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

     /*
      * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
      *
      * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
      * 
      * This file contains Original Code and/or Modifications of Original Code
      * as defined in and that are subject to the Apple Public Source License
      * Version 2.0 (the 'License'). You may not use this file except in
      * compliance with the License. The rights granted to you under the License
     * may not be used to create, or enable the creation or redistribution of,
     * unlawful or unlicensed copies of an Apple operating system, or to
     * circumvent, violate, or enable the circumvention or violation of, any
     * terms of an Apple operating system software license agreement.
     * 
     * Please obtain a copy of the License at
     * http://www.opensource.apple.com/apsl/ and read it before using this file.
     * 
     * The Original Code and all software distributed under the License are
     * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
     * Please see the License for the specific language governing rights and
     * limitations under the License.
     * 
     * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
     */
    /*
     * This file is derived from various .h and .c files from the zlib-1.0.4
     * distribution by Jean-loup Gailly and Mark Adler, with some additions
     * by Paul Mackerras to aid in implementing Deflate compression and
     * decompression for PPP packets.  See zlib.h for conditions of
     * distribution and use.
     *
     * Changes that have been made include:
     * - added Z_PACKET_FLUSH (see zlib.h for details)
     * - added inflateIncomp and deflateOutputPending
     * - allow strm->next_out to be NULL, meaning discard the output
     *
     * $FreeBSD: src/sys/net/zlib.c,v 1.10 1999/12/29 04:38:38 peter Exp $
     */
    
    #define STDC
    #define NO_DUMMY_DECL
    #define NO_ZCFUNCS
    #define MY_ZCALLOC
    
    /* +++ zutil.h */
    /* zutil.h -- internal interface and configuration of the compression library
     * Copyright (C) 1995-2002 Jean-loup Gailly.
     * For conditions of distribution and use, see copyright notice in zlib.h
     */
    
    /* WARNING: this file should *not* be used by applications. It is
       part of the implementation of the compression library and is
       subject to change. Applications should only use zlib.h.
     */
    
    #ifndef _Z_UTIL_H
    #define _Z_UTIL_H
    
    #ifdef KERNEL
    #include <libkern/zlib.h>
    #else
    #include "zlib.h"
    #endif
    
    #ifdef KERNEL
    /* Assume this is a *BSD or SVR4 kernel */
    #include <sys/types.h>
    #include <sys/time.h>
    #include <sys/systm.h>
    #  define HAVE_MEMCPY
    #  define memcpy(d, s, n)       bcopy((s), (d), (n))
    #  define memset(d, v, n)       bzero((d), (n))
    #  define memcmp                bcmp
    
    #else
    #if defined(__KERNEL__)
    /* Assume this is a Linux kernel */
    #include <linux/string.h>
    #define HAVE_MEMCPY
    
    #else /* not kernel */
    #ifdef STDC
    #  include <stddef.h>
    #  include <string.h>
    #  include <stdlib.h>
    #endif
    #ifdef NO_ERRNO_H
        extern int errno;
    #else
    #   include <errno.h>
    #endif
    #endif /* __KERNEL__ */
    #endif /* KERNEL */
    
    typedef unsigned char  uch;
    typedef uch FAR uchf;
   typedef unsigned short ush;
   typedef ush FAR ushf;
   typedef unsigned long  ulg;
   
   /* (size given to avoid silly warnings with Visual C++) */
   static const char *z_errmsg[10] = {  /* indexed by 2-zlib_error */
   "need dictionary",     /* Z_NEED_DICT       2  */
   "stream end",          /* Z_STREAM_END      1  */
   "",                    /* Z_OK              0  */
   "file error",          /* Z_ERRNO         (-1) */
   "stream error",        /* Z_STREAM_ERROR  (-2) */
   "data error",          /* Z_DATA_ERROR    (-3) */
   "insufficient memory", /* Z_MEM_ERROR     (-4) */
   "buffer error",        /* Z_BUF_ERROR     (-5) */
   "incompatible version",/* Z_VERSION_ERROR (-6) */
   ""};
   
   #define ERR_MSG(err) z_errmsg[Z_NEED_DICT-(err)]
   
   #define ERR_RETURN(strm,err) \
     return (strm->msg = (char*)ERR_MSG(err), (err))
   /* To be used only when the state is known to be valid */
   
           /* common constants */
   
   #ifndef DEF_WBITS
   #  define DEF_WBITS MAX_WBITS
   #endif
   /* default windowBits for decompression. MAX_WBITS is for compression only */
   
   #if MAX_MEM_LEVEL >= 8
   #  define DEF_MEM_LEVEL 8
   #else
   #  define DEF_MEM_LEVEL  MAX_MEM_LEVEL
   #endif
   /* default memLevel */
   
   #define STORED_BLOCK 0
   #define STATIC_TREES 1
   #define DYN_TREES    2
   /* The three kinds of block type */
   
   #define MIN_MATCH  3
   #define MAX_MATCH  258
   /* The minimum and maximum match lengths */
   
   #define PRESET_DICT 0x20 /* preset dictionary flag in zlib header */
   
           /* target dependencies */
   
   #ifdef MSDOS
   #  define OS_CODE  0x00
   #  if defined(__TURBOC__) || defined(__BORLANDC__)
   #    if(__STDC__ == 1) && (defined(__LARGE__) || defined(__COMPACT__))
          /* Allow compilation with ANSI keywords only enabled */
          void _Cdecl farfree( void *block );
          void *_Cdecl farmalloc( unsigned long nbytes );
   #    else
   #     include <alloc.h>
   #    endif
   #  else /* MSC or DJGPP */
   #    include <malloc.h>
   #  endif
   #endif
   
   #ifdef OS2
   #  define OS_CODE  0x06
   #endif
   
   #ifdef WIN32 /* Window 95 & Windows NT */
   #  define OS_CODE  0x0b
   #endif
   
   #if defined(VAXC) || defined(VMS)
   #  define OS_CODE  0x02
   #  define F_OPEN(name, mode) \
        fopen((name), (mode), "mbc=60", "ctx=stm", "rfm=fix", "mrs=512")
   #endif
   
   #ifdef AMIGA
   #  define OS_CODE  0x01
   #endif
   
   #if defined(ATARI) || defined(atarist)
   #  define OS_CODE  0x05
   #endif
   
   #if defined(MACOS) || defined(TARGET_OS_MAC)
   #  define OS_CODE  0x07
   #  if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
   #    include <unix.h> /* for fdopen */
   #  else
   #    ifndef fdopen
   #      define fdopen(fd,mode) NULL /* No fdopen() */
   #    endif
   #  endif
   #endif
   
   #ifdef __50SERIES /* Prime/PRIMOS */
   #  define OS_CODE  0x0F
   #endif
   
   #ifdef TOPS20
   #  define OS_CODE  0x0a
   #endif
   
   #if defined(_BEOS_) || defined(RISCOS)
   #  define fdopen(fd,mode) NULL /* No fdopen() */
   #endif
   
   #if (defined(_MSC_VER) && (_MSC_VER > 600))
   #  define fdopen(fd,type)  _fdopen(fd,type)
   #endif
   
   
           /* Common defaults */
   
   #ifndef OS_CODE
   #  define OS_CODE  0x03  /* assume Unix */
   #endif
   
   #ifndef F_OPEN
   #  define F_OPEN(name, mode) fopen((name), (mode))
   #endif
   
            /* functions */
   
   #ifdef HAVE_STRERROR
      extern char *strerror OF((int));
   #  define zstrerror(errnum) strerror(errnum)
   #else
   #  define zstrerror(errnum) ""
   #endif
   
   #if defined(pyr)
   #  define NO_MEMCPY
   #endif
   #if defined(SMALL_MEDIUM) && !defined(_MSC_VER) && !defined(__SC__)
    /* Use our own functions for small and medium model with MSC <= 5.0.
     * You may have to use the same strategy for Borland C (untested).
     * The __SC__ check is for Symantec.
     */
   #  define NO_MEMCPY
   #endif
   #if defined(STDC) && !defined(HAVE_MEMCPY) && !defined(NO_MEMCPY)
   #  define HAVE_MEMCPY
   #endif
   #ifdef HAVE_MEMCPY
   #  ifdef SMALL_MEDIUM /* MSDOS small or medium model */
   #    define zmemcpy _fmemcpy
   #    define zmemcmp _fmemcmp
   #    define zmemzero(dest, len) _fmemset(dest, 0, len)
   #  else
   #    define zmemcpy memcpy
   #    define zmemcmp memcmp
   #    define zmemzero(dest, len) memset(dest, 0, len)
   #  endif
   #else
      extern void zmemcpy  OF((Bytef* dest, const Bytef* source, uInt len));
      extern int  zmemcmp  OF((const Bytef* s1, const Bytef* s2, uInt len));
      extern void zmemzero OF((Bytef* dest, uInt len));
   #endif
   
   /* Diagnostic functions */
   #ifdef DEBUG_ZLIB
   #  include <stdio.h>
      extern int z_verbose;
      extern void z_error    OF((char *m));
   #  define Assert(cond,msg) {if(!(cond)) z_error(msg);}
   #  define Trace(x) {if (z_verbose>=0) fprintf x ;}
   #  define Tracev(x) {if (z_verbose>0) fprintf x ;}
   #  define Tracevv(x) {if (z_verbose>1) fprintf x ;}
   #  define Tracec(c,x) {if (z_verbose>0 && (c)) fprintf x ;}
   #  define Tracecv(c,x) {if (z_verbose>1 && (c)) fprintf x ;}
   #else
   #  define Assert(cond,msg) do {} while(0)
   #  define Trace(x) do {} while(0)
   #  define Tracev(x) do {} while(0)
   #  define Tracevv(x) do {} while(0)
   #  define Tracec(c,x) do {} while(0)
   #  define Tracecv(c,x) do {} while(0)
   #endif
   
   
   typedef uLong (ZEXPORT *check_func) OF((uLong check, const Bytef *buf,
                                          uInt len));
   voidpf zcalloc OF((voidpf opaque, unsigned items, unsigned size));
   void   zcfree  OF((voidpf opaque, voidpf ptr));
   
