (buf != (char*)0) { /* force stored block */
 2753 #else
 2754     if (stored_len+4 <= opt_lenb && buf != (char*)0) {
 2755                        /* 4: two words for the lengths */
 2756 #endif
 2757         /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
 2758          * Otherwise we can't have processed more than WSIZE input bytes since
 2759          * the last block flush, because compression would have been
 2760          * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
 2761          * transform a block into a stored block.
 2762          */
 2763         _tr_stored_block(s, buf, stored_len, eof);
 2764 
 2765 #ifdef FORCE_STATIC
 2766     } else if (static_lenb >= 0) { /* force static trees */
 2767 #else
 2768     } else if (static_lenb == opt_lenb) {
 2769 #endif
 2770         send_bits(s, (STATIC_TREES<<1)+eof, 3);
 2771         compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
 2772         s->compressed_len += 3 + s->static_len;
 2773     } else {
 2774         send_bits(s, (DYN_TREES<<1)+eof, 3);
 2775         send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
 2776                        max_blindex+1);
 2777         compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
 2778         s->compressed_len += 3 + s->opt_len;
 2779     }
 2780     Assert (s->compressed_len == s->bits_sent, "bad compressed size");
 2781     init_block(s);
 2782 
 2783     if (eof) {
 2784         bi_windup(s);
 2785         s->compressed_len += 7;  /* align on byte boundary */
 2786     }
 2787     Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
 2788            s->compressed_len-7*eof));
 2789 
 2790     return s->compressed_len >> 3;
 2791 }
 2792 
 2793 /* ===========================================================================
 2794  * Save the match info and tally the frequency counts. Return true if
 2795  * the current block must be flushed.
 2796  */
 2797 int _tr_tally (s, dist, lc)
 2798     deflate_state *s;
 2799     unsigned dist;  /* distance of matched string */
 2800     unsigned lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */
 2801 {
 2802     s->d_buf[s->last_lit] = (ush)dist;
 2803     s->l_buf[s->last_lit++] = (uch)lc;
 2804     if (dist == 0) {
 2805         /* lc is the unmatched char */
 2806         s->dyn_ltree[lc].Freq++;
 2807     } else {
 2808         s->matches++;
 2809         /* Here, lc is the match length - MIN_MATCH */
 2810         dist--;             /* dist = match distance - 1 */
 2811         Assert((ush)dist < (ush)MAX_DIST(s) &&
 2812                (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
 2813                (ush)d_code(dist) < (ush)D_CODES,  "_tr_tally: bad match");
 2814 
 2815         s->dyn_ltree[length_code[lc]+LITERALS+1].Freq++;
 2816         s->dyn_dtree[d_code(dist)].Freq++;
 2817     }
 2818 
 2819     /* Try to guess if it is profitable to stop the current block here */
 2820     if (s->level > 2 && (s->last_lit & 0xfff) == 0) {
 2821         /* Compute an upper bound for the compressed length */
 2822         ulg out_length = (ulg)s->last_lit*8L;
 2823         ulg in_length = (ulg)((long)s->strstart - s->block_start);
 2824         int dcode;
 2825         for (dcode = 0; dcode < D_CODES; dcode++) {
 2826             out_length += (ulg)s->dyn_dtree[dcode].Freq *
 2827                 (5L+extra_dbits[dcode]);
 2828         }
 2829         out_length >>= 3;
 2830         Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
 2831                s->last_lit, in_length, out_length,
 2832                100L - out_length*100L/in_length));
 2833         if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
 2834     }
 2835     return (s->last_lit == s->lit_bufsize-1);
 2836     /* We avoid equality with lit_bufsize because of wraparound at 64K
 2837      * on 16 bit machines and because stored blocks are restricted to
 2838      * 64K-1 bytes.
 2839      */
 2840 }
 2841 
 2842 /* ===========================================================================
 2843  * Send the block data compressed using the given Huffman trees
 2844  */
 2845 local void compress_block(s, ltree, dtree)
 2846     deflate_state *s;
 2847     ct_data *ltree; /* literal tree */
 2848     ct_data *dtree; /* distance tree */
 2849 {
 2850     unsigned dist;      /* distance of matched string */
 2851     int lc;             /* match length or unmatched char (if dist == 0) */
 2852     unsigned lx = 0;    /* running index in l_buf */
 2853     unsigned code;      /* the code to send */
 2854     int extra;          /* number of extra bits to send */
 2855 
 2856     if (s->last_lit != 0) do {
 2857         dist = s->d_buf[lx];
 2858         lc = s->l_buf[lx++];
 2859         if (dist == 0) {
 2860             send_code(s, lc, ltree); /* send a literal byte */
 2861             Tracecv(isgraph(lc), (stderr," '%c' ", lc));
 2862         } else {
 2863             /* Here, lc is the match length - MIN_MATCH */
 2864             code = length_code[lc];
 2865             send_code(s, code+LITERALS+1, ltree); /* send the length code */
 2866             extra = extra_lbits[code];
 2867             if (extra != 0) {
 2868                 lc -= base_length[code];
 2869                 send_bits(s, lc, extra);       /* send the extra length bits */
 2870             }
 2871             dist--; /* dist is now the match distance - 1 */
 2872             code = d_code(dist);
 2873             Assert (code < D_CODES, "bad d_code");
 2874 
 2875             send_code(s, code, dtree);       /* send the distance code */
 2876             extra = extra_dbits[code];
 2877             if (extra != 0) {
 2878                 dist -= base_dist[code];
 2879                 send_bits(s, dist, extra);   /* send the extra distance bits */
 2880             }
 2881         } /* literal or match pair ? */
 2882 
 2883         /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
 2884         Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow");
 2885 
 2886     } while (lx < s->last_lit);
 2887 
 2888     send_code(s, END_BLOCK, ltree);
 2889     s->last_eob_len = ltree[END_BLOCK].Len;
 2890 }
 2891 
 2892 /* ===========================================================================
 2893  * Set the data type to ASCII or BINARY, using a crude approximation:
 2894  * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
 2895  * IN assertion: the fields freq of dyn_ltree are set and the total of all
 2896  * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
 2897  */
 2898 local void set_data_type(s)
 2899     deflate_state *s;
 2900 {
 2901     int n = 0;
 2902     unsigned ascii_freq = 0;
 2903     unsigned bin_freq = 0;
 2904     while (n < 7)        bin_freq += s->dyn_ltree[n++].Freq;
 2905     while (n < 128)    ascii_freq += s->dyn_ltree[n++].Freq;
 2906     while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq;
 2907     s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII);
 2908 }
 2909 
 2910 /* ===========================================================================
 2911  * Reverse the first len bits of a code, using straightforward code (a faster
 2912  * method would use a table)
 2913  * IN assertion: 1 <= len <= 15
 2914  */
 2915 local unsigned bi_reverse(code, len)
 2916     unsigned code; /* the value to invert */
 2917     int len;       /* its bit length */
 2918 {
 2919     register unsigned res = 0;
 2920     do {
 2921         res |= code & 1;
 2922         code >>= 1, res <<= 1;
 2923     } while (--len > 0);
 2924     return res >> 1;
 2925 }
 2926 
 2927 /* ===========================================================================
 2928  * Flush the bit buffer, keeping at most 7 bits in it.
 2929  */
 2930 local void bi_flush(s)
 2931     deflate_state *s;
 2932 {
 2933     if (s->bi_valid == 16) {
 2934         put_short(s, s->bi_buf);
 2935         s->bi_buf = 0;
 2936         s->bi_valid = 0;
 2937     } else if (s->bi_valid >= 8) {
 2938         put_byte(s, (Byte)s->bi_buf);
 2939         s->bi_buf >>= 8;
 2940         s->bi_valid -= 8;
 2941     }
 2942 }
 2943 
 2944 /* ===========================================================================
 2945  * Flush the bit buffer and align the output on a byte boundary
 2946  */
 2947 local void bi_windup(s)
 2948     deflate_state *s;
 2949 {
 2950     if (s->bi_valid > 8) {
 2951         put_short(s, s->bi_buf);
 2952     } else if (s->bi_valid > 0) {
 2953         put_byte(s, (Byte)s->bi_buf);
 2954     }
 2955     s->bi_buf = 0;
 2956     s->bi_valid = 0;
 2957 #ifdef DEBUG_ZLIB
 2958     s->bits_sent = (s->bits_sent+7) & ~7;
 2959 #endif
 2960 }
 2961 
 2962 /* ===========================================================================
 2963  * Copy a stored block, storing first the length and its
 2964  * one's complement if requested.
 2965  */
 2966 local void copy_block(s, buf, len, header)
 2967     deflate_state *s;
 2968     charf    *buf;    /* the input data */
 2969     unsigned len;     /* its length */
 2970     int      header;  /* true if block header must be written */
 2971 {
 2972     bi_windup(s);        /* align on byte boundary */
 2973     s->last_eob_len = 8; /* enough lookahead for inflate */
 2974 
 2975     if (header) {
 2976         put_short(s, (ush)len);   
 2977         put_short(s, (ush)~len);
 2978 #ifdef DEBUG_ZLIB
 2979         s->bits_sent += 2*16;
 2980 #endif
 2981     }
 2982 #ifdef DEBUG_ZLIB
 2983     s->bits_sent += (ulg)len<<3;
 2984 #endif
 2985     /* bundle up the put_byte(s, *buf++) calls */
 2986     zmemcpy(&s->pending_buf[s->pending], buf, len);
 2987     s->pending += len;
 2988 }
 2989 /* --- trees.c */
 2990 
 2991 /* +++ inflate.c */
 2992 /* inflate.c -- zlib interface to inflate modules
 2993  * Copyright (C) 1995-1996 Mark Adler
 2994  * For conditions of distribution and use, see copyright notice in zlib.h 
 2995  */
 2996 
 2997 /* #include "zutil.h" */
 2998 
 2999 /* +++ infblock.h */
 3000 /* infblock.h -- header to use infblock.c
 3001  * Copyright (C) 1995-1996 Mark Adler
 3002  * For conditions of distribution and use, see copyright notice in zlib.h 
 3003  */
 3004 
 3005 /* WARNING: this file should *not* be used by applications. It is
 3006    part of the implementation of the compression library and is
 3007    subject to change. Applications should only use zlib.h.