   #define ZALLOC(strm, items, size) \
              (*((strm)->zalloc))((strm)->opaque, (items), (size))
   #define ZFREE(strm, addr)  (*((strm)->zfree))((strm)->opaque, (voidpf)(addr))
   #define TRY_FREE(s, p) {if (p) ZFREE(s, p);}
   
   #endif /* _Z_UTIL_H */
   /* --- zutil.h */
   
   /* +++ deflate.h */
   /* deflate.h -- internal compression state
    * Copyright (C) 1995-2002 Jean-loup Gailly
    * For conditions of distribution and use, see copyright notice in zlib.h 
    */
   
   /* WARNING: this file should *not* be used by applications. It is
      part of the implementation of the compression library and is
      subject to change. Applications should only use zlib.h.
    */
   
   #ifndef _DEFLATE_H
   #define _DEFLATE_H
   
   /* #include "zutil.h" */
   
   /* ===========================================================================
    * Internal compression state.
    */
   
   #define LENGTH_CODES 29
   /* number of length codes, not counting the special END_BLOCK code */
   
   #define LITERALS  256
   /* number of literal bytes 0..255 */
   
   #define L_CODES (LITERALS+1+LENGTH_CODES)
   /* number of Literal or Length codes, including the END_BLOCK code */
   
   #define D_CODES   30
   /* number of distance codes */
   
   #define BL_CODES  19
   /* number of codes used to transfer the bit lengths */
   
   #define HEAP_SIZE (2*L_CODES+1)
   /* maximum heap size */
   
   #define MAX_BITS 15
   /* All codes must not exceed MAX_BITS bits */
   
   #define INIT_STATE    42
   #define BUSY_STATE   113
   #define FINISH_STATE 666
   /* Stream status */
   
   
   /* Data structure describing a single value and its code string. */
   typedef struct ct_data_s {
       union {
           ush  freq;       /* frequency count */
           ush  code;       /* bit string */
       } fc;
       union {
           ush  dad;        /* father node in Huffman tree */
           ush  len;        /* length of bit string */
       } dl;
   } FAR ct_data;
   
   #define Freq fc.freq
   #define Code fc.code
   #define Dad  dl.dad
   #define Len  dl.len
   
   typedef struct static_tree_desc_s  static_tree_desc;
   
   typedef struct tree_desc_s {
       ct_data *dyn_tree;           /* the dynamic tree */
       int     max_code;            /* largest code with non zero frequency */
       static_tree_desc *stat_desc; /* the corresponding static tree */
   } FAR tree_desc;
   
   typedef ush Pos;
   typedef Pos FAR Posf;
   typedef unsigned IPos;
   
   /* A Pos is an index in the character window. We use short instead of int to
    * save space in the various tables. IPos is used only for parameter passing.
    */
   
   typedef struct deflate_state {
       z_streamp strm;      /* pointer back to this zlib stream */
       int   status;        /* as the name implies */
       Bytef *pending_buf;  /* output still pending */
       ulg   pending_buf_size; /* size of pending_buf */
       Bytef *pending_out;  /* next pending byte to output to the stream */
       int   pending;       /* nb of bytes in the pending buffer */
       int   noheader;      /* suppress zlib header and adler32 */
       Byte  data_type;     /* UNKNOWN, BINARY or ASCII */
       Byte  method;        /* STORED (for zip only) or DEFLATED */
       int   last_flush;    /* value of flush param for previous deflate call */
   
                   /* used by deflate.c: */
   
       uInt  w_size;        /* LZ77 window size (32K by default) */
       uInt  w_bits;        /* log2(w_size)  (8..16) */
       uInt  w_mask;        /* w_size - 1 */
   
       Bytef *window;
       /* Sliding window. Input bytes are read into the second half of the window,
        * and move to the first half later to keep a dictionary of at least wSize
        * bytes. With this organization, matches are limited to a distance of
        * wSize-MAX_MATCH bytes, but this ensures that IO is always
        * performed with a length multiple of the block size. Also, it limits
        * the window size to 64K, which is quite useful on MSDOS.
        * To do: use the user input buffer as sliding window.
        */
   
       ulg window_size;
       /* Actual size of window: 2*wSize, except when the user input buffer
        * is directly used as sliding window.
        */
   
       Posf *prev;
       /* Link to older string with same hash index. To limit the size of this
        * array to 64K, this link is maintained only for the last 32K strings.
        * An index in this array is thus a window index modulo 32K.
        */
   
       Posf *head; /* Heads of the hash chains or NIL. */
   
       uInt  ins_h;          /* hash index of string to be inserted */
       uInt  hash_size;      /* number of elements in hash table */
       uInt  hash_bits;      /* log2(hash_size) */
       uInt  hash_mask;      /* hash_size-1 */
   
       uInt  hash_shift;
       /* Number of bits by which ins_h must be shifted at each input
        * step. It must be such that after MIN_MATCH steps, the oldest
        * byte no longer takes part in the hash key, that is:
        *   hash_shift * MIN_MATCH >= hash_bits
        */
   
       long block_start;
       /* Window position at the beginning of the current output block. Gets
        * negative when the window is moved backwards.
        */
   
       uInt match_length;           /* length of best match */
       IPos prev_match;             /* previous match */
       int match_available;         /* set if previous match exists */
       uInt strstart;               /* start of string to insert */
       uInt match_start;            /* start of matching string */
       uInt lookahead;              /* number of valid bytes ahead in window */
   
       uInt prev_length;
       /* Length of the best match at previous step. Matches not greater than this
        * are discarded. This is used in the lazy match evaluation.
        */
   
       uInt max_chain_length;
       /* To speed up deflation, hash chains are never searched beyond this
        * length.  A higher limit improves compression ratio but degrades the
        * speed.
        */
   
       uInt max_lazy_match;
       /* Attempt to find a better match only when the current match is strictly
        * smaller than this value. This mechanism is used only for compression
        * levels >= 4.
        */
   #   define max_insert_length  max_lazy_match
       /* Insert new strings in the hash table only if the match length is not
        * greater than this length. This saves time but degrades compression.
        * max_insert_length is used only for compression levels <= 3.
        */
   
       int level;    /* compression level (1..9) */
       int strategy; /* favor or force Huffman coding*/
   
       uInt good_match;
       /* Use a faster search when the previous match is longer than this */
   
       int nice_match; /* Stop searching when current match exceeds this */
   
                   /* used by trees.c: */
       /* Didn't use ct_data typedef below to supress compiler warning */
       struct ct_data_s dyn_ltree[HEAP_SIZE];   /* literal and length tree */
       struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
       struct ct_data_s bl_tree[2*BL_CODES+1];  /* Huffman tree for bit lengths */
   
       struct tree_desc_s l_desc;               /* desc. for literal tree */
       struct tree_desc_s d_desc;               /* desc. for distance tree */
       struct tree_desc_s bl_desc;              /* desc. for bit length tree */
   
       ush bl_count[MAX_BITS+1];
       /* number of codes at each bit length for an optimal tree */
   
       int heap[2*L_CODES+1];      /* heap used to build the Huffman trees */
       int heap_len;               /* number of elements in the heap */
       int heap_max;               /* element of largest frequency */
       /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
        * The same heap array is used to build all trees.
        */
   
       uch depth[2*L_CODES+1];
       /* Depth of each subtree used as tie breaker for trees of equal frequency
        */
   
       uchf *l_buf;          /* buffer for literals or lengths */
   
       uInt  lit_bufsize;
       /* Size of match buffer for literals/lengths.  There are 4 reasons for
        * limiting lit_bufsize to 64K:
        *   - frequencies can be kept in 16 bit counters
        *   - if compression is not successful for the first block, all input
        *     data is still in the window so we can still emit a stored block even
        *     when input comes from standard input.  (This can also be done for
        *     all blocks if lit_bufsize is not greater than 32K.)
        *   - if compression is not successful for a file smaller than 64K, we can
        *     even emit a stored file instead of a stored block (saving 5 bytes).
        *     This is applicable only for zip (not gzip or zlib).
        *   - creating new Huffman trees less frequently may not provide fast
        *     adaptation to changes in the input data statistics. (Take for
        *     example a binary file with poorly compressible code followed by
        *     a highly compressible string table.) Smaller buffer sizes give
        *     fast adaptation but have of course the overhead of transmitting
        *     trees more frequently.
        *   - I can't count above 4
        */
   
       uInt last_lit;      /* running index in l_buf */
   
       ushf *d_buf;
       /* Buffer for distances. To simplify the code, d_buf and l_buf have
        * the same number of elements. To use different lengths, an extra flag
        * array would be necessary.
        */
   
       ulg opt_len;        /* bit length of current block with optimal trees */
       ulg static_len;     /* bit length of current block with static trees */
       uInt matches;       /* number of string matches in current block */
       int last_eob_len;   /* bit length of EOB code for last block */
   
   #ifdef DEBUG_ZLIB
       ulg compressed_len; /* total bit length of compressed file mod 2^32 */
       ulg bits_sent;      /* bit length of compressed data sent mod 2^32 */
   #endif
   
       ush bi_buf;
       /* Output buffer. bits are inserted starting at the bottom (least
        * significant bits).
        */
       int bi_valid;
       /* Number of valid bits in bi_buf.  All bits above the last valid bit
        * are always zero.
        */
   
   } FAR deflate_state;
   
   /* Output a byte on the stream.
    * IN assertion: there is enough room in pending_buf.
    */
   #define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
   
   
   #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
   /* Minimum amount of lookahead, except at the end of the input file.
    * See deflate.c for comments about the MIN_MATCH+1.
    */
   
   #define MAX_DIST(s)  ((s)->w_size-MIN_LOOKAHEAD)
   /* In order to simplify the code, particularly on 16 bit machines, match
    * distances are limited to MAX_DIST instead of WSIZE.
    */
   
           /* in trees.c */
   static void _tr_init         OF((deflate_state *s));
   static int  _tr_tally        OF((deflate_state *s, unsigned dist, unsigned lc));
   static void _tr_flush_block  OF((deflate_state *s, charf *buf, ulg stored_len,
                             int eof));
   static void _tr_align        OF((deflate_state *s));
   static void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
                             int eof));
   
   #define d_code(dist) \
      ((dist) < 256 ? _dist_code[dist] : _dist_code[256+((dist)>>7)])
   /* Mapping from a distance to a distance code. dist is the distance - 1 and
    * must not have side effects. _dist_code[256] and _dist_code[257] are never
    * used.
    */
   
   #ifndef DEBUG_ZLIB
   /* Inline versions of _tr_tally for speed: */
   
   #if defined(GEN_TREES_H) || !defined(STDC)
     extern uch _length_code[];
     extern uch _dist_code[];
   #else
     extern const uch _length_code[];
     extern const uch _dist_code[];
   #endif
   
   # define _tr_tally_lit(s, c, flush) \
     { uch cc = (c); \
       s->d_buf[s->last_lit] = 0; \
       s->l_buf[s->last_lit++] = cc; \
       s->dyn_ltree[cc].Freq++; \
       flush = (s->last_lit == s->lit_bufsize-1); \
      }
   # define _tr_tally_dist(s, distance, length, flush) \
     { uch len = (length); \
       ush dist = (distance); \
       s->d_buf[s->last_lit] = dist; \
       s->l_buf[s->last_lit++] = len; \
       dist--; \
       s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \
       s->dyn_dtree[d_code(dist)].Freq++; \
       flush = (s->last_lit == s->lit_bufsize-1); \
     }
   #else
   # define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c)
   # define _tr_tally_dist(s, distance, length, flush) \
                 flush = _tr_tally(s, distance, length) 
   #endif
   
   #endif
   /* --- deflate.h */
   
   /* +++ deflate.c */
   /* deflate.c -- compress data using the deflation algorithm
    * Copyright (C) 1995-2002 Jean-loup Gailly.
    * For conditions of distribution and use, see copyright notice in zlib.h 
    */
   
   /*
    *  ALGORITHM
    *
    *      The "deflation" process depends on being able to identify portions
    *      of the input text which are identical to earlier input (within a
    *      sliding window trailing behind the input currently being processed).
    *
    *      The most straightforward technique turns out to be the fastest for
    *      most input files: try all possible matches and select the longest.
    *      The key feature of this algorithm is that insertions into the string
    *      dictionary are very simple and thus fast, and deletions are avoided
    *      completely. Insertions are performed at each input character, whereas
    *      string matches are performed only when the previous match ends. So it
    *      is preferable to spend more time in matches to allow very fast string
    *      insertions and avoid deletions. The matching algorithm for small
    *      strings is inspired from that of Rabin & Karp. A brute force approach
    *      is used to find longer strings when a small match has been found.
    *      A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
    *      (by Leonid Broukhis).
    *         A previous version of this file used a more sophisticated algorithm
    *      (by Fiala and Greene) which is guaranteed to run in linear amortized
    *      time, but has a larger average cost, uses more memory and is patented.
    *      However the F&G algorithm may be faster for some highly redundant
    *      files if the parameter max_chain_length (described below) is too large.
    *
    *  ACKNOWLEDGEMENTS
    *
    *      The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
    *      I found it in 'freeze' written by Leonid Broukhis.
    *      Thanks to many people for bug reports and testing.
    *
    *  REFERENCES
    *
    *      Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
    *      Available in ftp://ds.internic.net/rfc/rfc1951.txt
    *
    *      A description of the Rabin and Karp algorithm is given in the book
    *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
    *
    *      Fiala,E.R., and Greene,D.H.
    *         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
    *
    */
   
   /* #include "deflate.h" */
   
   const char deflate_copyright[] =
      " deflate 1.1.4 Copyright 1995-2002 Jean-loup Gailly ";
   /*
     If you use the zlib library in a product, an acknowledgment is welcome
     in the documentation of your product. If for some reason you cannot
     include such an acknowledgment, I would appreciate that you keep this
     copyright string in the executable of your product.
    */
   
   /* ===========================================================================
    *  Function prototypes.
    */
   typedef enum {
       need_more,      /* block not completed, need more input or more output */
       block_done,     /* block flush performed */
       finish_started, /* finish started, need only more output at next deflate */
       finish_done     /* finish done, accept no more input or output */
   } block_state;
   
   typedef block_state (*compress_func) OF((deflate_state *s, int flush));
   /* Compression function. Returns the block state after the call. */
   
   static void fill_window    OF((deflate_state *s));
   static block_state deflate_stored OF((deflate_state *s, int flush));
   static block_state deflate_fast   OF((deflate_state *s, int flush));
   static block_state deflate_slow   OF((deflate_state *s, int flush));
   static void lm_init        OF((deflate_state *s));
   static void putShortMSB    OF((deflate_state *s, uInt b));
   static void flush_pending  OF((z_streamp strm));
   static int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));
   #ifdef ASMV
         void match_init OF((void)); /* asm code initialization */
         uInt longest_match  OF((deflate_state *s, IPos cur_match));
   #else
   static uInt longest_match  OF((deflate_state *s, IPos cur_match));
   #endif
   
   #ifdef DEBUG_ZLIB
   static  void check_match OF((deflate_state *s, IPos start, IPos match,
                               int length));
   #endif
   
   /* ===========================================================================
    * Local data
    */
   
   #define NIL 0
   /* Tail of hash chains */
   
   #ifndef TOO_FAR
   #  define TOO_FAR 4096
   #endif
   /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
   
   #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
   /* Minimum amount of lookahead, except at the end of the input file.
    * See deflate.c for comments about the MIN_MATCH+1.
    */
   
   /* Values for max_lazy_match, good_match and max_chain_length, depending on
    * the desired pack level (0..9). The values given below have been tuned to
    * exclude worst case performance for pathological files. Better values may be
    * found for specific files.
    */
   typedef struct config_s {
      ush good_length; /* reduce lazy search above this match length */
      ush max_lazy;    /* do not perform lazy search above this match length */
      ush nice_length; /* quit search above this match length */
      ush max_chain;
      compress_func func;
   } config;
   
   static const config configuration_table[10] = {
   /*      good lazy nice chain */
   /* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
   /* 1 */ {4,    4,  8,    4, deflate_fast}, /* maximum speed, no lazy matches */
   /* 2 */ {4,    5, 16,    8, deflate_fast},
   /* 3 */ {4,    6, 32,   32, deflate_fast},
   
   /* 4 */ {4,    4, 16,   16, deflate_slow},  /* lazy matches */
   /* 5 */ {8,   16, 32,   32, deflate_slow},
   /* 6 */ {8,   16, 128, 128, deflate_slow},
   /* 7 */ {8,   32, 128, 256, deflate_slow},
   /* 8 */ {32, 128, 258, 1024, deflate_slow},
   /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* maximum compression */
   
   /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
    * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
    * meaning.
    */
   
   #define EQUAL 0
   /* result of memcmp for equal strings */
   
   #ifndef NO_DUMMY_DECL
   struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
   #endif
   
   /* ===========================================================================
    * Update a hash value with the given input byte
    * IN  assertion: all calls to to UPDATE_HASH are made with consecutive
    *    input characters, so that a running hash key can be computed from the
    *    previous key instead of complete recalculation each time.
    */
   #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
   
   
   /* ===========================================================================
    * Insert string str in the dictionary and set match_head to the previous head
    * of the hash chain (the most recent string with same hash key). Return
    * the previous length of the hash chain.
    * If this file is compiled with -DFASTEST, the compression level is forced
    * to 1, and no hash chains are maintained.
    * IN  assertion: all calls to to INSERT_STRING are made with consecutive
    *    input characters and the first MIN_MATCH bytes of str are valid
    *    (except for the last MIN_MATCH-1 bytes of the input file).
    */
   #ifdef FASTEST
   #define INSERT_STRING(s, str, match_head) \
      (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
       match_head = s->head[s->ins_h], \
       s->head[s->ins_h] = (Pos)(str))
   #else
   #define INSERT_STRING(s, str, match_head) \
      (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
       s->prev[(str) & s->w_mask] = match_head = s->head[s->ins_h], \
       s->head[s->ins_h] = (Pos)(str))
   #endif
   
   /* ===========================================================================
    * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
    * prev[] will be initialized on the fly.
    */
   #define CLEAR_HASH(s) \
       s->head[s->hash_size-1] = NIL; \
       zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
   
   /* ========================================================================= */
   int ZEXPORT
   deflateInit_(z_streamp strm, int level, const char *ver, int stream_size)
   {
       return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
                            Z_DEFAULT_STRATEGY, ver, stream_size);
       /* To do: ignore strm->next_in if we use it as window */
   }
   