 3008  */
 3009 
 3010 struct inflate_blocks_state;
 3011 typedef struct inflate_blocks_state FAR inflate_blocks_statef;
 3012 
 3013 extern inflate_blocks_statef * inflate_blocks_new OF((
 3014     z_streamp z,
 3015     check_func c,               /* check function */
 3016     uInt w));                   /* window size */
 3017 
 3018 extern int inflate_blocks OF((
 3019     inflate_blocks_statef *,
 3020     z_streamp ,
 3021     int));                      /* initial return code */
 3022 
 3023 extern void inflate_blocks_reset OF((
 3024     inflate_blocks_statef *,
 3025     z_streamp ,
 3026     uLongf *));                  /* check value on output */
 3027 
 3028 extern int inflate_blocks_free OF((
 3029     inflate_blocks_statef *,
 3030     z_streamp ,
 3031     uLongf *));                  /* check value on output */
 3032 
 3033 extern void inflate_set_dictionary OF((
 3034     inflate_blocks_statef *s,
 3035     const Bytef *d,  /* dictionary */
 3036     uInt  n));       /* dictionary length */
 3037 
 3038 extern int inflate_addhistory OF((
 3039     inflate_blocks_statef *,
 3040     z_streamp));
 3041 
 3042 extern int inflate_packet_flush OF((
 3043     inflate_blocks_statef *));
 3044 /* --- infblock.h */
 3045 
 3046 #ifndef NO_DUMMY_DECL
 3047 struct inflate_blocks_state {int dummy;}; /* for buggy compilers */
 3048 #endif
 3049 
 3050 /* inflate private state */
 3051 struct internal_state {
 3052 
 3053   /* mode */
 3054   enum {
 3055       METHOD,   /* waiting for method byte */
 3056       FLAG,     /* waiting for flag byte */
 3057       DICT4,    /* four dictionary check bytes to go */
 3058       DICT3,    /* three dictionary check bytes to go */
 3059       DICT2,    /* two dictionary check bytes to go */
 3060       DICT1,    /* one dictionary check byte to go */
 3061       DICT0,    /* waiting for inflateSetDictionary */
 3062       BLOCKS,   /* decompressing blocks */
 3063       CHECK4,   /* four check bytes to go */
 3064       CHECK3,   /* three check bytes to go */
 3065       CHECK2,   /* two check bytes to go */
 3066       CHECK1,   /* one check byte to go */
 3067       DONE,     /* finished check, done */
 3068       BAD}      /* got an error--stay here */
 3069     mode;               /* current inflate mode */
 3070 
 3071   /* mode dependent information */
 3072   union {
 3073     uInt method;        /* if FLAGS, method byte */
 3074     struct {
 3075       uLong was;                /* computed check value */
 3076       uLong need;               /* stream check value */
 3077     } check;            /* if CHECK, check values to compare */
 3078     uInt marker;        /* if BAD, inflateSync's marker bytes count */
 3079   } sub;        /* submode */
 3080 
 3081   /* mode independent information */
 3082   int  nowrap;          /* flag for no wrapper */
 3083   uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */
 3084   inflate_blocks_statef 
 3085     *blocks;            /* current inflate_blocks state */
 3086 
 3087 };
 3088 
 3089 
 3090 int inflateReset(z)
 3091 z_streamp z;
 3092 {
 3093   uLong c;
 3094 
 3095   if (z == Z_NULL || z->state == Z_NULL)
 3096     return Z_STREAM_ERROR;
 3097   z->total_in = z->total_out = 0;
 3098   z->msg = Z_NULL;
 3099   z->state->mode = z->state->nowrap ? BLOCKS : METHOD;
 3100   inflate_blocks_reset(z->state->blocks, z, &c);
 3101   Trace((stderr, "inflate: reset\n"));
 3102   return Z_OK;
 3103 }
 3104 
 3105 
 3106 int inflateEnd(z)
 3107 z_streamp z;
 3108 {
 3109   uLong c;
 3110 
 3111   if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
 3112     return Z_STREAM_ERROR;
 3113   if (z->state->blocks != Z_NULL)
 3114     inflate_blocks_free(z->state->blocks, z, &c);
 3115   ZFREE(z, z->state);
 3116   z->state = Z_NULL;
 3117   Trace((stderr, "inflate: end\n"));
 3118   return Z_OK;
 3119 }
 3120 
 3121 
 3122 int inflateInit2_(z, w, version, stream_size)
 3123 z_streamp z;
 3124 int w;
 3125 const char *version;
 3126 int stream_size;
 3127 {
 3128   if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
 3129       stream_size != sizeof(z_stream))
 3130       return Z_VERSION_ERROR;
 3131 
 3132   /* initialize state */
 3133   if (z == Z_NULL)
 3134     return Z_STREAM_ERROR;
 3135   z->msg = Z_NULL;
 3136 #ifndef NO_ZCFUNCS
 3137   if (z->zalloc == Z_NULL)
 3138   {
 3139     z->zalloc = zcalloc;
 3140     z->opaque = (voidpf)0;
 3141   }
 3142   if (z->zfree == Z_NULL) z->zfree = zcfree;
 3143 #endif
 3144   if ((z->state = (struct internal_state FAR *)
 3145        ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL)
 3146     return Z_MEM_ERROR;
 3147   z->state->blocks = Z_NULL;
 3148 
 3149   /* handle undocumented nowrap option (no zlib header or check) */
 3150   z->state->nowrap = 0;
 3151   if (w < 0)
 3152   {
 3153     w = - w;
 3154     z->state->nowrap = 1;
 3155   }
 3156 
 3157   /* set window size */
 3158   if (w < 8 || w > 15)
 3159   {
 3160     inflateEnd(z);
 3161     return Z_STREAM_ERROR;
 3162   }
 3163   z->state->wbits = (uInt)w;
 3164 
 3165   /* create inflate_blocks state */
 3166   if ((z->state->blocks =
 3167       inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, (uInt)1 << w))
 3168       == Z_NULL)
 3169   {
 3170     inflateEnd(z);
 3171     return Z_MEM_ERROR;
 3172   }
 3173   Trace((stderr, "inflate: allocated\n"));
 3174 
 3175   /* reset state */
 3176   inflateReset(z);
 3177   return Z_OK;
 3178 }
 3179 
 3180 
 3181 int inflateInit_(z, version, stream_size)
 3182 z_streamp z;
 3183 const char *version;
 3184 int stream_size;
 3185 {
 3186   return inflateInit2_(z, DEF_WBITS, version, stream_size);
 3187 }
 3188 
 3189 
 3190 #define NEEDBYTE {if(z->avail_in==0)goto empty;r=Z_OK;}
 3191 #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
 3192 
 3193 int inflate(z, f)
 3194 z_streamp z;
 3195 int f;
 3196 {
 3197   int r;
 3198   uInt b;
 3199 
 3200   if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL || f < 0)
 3201     return Z_STREAM_ERROR;
 3202   r = Z_BUF_ERROR;
 3203   while (1) switch (z->state->mode)
 3204   {
 3205     case METHOD:
 3206       NEEDBYTE
 3207       if (((z->state->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
 3208       {
 3209         z->state->mode = BAD;
 3210         z->msg = (char*)"unknown compression method";
 3211         z->state->sub.marker = 5;       /* can't try inflateSync */
 3212         break;
 3213       }
 3214       if ((z->state->sub.method >> 4) + 8 > z->state->wbits)
 3215       {
 3216         z->state->mode = BAD;
 3217         z->msg = (char*)"invalid window size";
 3218         z->state->sub.marker = 5;       /* can't try inflateSync */
 3219         break;
 3220       }
 3221       z->state->mode = FLAG;
 3222     case FLAG:
 3223       NEEDBYTE
 3224       b = NEXTBYTE;
 3225       if (((z->state->sub.method << 8) + b) % 31)
 3226       {
 3227         z->state->mode = BAD;
 3228         z->msg = (char*)"incorrect header check";
 3229         z->state->sub.marker = 5;       /* can't try inflateSync */
 3230         break;
 3231       }
 3232       Trace((stderr, "inflate: zlib header ok\n"));
 3233       if (!(b & PRESET_DICT))
 3234       {
 3235         z->state->mode = BLOCKS;
 3236         break;
 3237       }
 3238       z->state->mode = DICT4;
 3239     case DICT4:
 3240       NEEDBYTE
 3241       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 3242       z->state->mode = DICT3;
 3243     case DICT3:
 3244       NEEDBYTE
 3245       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 3246       z->state->mode = DICT2;
 3247     case DICT2:
 3248       NEEDBYTE
 3249       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 3250       z->state->mode = DICT1;
 3251     case DICT1:
 3252       NEEDBYTE
 3253       z->state->sub.check.need += (uLong)NEXTBYTE;
 3254       z->adler = z->state->sub.check.need;
 3255       z->state->mode = DICT0;
 3256       return Z_NEED_DICT;
 3257     case DICT0:
 3258       z->state->mode = BAD;
 3259       z->msg = (char*)"need dictionary";
 3260       z->state->sub.marker = 0;       /* can try inflateSync */
 3261       return Z_STREAM_ERROR;
 3262     case BLOCKS:
 3263       r = inflate_blocks(z->state->blocks, z, r);
 3264       if (f == Z_PACKET_FLUSH && z->avail_in == 0 && z->avail_out != 0)
 3265           r = inflate_packet_flush(z->state->blocks);
 3266       if (r == Z_DATA_ERROR)
 3267       {
 3268         z->state->mode = BAD;
 3269         z->state->sub.marker = 0;       /* can try inflateSync */
 3270         break;
 3271       }
 3272       if (r != Z_STREAM_END)
 3273         return r;
 3274       r = Z_OK;
 3275       inflate_blocks_reset(z->state->blocks, z, &z->state->sub.check.was);
 3276       if (z->state->nowrap)
 3277       {
 3278         z->state->mode = DONE;
 3279         break;
 3280       }
 3281       z->state->mode = CHECK4;
 3282     case CHECK4:
 3283       NEEDBYTE
 3284       z->state->sub.check.need = (uLong)NEXTBYTE << 24;
 3285       z->state->mode = CHECK3;
 3286     case CHECK3:
 3287       NEEDBYTE
 3288       z->state->sub.check.need += (uLong)NEXTBYTE << 16;
 3289       z->state->mode = CHECK2;
 3290     case CHECK2:
 3291       NEEDBYTE
 3292       z->state->sub.check.need += (uLong)NEXTBYTE << 8;
 3293       z->state->mode = CHECK1;
 3294     case CHECK1:
 3295       NEEDBYTE
 3296       z->state->sub.check.need += (uLong)NEXTBYTE;
 3297 
 3298       if (z->state->sub.check.was != z->state->sub.check.need)
 3299       {
 3300         z->state->mode = BAD;
 3301         z->msg = (char*)"incorrect data check";
 3302         z->state->sub.marker = 5;       /* can't try inflateSync */
 3303         break;
 3304       }
 3305       Trace((stderr, "inflate: zlib check ok\n"));
 3306       z->state->mode = DONE;
 3307     case DONE:
 3308       return Z_STREAM_END;
 3309     case BAD:
 3310       return Z_DATA_ERROR;
 3311     default:
 3312       return Z_STREAM_ERROR;
 3313   }
 3314 
 3315  empty:
 3316   if (f != Z_PACKET_FLUSH)
 3317     return r;
 3318   z->state->mode = BAD;
 3319   z->msg = (char *)"need more for packet flush";
 3320   z->state->sub.marker = 0;       /* can try inflateSync */
 3321   return Z_DATA_ERROR;
 3322 }
 3323 
 3324 
 3325 int inflateSetDictionary(z, dictionary, dictLength)
 3326 z_streamp z;
 3327 const Bytef *dictionary;
 3328 uInt  dictLength;
 3329 {
 3330   uInt length = dictLength;
 3331 
 3332   if (z == Z_NULL || z->state == Z_NULL || z->state->mode != DICT0)
 3333     return Z_STREAM_ERROR;
 3334 
 3335   if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
 3336   z->adler = 1L;
 3337 
 3338   if (length >= ((uInt)1<<z->state->wbits))
 3339   {
 3340     length = (1<<z->state->wbits)-1;
 3341     dictionary += dictLength - length;
 3342   }
 3343   inflate_set_dictionary(z->state->blocks, dictionary, length);
 3344   z->state->mode = BLOCKS;
 3345   return Z_OK;
 3346 }
 3347 
 3348 /*
 3349  * This subroutine adds the data at next_in/avail_in to the output history
 3350  * without performing any output.  The output buffer must be "caught up";
 3351  * i.e. no pending output (hence s->read equals s->write), and the state must
 3352  * be BLOCKS (i.e. we should be willing to see the start of a series of
 3353  * BLOCKS).  On exit, the output will also be caught up, and the checksum
 3354  * will have been updated if need be.
 3355  */
 3356 
 3357 int inflateIncomp(z)
 3358 z_stream *z;
 3359 {
 3360     if (z->state->mode != BLOCKS)
 3361         return Z_DATA_ERROR;
 3362     return inflate_addhistory(z->state->blocks, z);
 3363 }
 3364 
 3365 
 3366 int inflateSync(z)
 3367 z_streamp z;
 3368 {
 3369   uInt n;       /* number of bytes to look at */
 3370   Bytef *p;     /* pointer to bytes */
 3371   uInt m;       /* number of marker bytes found in a row */
 3372   uLong r, w;   /* temporaries to save total_in and total_out */
 3373 
 3374   /* set up */
 3375   if (z == Z_NULL || z->state == Z_NULL)
 3376     return Z_STREAM_ERROR;
 3377   if (z->state->mode != BAD)
 3378   {
 3379     z->state->mode = BAD;
 3380     z->state->sub.marker = 0;
 3381   }
 3382   if ((n = z->avail_in) == 0)
 3383     return Z_BUF_ERROR;
 3384   p = z->next_in;
 3385   m = z->state->sub.marker;
 3386 
 3387   /* search */
 3388   while (n && m < 4)
 3389   {
 3390     if (*p == (Byte)(m < 2 ? 0 : 0xff))
 3391       m++;
 3392     else if (*p)
 3393       m = 0;
 3394     else
 3395       m = 4 - m;
 3396     p++, n--;
 3397   }
 3398 
 3399   /* restore */
 3400   z->total_in += p - z->next_in;
 3401   z->next_in = p;
 3402   z->avail_in = n;
 3403   z->state->sub.marker = m;
 3404 
 3405   /* return no joy or set up to restart on a new block */
 3406   if (m != 4)
 3407     return Z_DATA_ERROR;
 3408   r = z->total_in;  w = z->total_out;
 3409   inflateReset(z);
 3410   z->total_in = r;  z->total_out = w;
 3411   z->state->mode = BLOCKS;
 3412   return Z_OK;
 3413 }
 3414 
 3415 #undef NEEDBYTE
 3416 #undef NEXTBYTE
 3417 /* --- inflate.c */
 3418 
 3419 /* +++ infblock.c */
 3420 /* infblock.c -- interpret and process block types to last block
 3421  * Copyright (C) 1995-1996 Mark Adler
 3422  * For conditions of distribution and use, see copyright notice in zlib.h 
 3423  */
 3424 
 3425 /* #include "zutil.h" */
 3426 /* #include "infblock.h" */
 3427 
 3428 /* +++ inftrees.h */
 3429 /* inftrees.h -- header to use inftrees.c
 3430  * Copyright (C) 1995-1996 Mark Adler
 3431  * For conditions of distribution and use, see copyright notice in zlib.h 
 3432  */
 3433 
 3434 /* WARNING: this file should *not* be used by applications. It is
 3435    part of the implementation of the compression library and is
 3436    subject to change. Applications should only use zlib.h.