   /* ========================================================================= */
   int ZEXPORT
   deflateInit2_(z_streamp strm, int level, int method, int windowBits,
                 int memLevel, int strategy, const char *ver, int stream_size)
   {
       deflate_state *s;
       int noheader = 0;
       static const char* my_version = ZLIB_VERSION;
   
       ushf *overlay;
       /* We overlay pending_buf and d_buf+l_buf. This works since the average
        * output size for (length,distance) codes is <= 24 bits.
        */
   
       if (ver == Z_NULL || ver[0] != my_version[0] ||
           stream_size != sizeof(z_stream)) {
           return Z_VERSION_ERROR;
       }
       if (strm == Z_NULL) return Z_STREAM_ERROR;
   
       strm->msg = Z_NULL;
   #ifndef NO_ZCFUNCS
       if (strm->zalloc == Z_NULL) {
           strm->zalloc = zcalloc;
           strm->opaque = (voidpf)0;
       }
       if (strm->zfree == Z_NULL) strm->zfree = zcfree;
   #endif
   
       if (level == Z_DEFAULT_COMPRESSION) level = 6;
   #ifdef FASTEST
       level = 1;
   #endif
   
       if (windowBits < 0) { /* undocumented feature: suppress zlib header */
           noheader = 1;
           windowBits = -windowBits;
       }
       if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
           windowBits < 9 || windowBits > 15 || level < 0 || level > 9 ||
           strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
           return Z_STREAM_ERROR;
       }
       s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
       if (s == Z_NULL) return Z_MEM_ERROR;
       strm->state = (struct internal_state FAR *)s;
       s->strm = strm;
   
       s->noheader = noheader;
       s->w_bits = windowBits;
       s->w_size = 1 << s->w_bits;
       s->w_mask = s->w_size - 1;
   
       s->hash_bits = memLevel + 7;
       s->hash_size = 1 << s->hash_bits;
       s->hash_mask = s->hash_size - 1;
       s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
   
       s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
       s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
       s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
   
       s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
   
       overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
       s->pending_buf = (uchf *) overlay;
       s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
   
       if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
           s->pending_buf == Z_NULL) {
           strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
           deflateEnd (strm);
           return Z_MEM_ERROR;
       }
       s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
       s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
   
       s->level = level;
       s->strategy = strategy;
       s->method = (Byte)method;
   
       return deflateReset(strm);
   }
   
   /* ========================================================================= */
   int ZEXPORT
   deflateSetDictionary(z_streamp strm, const Bytef *dictionary, uInt dictLength)
   {
       deflate_state *s;
       uInt length = dictLength;
       uInt n;
       IPos hash_head = 0;
   
       if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
           ((deflate_state*)strm->state)->status != INIT_STATE) return Z_STREAM_ERROR;
   
       s = (deflate_state*)strm->state;
       strm->adler = adler32(strm->adler, dictionary, dictLength);
   
       if (length < MIN_MATCH) return Z_OK;
       if (length > MAX_DIST(s)) {
           length = MAX_DIST(s);
   #ifndef USE_DICT_HEAD
           dictionary += dictLength - length; /* use the tail of the dictionary */
   #endif
       }
       zmemcpy(s->window, dictionary, length);
       s->strstart = length;
       s->block_start = (long)length;
   
       /* Insert all strings in the hash table (except for the last two bytes).
        * s->lookahead stays null, so s->ins_h will be recomputed at the next
        * call of fill_window.
        */
       s->ins_h = s->window[0];
       UPDATE_HASH(s, s->ins_h, s->window[1]);
       for (n = 0; n <= length - MIN_MATCH; n++) {
           INSERT_STRING(s, n, hash_head);
       }
       if (hash_head) hash_head = 0;  /* to make compiler happy */
       return Z_OK;
   }
   
   /* ========================================================================= */
   int ZEXPORT
   deflateReset(z_streamp strm)
   {
       deflate_state *s;
       
       if (strm == Z_NULL || strm->state == Z_NULL ||
           strm->zalloc == Z_NULL || strm->zfree == Z_NULL) return Z_STREAM_ERROR;
   
       strm->total_in = strm->total_out = 0;
       strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
       strm->data_type = Z_UNKNOWN;
   
       s = (deflate_state *)strm->state;
       s->pending = 0;
       s->pending_out = s->pending_buf;
   
       if (s->noheader < 0) {
           s->noheader = 0; /* was set to -1 by deflate(..., Z_FINISH); */
       }
       s->status = s->noheader ? BUSY_STATE : INIT_STATE;
       strm->adler = 1;
       s->last_flush = Z_NO_FLUSH;
   
       _tr_init(s);
       lm_init(s);
   
       return Z_OK;
   }
   
   /* ========================================================================= */
   int ZEXPORT
   deflateParams(z_streamp strm, int level, int strategy)
   {
       deflate_state *s;
       compress_func func;
       int err = Z_OK;
   
       if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
       s = (deflate_state*)strm->state;
   
       if (level == Z_DEFAULT_COMPRESSION) {
           level = 6;
       }
       if (level < 0 || level > 9 || strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
           return Z_STREAM_ERROR;
       }
       func = configuration_table[s->level].func;
   
       if (func != configuration_table[level].func && strm->total_in != 0) {
           /* Flush the last buffer: */
           err = deflate(strm, Z_PARTIAL_FLUSH);
       }
       if (s->level != level) {
           s->level = level;
           s->max_lazy_match   = configuration_table[level].max_lazy;
           s->good_match       = configuration_table[level].good_length;
           s->nice_match       = configuration_table[level].nice_length;
           s->max_chain_length = configuration_table[level].max_chain;
       }
       s->strategy = strategy;
       return err;
   }
  
  /* =========================================================================
   * Put a short in the pending buffer. The 16-bit value is put in MSB order.
   * IN assertion: the stream state is correct and there is enough room in
   * pending_buf.
   */
  static void
  putShortMSB(deflate_state *s, uInt b)
  {
      put_byte(s, (Byte)(b >> 8));
      put_byte(s, (Byte)(b & 0xff));
  }   
  
  /* =========================================================================
   * Flush as much pending output as possible. All deflate() output goes
   * through this function so some applications may wish to modify it
   * to avoid allocating a large strm->next_out buffer and copying into it.
   * (See also read_buf()).
   */
  static void
  flush_pending(z_streamp strm)
  {
          deflate_state* s = (deflate_state*)strm->state;
      unsigned len = s->pending;
  
      if (len > strm->avail_out) len = strm->avail_out;
      if (len == 0) return;
  
      zmemcpy(strm->next_out, s->pending_out, len);
      strm->next_out  += len;
      s->pending_out  += len;
      strm->total_out += len;
      strm->avail_out  -= len;
      s->pending -= len;
      if (s->pending == 0) {
          s->pending_out = s->pending_buf;
      }
  }
  
  /* ========================================================================= */
  int ZEXPORT
  deflate (z_streamp strm, int flush)
  {
      int old_flush; /* value of flush param for previous deflate call */
      deflate_state *s;
  
      if (strm == Z_NULL || strm->state == Z_NULL ||
          flush > Z_FINISH || flush < 0) {
          return Z_STREAM_ERROR;
      }
      s = (deflate_state*)strm->state;
  
      if (strm->next_out == Z_NULL ||
          (strm->next_in == Z_NULL && strm->avail_in != 0) ||
          (s->status == FINISH_STATE && flush != Z_FINISH)) {
          ERR_RETURN(strm, Z_STREAM_ERROR);
      }
      if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
  
      s->strm = strm; /* just in case */
      old_flush = s->last_flush;
      s->last_flush = flush;
  
      /* Write the zlib header */
      if (s->status == INIT_STATE) {
  
          uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
          uInt level_flags = (s->level-1) >> 1;
  
          if (level_flags > 3) level_flags = 3;
          header |= (level_flags << 6);
          if (s->strstart != 0) header |= PRESET_DICT;
          header += 31 - (header % 31);
  
          s->status = BUSY_STATE;
          putShortMSB(s, header);
  
          /* Save the adler32 of the preset dictionary: */
          if (s->strstart != 0) {
              putShortMSB(s, (uInt)(strm->adler >> 16));
              putShortMSB(s, (uInt)(strm->adler & 0xffff));
          }
          strm->adler = 1L;
      }
  
      /* Flush as much pending output as possible */
      if (s->pending != 0) {
          flush_pending(strm);
          if (strm->avail_out == 0) {
              /* Since avail_out is 0, deflate will be called again with
               * more output space, but possibly with both pending and
               * avail_in equal to zero. There won't be anything to do,
               * but this is not an error situation so make sure we
               * return OK instead of BUF_ERROR at next call of deflate:
               */
              s->last_flush = -1;
              return Z_OK;
          }
  
      /* Make sure there is something to do and avoid duplicate consecutive
       * flushes. For repeated and useless calls with Z_FINISH, we keep
       * returning Z_STREAM_END instead of Z_BUFF_ERROR.
       */
      } else if (strm->avail_in == 0 && flush <= old_flush &&
                 flush != Z_FINISH) {
          ERR_RETURN(strm, Z_BUF_ERROR);
      }
  
      /* User must not provide more input after the first FINISH: */
      if (s->status == FINISH_STATE && strm->avail_in != 0) {
          ERR_RETURN(strm, Z_BUF_ERROR);
      }
  
      /* Start a new block or continue the current one.
       */
      if (strm->avail_in != 0 || s->lookahead != 0 ||
          (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
          block_state bstate;
  
          bstate = (*(configuration_table[s->level].func))(s, flush);
  
          if (bstate == finish_started || bstate == finish_done) {
              s->status = FINISH_STATE;
          }
          if (bstate == need_more || bstate == finish_started) {
              if (strm->avail_out == 0) {
                  s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
              }
              return Z_OK;
              /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
               * of deflate should use the same flush parameter to make sure
               * that the flush is complete. So we don't have to output an
               * empty block here, this will be done at next call. This also
               * ensures that for a very small output buffer, we emit at most
               * one empty block.
               */
          }
          if (bstate == block_done) {
              if (flush == Z_PARTIAL_FLUSH) {
                  _tr_align(s);
              } else { /* FULL_FLUSH or SYNC_FLUSH */
                  _tr_stored_block(s, (char*)0, 0L, 0);
                  /* For a full flush, this empty block will be recognized
                   * as a special marker by inflate_sync().
                   */
                  if (flush == Z_FULL_FLUSH) {
                      CLEAR_HASH(s);             /* forget history */
                  }
              }
              flush_pending(strm);
              if (strm->avail_out == 0) {
                s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
                return Z_OK;
              }
          }
      }
      Assert(strm->avail_out > 0, "bug2");
  
      if (flush != Z_FINISH) return Z_OK;
      if (s->noheader) return Z_STREAM_END;
  