 3437  */
 3438 
 3439 /* Huffman code lookup table entry--this entry is four bytes for machines
 3440    that have 16-bit pointers (e.g. PC's in the small or medium model). */
 3441 
 3442 typedef struct inflate_huft_s FAR inflate_huft;
 3443 
 3444 struct inflate_huft_s {
 3445   union {
 3446     struct {
 3447       Byte Exop;        /* number of extra bits or operation */
 3448       Byte Bits;        /* number of bits in this code or subcode */
 3449     } what;
 3450     Bytef *pad;         /* pad structure to a power of 2 (4 bytes for */
 3451   } word;               /*  16-bit, 8 bytes for 32-bit machines) */
 3452   union {
 3453     uInt Base;          /* literal, length base, or distance base */
 3454     inflate_huft *Next; /* pointer to next level of table */
 3455   } more;
 3456 };
 3457 
 3458 #ifdef DEBUG_ZLIB
 3459   extern uInt inflate_hufts;
 3460 #endif
 3461 
 3462 extern int inflate_trees_bits OF((
 3463     uIntf *,                    /* 19 code lengths */
 3464     uIntf *,                    /* bits tree desired/actual depth */
 3465     inflate_huft * FAR *,       /* bits tree result */
 3466     z_streamp ));               /* for zalloc, zfree functions */
 3467 
 3468 extern int inflate_trees_dynamic OF((
 3469     uInt,                       /* number of literal/length codes */
 3470     uInt,                       /* number of distance codes */
 3471     uIntf *,                    /* that many (total) code lengths */
 3472     uIntf *,                    /* literal desired/actual bit depth */
 3473     uIntf *,                    /* distance desired/actual bit depth */
 3474     inflate_huft * FAR *,       /* literal/length tree result */
 3475     inflate_huft * FAR *,       /* distance tree result */
 3476     z_streamp ));               /* for zalloc, zfree functions */
 3477 
 3478 extern int inflate_trees_fixed OF((
 3479     uIntf *,                    /* literal desired/actual bit depth */
 3480     uIntf *,                    /* distance desired/actual bit depth */
 3481     inflate_huft * FAR *,       /* literal/length tree result */
 3482     inflate_huft * FAR *));     /* distance tree result */
 3483 
 3484 extern int inflate_trees_free OF((
 3485     inflate_huft *,             /* tables to free */
 3486     z_streamp ));               /* for zfree function */
 3487 
 3488 /* --- inftrees.h */
 3489 
 3490 /* +++ infcodes.h */
 3491 /* infcodes.h -- header to use infcodes.c
 3492  * Copyright (C) 1995-1996 Mark Adler
 3493  * For conditions of distribution and use, see copyright notice in zlib.h 
 3494  */
 3495 
 3496 /* WARNING: this file should *not* be used by applications. It is
 3497    part of the implementation of the compression library and is
 3498    subject to change. Applications should only use zlib.h.
 3499  */
 3500 
 3501 struct inflate_codes_state;
 3502 typedef struct inflate_codes_state FAR inflate_codes_statef;
 3503 
 3504 extern inflate_codes_statef *inflate_codes_new OF((
 3505     uInt, uInt,
 3506     inflate_huft *, inflate_huft *,
 3507     z_streamp ));
 3508 
 3509 extern int inflate_codes OF((
 3510     inflate_blocks_statef *,
 3511     z_streamp ,
 3512     int));
 3513 
 3514 extern void inflate_codes_free OF((
 3515     inflate_codes_statef *,
 3516     z_streamp ));
 3517 
 3518 /* --- infcodes.h */
 3519 
 3520 /* +++ infutil.h */
 3521 /* infutil.h -- types and macros common to blocks and codes
 3522  * Copyright (C) 1995-1996 Mark Adler
 3523  * For conditions of distribution and use, see copyright notice in zlib.h 
 3524  */
 3525 
 3526 /* WARNING: this file should *not* be used by applications. It is
 3527    part of the implementation of the compression library and is
 3528    subject to change. Applications should only use zlib.h.
 3529  */
 3530 
 3531 #ifndef _INFUTIL_H
 3532 #define _INFUTIL_H
 3533 
 3534 typedef enum {
 3535       TYPE,     /* get type bits (3, including end bit) */
 3536       LENS,     /* get lengths for stored */
 3537       STORED,   /* processing stored block */
 3538       TABLE,    /* get table lengths */
 3539       BTREE,    /* get bit lengths tree for a dynamic block */
 3540       DTREE,    /* get length, distance trees for a dynamic block */
 3541       CODES,    /* processing fixed or dynamic block */
 3542       DRY,      /* output remaining window bytes */
 3543       DONEB,    /* finished last block, done */
 3544       BADB}     /* got a data error--stuck here */
 3545 inflate_block_mode;
 3546 
 3547 /* inflate blocks semi-private state */
 3548 struct inflate_blocks_state {
 3549 
 3550   /* mode */
 3551   inflate_block_mode  mode;     /* current inflate_block mode */
 3552 
 3553   /* mode dependent information */
 3554   union {
 3555     uInt left;          /* if STORED, bytes left to copy */
 3556     struct {
 3557       uInt table;               /* table lengths (14 bits) */
 3558       uInt index;               /* index into blens (or border) */
 3559       uIntf *blens;             /* bit lengths of codes */
 3560       uInt bb;                  /* bit length tree depth */
 3561       inflate_huft *tb;         /* bit length decoding tree */
 3562     } trees;            /* if DTREE, decoding info for trees */
 3563     struct {
 3564       inflate_huft *tl;
 3565       inflate_huft *td;         /* trees to free */
 3566       inflate_codes_statef 
 3567          *codes;
 3568     } decode;           /* if CODES, current state */
 3569   } sub;                /* submode */
 3570   uInt last;            /* true if this block is the last block */
 3571 
 3572   /* mode independent information */
 3573   uInt bitk;            /* bits in bit buffer */
 3574   uLong bitb;           /* bit buffer */
 3575   Bytef *window;        /* sliding window */
 3576   Bytef *end;           /* one byte after sliding window */
 3577   Bytef *read;          /* window read pointer */
 3578   Bytef *write;         /* window write pointer */
 3579   check_func checkfn;   /* check function */
 3580   uLong check;          /* check on output */
 3581 
 3582 };
 3583 
 3584 
 3585 /* defines for inflate input/output */
 3586 /*   update pointers and return */
 3587 #define UPDBITS {s->bitb=b;s->bitk=k;}
 3588 #define UPDIN {z->avail_in=n;z->total_in+=p-z->next_in;z->next_in=p;}
 3589 #define UPDOUT {s->write=q;}
 3590 #define UPDATE {UPDBITS UPDIN UPDOUT}
 3591 #define LEAVE {UPDATE return inflate_flush(s,z,r);}
 3592 /*   get bytes and bits */
 3593 #define LOADIN {p=z->next_in;n=z->avail_in;b=s->bitb;k=s->bitk;}
 3594 #define NEEDBYTE {if(n)r=Z_OK;else LEAVE}
 3595 #define NEXTBYTE (n--,*p++)
 3596 #define NEEDBITS(j) {while(k<(j)){NEEDBYTE;b|=((uLong)NEXTBYTE)<<k;k+=8;}}
 3597 #define DUMPBITS(j) {b>>=(j);k-=(j);}
 3598 /*   output bytes */
 3599 #define WAVAIL (uInt)(q<s->read?s->read-q-1:s->end-q)
 3600 #define LOADOUT {q=s->write;m=(uInt)WAVAIL;}
 3601 #define WWRAP {if(q==s->end&&s->read!=s->window){q=s->window;m=(uInt)WAVAIL;}}
 3602 #define FLUSH {UPDOUT r=inflate_flush(s,z,r); LOADOUT}
 3603 #define NEEDOUT {if(m==0){WWRAP if(m==0){FLUSH WWRAP if(m==0) LEAVE}}r=Z_OK;}
 3604 #define OUTBYTE(a) {*q++=(Byte)(a);m--;}
 3605 /*   load local pointers */
 3606 #define LOAD {LOADIN LOADOUT}
 3607 
 3608 /* masks for lower bits (size given to avoid silly warnings with Visual C++) */
 3609 extern uInt inflate_mask[17];
 3610 
 3611 /* copy as much as possible from the sliding window to the output area */
 3612 extern int inflate_flush OF((
 3613     inflate_blocks_statef *,
 3614     z_streamp ,
 3615     int));
 3616 
 3617 #ifndef NO_DUMMY_DECL
 3618 struct internal_state      {int dummy;}; /* for buggy compilers */
 3619 #endif
 3620 
 3621 #endif
 3622 /* --- infutil.h */
 3623 
 3624 #ifndef NO_DUMMY_DECL
 3625 struct inflate_codes_state {int dummy;}; /* for buggy compilers */
 3626 #endif
 3627 
 3628 /* Table for deflate from PKZIP's appnote.txt. */
 3629 local const uInt border[] = { /* Order of the bit length code lengths */
 3630         16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
 3631 
 3632 /*
 3633    Notes beyond the 1.93a appnote.txt:
 3634 
 3635    1. Distance pointers never point before the beginning of the output
 3636       stream.
 3637    2. Distance pointers can point back across blocks, up to 32k away.
 3638    3. There is an implied maximum of 7 bits for the bit length table and
 3639       15 bits for the actual data.
 3640    4. If only one code exists, then it is encoded using one bit.  (Zero
 3641       would be more efficient, but perhaps a little confusing.)  If two
 3642       codes exist, they are coded using one bit each (0 and 1).
 3643    5. There is no way of sending zero distance codes--a dummy must be
 3644       sent if there are none.  (History: a pre 2.0 version of PKZIP would
 3645       store blocks with no distance codes, but this was discovered to be
 3646       too harsh a criterion.)  Valid only for 1.93a.  2.04c does allow
 3647       zero distance codes, which is sent as one code of zero bits in
 3648       length.
 3649    6. There are up to 286 literal/length codes.  Code 256 represents the
 3650       end-of-block.  Note however that the static length tree defines
 3651       288 codes just to fill out the Huffman codes.  Codes 286 and 287
 3652       cannot be used though, since there is no length base or extra bits
 3653       defined for them.  Similarily, there are up to 30 distance codes.
 3654       However, static trees define 32 codes (all 5 bits) to fill out the
 3655       Huffman codes, but the last two had better not show up in the data.
 3656    7. Unzip can check dynamic Huffman blocks for complete code sets.
 3657       The exception is that a single code would not be complete (see #4).
 3658    8. The five bits following the block type is really the number of
 3659       literal codes sent minus 257.
 3660    9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
 3661       (1+6+6).  Therefore, to output three times the length, you output
 3662       three codes (1+1+1), whereas to output four times the same length,
 3663       you only need two codes (1+3).  Hmm.
 3664   10. In the tree reconstruction algorithm, Code = Code + Increment
 3665       only if BitLength(i) is not zero.  (Pretty obvious.)
 3666   11. Correction: 4 Bits: # of Bit Length codes - 4     (4 - 19)
 3667   12. Note: length code 284 can represent 227-258, but length code 285
 3668       really is 258.  The last length deserves its own, short code
 3669       since it gets used a lot in very redundant files.  The length
 3670       258 is special since 258 - 3 (the min match length) is 255.
 3671   13. The literal/length and distance code bit lengths are read as a
 3672       single stream of lengths.  It is possible (and advantageous) for
 3673       a repeat code (16, 17, or 18) to go across the boundary between
 3674       the two sets of lengths.
 3675  */
 3676 
 3677 
 3678 void inflate_blocks_reset(s, z, c)
 3679 inflate_blocks_statef *s;
 3680 z_streamp z;
 3681 uLongf *c;
 3682 {
 3683   if (s->checkfn != Z_NULL)
 3684     *c = s->check;
 3685   if (s->mode == BTREE || s->mode == DTREE)
 3686     ZFREE(z, s->sub.trees.blens);
 3687   if (s->mode == CODES)
 3688   {
 3689     inflate_codes_free(s->sub.decode.codes, z);
 3690     inflate_trees_free(s->sub.decode.td, z);
 3691     inflate_trees_free(s->sub.decode.tl, z);
 3692   }
 3693   s->mode = TYPE;
 3694   s->bitk = 0;
 3695   s->bitb = 0;
 3696   s->read = s->write = s->window;
 3697   if (s->checkfn != Z_NULL)
 3698     z->adler = s->check = (*s->checkfn)(0L, Z_NULL, 0);
 3699   Trace((stderr, "inflate:   blocks reset\n"));
 3700 }
 3701 
 3702 
 3703 inflate_blocks_statef *inflate_blocks_new(z, c, w)
 3704 z_streamp z;
 3705 check_func c;
 3706 uInt w;
 3707 {
 3708   inflate_blocks_statef *s;
 3709 
 3710   if ((s = (inflate_blocks_statef *)ZALLOC
 3711        (z,1,sizeof(struct inflate_blocks_state))) == Z_NULL)
 3712     return s;
 3713   if ((s->window = (Bytef *)ZALLOC(z, 1, w)) == Z_NULL)
 3714   {
 3715     ZFREE(z, s);
 3716     return Z_NULL;
 3717   }
 3718   s->end = s->window + w;
 3719   s->checkfn = c;
 3720   s->mode = TYPE;
 3721   Trace((stderr, "inflate:   blocks allocated\n"));
 3722   inflate_blocks_reset(s, z, &s->check);
 3723   return s;
 3724 }
 3725 
 3726 
 3727 #ifdef DEBUG_ZLIB
 3728   extern uInt inflate_hufts;
 3729 #endif
 3730 int inflate_blocks(s, z, r)
 3731 inflate_blocks_statef *s;
 3732 z_streamp z;
 3733 int r;
 3734 {
 3735   uInt t;               /* temporary storage */
 3736   uLong b;              /* bit buffer */
 3737   uInt k;               /* bits in bit buffer */
 3738   Bytef *p;             /* input data pointer */
 3739   uInt n;               /* bytes available there */
 3740   Bytef *q;             /* output window write pointer */
 3741   uInt m;               /* bytes to end of window or read pointer */
 3742 
 3743   /* copy input/output information to locals (UPDATE macro restores) */
 3744   LOAD
 3745 
 3746   /* process input based on current state */
 3747   while (1) switch (s->mode)
 3748   {
 3749     case TYPE:
 3750       NEEDBITS(3)
 3751       t = (uInt)b & 7;
 3752       s->last = t & 1;
 3753       switch (t >> 1)
 3754       {
 3755         case 0:                         /* stored */
 3756           Trace((stderr, "inflate:     stored block%s\n",
 3757                  s->last ? " (last)" : ""));
 3758           DUMPBITS(3)
 3759           t = k & 7;                    /* go to byte boundary */
 3760           DUMPBITS(t)
 3761           s->mode = LENS;               /* get length of stored block */
 3762           break;
 3763         case 1:                         /* fixed */
 3764           Trace((stderr, "inflate:     fixed codes block%s\n",
 3765                  s->last ? " (last)" : ""));
 3766           {
 3767             uInt bl, bd;
 3768             inflate_huft *tl, *td;
 3769 
 3770             inflate_trees_fixed(&bl, &bd, &tl, &td);
 3771             s->sub.decode.codes = inflate_codes_new(bl, bd, tl, td, z);
 3772             if (s->sub.decode.codes == Z_NULL)
 3773             {
 3774               r = Z_MEM_ERROR;
 3775               LEAVE
 3776             }
 3777             s->sub.decode.tl = Z_NULL;  /* don't try to free these */
 3778             s->sub.decode.td = Z_NULL;
 3779           }
 3780           DUMPBITS(3)
 3781           s->mode = CODES;
 3782           break;
 3783         case 2:                         /* dynamic */
 3784           Trace((stderr, "inflate:     dynamic codes block%s\n",
 3785                  s->last ? " (last)" : ""));
 3786           DUMPBITS(3)
 3787           s->mode = TABLE;
 3788           break;
 3789         case 3:                         /* illegal */
 3790           DUMPBITS(3)
 3791           s->mode = BADB;
 3792           z->msg = (char*)"invalid block type";
 3793           r = Z_DATA_ERROR;
 3794           LEAVE
 3795       }
 3796       break;
 3797     case LENS:
 3798       NEEDBITS(32)
 3799       if ((((~b) >> 16) & 0xffff) != (b & 0xffff))
 3800       {
 3801         s->mode = BADB;
 3802         z->msg = (char*)"invalid stored block lengths";
 3803         r = Z_DATA_ERROR;
 3804         LEAVE
 3805       }
 3806       s->sub.left = (uInt)b & 0xffff;
 3807       b = k = 0;                      /* dump bits */
 3808       Tracev((stderr, "inflate:       stored length %u\n", s->sub.left));
 3809       s->mode = s->sub.left ? STORED : (s->last ? DRY : TYPE);
 3810       break;
 3811     case STORED:
 3812       if (n == 0)
 3813         LEAVE
 3814       NEEDOUT
 3815       t = s->sub.left;
 3816       if (t > n) t = n;
 3817       if (t > m) t = m;
 3818       zmemcpy(q, p, t);
 3819       p += t;  n -= t;
 3820       q += t;  m -= t;
 3821       if ((s->sub.left -= t) != 0)
 3822         break;
 3823       Tracev((stderr, "inflate:       stored end, %lu total out\n",
 3824               z->total_out + (q >= s->read ? q - s->read :
 3825               (s->end - s->read) + (q - s->window))));
 3826       s->mode = s->last ? DRY : TYPE;
 3827       break;
 3828     case TABLE:
 3829       NEEDBITS(14)
 3830       s->sub.trees.table = t = (uInt)b & 0x3fff;
 3831 #ifndef PKZIP_BUG_WORKAROUND
 3832       if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29)
 3833       {
 3834         s->mode = BADB;
 3835         z->msg = (char*)"too many length or distance symbols";
 3836         r = Z_DATA_ERROR;
 3837         LEAVE
 3838       }
 3839 #endif
 3840       t = 258 + (t & 0x1f) + ((t >> 5) & 0x1f);
 3841       if (t < 19)
 3842         t = 19;
 3843       if ((s->sub.trees.blens = (uIntf*)ZALLOC(z, t, sizeof(uInt))) == Z_NULL)
 3844       {
 3845         r = Z_MEM_ERROR;
 3846         LEAVE
 3847       }
 3848       DUMPBITS(14)
 3849       s->sub.trees.index = 0;
 3850       Tracev((stderr, "inflate:       table sizes ok\n"));
 3851       s->mode = BTREE;
 3852     case BTREE:
 3853       while (s->sub.trees.index < 4 + (s->sub.trees.table >> 10))
 3854       {
 3855         NEEDBITS(3)
 3856         s->sub.trees.blens[border[s->sub.trees.index++]] = (uInt)b & 7;
 3857         DUMPBITS(3)
 3858       }
 3859       while (s->sub.trees.index < 19)
 3860         s->sub.trees.blens[border[s->sub.trees.index++]] = 0;
 3861       s->sub.trees.bb = 7;
 3862       t = inflate_trees_bits(s->sub.trees.blens, &s->sub.trees.bb,
 3863                              &s->sub.trees.tb, z);
 3864       if (t != Z_OK)
 3865       {
 3866         r = t;
 3867         if (r == Z_DATA_ERROR) {
 3868           ZFREE(z, s->sub.trees.blens);
 3869           s->mode = BADB;
 3870         }
 3871         LEAVE
 3872       }
 3873       s->sub.trees.index = 0;
 3874       Tracev((stderr, "inflate:       bits tree ok\n"));
 3875       s->mode = DTREE;
 3876     case DTREE:
 3877       while (t = s->sub.trees.table,
 3878              s->sub.trees.index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))
 3879       {
 3880         inflate_huft *h;
 3881         uInt i, j, c;
 3882 
 3883         t = s->sub.trees.bb;
 3884         NEEDBITS(t)
 3885         h = s->sub.trees.tb + ((uInt)b & inflate_mask[t]);
 3886         t = h->word.what.Bits;
 3887         c = h->more.Base;
 3888         if (c < 16)
 3889         {
 3890           DUMPBITS(t)
 3891           s->sub.trees.blens[s->sub.trees.index++] = c;
 3892         }
 3893         else /* c == 16..18 */
 3894         {
 3895           i = c == 18 ? 7 : c - 14;
 3896           j = c == 18 ? 11 : 3;
 3897           NEEDBITS(t + i)
 3898           DUMPBITS(t)
 3899           j += (uInt)b & inflate_mask[i];
 3900           DUMPBITS(i)
 3901           i = s->sub.trees.index;
 3902           t = s->sub.trees.table;
 3903           if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) ||
 3904               (c == 16 && i < 1))
 3905           {
 3906             inflate_trees_free(s->sub.trees.tb, z);
 3907             ZFREE(z, s->sub.trees.blens);
 3908             s->mode = BADB;
 3909             z->msg = (char*)"invalid bit length repeat";
 3910             r = Z_DATA_ERROR;
 3911             LEAVE
 3912           }
 3913           c = c == 16 ? s->sub.trees.blens[i - 1] : 0;
 3914           do {
 3915             s->sub.trees.blens[i++] = c;
 3916           } while (--j);
 3917           s->sub.trees.index = i;
 3918         }
 3919       }
 3920       inflate_trees_free(s->sub.trees.tb, z);
 3921       s->sub.trees.tb = Z_NULL;
 3922       {
 3923         uInt bl, bd;
 3924         inflate_huft *tl, *td;
 3925         inflate_codes_statef *c;
 3926 
 3927         bl = 9;         /* must be <= 9 for lookahead assumptions */
 3928         bd = 6;         /* must be <= 9 for lookahead assumptions */
 3929         t = s->sub.trees.table;
 3930 #ifdef DEBUG_ZLIB
 3931       inflate_hufts = 0;
 3932 #endif
 3933         t = inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f),
 3934                                   s->sub.trees.blens, &bl, &bd, &tl, &td, z);
 3935         if (t != Z_OK)
 3936         {
 3937           if (t == (uInt)Z_DATA_ERROR) {
 3938             ZFREE(z, s->sub.trees.blens);
 3939             s->mode = BADB;
 3940           }
 3941           r = t;
 3942           LEAVE
 3943         }
 3944         Tracev((stderr, "inflate:       trees ok, %d * %d bytes used\n",
 3945               inflate_hufts, sizeof(inflate_huft)));
 3946         if ((c = inflate_codes_new(bl, bd, tl, td, z)) == Z_NULL)
 3947         {
 3948           inflate_trees_free(td, z);
 3949           inflate_trees_free(tl, z);
 3950           r = Z_MEM_ERROR;
 3951           LEAVE
 3952         }
 3953         /*
 3954          * this ZFREE must occur *BEFORE* we mess with sub.decode, because
 3955          * sub.trees is union'd with sub.decode.
 3956          */
 3957         ZFREE(z, s->sub.trees.blens);
 3958         s->sub.decode.codes = c;
 3959         s->sub.decode.tl = tl;
 3960         s->sub.decode.td = td;
 3961       }
 3962       s->mode = CODES;
 3963     case CODES:
 3964       UPDATE
 3965       if ((r = inflate_codes(s, z, r)) != Z_STREAM_END)
 3966         return inflate_flush(s, z, r);
 3967       r = Z_OK;
 3968       inflate_codes_free(s->sub.decode.codes, z);
 3969       inflate_trees_free(s->sub.decode.td, z);
 3970       inflate_trees_free(s->sub.decode.tl, z);
 3971       LOAD
 3972       Tracev((stderr, "inflate:       codes end, %lu total out\n",
 3973               z->total_out + (q >= s->read ? q - s->read :
 3974               (s->end - s->read) + (q - s->window))));
 3975       if (!s->last)
 3976       {
 3977         s->mode = TYPE;
 3978         break;
 3979       }
 3980       if (k > 7)              /* return unused byte, if any */
 3981       {
 3982         Assert(k < 16, "inflate_codes grabbed too many bytes")
 3983         k -= 8;
 3984         n++;
 3985         p--;                    /* can always return one */
 3986       }
 3987       s->mode = DRY;
 3988     case DRY:
 3989       FLUSH
 3990       if (s->read != s->write)
 3991         LEAVE
 3992       s->mode = DONEB;
 3993     case DONEB:
 3994       r = Z_STREAM_END;
 3995       LEAVE
 3996     case BADB:
 3997       r = Z_DATA_ERROR;
 3998       LEAVE
 3999     default:
 4000       r = Z_STREAM_ERROR;
 4001       LEAVE
 4002   }
 4003 }
 4004 
 4005 
 4006 int inflate_blocks_free(s, z, c)
 4007 inflate_blocks_statef *s;
 4008 z_streamp z;
 4009 uLongf *c;
 4010 {
 4011   inflate_blocks_reset(s, z, c);
 4012   ZFREE(z, s->window);
 4013   ZFREE(z, s);
 4014   Trace((stderr, "inflate:   blocks freed\n"));
 4015   return Z_OK;
 4016 }
 4017 
 4018 
 4019 void inflate_set_dictionary(s, d, n)
 4020 inflate_blocks_statef *s;
 4021 const Bytef *d;
 4022 uInt  n;
 4023 {
 4024   zmemcpy((charf *)s->window, d, n);
 4025   s->read = s->write = s->window + n;
 4026 }
 4027 
 4028 /*
 4029  * This subroutine adds the data at next_in/avail_in to the output history
 4030  * without performing any output.  The output buffer must be "caught up";
 4031  * i.e. no pending output (hence s->read equals s->write), and the state must
 4032  * be BLOCKS (i.e. we should be willing to see the start of a series of
 4033  * BLOCKS).  On exit, the output will also be caught up, and the checksum
 4034  * will have been updated if need be.
 4035  */
 4036 int inflate_addhistory(s, z)
 4037 inflate_blocks_statef *s;
 4038 z_stream *z;
 4039 {
 4040     uLong b;              /* bit buffer */  /* NOT USED HERE */
 4041     uInt k;               /* bits in bit buffer */ /* NOT USED HERE */
 4042     uInt t;               /* temporary storage */
 4043     Bytef *p;             /* input data pointer */
 4044     uInt n;               /* bytes available there */
 4045     Bytef *q;             /* output window write pointer */
 4046     uInt m;               /* bytes to end of window or read pointer */
 4047 
 4048     if (s->read != s->write)
 4049         return Z_STREAM_ERROR;
 4050     if (s->mode != TYPE)
 4051         return Z_DATA_ERROR;
 4052 
 4053     /* we're ready to rock */
 4054     LOAD
 4055     /* while there is input ready, copy to output buffer, moving
 4056      * pointers as needed.