      /* Write the zlib trailer (adler32) */
      putShortMSB(s, (uInt)(strm->adler >> 16));
      putShortMSB(s, (uInt)(strm->adler & 0xffff));
      flush_pending(strm);
      /* If avail_out is zero, the application will call deflate again
       * to flush the rest.
       */
      s->noheader = -1; /* write the trailer only once! */
      return s->pending != 0 ? Z_OK : Z_STREAM_END;
  }
  
  /* ========================================================================= */
  int ZEXPORT
  deflateEnd(z_streamp strm)
  {
          deflate_state*  s;
      int status;
  
      if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
  
          s = (deflate_state*)strm->state;
      status = s->status;
      if (status != INIT_STATE && status != BUSY_STATE &&
          status != FINISH_STATE) {
        return Z_STREAM_ERROR;
      }
  
      /* Deallocate in reverse order of allocations: */
      TRY_FREE(strm, s->pending_buf);
      TRY_FREE(strm, s->head);
      TRY_FREE(strm, s->prev);
      TRY_FREE(strm, s->window);
  
      ZFREE(strm, s);
      strm->state = Z_NULL;
  
      return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
  }
  
  /* =========================================================================
   * Copy the source state to the destination state.
   * To simplify the source, this is not supported for 16-bit MSDOS (which
   * doesn't have enough memory anyway to duplicate compression states).
   */
  int ZEXPORT
  deflateCopy(z_streamp dest, z_streamp source)
  {
  #ifdef MAXSEG_64K
      return Z_STREAM_ERROR;
  #else
      deflate_state *ds;
      deflate_state *ss;
      ushf *overlay;
  
  
      if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
          return Z_STREAM_ERROR;
      }
  
      ss = (deflate_state*)source->state;
  
      *dest = *source;
  
      ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
      if (ds == Z_NULL) return Z_MEM_ERROR;
      dest->state = (struct internal_state FAR *) ds;
      *ds = *ss;
      ds->strm = dest;
  
      ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
      ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
      ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
      overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
      ds->pending_buf = (uchf *) overlay;
  
      if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
          ds->pending_buf == Z_NULL) {
          deflateEnd (dest);
          return Z_MEM_ERROR;
      }
      /* following zmemcpy do not work for 16-bit MSDOS */
      zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
      zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
      zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
      zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
  
      ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
      ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
      ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
  
      ds->l_desc.dyn_tree = ds->dyn_ltree;
      ds->d_desc.dyn_tree = ds->dyn_dtree;
      ds->bl_desc.dyn_tree = ds->bl_tree;
  
      return Z_OK;
  #endif
  }
  
  /* ===========================================================================
   * Read a new buffer from the current input stream, update the adler32
   * and total number of bytes read.  All deflate() input goes through
   * this function so some applications may wish to modify it to avoid
   * allocating a large strm->next_in buffer and copying from it.
   * (See also flush_pending()).
   */
  static int
  read_buf(z_streamp strm, Bytef *buf, unsigned int size)
  {
      unsigned len = strm->avail_in;
  
      if (len > size) len = size;
      if (len == 0) return 0;
  
      strm->avail_in  -= len;
  
      if (!((deflate_state*)strm->state)->noheader) {
          strm->adler = adler32(strm->adler, strm->next_in, len);
      }
      zmemcpy(buf, strm->next_in, len);
      strm->next_in  += len;
      strm->total_in += len;
  
      return (int)len;
  }
  
  /* ===========================================================================
   * Initialize the "longest match" routines for a new zlib stream
   */
  static void
  lm_init(deflate_state *s)
  {
      s->window_size = (ulg)2L*s->w_size;
  
      CLEAR_HASH(s);
  
      /* Set the default configuration parameters:
       */
      s->max_lazy_match   = configuration_table[s->level].max_lazy;
      s->good_match       = configuration_table[s->level].good_length;
      s->nice_match       = configuration_table[s->level].nice_length;
      s->max_chain_length = configuration_table[s->level].max_chain;
  
      s->strstart = 0;
      s->block_start = 0L;
      s->lookahead = 0;
      s->match_length = s->prev_length = MIN_MATCH-1;
      s->match_available = 0;
      s->ins_h = 0;
  #ifdef ASMV
      match_init(); /* initialize the asm code */
  #endif
  }
  
  /* ===========================================================================
   * Set match_start to the longest match starting at the given string and
   * return its length. Matches shorter or equal to prev_length are discarded,
   * in which case the result is equal to prev_length and match_start is
   * garbage.
   * IN assertions: cur_match is the head of the hash chain for the current
   *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
   * OUT assertion: the match length is not greater than s->lookahead.
   */
  #ifndef ASMV
  /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
   * match.S. The code will be functionally equivalent.
   */
  #ifndef FASTEST
  static uInt
  longest_match(deflate_state *s, IPos cur_match)
  {
      unsigned chain_length = s->max_chain_length;/* max hash chain length */
      Bytef *scan = s->window + s->strstart; /* current string */
      Bytef *match;                       /* matched string */
      int len;                           /* length of current match */
      int best_len = s->prev_length;              /* best match length so far */
      int nice_match = s->nice_match;             /* stop if match long enough */
      IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
          s->strstart - (IPos)MAX_DIST(s) : NIL;
      /* Stop when cur_match becomes <= limit. To simplify the code,
       * we prevent matches with the string of window index 0.
       */
      Posf *prev = s->prev;
      uInt wmask = s->w_mask;
  
  #ifdef UNALIGNED_OK
      /* Compare two bytes at a time. Note: this is not always beneficial.
       * Try with and without -DUNALIGNED_OK to check.
       */
      Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
      ush scan_start = *(ushf*)scan;
      ush scan_end   = *(ushf*)(scan+best_len-1);
  #else
      Bytef *strend = s->window + s->strstart + MAX_MATCH;
      Byte scan_end1  = scan[best_len-1];
      Byte scan_end   = scan[best_len];
  #endif
  
      /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
       * It is easy to get rid of this optimization if necessary.
       */
      Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
  
      /* Do not waste too much time if we already have a good match: */
      if (s->prev_length >= s->good_match) {
          chain_length >>= 2;
      }
      /* Do not look for matches beyond the end of the input. This is necessary
       * to make deflate deterministic.
       */
      if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
  
      Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
  
      do {
          Assert(cur_match < s->strstart, "no future");
          match = s->window + cur_match;
  
          /* Skip to next match if the match length cannot increase
           * or if the match length is less than 2:
           */
  #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
          /* This code assumes sizeof(unsigned short) == 2. Do not use
           * UNALIGNED_OK if your compiler uses a different size.
           */
          if (*(ushf*)(match+best_len-1) != scan_end ||
              *(ushf*)match != scan_start) continue;
  
          /* It is not necessary to compare scan[2] and match[2] since they are
           * always equal when the other bytes match, given that the hash keys
           * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
           * strstart+3, +5, ... up to strstart+257. We check for insufficient
           * lookahead only every 4th comparison; the 128th check will be made
           * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
           * necessary to put more guard bytes at the end of the window, or
           * to check more often for insufficient lookahead.
           */
          Assert(scan[2] == match[2], "scan[2]?");
          scan++, match++;
          do {
          } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                   *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                   *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                   *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                   scan < strend);
          /* The funny "do {}" generates better code on most compilers */
  
          /* Here, scan <= window+strstart+257 */
          Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
          if (*scan == *match) scan++;
  
          len = (MAX_MATCH - 1) - (int)(strend-scan);
          scan = strend - (MAX_MATCH-1);
  
  #else /* UNALIGNED_OK */
  
          if (match[best_len]   != scan_end  ||
              match[best_len-1] != scan_end1 ||
              *match            != *scan     ||
              *++match          != scan[1])      continue;
  
          /* The check at best_len-1 can be removed because it will be made
           * again later. (This heuristic is not always a win.)
           * It is not necessary to compare scan[2] and match[2] since they
           * are always equal when the other bytes match, given that
           * the hash keys are equal and that HASH_BITS >= 8.
           */
          scan += 2, match++;
          Assert(*scan == *match, "match[2]?");
  
          /* We check for insufficient lookahead only every 8th comparison;
           * the 256th check will be made at strstart+258.
           */
          do {
          } while (*++scan == *++match && *++scan == *++match &&
                   *++scan == *++match && *++scan == *++match &&
                   *++scan == *++match && *++scan == *++match &&
                   *++scan == *++match && *++scan == *++match &&
                   scan < strend);
  
          Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
  
          len = MAX_MATCH - (int)(strend - scan);
          scan = strend - MAX_MATCH;
  
  #endif /* UNALIGNED_OK */
  
          if (len > best_len) {
              s->match_start = cur_match;
              best_len = len;
              if (len >= nice_match) break;
  #ifdef UNALIGNED_OK
              scan_end = *(ushf*)(scan+best_len-1);
  #else
              scan_end1  = scan[best_len-1];
              scan_end   = scan[best_len];
  #endif
          }
      } while ((cur_match = prev[cur_match & wmask]) > limit
               && --chain_length != 0);
  
      if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
      return s->lookahead;
  }
  
  #else /* FASTEST */
  /* ---------------------------------------------------------------------------
   * Optimized version for level == 1 only
   */
  static uInt
  longest_match(deflate_state *s, IPos cur_match)
  {
      Bytef *scan = s->window + s->strstart; /* current string */
      Bytef *match;                       /* matched string */
      int len;                           /* length of current match */
      Bytef *strend = s->window + s->strstart + MAX_MATCH;
  
      /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
       * It is easy to get rid of this optimization if necessary.
       */
      Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
  
      Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
  
      Assert(cur_match < s->strstart, "no future");
  
      match = s->window + cur_match;
  
      /* Return failure if the match length is less than 2:
       */
      if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
  