 4057      */
 4058     while (n) {
 4059         t = n;  /* how many to do */
 4060         /* is there room until end of buffer? */
 4061         if (t > m) t = m;
 4062         /* update check information */
 4063         if (s->checkfn != Z_NULL)
 4064             s->check = (*s->checkfn)(s->check, q, t);
 4065         zmemcpy(q, p, t);
 4066         q += t;
 4067         p += t;
 4068         n -= t;
 4069         z->total_out += t;
 4070         s->read = q;    /* drag read pointer forward */
 4071 /*      WWRAP  */       /* expand WWRAP macro by hand to handle s->read */
 4072         if (q == s->end) {
 4073             s->read = q = s->window;
 4074             m = WAVAIL;
 4075         }
 4076     }
 4077     UPDATE
 4078     return Z_OK;
 4079 }
 4080 
 4081 
 4082 /*
 4083  * At the end of a Deflate-compressed PPP packet, we expect to have seen
 4084  * a `stored' block type value but not the (zero) length bytes.
 4085  */
 4086 int inflate_packet_flush(s)
 4087     inflate_blocks_statef *s;
 4088 {
 4089     if (s->mode != LENS)
 4090         return Z_DATA_ERROR;
 4091     s->mode = TYPE;
 4092     return Z_OK;
 4093 }
 4094 /* --- infblock.c */
 4095 
 4096 /* +++ inftrees.c */
 4097 /* inftrees.c -- generate Huffman trees for efficient decoding
 4098  * Copyright (C) 1995-1996 Mark Adler
 4099  * For conditions of distribution and use, see copyright notice in zlib.h 
 4100  */
 4101 
 4102 /* #include "zutil.h" */
 4103 /* #include "inftrees.h" */
 4104 
 4105 char inflate_copyright[] = " inflate 1.0.4 Copyright 1995-1996 Mark Adler ";
 4106 /*
 4107   If you use the zlib library in a product, an acknowledgment is welcome
 4108   in the documentation of your product. If for some reason you cannot
 4109   include such an acknowledgment, I would appreciate that you keep this
 4110   copyright string in the executable of your product.
 4111  */
 4112 
 4113 #ifndef NO_DUMMY_DECL
 4114 struct internal_state  {int dummy;}; /* for buggy compilers */
 4115 #endif
 4116 
 4117 /* simplify the use of the inflate_huft type with some defines */
 4118 #define base more.Base
 4119 #define next more.Next
 4120 #define exop word.what.Exop
 4121 #define bits word.what.Bits
 4122 
 4123 
 4124 local int huft_build OF((
 4125     uIntf *,            /* code lengths in bits */
 4126     uInt,               /* number of codes */
 4127     uInt,               /* number of "simple" codes */
 4128     const uIntf *,      /* list of base values for non-simple codes */
 4129     const uIntf *,      /* list of extra bits for non-simple codes */
 4130     inflate_huft * FAR*,/* result: starting table */
 4131     uIntf *,            /* maximum lookup bits (returns actual) */
 4132     z_streamp ));       /* for zalloc function */
 4133 
 4134 local voidpf falloc OF((
 4135     voidpf,             /* opaque pointer (not used) */
 4136     uInt,               /* number of items */
 4137     uInt));             /* size of item */
 4138 
 4139 /* Tables for deflate from PKZIP's appnote.txt. */
 4140 local const uInt cplens[31] = { /* Copy lengths for literal codes 257..285 */
 4141         3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
 4142         35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
 4143         /* see note #13 above about 258 */
 4144 local const uInt cplext[31] = { /* Extra bits for literal codes 257..285 */
 4145         0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
 4146         3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 112, 112}; /* 112==invalid */
 4147 local const uInt cpdist[30] = { /* Copy offsets for distance codes 0..29 */
 4148         1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
 4149         257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
 4150         8193, 12289, 16385, 24577};
 4151 local const uInt cpdext[30] = { /* Extra bits for distance codes */
 4152         0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
 4153         7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
 4154         12, 12, 13, 13};
 4155 
 4156 /*
 4157    Huffman code decoding is performed using a multi-level table lookup.
 4158    The fastest way to decode is to simply build a lookup table whose
 4159    size is determined by the longest code.  However, the time it takes
 4160    to build this table can also be a factor if the data being decoded
 4161    is not very long.  The most common codes are necessarily the
 4162    shortest codes, so those codes dominate the decoding time, and hence
 4163    the speed.  The idea is you can have a shorter table that decodes the
 4164    shorter, more probable codes, and then point to subsidiary tables for
 4165    the longer codes.  The time it costs to decode the longer codes is
 4166    then traded against the time it takes to make longer tables.
 4167 
 4168    This results of this trade are in the variables lbits and dbits
 4169    below.  lbits is the number of bits the first level table for literal/
 4170    length codes can decode in one step, and dbits is the same thing for
 4171    the distance codes.  Subsequent tables are also less than or equal to
 4172    those sizes.  These values may be adjusted either when all of the
 4173    codes are shorter than that, in which case the longest code length in
 4174    bits is used, or when the shortest code is *longer* than the requested
 4175    table size, in which case the length of the shortest code in bits is
 4176    used.
 4177 
 4178    There are two different values for the two tables, since they code a
 4179    different number of possibilities each.  The literal/length table
 4180    codes 286 possible values, or in a flat code, a little over eight
 4181    bits.  The distance table codes 30 possible values, or a little less
 4182    than five bits, flat.  The optimum values for speed end up being
 4183    about one bit more than those, so lbits is 8+1 and dbits is 5+1.
 4184    The optimum values may differ though from machine to machine, and
 4185    possibly even between compilers.  Your mileage may vary.
 4186  */
 4187 
 4188 
 4189 /* If BMAX needs to be larger than 16, then h and x[] should be uLong. */
 4190 #define BMAX 15         /* maximum bit length of any code */
 4191 #define N_MAX 288       /* maximum number of codes in any set */
 4192 
 4193 #ifdef DEBUG_ZLIB
 4194   uInt inflate_hufts;
 4195 #endif
 4196 
 4197 local int huft_build(b, n, s, d, e, t, m, zs)
 4198 uIntf *b;               /* code lengths in bits (all assumed <= BMAX) */
 4199 uInt n;                 /* number of codes (assumed <= N_MAX) */
 4200 uInt s;                 /* number of simple-valued codes (0..s-1) */
 4201 const uIntf *d;         /* list of base values for non-simple codes */
 4202 const uIntf *e;         /* list of extra bits for non-simple codes */
 4203 inflate_huft * FAR *t;  /* result: starting table */
 4204 uIntf *m;               /* maximum lookup bits, returns actual */
 4205 z_streamp zs;           /* for zalloc function */
 4206 /* Given a list of code lengths and a maximum table size, make a set of
 4207    tables to decode that set of codes.  Return Z_OK on success, Z_BUF_ERROR
 4208    if the given code set is incomplete (the tables are still built in this
 4209    case), Z_DATA_ERROR if the input is invalid (an over-subscribed set of
 4210    lengths), or Z_MEM_ERROR if not enough memory. */
 4211 {
 4212 
 4213   uInt a;                       /* counter for codes of length k */
 4214   uInt c[BMAX+1];               /* bit length count table */
 4215   uInt f;                       /* i repeats in table every f entries */
 4216   int g;                        /* maximum code length */
 4217   int h;                        /* table level */
 4218   register uInt i;              /* counter, current code */
 4219   register uInt j;              /* counter */
 4220   register int k;               /* number of bits in current code */
 4221   int l;                        /* bits per table (returned in m) */
 4222   register uIntf *p;            /* pointer into c[], b[], or v[] */
 4223   inflate_huft *q;              /* points to current table */
 4224   struct inflate_huft_s r;      /* table entry for structure assignment */
 4225   inflate_huft *u[BMAX];        /* table stack */
 4226   uInt v[N_MAX];                /* values in order of bit length */
 4227   register int w;               /* bits before this table == (l * h) */
 4228   uInt x[BMAX+1];               /* bit offsets, then code stack */
 4229   uIntf *xp;                    /* pointer into x */
 4230   int y;                        /* number of dummy codes added */
 4231   uInt z;                       /* number of entries in current table */
 4232 
 4233 
 4234   /* Generate counts for each bit length */
 4235   p = c;
 4236 #define C0 *p++ = 0;
 4237 #define C2 C0 C0 C0 C0
 4238 #define C4 C2 C2 C2 C2
 4239   C4                            /* clear c[]--assume BMAX+1 is 16 */
 4240   p = b;  i = n;
 4241   do {
 4242     c[*p++]++;                  /* assume all entries <= BMAX */
 4243   } while (--i);
 4244   if (c[0] == n)                /* null input--all zero length codes */
 4245   {
 4246     *t = (inflate_huft *)Z_NULL;
 4247     *m = 0;
 4248     return Z_OK;
 4249   }
 4250 
 4251 
 4252   /* Find minimum and maximum length, bound *m by those */
 4253   l = *m;
 4254   for (j = 1; j <= BMAX; j++)
 4255     if (c[j])
 4256       break;
 4257   k = j;                        /* minimum code length */
 4258   if ((uInt)l < j)
 4259     l = j;
 4260   for (i = BMAX; i; i--)
 4261     if (c[i])
 4262       break;
 4263   g = i;                        /* maximum code length */
 4264   if ((uInt)l > i)
 4265     l = i;
 4266   *m = l;
 4267 
 4268 
 4269   /* Adjust last length count to fill out codes, if needed */
 4270   for (y = 1 << j; j < i; j++, y <<= 1)
 4271     if ((y -= c[j]) < 0)
 4272       return Z_DATA_ERROR;
 4273   if ((y -= c[i]) < 0)
 4274     return Z_DATA_ERROR;
 4275   c[i] += y;
 4276 
 4277 
 4278   /* Generate starting offsets into the value table for each length */
 4279   x[1] = j = 0;
 4280   p = c + 1;  xp = x + 2;
 4281   while (--i) {                 /* note that i == g from above */
 4282     *xp++ = (j += *p++);
 4283   }
 4284 
 4285 
 4286   /* Make a table of values in order of bit lengths */
 4287   p = b;  i = 0;
 4288   do {
 4289     if ((j = *p++) != 0)
 4290       v[x[j]++] = i;
 4291   } while (++i < n);
 4292   n = x[g];                   /* set n to length of v */
 4293 
 4294 
 4295   /* Generate the Huffman codes and for each, make the table entries */
 4296   x[0] = i = 0;                 /* first Huffman code is zero */
 4297   p = v;                        /* grab values in bit order */
 4298   h = -1;                       /* no tables yet--level -1 */
 4299   w = -l;                       /* bits decoded == (l * h) */
 4300   u[0] = (inflate_huft *)Z_NULL;        /* just to keep compilers happy */
 4301   q = (inflate_huft *)Z_NULL;   /* ditto */
 4302   z = 0;                        /* ditto */
 4303 
 4304   /* go through the bit lengths (k already is bits in shortest code) */
 4305   for (; k <= g; k++)
 4306   {
 4307     a = c[k];
 4308     while (a--)
 4309     {
 4310       /* here i is the Huffman code of length k bits for value *p */
 4311       /* make tables up to required level */
 4312       while (k > w + l)
 4313       {
 4314         h++;
 4315         w += l;                 /* previous table always l bits */
 4316 
 4317         /* compute minimum size table less than or equal to l bits */
 4318         z = g - w;
 4319         z = z > (uInt)l ? l : z;        /* table size upper limit */
 4320         if ((f = 1 << (j = k - w)) > a + 1)     /* try a k-w bit table */
 4321         {                       /* too few codes for k-w bit table */
 4322           f -= a + 1;           /* deduct codes from patterns left */
 4323           xp = c + k;
 4324           if (j < z)
 4325             while (++j < z)     /* try smaller tables up to z bits */
 4326             {
 4327               if ((f <<= 1) <= *++xp)
 4328                 break;          /* enough codes to use up j bits */
 4329               f -= *xp;         /* else deduct codes from patterns */
 4330             }
 4331         }
 4332         z = 1 << j;             /* table entries for j-bit table */
 4333 
 4334         /* allocate and link in new table */
 4335         if ((q = (inflate_huft *)ZALLOC
 4336              (zs,z + 1,sizeof(inflate_huft))) == Z_NULL)
 4337         {
 4338           if (h)
 4339             inflate_trees_free(u[0], zs);
 4340           return Z_MEM_ERROR;   /* not enough memory */
 4341         }
 4342 #ifdef DEBUG_ZLIB
 4343         inflate_hufts += z + 1;
 4344 #endif
 4345         *t = q + 1;             /* link to list for huft_free() */
 4346         *(t = &(q->next)) = Z_NULL;
 4347         u[h] = ++q;             /* table starts after link */
 4348 
 4349         /* connect to last table, if there is one */
 4350         if (h)
 4351         {
 4352           x[h] = i;             /* save pattern for backing up */
 4353           r.bits = (Byte)l;     /* bits to dump before this table */
 4354           r.exop = (Byte)j;     /* bits in this table */
 4355           r.next = q;           /* pointer to this table */
 4356           j = i >> (w - l);     /* (get around Turbo C bug) */
 4357           u[h-1][j] = r;        /* connect to last table */
 4358         }
 4359       }
 4360 
 4361       /* set up table entry in r */
 4362       r.bits = (Byte)(k - w);
 4363       if (p >= v + n)
 4364         r.exop = 128 + 64;      /* out of values--invalid code */
 4365       else if (*p < s)
 4366       {
 4367         r.exop = (Byte)(*p < 256 ? 0 : 32 + 64);     /* 256 is end-of-block */
 4368         r.base = *p++;          /* simple code is just the value */
 4369       }
 4370       else
 4371       {
 4372         r.exop = (Byte)(e[*p - s] + 16 + 64);/* non-simple--look up in lists */
 4373         r.base = d[*p++ - s];
 4374       }
 4375 
 4376       /* fill code-like entries with r */
 4377       f = 1 << (k - w);
 4378       for (j = i >> w; j < z; j += f)
 4379         q[j] = r;
 4380 
 4381       /* backwards increment the k-bit code i */
 4382       for (j = 1 << (k - 1); i & j; j >>= 1)
 4383         i ^= j;
 4384       i ^= j;
 4385 
 4386       /* backup over finished tables */
 4387       while ((i & ((1 << w) - 1)) != x[h])
 4388       {
 4389         h--;                    /* don't need to update q */
 4390         w -= l;
 4391       }
 4392     }
 4393   }
 4394 
 4395 
 4396   /* Return Z_BUF_ERROR if we were given an incomplete table */
 4397   return y != 0 && g != 1 ? Z_BUF_ERROR : Z_OK;
 4398 }
 4399 
 4400 
 4401 int inflate_trees_bits(c, bb, tb, z)
 4402 uIntf *c;               /* 19 code lengths */
 4403 uIntf *bb;              /* bits tree desired/actual depth */
 4404 inflate_huft * FAR *tb; /* bits tree result */
 4405 z_streamp z;            /* for zfree function */
 4406 {
 4407   int r;
 4408 
 4409   r = huft_build(c, 19, 19, (uIntf*)Z_NULL, (uIntf*)Z_NULL, tb, bb, z);
 4410   if (r == Z_DATA_ERROR)
 4411     z->msg = (char*)"oversubscribed dynamic bit lengths tree";
 4412   else if (r == Z_BUF_ERROR || *bb == 0)
 4413   {
 4414     inflate_trees_free(*tb, z);
 4415     z->msg = (char*)"incomplete dynamic bit lengths tree";
 4416     r = Z_DATA_ERROR;
 4417   }
 4418   return r;
 4419 }
 4420 
 4421 
 4422 int inflate_trees_dynamic(nl, nd, c, bl, bd, tl, td, z)
 4423 uInt nl;                /* number of literal/length codes */
 4424 uInt nd;                /* number of distance codes */
 4425 uIntf *c;               /* that many (total) code lengths */
 4426 uIntf *bl;              /* literal desired/actual bit depth */
 4427 uIntf *bd;              /* distance desired/actual bit depth */
 4428 inflate_huft * FAR *tl; /* literal/length tree result */
 4429 inflate_huft * FAR *td; /* distance tree result */
 4430 z_streamp z;            /* for zfree function */
 4431 {
 4432   int r;
 4433 
 4434   /* build literal/length tree */
 4435   r = huft_build(c, nl, 257, cplens, cplext, tl, bl, z);
 4436   if (r != Z_OK || *bl == 0)
 4437   {
 4438     if (r == Z_DATA_ERROR)
 4439       z->msg = (char*)"oversubscribed literal/length tree";
 4440     else if (r != Z_MEM_ERROR)
 4441     {
 4442       inflate_trees_free(*tl, z);
 4443       z->msg = (char*)"incomplete literal/length tree";
 4444       r = Z_DATA_ERROR;
 4445     }
 4446     return r;
 4447   }
 4448 
 4449   /* build distance tree */
 4450   r = huft_build(c + nl, nd, 0, cpdist, cpdext, td, bd, z);
 4451   if (r != Z_OK || (*bd == 0 && nl > 257))
 4452   {
 4453     if (r == Z_DATA_ERROR)
 4454       z->msg = (char*)"oversubscribed distance tree";
 4455     else if (r == Z_BUF_ERROR) {
 4456 #ifdef PKZIP_BUG_WORKAROUND
 4457       r = Z_OK;
 4458     }
 4459 #else
 4460       inflate_trees_free(*td, z);
 4461       z->msg = (char*)"incomplete distance tree";
 4462       r = Z_DATA_ERROR;
 4463     }
 4464     else if (r != Z_MEM_ERROR)
 4465     {
 4466       z->msg = (char*)"empty distance tree with lengths";
 4467       r = Z_DATA_ERROR;
 4468     }
 4469     inflate_trees_free(*tl, z);
 4470     return r;
 4471 #endif
 4472   }
 4473 
 4474   /* done */
 4475   return Z_OK;
 4476 }
 4477 
 4478 
 4479 /* build fixed tables only once--keep them here */
 4480 local int fixed_built = 0;
 4481 #define FIXEDH 530      /* number of hufts used by fixed tables */
 4482 local inflate_huft fixed_mem[FIXEDH];
 4483 local uInt fixed_bl;
 4484 local uInt fixed_bd;
 4485 local inflate_huft *fixed_tl;
 4486 local inflate_huft *fixed_td;
 4487 
 4488 
 4489 local voidpf falloc(q, n, s)
 4490 voidpf q;       /* opaque pointer */
 4491 uInt n;         /* number of items */
 4492 uInt s;         /* size of item */
 4493 {
 4494   Assert(s == sizeof(inflate_huft) && n <= *(intf *)q,
 4495          "inflate_trees falloc overflow");
 4496   *(intf *)q -= n+s-s; /* s-s to avoid warning */
 4497   return (voidpf)(fixed_mem + *(intf *)q);
 4498 }
 4499 
 4500 
 4501 int inflate_trees_fixed(bl, bd, tl, td)
 4502 uIntf *bl;               /* literal desired/actual bit depth */
 4503 uIntf *bd;               /* distance desired/actual bit depth */
 4504 inflate_huft * FAR *tl;  /* literal/length tree result */
 4505 inflate_huft * FAR *td;  /* distance tree result */
 4506 {
 4507   /* build fixed tables if not already (multiple overlapped executions ok) */
 4508   if (!fixed_built)
 4509   {
 4510     int k;              /* temporary variable */
 4511     unsigned c[288];    /* length list for huft_build */
 4512     z_stream z;         /* for falloc function */
 4513     int f = FIXEDH;     /* number of hufts left in fixed_mem */
 4514 
 4515     /* set up fake z_stream for memory routines */
 4516     z.zalloc = falloc;
 4517     z.zfree = Z_NULL;
 4518     z.opaque = (voidpf)&f;
 4519 
 4520     /* literal table */
 4521     for (k = 0; k < 144; k++)
 4522       c[k] = 8;
 4523     for (; k < 256; k++)
 4524       c[k] = 9;
 4525     for (; k < 280; k++)
 4526       c[k] = 7;
 4527     for (; k < 288; k++)
 4528       c[k] = 8;
 4529     fixed_bl = 7;
 4530     huft_build(c, 288, 257, cplens, cplext, &fixed_tl, &fixed_bl, &z);
 4531 
 4532     /* distance table */
 4533     for (k = 0; k < 30; k++)
 4534       c[k] = 5;
 4535     fixed_bd = 5;
 4536     huft_build(c, 30, 0, cpdist, cpdext, &fixed_td, &fixed_bd, &z);
 4537 
 4538     /* done */
 4539     Assert(f == 0, "invalid build of fixed tables");
 4540     fixed_built = 1;
 4541   }
 4542   *bl = fixed_bl;
 4543   *bd = fixed_bd;
 4544   *tl = fixed_tl;
 4545   *td = fixed_td;
 4546   return Z_OK;
 4547 }
 4548 
 4549 
 4550 int inflate_trees_free(t, z)
 4551 inflate_huft *t;        /* table to free */
 4552 z_streamp z;            /* for zfree function */
 4553 /* Free the malloc'ed tables built by huft_build(), which makes a linked
 4554    list of the tables it made, with the links in a dummy first entry of
 4555    each table. */
 4556 {
 4557   register inflate_huft *p, *q, *r;
 4558 
 4559   /* Reverse linked list */
 4560   p = Z_NULL;
 4561   q = t;
 4562   while (q != Z_NULL)
 4563   {
 4564     r = (q - 1)->next;
 4565     (q - 1)->next = p;
 4566     p = q;
 4567     q = r;
 4568   }
 4569   /* Go through linked list, freeing from the malloced (t[-1]) address. */
 4570   while (p != Z_NULL)
 4571   {
 4572     q = (--p)->next;
 4573     ZFREE(z,p);
 4574     p = q;
 4575   } 
 4576   return Z_OK;
 4577 }
 4578 /* --- inftrees.c */
 4579 
 4580 /* +++ infcodes.c */
 4581 /* infcodes.c -- process literals and length/distance pairs
 4582  * Copyright (C) 1995-1996 Mark Adler
 4583  * For conditions of distribution and use, see copyright notice in zlib.h 
 4584  */
 4585 
 4586 /* #include "zutil.h" */
 4587 /* #include "inftrees.h" */
 4588 /* #include "infblock.h" */
 4589 /* #include "infcodes.h" */
 4590 /* #include "infutil.h" */
 4591 
 4592 /* +++ inffast.h */
 4593 /* inffast.h -- header to use inffast.c
 4594  * Copyright (C) 1995-1996 Mark Adler
 4595  * For conditions of distribution and use, see copyright notice in zlib.h 
 4596  */
 4597 
 4598 /* WARNING: this file should *not* be used by applications. It is
 4599    part of the implementation of the compression library and is
 4600    subject to change. Applications should only use zlib.h.