      /* The check at best_len-1 can be removed because it will be made
       * again later. (This heuristic is not always a win.)
       * It is not necessary to compare scan[2] and match[2] since they
       * are always equal when the other bytes match, given that
       * the hash keys are equal and that HASH_BITS >= 8.
       */
      scan += 2, match += 2;
      Assert(*scan == *match, "match[2]?");
  
      /* We check for insufficient lookahead only every 8th comparison;
       * the 256th check will be made at strstart+258.
       */
      do {
      } while (*++scan == *++match && *++scan == *++match &&
               *++scan == *++match && *++scan == *++match &&
               *++scan == *++match && *++scan == *++match &&
               *++scan == *++match && *++scan == *++match &&
               scan < strend);
  
      Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
  
      len = MAX_MATCH - (int)(strend - scan);
  
      if (len < MIN_MATCH) return MIN_MATCH - 1;
  
      s->match_start = cur_match;
      return len <= s->lookahead ? len : s->lookahead;
  }
  #endif /* FASTEST */
  #endif /* ASMV */
  
  #ifdef DEBUG_ZLIB
  /* ===========================================================================
   * Check that the match at match_start is indeed a match.
   */
  static void
  check_match(deflate_state *s, IPos start, IPos match, int length)
  {
      /* check that the match is indeed a match */
      if (zmemcmp(s->window + match,
                  s->window + start, length) != EQUAL) {
          fprintf(stderr, " start %u, match %u, length %d\n",
                  start, match, length);
          do {
              fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
          } while (--length != 0);
          z_error("invalid match");
      }
      if (z_verbose > 1) {
          fprintf(stderr,"\\[%d,%d]", start-match, length);
          do { putc(s->window[start++], stderr); } while (--length != 0);
      }
  }
  #else
  #  define check_match(s, start, match, length)
  #endif
  
  /* ===========================================================================
   * Fill the window when the lookahead becomes insufficient.
   * Updates strstart and lookahead.
   *
   * IN assertion: lookahead < MIN_LOOKAHEAD
   * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
   *    At least one byte has been read, or avail_in == 0; reads are
   *    performed for at least two bytes (required for the zip translate_eol
   *    option -- not supported here).
   */
  static void
  fill_window(deflate_state *s)
  {
      unsigned n, m;
      Posf *p;
      unsigned more;    /* Amount of free space at the end of the window. */
      uInt wsize = s->w_size;
  
      do {
          more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
  
          /* Deal with !@#$% 64K limit: */
          if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
              more = wsize;
  
          } else if (more == (unsigned)(-1)) {
              /* Very unlikely, but possible on 16 bit machine if strstart == 0
               * and lookahead == 1 (input done one byte at time)
               */
              more--;
  
          /* If the window is almost full and there is insufficient lookahead,
           * move the upper half to the lower one to make room in the upper half.
           */
          } else if (s->strstart >= wsize+MAX_DIST(s)) {
  
              zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
              s->match_start -= wsize;
              s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
              s->block_start -= (long) wsize;
  
              /* Slide the hash table (could be avoided with 32 bit values
                 at the expense of memory usage). We slide even when level == 0
                 to keep the hash table consistent if we switch back to level > 0
                 later. (Using level 0 permanently is not an optimal usage of
                 zlib, so we don't care about this pathological case.)
               */
              n = s->hash_size;
              p = &s->head[n];
              do {
                  m = *--p;
                  *p = (Pos)(m >= wsize ? m-wsize : NIL);
              } while (--n);
  
              n = wsize;
  #ifndef FASTEST
              p = &s->prev[n];
              do {
                  m = *--p;
                  *p = (Pos)(m >= wsize ? m-wsize : NIL);
                  /* If n is not on any hash chain, prev[n] is garbage but
                   * its value will never be used.
                   */
              } while (--n);
  #endif
              more += wsize;
          }
          if (s->strm->avail_in == 0) return;
  
          /* If there was no sliding:
           *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
           *    more == window_size - lookahead - strstart
           * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
           * => more >= window_size - 2*WSIZE + 2
           * In the BIG_MEM or MMAP case (not yet supported),
           *   window_size == input_size + MIN_LOOKAHEAD  &&
           *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
           * Otherwise, window_size == 2*WSIZE so more >= 2.
           * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
           */
          Assert(more >= 2, "more < 2");
  
          n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
          s->lookahead += n;
  
          /* Initialize the hash value now that we have some input: */
          if (s->lookahead >= MIN_MATCH) {
              s->ins_h = s->window[s->strstart];
              UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
  #if MIN_MATCH != 3
              Call UPDATE_HASH() MIN_MATCH-3 more times
  #endif
          }
          /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
           * but this is not important since only literal bytes will be emitted.
           */
  
      } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
  }
  
  /* ===========================================================================
   * Flush the current block, with given end-of-file flag.
   * IN assertion: strstart is set to the end of the current match.
   */
  #define FLUSH_BLOCK_ONLY(s, eof) { \
     _tr_flush_block(s, (s->block_start >= 0L ? \
                     (charf *)&s->window[(unsigned)s->block_start] : \
                     (charf *)Z_NULL), \
                  (ulg)((long)s->strstart - s->block_start), \
                  (eof)); \
     s->block_start = s->strstart; \
     flush_pending(s->strm); \
     Tracev((stderr,"[FLUSH]")); \
  }
  
  /* Same but force premature exit if necessary. */
  #define FLUSH_BLOCK(s, eof) { \
     FLUSH_BLOCK_ONLY(s, eof); \
     if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
  }
  
  /* ===========================================================================
   * Copy without compression as much as possible from the input stream, return
   * the current block state.
   * This function does not insert new strings in the dictionary since
   * uncompressible data is probably not useful. This function is used
   * only for the level=0 compression option.
   * NOTE: this function should be optimized to avoid extra copying from
   * window to pending_buf.
   */
  static block_state
  deflate_stored(deflate_state *s, int flush)
  {
      /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
       * to pending_buf_size, and each stored block has a 5 byte header:
       */
      ulg max_block_size = 0xffff;
      ulg max_start;
  
      if (max_block_size > s->pending_buf_size - 5) {
          max_block_size = s->pending_buf_size - 5;
      }
  
      /* Copy as much as possible from input to output: */
      for (;;) {
          /* Fill the window as much as possible: */
          if (s->lookahead <= 1) {
  
              Assert(s->strstart < s->w_size+MAX_DIST(s) ||
                     s->block_start >= (long)s->w_size, "slide too late");
  
              fill_window(s);
              if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
  
              if (s->lookahead == 0) break; /* flush the current block */
          }
          Assert(s->block_start >= 0L, "block gone");
  
          s->strstart += s->lookahead;
          s->lookahead = 0;
  
          /* Emit a stored block if pending_buf will be full: */
          max_start = s->block_start + max_block_size;
          if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
              /* strstart == 0 is possible when wraparound on 16-bit machine */
              s->lookahead = (uInt)(s->strstart - max_start);
              s->strstart = (uInt)max_start;
              FLUSH_BLOCK(s, 0);
          }
          /* Flush if we may have to slide, otherwise block_start may become
           * negative and the data will be gone:
           */
          if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
              FLUSH_BLOCK(s, 0);
          }
      }
      FLUSH_BLOCK(s, flush == Z_FINISH);
      return flush == Z_FINISH ? finish_done : block_done;
  }
  
  /* ===========================================================================
   * Compress as much as possible from the input stream, return the current
   * block state.
   * This function does not perform lazy evaluation of matches and inserts
   * new strings in the dictionary only for unmatched strings or for short
   * matches. It is used only for the fast compression options.
   */
  static block_state
  deflate_fast(deflate_state *s, int flush)
  {
      IPos hash_head = NIL; /* head of the hash chain */
      int bflush;           /* set if current block must be flushed */
  
      for (;;) {
          /* Make sure that we always have enough lookahead, except
           * at the end of the input file. We need MAX_MATCH bytes
           * for the next match, plus MIN_MATCH bytes to insert the
           * string following the next match.
           */
          if (s->lookahead < MIN_LOOKAHEAD) {
              fill_window(s);
              if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
                  return need_more;
              }
              if (s->lookahead == 0) break; /* flush the current block */
          }
  
          /* Insert the string window[strstart .. strstart+2] in the
           * dictionary, and set hash_head to the head of the hash chain:
           */
          if (s->lookahead >= MIN_MATCH) {
              INSERT_STRING(s, s->strstart, hash_head);
          }
  
          /* Find the longest match, discarding those <= prev_length.
           * At this point we have always match_length < MIN_MATCH
           */
          if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
              /* To simplify the code, we prevent matches with the string
               * of window index 0 (in particular we have to avoid a match
               * of the string with itself at the start of the input file).
               */
              if (s->strategy != Z_HUFFMAN_ONLY) {
                  s->match_length = longest_match (s, hash_head);
              }
              /* longest_match() sets match_start */
          }
          if (s->match_length >= MIN_MATCH) {
              check_match(s, s->strstart, s->match_start, s->match_length);
  
              _tr_tally_dist(s, s->strstart - s->match_start,
                             s->match_length - MIN_MATCH, bflush);
  
              s->lookahead -= s->match_length;
  
              /* Insert new strings in the hash table only if the match length
               * is not too large. This saves time but degrades compression.
               */
  #ifndef FASTEST
              if (s->match_length <= s->max_insert_length &&
                  s->lookahead >= MIN_MATCH) {
                  s->match_length--; /* string at strstart already in hash table */
                  do {
                      s->strstart++;
                      INSERT_STRING(s, s->strstart, hash_head);
                      /* strstart never exceeds WSIZE-MAX_MATCH, so there are
                       * always MIN_MATCH bytes ahead.
                       */
                  } while (--s->match_length != 0);
                  s->strstart++; 
              } else
  #endif
              {
                  s->strstart += s->match_length;
                  s->match_length = 0;
                  s->ins_h = s->window[s->strstart];
                  UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
  #if MIN_MATCH != 3
                  Call UPDATE_HASH() MIN_MATCH-3 more times
  #endif
                  /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
                   * matter since it will be recomputed at next deflate call.
                   */
              }
          } else {
              /* No match, output a literal byte */
              Tracevv((stderr,"%c", s->window[s->strstart]));
              _tr_tally_lit (s, s->window[s->strstart], bflush);
              s->lookahead--;
              s->strstart++; 
          }
          if (bflush) FLUSH_BLOCK(s, 0);
      }
      FLUSH_BLOCK(s, flush == Z_FINISH);
      return flush == Z_FINISH ? finish_done : block_done;
  }
  