 4601  */
 4602 
 4603 extern int inflate_fast OF((
 4604     uInt,
 4605     uInt,
 4606     inflate_huft *,
 4607     inflate_huft *,
 4608     inflate_blocks_statef *,
 4609     z_streamp ));
 4610 /* --- inffast.h */
 4611 
 4612 /* simplify the use of the inflate_huft type with some defines */
 4613 #define base more.Base
 4614 #define next more.Next
 4615 #define exop word.what.Exop
 4616 #define bits word.what.Bits
 4617 
 4618 /* inflate codes private state */
 4619 struct inflate_codes_state {
 4620 
 4621   /* mode */
 4622   enum {        /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
 4623       START,    /* x: set up for LEN */
 4624       LEN,      /* i: get length/literal/eob next */
 4625       LENEXT,   /* i: getting length extra (have base) */
 4626       DIST,     /* i: get distance next */
 4627       DISTEXT,  /* i: getting distance extra */
 4628       COPY,     /* o: copying bytes in window, waiting for space */
 4629       LIT,      /* o: got literal, waiting for output space */
 4630       WASH,     /* o: got eob, possibly still output waiting */
 4631       END,      /* x: got eob and all data flushed */
 4632       BADCODE}  /* x: got error */
 4633     mode;               /* current inflate_codes mode */
 4634 
 4635   /* mode dependent information */
 4636   uInt len;
 4637   union {
 4638     struct {
 4639       inflate_huft *tree;       /* pointer into tree */
 4640       uInt need;                /* bits needed */
 4641     } code;             /* if LEN or DIST, where in tree */
 4642     uInt lit;           /* if LIT, literal */
 4643     struct {
 4644       uInt get;                 /* bits to get for extra */
 4645       uInt dist;                /* distance back to copy from */
 4646     } copy;             /* if EXT or COPY, where and how much */
 4647   } sub;                /* submode */
 4648 
 4649   /* mode independent information */
 4650   Byte lbits;           /* ltree bits decoded per branch */
 4651   Byte dbits;           /* dtree bits decoder per branch */
 4652   inflate_huft *ltree;          /* literal/length/eob tree */
 4653   inflate_huft *dtree;          /* distance tree */
 4654 
 4655 };
 4656 
 4657 
 4658 inflate_codes_statef *inflate_codes_new(bl, bd, tl, td, z)
 4659 uInt bl, bd;
 4660 inflate_huft *tl;
 4661 inflate_huft *td; /* need separate declaration for Borland C++ */
 4662 z_streamp z;
 4663 {
 4664   inflate_codes_statef *c;
 4665 
 4666   if ((c = (inflate_codes_statef *)
 4667        ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL)
 4668   {
 4669     c->mode = START;
 4670     c->lbits = (Byte)bl;
 4671     c->dbits = (Byte)bd;
 4672     c->ltree = tl;
 4673     c->dtree = td;
 4674     Tracev((stderr, "inflate:       codes new\n"));
 4675   }
 4676   return c;
 4677 }
 4678 
 4679 
 4680 int inflate_codes(s, z, r)
 4681 inflate_blocks_statef *s;
 4682 z_streamp z;
 4683 int r;
 4684 {
 4685   uInt j;               /* temporary storage */
 4686   inflate_huft *t;      /* temporary pointer */
 4687   uInt e;               /* extra bits or operation */
 4688   uLong b;              /* bit buffer */
 4689   uInt k;               /* bits in bit buffer */
 4690   Bytef *p;             /* input data pointer */
 4691   uInt n;               /* bytes available there */
 4692   Bytef *q;             /* output window write pointer */
 4693   uInt m;               /* bytes to end of window or read pointer */
 4694   Bytef *f;             /* pointer to copy strings from */
 4695   inflate_codes_statef *c = s->sub.decode.codes;  /* codes state */
 4696 
 4697   /* copy input/output information to locals (UPDATE macro restores) */
 4698   LOAD
 4699 
 4700   /* process input and output based on current state */
 4701   while (1) switch (c->mode)
 4702   {             /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
 4703     case START:         /* x: set up for LEN */
 4704 #ifndef SLOW
 4705       if (m >= 258 && n >= 10)
 4706       {
 4707         UPDATE
 4708         r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
 4709         LOAD
 4710         if (r != Z_OK)
 4711         {
 4712           c->mode = r == Z_STREAM_END ? WASH : BADCODE;
 4713           break;
 4714         }
 4715       }
 4716 #endif /* !SLOW */
 4717       c->sub.code.need = c->lbits;
 4718       c->sub.code.tree = c->ltree;
 4719       c->mode = LEN;
 4720     case LEN:           /* i: get length/literal/eob next */
 4721       j = c->sub.code.need;
 4722       NEEDBITS(j)
 4723       t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
 4724       DUMPBITS(t->bits)
 4725       e = (uInt)(t->exop);
 4726       if (e == 0)               /* literal */
 4727       {
 4728         c->sub.lit = t->base;
 4729         Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
 4730                  "inflate:         literal '%c'\n" :
 4731                  "inflate:         literal 0x%02x\n", t->base));
 4732         c->mode = LIT;
 4733         break;
 4734       }
 4735       if (e & 16)               /* length */
 4736       {
 4737         c->sub.copy.get = e & 15;
 4738         c->len = t->base;
 4739         c->mode = LENEXT;
 4740         break;
 4741       }
 4742       if ((e & 64) == 0)        /* next table */
 4743       {
 4744         c->sub.code.need = e;
 4745         c->sub.code.tree = t->next;
 4746         break;
 4747       }
 4748       if (e & 32)               /* end of block */
 4749       {
 4750         Tracevv((stderr, "inflate:         end of block\n"));
 4751         c->mode = WASH;
 4752         break;
 4753       }
 4754       c->mode = BADCODE;        /* invalid code */
 4755       z->msg = (char*)"invalid literal/length code";
 4756       r = Z_DATA_ERROR;
 4757       LEAVE
 4758     case LENEXT:        /* i: getting length extra (have base) */
 4759       j = c->sub.copy.get;
 4760       NEEDBITS(j)
 4761       c->len += (uInt)b & inflate_mask[j];
 4762       DUMPBITS(j)
 4763       c->sub.code.need = c->dbits;
 4764       c->sub.code.tree = c->dtree;
 4765       Tracevv((stderr, "inflate:         length %u\n", c->len));
 4766       c->mode = DIST;
 4767     case DIST:          /* i: get distance next */
 4768       j = c->sub.code.need;
 4769       NEEDBITS(j)
 4770       t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
 4771       DUMPBITS(t->bits)
 4772       e = (uInt)(t->exop);
 4773       if (e & 16)               /* distance */
 4774       {
 4775         c->sub.copy.get = e & 15;
 4776         c->sub.copy.dist = t->base;
 4777         c->mode = DISTEXT;
 4778         break;
 4779       }
 4780       if ((e & 64) == 0)        /* next table */
 4781       {
 4782         c->sub.code.need = e;
 4783         c->sub.code.tree = t->next;
 4784         break;
 4785       }
 4786       c->mode = BADCODE;        /* invalid code */
 4787       z->msg = (char*)"invalid distance code";
 4788       r = Z_DATA_ERROR;
 4789       LEAVE
 4790     case DISTEXT:       /* i: getting distance extra */
 4791       j = c->sub.copy.get;
 4792       NEEDBITS(j)
 4793       c->sub.copy.dist += (uInt)b & inflate_mask[j];
 4794       DUMPBITS(j)
 4795       Tracevv((stderr, "inflate:         distance %u\n", c->sub.copy.dist));
 4796       c->mode = COPY;
 4797     case COPY:          /* o: copying bytes in window, waiting for space */
 4798 #ifndef __TURBOC__ /* Turbo C bug for following expression */
 4799       f = (uInt)(q - s->window) < c->sub.copy.dist ?
 4800           s->end - (c->sub.copy.dist - (q - s->window)) :
 4801           q - c->sub.copy.dist;
 4802 #else
 4803       f = q - c->sub.copy.dist;
 4804       if ((uInt)(q - s->window) < c->sub.copy.dist)
 4805         f = s->end - (c->sub.copy.dist - (uInt)(q - s->window));
 4806 #endif
 4807       while (c->len)
 4808       {
 4809         NEEDOUT
 4810         OUTBYTE(*f++)
 4811         if (f == s->end)
 4812           f = s->window;
 4813         c->len--;
 4814       }
 4815       c->mode = START;
 4816       break;
 4817     case LIT:           /* o: got literal, waiting for output space */
 4818       NEEDOUT
 4819       OUTBYTE(c->sub.lit)
 4820       c->mode = START;
 4821       break;
 4822     case WASH:          /* o: got eob, possibly more output */
 4823       FLUSH
 4824       if (s->read != s->write)
 4825         LEAVE
 4826       c->mode = END;
 4827     case END:
 4828       r = Z_STREAM_END;
 4829       LEAVE
 4830     case BADCODE:       /* x: got error */
 4831       r = Z_DATA_ERROR;
 4832       LEAVE
 4833     default:
 4834       r = Z_STREAM_ERROR;
 4835       LEAVE
 4836   }
 4837 }
 4838 
 4839 
 4840 void inflate_codes_free(c, z)
 4841 inflate_codes_statef *c;
 4842 z_streamp z;
 4843 {
 4844   ZFREE(z, c);
 4845   Tracev((stderr, "inflate:       codes free\n"));
 4846 }
 4847 /* --- infcodes.c */
 4848 
 4849 /* +++ infutil.c */
 4850 /* inflate_util.c -- data and routines common to blocks and codes
 4851  * Copyright (C) 1995-1996 Mark Adler
 4852  * For conditions of distribution and use, see copyright notice in zlib.h 
 4853  */
 4854 
 4855 /* #include "zutil.h" */
 4856 /* #include "infblock.h" */
 4857 /* #include "inftrees.h" */
 4858 /* #include "infcodes.h" */
 4859 /* #include "infutil.h" */
 4860 
 4861 #ifndef NO_DUMMY_DECL
 4862 struct inflate_codes_state {int dummy;}; /* for buggy compilers */
 4863 #endif
 4864 
 4865 /* And'ing with mask[n] masks the lower n bits */
 4866 uInt inflate_mask[17] = {
 4867     0x0000,
 4868     0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
 4869     0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
 4870 };
 4871 
 4872 
 4873 /* copy as much as possible from the sliding window to the output area */
 4874 int inflate_flush(s, z, r)
 4875 inflate_blocks_statef *s;
 4876 z_streamp z;
 4877 int r;
 4878 {
 4879   uInt n;
 4880   Bytef *p;
 4881   Bytef *q;
 4882 
 4883   /* local copies of source and destination pointers */
 4884   p = z->next_out;
 4885   q = s->read;
 4886 
 4887   /* compute number of bytes to copy as far as end of window */
 4888   n = (uInt)((q <= s->write ? s->write : s->end) - q);
 4889   if (n > z->avail_out) n = z->avail_out;
 4890   if (n && r == Z_BUF_ERROR) r = Z_OK;
 4891 
 4892   /* update counters */
 4893   z->avail_out -= n;
 4894   z->total_out += n;
 4895 
 4896   /* update check information */
 4897   if (s->checkfn != Z_NULL)
 4898     z->adler = s->check = (*s->checkfn)(s->check, q, n);
 4899 
 4900   /* copy as far as end of window */
 4901   if (p != Z_NULL) {
 4902     zmemcpy(p, q, n);
 4903     p += n;
 4904   }
 4905   q += n;
 4906 
 4907   /* see if more to copy at beginning of window */
 4908   if (q == s->end)
 4909   {
 4910     /* wrap pointers */
 4911     q = s->window;
 4912     if (s->write == s->end)
 4913       s->write = s->window;
 4914 
 4915     /* compute bytes to copy */
 4916     n = (uInt)(s->write - q);
 4917     if (n > z->avail_out) n = z->avail_out;
 4918     if (n && r == Z_BUF_ERROR) r = Z_OK;
 4919 
 4920     /* update counters */
 4921     z->avail_out -= n;
 4922     z->total_out += n;
 4923 
 4924     /* update check information */
 4925     if (s->checkfn != Z_NULL)
 4926       z->adler = s->check = (*s->checkfn)(s->check, q, n);
 4927 
 4928     /* copy */
 4929     if (p != Z_NULL) {
 4930       zmemcpy(p, q, n);
 4931       p += n;
 4932     }
 4933     q += n;
 4934   }
 4935 
 4936   /* update pointers */
 4937   z->next_out = p;
 4938   s->read = q;
 4939 
 4940   /* done */
 4941   return r;
 4942 }
 4943 /* --- infutil.c */
 4944 
 4945 /* +++ inffast.c */
 4946 /* inffast.c -- process literals and length/distance pairs fast
 4947  * Copyright (C) 1995-1996 Mark Adler
 4948  * For conditions of distribution and use, see copyright notice in zlib.h 
 4949  */
 4950 
 4951 /* #include "zutil.h" */
 4952 /* #include "inftrees.h" */
 4953 /* #include "infblock.h" */
 4954 /* #include "infcodes.h" */
 4955 /* #include "infutil.h" */
 4956 /* #include "inffast.h" */
 4957 
 4958 #ifndef NO_DUMMY_DECL
 4959 struct inflate_codes_state {int dummy;}; /* for buggy compilers */
 4960 #endif
 4961 
 4962 /* simplify the use of the inflate_huft type with some defines */
 4963 #define base more.Base
 4964 #define next more.Next
 4965 #define exop word.what.Exop
 4966 #define bits word.what.Bits
 4967 
 4968 /* macros for bit input with no checking and for returning unused bytes */
 4969 #define GRABBITS(j) {while(k<(j)){b|=((uLong)NEXTBYTE)<<k;k+=8;}}
 4970 #define UNGRAB {n+=(c=k>>3);p-=c;k&=7;}
 4971 
 4972 /* Called with number of bytes left to write in window at least 258
 4973    (the maximum string length) and number of input bytes available
 4974    at least ten.  The ten bytes are six bytes for the longest length/
 4975    distance pair plus four bytes for overloading the bit buffer. */
 4976 
 4977 int inflate_fast(bl, bd, tl, td, s, z)
 4978 uInt bl, bd;
 4979 inflate_huft *tl;
 4980 inflate_huft *td; /* need separate declaration for Borland C++ */
 4981 inflate_blocks_statef *s;
 4982 z_streamp z;
 4983 {
 4984   inflate_huft *t;      /* temporary pointer */
 4985   uInt e;               /* extra bits or operation */
 4986   uLong b;              /* bit buffer */
 4987   uInt k;               /* bits in bit buffer */
 4988   Bytef *p;             /* input data pointer */
 4989   uInt n;               /* bytes available there */
 4990   Bytef *q;             /* output window write pointer */
 4991   uInt m;               /* bytes to end of window or read pointer */
 4992   uInt ml;              /* mask for literal/length tree */
 4993   uInt md;              /* mask for distance tree */
 4994   uInt c;               /* bytes to copy */
 4995   uInt d;               /* distance back to copy from */
 4996   Bytef *r;             /* copy source pointer */
 4997 
 4998   /* load input, output, bit values */
 4999   LOAD
 5000 
 5001   /* initialize masks */
 5002   ml = inflate_mask[bl];
 5003   md = inflate_mask[bd];
 5004 
 5005   /* do until not enough input or output space for fast loop */
 5006   do {                          /* assume called with m >= 258 && n >= 10 */
 5007     /* get literal/length code */
 5008     GRABBITS(20)                /* max bits for literal/length code */
 5009     if ((e = (t = tl + ((uInt)b & ml))->exop) == 0)
 5010     {
 5011       DUMPBITS(t->bits)
 5012       Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
 5013                 "inflate:         * literal '%c'\n" :
 5014                 "inflate:         * literal 0x%02x\n", t->base));
 5015       *q++ = (Byte)t->base;
 5016       m--;
 5017       continue;
 5018     }
 5019     do {
 5020       DUMPBITS(t->bits)
 5021       if (e & 16)
 5022       {
 5023         /* get extra bits for length */
 5024         e &= 15;
 5025         c = t->base + ((uInt)b & inflate_mask[e]);
 5026         DUMPBITS(e)
 5027         Tracevv((stderr, "inflate:         * length %u\n", c));
 5028 
 5029         /* decode distance base of block to copy */
 5030         GRABBITS(15);           /* max bits for distance code */
 5031         e = (t = td + ((uInt)b & md))->exop;
 5032         do {
 5033           DUMPBITS(t->bits)
 5034           if (e & 16)
 5035           {
 5036             /* get extra bits to add to distance base */
 5037             e &= 15;
 5038             GRABBITS(e)         /* get extra bits (up to 13) */
 5039             d = t->base + ((uInt)b & inflate_mask[e]);
 5040             DUMPBITS(e)
 5041             Tracevv((stderr, "inflate:         * distance %u\n", d));
 5042 
 5043             /* do the copy */
 5044             m -= c;
 5045             if ((uInt)(q - s->window) >= d)     /* offset before dest */
 5046             {                                   /*  just copy */
 5047               r = q - d;
 5048               *q++ = *r++;  c--;        /* minimum count is three, */
 5049               *q++ = *r++;  c--;        /*  so unroll loop a little */
 5050             }
 5051             else                        /* else offset after destination */
 5052             {
 5053               e = d - (uInt)(q - s->window); /* bytes from offset to end */
 5054               r = s->end - e;           /* pointer to offset */
 5055               if (c > e)                /* if source crosses, */
 5056               {
 5057                 c -= e;                 /* copy to end of window */
 5058                 do {
 5059                   *q++ = *r++;
 5060                 } while (--e);
 5061                 r = s->window;          /* copy rest from start of window */
 5062               }
 5063             }
 5064             do {                        /* copy all or what's left */
 5065               *q++ = *r++;
 5066             } while (--c);
 5067             break;
 5068           }
 5069           else if ((e & 64) == 0)
 5070             e = (t = t->next + ((uInt)b & inflate_mask[e]))->exop;
 5071           else
 5072           {
 5073             z->msg = (char*)"invalid distance code";
 5074             UNGRAB
 5075             UPDATE
 5076             return Z_DATA_ERROR;
 5077           }
 5078         } while (1);
 5079         break;
 5080       }
 5081       if ((e & 64) == 0)
 5082       {
 5083         if ((e = (t = t->next + ((uInt)b & inflate_mask[e]))->exop) == 0)
 5084         {
 5085           DUMPBITS(t->bits)
 5086           Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
 5087                     "inflate:         * literal '%c'\n" :
 5088                     "inflate:         * literal 0x%02x\n", t->base));
 5089           *q++ = (Byte)t->base;
 5090           m--;
 5091           break;
 5092         }
 5093       }
 5094       else if (e & 32)
 5095       {
 5096         Tracevv((stderr, "inflate:         * end of block\n"));
 5097         UNGRAB
 5098         UPDATE
 5099         return Z_STREAM_END;
 5100       }
 5101       else
 5102       {
 5103         z->msg = (char*)"invalid literal/length code";
 5104         UNGRAB
 5105         UPDATE
 5106         return Z_DATA_ERROR;
 5107       }
 5108     } while (1);
 5109   } while (m >= 258 && n >= 10);
 5110 
 5111   /* not enough input or output--restore pointers and return */
 5112   UNGRAB
 5113   UPDATE
 5114   return Z_OK;
 5115 }
 5116 /* --- inffast.c */
 5117 
 5118 /* +++ zutil.c */
 5119 /* zutil.c -- target dependent utility functions for the compression library
 5120  * Copyright (C) 1995-1996 Jean-loup Gailly.