  /* ===========================================================================
   * Same as above, but achieves better compression. We use a lazy
   * evaluation for matches: a match is finally adopted only if there is
   * no better match at the next window position.
   */
  static block_state
  deflate_slow(deflate_state *s, int flush)
  {
      IPos hash_head = NIL;    /* head of hash chain */
      int bflush;              /* set if current block must be flushed */
  
      /* Process the input block. */
      for (;;) {
          /* Make sure that we always have enough lookahead, except
           * at the end of the input file. We need MAX_MATCH bytes
           * for the next match, plus MIN_MATCH bytes to insert the
           * string following the next match.
           */
          if (s->lookahead < MIN_LOOKAHEAD) {
              fill_window(s);
              if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
                  return need_more;
              }
              if (s->lookahead == 0) break; /* flush the current block */
          }
  
          /* Insert the string window[strstart .. strstart+2] in the
           * dictionary, and set hash_head to the head of the hash chain:
           */
          if (s->lookahead >= MIN_MATCH) {
              INSERT_STRING(s, s->strstart, hash_head);
          }
  
          /* Find the longest match, discarding those <= prev_length.
           */
          s->prev_length = s->match_length, s->prev_match = s->match_start;
          s->match_length = MIN_MATCH-1;
  
          if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
              s->strstart - hash_head <= MAX_DIST(s)) {
              /* To simplify the code, we prevent matches with the string
               * of window index 0 (in particular we have to avoid a match
               * of the string with itself at the start of the input file).
               */
              if (s->strategy != Z_HUFFMAN_ONLY) {
                  s->match_length = longest_match (s, hash_head);
              }
              /* longest_match() sets match_start */
  
              if (s->match_length <= 5 && (s->strategy == Z_FILTERED ||
                   (s->match_length == MIN_MATCH &&
                    s->strstart - s->match_start > TOO_FAR))) {
  
                  /* If prev_match is also MIN_MATCH, match_start is garbage
                   * but we will ignore the current match anyway.
                   */
                  s->match_length = MIN_MATCH-1;
              }
          }
          /* If there was a match at the previous step and the current
           * match is not better, output the previous match:
           */
          if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
              uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
              /* Do not insert strings in hash table beyond this. */
  
              check_match(s, s->strstart-1, s->prev_match, s->prev_length);
  
              _tr_tally_dist(s, s->strstart -1 - s->prev_match,
                             s->prev_length - MIN_MATCH, bflush);
  
              /* Insert in hash table all strings up to the end of the match.
               * strstart-1 and strstart are already inserted. If there is not
               * enough lookahead, the last two strings are not inserted in
               * the hash table.
               */
              s->lookahead -= s->prev_length-1;
              s->prev_length -= 2;
              do {
                  if (++s->strstart <= max_insert) {
                      INSERT_STRING(s, s->strstart, hash_head);
                  }
              } while (--s->prev_length != 0);
              s->match_available = 0;
              s->match_length = MIN_MATCH-1;
              s->strstart++;
  
              if (bflush) FLUSH_BLOCK(s, 0);
  
          } else if (s->match_available) {
              /* If there was no match at the previous position, output a
               * single literal. If there was a match but the current match
               * is longer, truncate the previous match to a single literal.
               */
              Tracevv((stderr,"%c", s->window[s->strstart-1]));
              _tr_tally_lit(s, s->window[s->strstart-1], bflush);
              if (bflush) {
                  FLUSH_BLOCK_ONLY(s, 0);
              }
              s->strstart++;
              s->lookahead--;
              if (s->strm->avail_out == 0) return need_more;
          } else {
              /* There is no previous match to compare with, wait for
               * the next step to decide.
               */
              s->match_available = 1;
              s->strstart++;
              s->lookahead--;
          }
      }
      Assert (flush != Z_NO_FLUSH, "no flush?");
      if (s->match_available) {
          Tracevv((stderr,"%c", s->window[s->strstart-1]));
          _tr_tally_lit(s, s->window[s->strstart-1], bflush);
          s->match_available = 0;
      }
      FLUSH_BLOCK(s, flush == Z_FINISH);
      return flush == Z_FINISH ? finish_done : block_done;
  }
  /* --- deflate.c */
  
  /* +++ trees.c */
  /* trees.c -- output deflated data using Huffman coding
   * Copyright (C) 1995-2002 Jean-loup Gailly
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /*
   *  ALGORITHM
   *
   *      The "deflation" process uses several Huffman trees. The more
   *      common source values are represented by shorter bit sequences.
   *
   *      Each code tree is stored in a compressed form which is itself
   * a Huffman encoding of the lengths of all the code strings (in
   * ascending order by source values).  The actual code strings are
   * reconstructed from the lengths in the inflate process, as described
   * in the deflate specification.
   *
   *  REFERENCES
   *
   *      Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
   *      Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
   *
   *      Storer, James A.
   *          Data Compression:  Methods and Theory, pp. 49-50.
   *          Computer Science Press, 1988.  ISBN 0-7167-8156-5.
   *
   *      Sedgewick, R.
   *          Algorithms, p290.
   *          Addison-Wesley, 1983. ISBN 0-201-06672-6.
   */
  
  /* #define GEN_TREES_H */
  
  /* #include "deflate.h" */
  
  #ifdef DEBUG_ZLIB
  #  include <ctype.h>
  #endif
  
  /* ===========================================================================
   * Constants
   */
  
  #define MAX_BL_BITS 7
  /* Bit length codes must not exceed MAX_BL_BITS bits */
  
  #define END_BLOCK 256
  /* end of block literal code */
  
  #define REP_3_6      16
  /* repeat previous bit length 3-6 times (2 bits of repeat count) */
  
  #define REPZ_3_10    17
  /* repeat a zero length 3-10 times  (3 bits of repeat count) */
  
  #define REPZ_11_138  18
  /* repeat a zero length 11-138 times  (7 bits of repeat count) */
  
  static const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
     = {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};
  
  static const int extra_dbits[D_CODES] /* extra bits for each distance code */
     = {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};
  
  static const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
     = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
  
  static const uch bl_order[BL_CODES]
     = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
  /* The lengths of the bit length codes are sent in order of decreasing
   * probability, to avoid transmitting the lengths for unused bit length codes.
   */
  
  #define Buf_size (8 * 2*sizeof(char))
  /* Number of bits used within bi_buf. (bi_buf might be implemented on
   * more than 16 bits on some systems.)
   */
  
  /* ===========================================================================
   * Local data. These are initialized only once.
   */
  
  #define DIST_CODE_LEN  512 /* see definition of array dist_code below */
  
  #if defined(GEN_TREES_H) || !defined(STDC)
  /* non ANSI compilers may not accept trees.h */
  
  static ct_data *static_ltree = Z_NULL;
  /* The static literal tree. Since the bit lengths are imposed, there is no
   * need for the L_CODES extra codes used during heap construction. However
   * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
   * below).
   */
  
  static ct_data *static_dtree = Z_NULL;
  /* The static distance tree. (Actually a trivial tree since all codes use
   * 5 bits.)
   */
  
  uch *_dist_code = Z_NULL;
  /* Distance codes. The first 256 values correspond to the distances
   * 3 .. 258, the last 256 values correspond to the top 8 bits of
   * the 15 bit distances.
   */
  
  uch *_length_code = Z_NULL;
  /* length code for each normalized match length (0 == MIN_MATCH) */
  
  static int *base_length = Z_NULL;
  /* First normalized length for each code (0 = MIN_MATCH) */
  
  static int *base_dist = Z_NULL;
  /* First normalized distance for each code (0 = distance of 1) */
  
  #else
  /* +++ trees.h */
  /* header created automatically with -DGEN_TREES_H */
  