 5121  * For conditions of distribution and use, see copyright notice in zlib.h 
 5122  */
 5123 
 5124 /* From: zutil.c,v 1.17 1996/07/24 13:41:12 me Exp $ */
 5125 
 5126 #ifdef DEBUG_ZLIB
 5127 #include <stdio.h>
 5128 #endif
 5129 
 5130 /* #include "zutil.h" */
 5131 
 5132 #ifndef NO_DUMMY_DECL
 5133 struct internal_state      {int dummy;}; /* for buggy compilers */
 5134 #endif
 5135 
 5136 #ifndef STDC
 5137 extern void exit OF((int));
 5138 #endif
 5139 
 5140 static const char *z_errmsg[10] = {
 5141 "need dictionary",     /* Z_NEED_DICT       2  */
 5142 "stream end",          /* Z_STREAM_END      1  */
 5143 "",                    /* Z_OK              0  */
 5144 "file error",          /* Z_ERRNO         (-1) */
 5145 "stream error",        /* Z_STREAM_ERROR  (-2) */
 5146 "data error",          /* Z_DATA_ERROR    (-3) */
 5147 "insufficient memory", /* Z_MEM_ERROR     (-4) */
 5148 "buffer error",        /* Z_BUF_ERROR     (-5) */
 5149 "incompatible version",/* Z_VERSION_ERROR (-6) */
 5150 ""};
 5151 
 5152 
 5153 const char *zlibVersion()
 5154 {
 5155     return ZLIB_VERSION;
 5156 }
 5157 
 5158 #ifdef DEBUG_ZLIB
 5159 void z_error (m)
 5160     char *m;
 5161 {
 5162     fprintf(stderr, "%s\n", m);
 5163     exit(1);
 5164 }
 5165 #endif
 5166 
 5167 #ifndef HAVE_MEMCPY
 5168 
 5169 void zmemcpy(dest, source, len)
 5170     Bytef* dest;
 5171     Bytef* source;
 5172     uInt  len;
 5173 {
 5174     if (len == 0) return;
 5175     do {
 5176         *dest++ = *source++; /* ??? to be unrolled */
 5177     } while (--len != 0);
 5178 }
 5179 
 5180 int zmemcmp(s1, s2, len)
 5181     Bytef* s1;
 5182     Bytef* s2;
 5183     uInt  len;
 5184 {
 5185     uInt j;
 5186 
 5187     for (j = 0; j < len; j++) {
 5188         if (s1[j] != s2[j]) return 2*(s1[j] > s2[j])-1;
 5189     }
 5190     return 0;
 5191 }
 5192 
 5193 void zmemzero(dest, len)
 5194     Bytef* dest;
 5195     uInt  len;
 5196 {
 5197     if (len == 0) return;
 5198     do {
 5199         *dest++ = 0;  /* ??? to be unrolled */
 5200     } while (--len != 0);
 5201 }
 5202 #endif
 5203 
 5204 #ifdef __TURBOC__
 5205 #if (defined( __BORLANDC__) || !defined(SMALL_MEDIUM)) && !defined(__32BIT__)
 5206 /* Small and medium model in Turbo C are for now limited to near allocation
 5207  * with reduced MAX_WBITS and MAX_MEM_LEVEL
 5208  */
 5209 #  define MY_ZCALLOC
 5210 
 5211 /* Turbo C malloc() does not allow dynamic allocation of 64K bytes
 5212  * and farmalloc(64K) returns a pointer with an offset of 8, so we
 5213  * must fix the pointer. Warning: the pointer must be put back to its
 5214  * original form in order to free it, use zcfree().
 5215  */
 5216 
 5217 #define MAX_PTR 10
 5218 /* 10*64K = 640K */
 5219 
 5220 local int next_ptr = 0;
 5221 
 5222 typedef struct ptr_table_s {
 5223     voidpf org_ptr;
 5224     voidpf new_ptr;
 5225 } ptr_table;
 5226 
 5227 local ptr_table table[MAX_PTR];
 5228 /* This table is used to remember the original form of pointers
 5229  * to large buffers (64K). Such pointers are normalized with a zero offset.
 5230  * Since MSDOS is not a preemptive multitasking OS, this table is not
 5231  * protected from concurrent access. This hack doesn't work anyway on
 5232  * a protected system like OS/2. Use Microsoft C instead.
 5233  */
 5234 
 5235 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
 5236 {
 5237     voidpf buf = opaque; /* just to make some compilers happy */
 5238     ulg bsize = (ulg)items*size;
 5239 
 5240     /* If we allocate less than 65520 bytes, we assume that farmalloc
 5241      * will return a usable pointer which doesn't have to be normalized.
 5242      */
 5243     if (bsize < 65520L) {
 5244         buf = farmalloc(bsize);
 5245         if (*(ush*)&buf != 0) return buf;
 5246     } else {
 5247         buf = farmalloc(bsize + 16L);
 5248     }
 5249     if (buf == NULL || next_ptr >= MAX_PTR) return NULL;
 5250     table[next_ptr].org_ptr = buf;
 5251 
 5252     /* Normalize the pointer to seg:0 */
 5253     *((ush*)&buf+1) += ((ush)((uch*)buf-0) + 15) >> 4;
 5254     *(ush*)&buf = 0;
 5255     table[next_ptr++].new_ptr = buf;
 5256     return buf;
 5257 }
 5258 
 5259 void  zcfree (voidpf opaque, voidpf ptr)
 5260 {
 5261     int n;
 5262     if (*(ush*)&ptr != 0) { /* object < 64K */
 5263         farfree(ptr);
 5264         return;
 5265     }
 5266     /* Find the original pointer */
 5267     for (n = 0; n < next_ptr; n++) {
 5268         if (ptr != table[n].new_ptr) continue;
 5269 
 5270         farfree(table[n].org_ptr);
 5271         while (++n < next_ptr) {
 5272             table[n-1] = table[n];
 5273         }
 5274         next_ptr--;
 5275         return;
 5276     }
 5277     ptr = opaque; /* just to make some compilers happy */
 5278     Assert(0, "zcfree: ptr not found");
 5279 }
 5280 #endif
 5281 #endif /* __TURBOC__ */
 5282 
 5283 
 5284 #if defined(M_I86) && !defined(__32BIT__)
 5285 /* Microsoft C in 16-bit mode */
 5286 
 5287 #  define MY_ZCALLOC
 5288 
 5289 #if (!defined(_MSC_VER) || (_MSC_VER < 600))
 5290 #  define _halloc  halloc
 5291 #  define _hfree   hfree
 5292 #endif
 5293 
 5294 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
 5295 {
 5296     if (opaque) opaque = 0; /* to make compiler happy */
 5297     return _halloc((long)items, size);
 5298 }
 5299 
 5300 void  zcfree (voidpf opaque, voidpf ptr)
 5301 {
 5302     if (opaque) opaque = 0; /* to make compiler happy */
 5303     _hfree(ptr);
 5304 }
 5305 
 5306 #endif /* MSC */
 5307 
 5308 
 5309 #ifndef MY_ZCALLOC /* Any system without a special alloc function */
 5310 
 5311 #ifndef STDC
 5312 extern voidp  calloc OF((uInt items, uInt size));
 5313 extern void   free   OF((voidpf ptr));
 5314 #endif
 5315 
 5316 voidpf zcalloc (opaque, items, size)
 5317     voidpf opaque;
 5318     unsigned items;
 5319     unsigned size;
 5320 {
 5321     if (opaque) items += size - size; /* make compiler happy */
 5322     return (voidpf)calloc(items, size);
 5323 }
 5324 
 5325 void  zcfree (opaque, ptr)
 5326     voidpf opaque;
 5327     voidpf ptr;
 5328 {
 5329     free(ptr);
 5330     if (opaque) return; /* make compiler happy */
 5331 }
 5332 
 5333 #endif /* MY_ZCALLOC */
 5334 /* --- zutil.c */
 5335 
 5336 /* +++ adler32.c */
 5337 /* adler32.c -- compute the Adler-32 checksum of a data stream
 5338  * Copyright (C) 1995-1996 Mark Adler
 5339  * For conditions of distribution and use, see copyright notice in zlib.h 
 5340  */
 5341 
 5342 /* From: adler32.c,v 1.10 1996/05/22 11:52:18 me Exp $ */
 5343 
 5344 /* #include "zlib.h" */
 5345 
 5346 #define BASE 65521L /* largest prime smaller than 65536 */
 5347 #define NMAX 5552
 5348 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
 5349 
 5350 #define DO1(buf,i)  {s1 += buf[(i)]; s2 += s1;}
 5351 #define DO2(buf,i)  DO1(buf,i); DO1(buf,(i)+1);
 5352 #define DO4(buf,i)  DO2(buf,i); DO2(buf,(i)+2);
 5353 #define DO8(buf,i)  DO4(buf,i); DO4(buf,(i)+4);
 5354 #define DO16(buf)   DO8(buf,0); DO8(buf,8);
 5355 
 5356 /* ========================================================================= */
 5357 uLong adler32(adler, buf, len)
 5358     uLong adler;
 5359     const Bytef *buf;
 5360     uInt len;
 5361 {
 5362     unsigned long s1 = adler & 0xffff;
 5363     unsigned long s2 = (adler >> 16) & 0xffff;
 5364     int k;
 5365 
 5366     if (buf == Z_NULL) return 1L;
 5367 
 5368     while (len > 0) {
 5369         k = len < NMAX ? len : NMAX;
 5370         len -= k;
 5371         while (k >= 16) {
 5372             DO16(buf);
 5373             buf += 16;
 5374             k -= 16;
 5375         }
 5376         if (k != 0) do {
 5377             s1 += *buf++;
 5378             s2 += s1;
 5379         } while (--k);
 5380         s1 %= BASE;
 5381         s2 %= BASE;
 5382     }
 5383     return (s2 << 16) | s1;
 5384 }
 5385 /* --- adler32.c */
 5386 
 5387 #ifdef _KERNEL
 5388 static int
 5389 zlib_modevent(module_t mod, int type, void *unused)
 5390 {
 5391         switch (type) {
 5392         case MOD_LOAD:
 5393                 return 0;
 5394         case MOD_UNLOAD:
 5395                 return 0;
 5396         }
 5397         return EINVAL;
 5398 }
 5399 
 5400 static moduledata_t zlib_mod = {
 5401         "zlib",
 5402         zlib_modevent,
 5403         0
 5404 };
 5405 DECLARE_MODULE(zlib, zlib_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
 5406 MODULE_VERSION(zlib, 1);
 5407 #endif /* _KERNEL */

Cache object: 176e02fa8a2cafc1b153f51b7fbab008


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.