  static const ct_data static_ltree[L_CODES+2] = {
  {{ 12},{  8}}, {{140},{  8}}, {{ 76},{  8}}, {{204},{  8}}, {{ 44},{  8}},
  {{172},{  8}}, {{108},{  8}}, {{236},{  8}}, {{ 28},{  8}}, {{156},{  8}},
  {{ 92},{  8}}, {{220},{  8}}, {{ 60},{  8}}, {{188},{  8}}, {{124},{  8}},
  {{252},{  8}}, {{  2},{  8}}, {{130},{  8}}, {{ 66},{  8}}, {{194},{  8}},
  {{ 34},{  8}}, {{162},{  8}}, {{ 98},{  8}}, {{226},{  8}}, {{ 18},{  8}},
  {{146},{  8}}, {{ 82},{  8}}, {{210},{  8}}, {{ 50},{  8}}, {{178},{  8}},
  {{114},{  8}}, {{242},{  8}}, {{ 10},{  8}}, {{138},{  8}}, {{ 74},{  8}},
  {{202},{  8}}, {{ 42},{  8}}, {{170},{  8}}, {{106},{  8}}, {{234},{  8}},
  {{ 26},{  8}}, {{154},{  8}}, {{ 90},{  8}}, {{218},{  8}}, {{ 58},{  8}},
  {{186},{  8}}, {{122},{  8}}, {{250},{  8}}, {{  6},{  8}}, {{134},{  8}},
  {{ 70},{  8}}, {{198},{  8}}, {{ 38},{  8}}, {{166},{  8}}, {{102},{  8}},
  {{230},{  8}}, {{ 22},{  8}}, {{150},{  8}}, {{ 86},{  8}}, {{214},{  8}},
  {{ 54},{  8}}, {{182},{  8}}, {{118},{  8}}, {{246},{  8}}, {{ 14},{  8}},
  {{142},{  8}}, {{ 78},{  8}}, {{206},{  8}}, {{ 46},{  8}}, {{174},{  8}},
  {{110},{  8}}, {{238},{  8}}, {{ 30},{  8}}, {{158},{  8}}, {{ 94},{  8}},
  {{222},{  8}}, {{ 62},{  8}}, {{190},{  8}}, {{126},{  8}}, {{254},{  8}},
  {{  1},{  8}}, {{129},{  8}}, {{ 65},{  8}}, {{193},{  8}}, {{ 33},{  8}},
  {{161},{  8}}, {{ 97},{  8}}, {{225},{  8}}, {{ 17},{  8}}, {{145},{  8}},
  {{ 81},{  8}}, {{209},{  8}}, {{ 49},{  8}}, {{177},{  8}}, {{113},{  8}},
  {{241},{  8}}, {{  9},{  8}}, {{137},{  8}}, {{ 73},{  8}}, {{201},{  8}},
  {{ 41},{  8}}, {{169},{  8}}, {{105},{  8}}, {{233},{  8}}, {{ 25},{  8}},
  {{153},{  8}}, {{ 89},{  8}}, {{217},{  8}}, {{ 57},{  8}}, {{185},{  8}},
  {{121},{  8}}, {{249},{  8}}, {{  5},{  8}}, {{133},{  8}}, {{ 69},{  8}},
  {{197},{  8}}, {{ 37},{  8}}, {{165},{  8}}, {{101},{  8}}, {{229},{  8}},
  {{ 21},{  8}}, {{149},{  8}}, {{ 85},{  8}}, {{213},{  8}}, {{ 53},{  8}},
  {{181},{  8}}, {{117},{  8}}, {{245},{  8}}, {{ 13},{  8}}, {{141},{  8}},
  {{ 77},{  8}}, {{205},{  8}}, {{ 45},{  8}}, {{173},{  8}}, {{109},{  8}},
  {{237},{  8}}, {{ 29},{  8}}, {{157},{  8}}, {{ 93},{  8}}, {{221},{  8}},
  {{ 61},{  8}}, {{189},{  8}}, {{125},{  8}}, {{253},{  8}}, {{ 19},{  9}},
  {{275},{  9}}, {{147},{  9}}, {{403},{  9}}, {{ 83},{  9}}, {{339},{  9}},
  {{211},{  9}}, {{467},{  9}}, {{ 51},{  9}}, {{307},{  9}}, {{179},{  9}},
  {{435},{  9}}, {{115},{  9}}, {{371},{  9}}, {{243},{  9}}, {{499},{  9}},
  {{ 11},{  9}}, {{267},{  9}}, {{139},{  9}}, {{395},{  9}}, {{ 75},{  9}},
  {{331},{  9}}, {{203},{  9}}, {{459},{  9}}, {{ 43},{  9}}, {{299},{  9}},
  {{171},{  9}}, {{427},{  9}}, {{107},{  9}}, {{363},{  9}}, {{235},{  9}},
  {{491},{  9}}, {{ 27},{  9}}, {{283},{  9}}, {{155},{  9}}, {{411},{  9}},
  {{ 91},{  9}}, {{347},{  9}}, {{219},{  9}}, {{475},{  9}}, {{ 59},{  9}},
  {{315},{  9}}, {{187},{  9}}, {{443},{  9}}, {{123},{  9}}, {{379},{  9}},
  {{251},{  9}}, {{507},{  9}}, {{  7},{  9}}, {{263},{  9}}, {{135},{  9}},
  {{391},{  9}}, {{ 71},{  9}}, {{327},{  9}}, {{199},{  9}}, {{455},{  9}},
  {{ 39},{  9}}, {{295},{  9}}, {{167},{  9}}, {{423},{  9}}, {{103},{  9}},
  {{359},{  9}}, {{231},{  9}}, {{487},{  9}}, {{ 23},{  9}}, {{279},{  9}},
  {{151},{  9}}, {{407},{  9}}, {{ 87},{  9}}, {{343},{  9}}, {{215},{  9}},
  {{471},{  9}}, {{ 55},{  9}}, {{311},{  9}}, {{183},{  9}}, {{439},{  9}},
  {{119},{  9}}, {{375},{  9}}, {{247},{  9}}, {{503},{  9}}, {{ 15},{  9}},
  {{271},{  9}}, {{143},{  9}}, {{399},{  9}}, {{ 79},{  9}}, {{335},{  9}},
  {{207},{  9}}, {{463},{  9}}, {{ 47},{  9}}, {{303},{  9}}, {{175},{  9}},
  {{431},{  9}}, {{111},{  9}}, {{367},{  9}}, {{239},{  9}}, {{495},{  9}},
  {{ 31},{  9}}, {{287},{  9}}, {{159},{  9}}, {{415},{  9}}, {{ 95},{  9}},
  {{351},{  9}}, {{223},{  9}}, {{479},{  9}}, {{ 63},{  9}}, {{319},{  9}},
  {{191},{  9}}, {{447},{  9}}, {{127},{  9}}, {{383},{  9}}, {{255},{  9}},
  {{511},{  9}}, {{  0},{  7}}, {{ 64},{  7}}, {{ 32},{  7}}, {{ 96},{  7}},
  {{ 16},{  7}}, {{ 80},{  7}}, {{ 48},{  7}}, {{112},{  7}}, {{  8},{  7}},
  {{ 72},{  7}}, {{ 40},{  7}}, {{104},{  7}}, {{ 24},{  7}}, {{ 88},{  7}},
  {{ 56},{  7}}, {{120},{  7}}, {{  4},{  7}}, {{ 68},{  7}}, {{ 36},{  7}},
  {{100},{  7}}, {{ 20},{  7}}, {{ 84},{  7}}, {{ 52},{  7}}, {{116},{  7}},
  {{  3},{  8}}, {{131},{  8}}, {{ 67},{  8}}, {{195},{  8}}, {{ 35},{  8}},
  {{163},{  8}}, {{ 99},{  8}}, {{227},{  8}}
  };
  
  static const ct_data static_dtree[D_CODES] = {
  {{ 0},{ 5}}, {{16},{ 5}}, {{ 8},{ 5}}, {{24},{ 5}}, {{ 4},{ 5}},
  {{20},{ 5}}, {{12},{ 5}}, {{28},{ 5}}, {{ 2},{ 5}}, {{18},{ 5}},
  {{10},{ 5}}, {{26},{ 5}}, {{ 6},{ 5}}, {{22},{ 5}}, {{14},{ 5}},
  {{30},{ 5}}, {{ 1},{ 5}}, {{17},{ 5}}, {{ 9},{ 5}}, {{25},{ 5}},
  {{ 5},{ 5}}, {{21},{ 5}}, {{13},{ 5}}, {{29},{ 5}}, {{ 3},{ 5}},
  {{19},{ 5}}, {{11},{ 5}}, {{27},{ 5}}, {{ 7},{ 5}}, {{23},{ 5}}
  };
  
  const uch _dist_code[DIST_CODE_LEN] = {
   0,  1,  2,  3,  4,  4,  5,  5,  6,  6,  6,  6,  7,  7,  7,  7,  8,  8,  8,  8,
   8,  8,  8,  8,  9,  9,  9,  9,  9,  9,  9,  9, 10, 10, 10, 10, 10, 10, 10, 10,
  10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
  11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12,
  12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13,
  13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
  13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
  14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
  14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
  14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15,
  15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
  15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
  15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,  0,  0, 16, 17,
  18, 18, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22,
  23, 23, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
  24, 24, 24, 24, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
  26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
  26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 27, 27,
  27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
  27, 27, 27, 27, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
  28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
  28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
  28, 28, 28, 28, 28, 28, 28, 28, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
  29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
  29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
  29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29
  };
  
  const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {
   0,  1,  2,  3,  4,  5,  6,  7,  8,  8,  9,  9, 10, 10, 11, 11, 12, 12, 12, 12,
  13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16,
  17, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19,
  19, 19, 19, 19, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
  21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22,
  22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 23, 23,
  23, 23, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
  24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
  25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
  25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 26, 26, 26, 26, 26, 26, 26, 26,
  26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
  26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
  27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 28
  };
  
  static const int base_length[LENGTH_CODES] = {
  0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, 24, 28, 32, 40, 48, 56,
  64, 80, 96, 112, 128, 160, 192, 224, 0
  };
  
  static const int base_dist[D_CODES] = {
      0,     1,     2,     3,     4,     6,     8,    12,    16,    24,
     32,    48,    64,    96,   128,   192,   256,   384,   512,   768,
   1024,  1536,  2048,  3072,  4096,  6144,  8192, 12288, 16384, 24576
  };
  
  /* --- trees.h */
  #endif /* GEN_TREES_H */
  
  struct static_tree_desc_s {
      const ct_data *static_tree;  /* static tree or NULL */
      const intf *extra_bits;      /* extra bits for each code or NULL */
      int     extra_base;          /* base index for extra_bits */
      int     elems;               /* max number of elements in the tree */
      int     max_length;          /* max bit length for the codes */
  };
  
  static static_tree_desc  static_l_desc =
  {NULL, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
  
  static static_tree_desc  static_d_desc =
  {NULL, extra_dbits, 0,          D_CODES, MAX_BITS};
  
  static static_tree_desc  static_bl_desc =
  {(const ct_data *)0, extra_blbits, 0,   BL_CODES, MAX_BL_BITS};
  
  /* ===========================================================================
   * Local (static) routines in this file.
   */
  
  static int tr_static_init  OF((z_streamp z));
  static void init_block     OF((deflate_state *s));
  static void pqdownheap     OF((deflate_state *s, ct_data *tree, int k));
  static void gen_bitlen     OF((deflate_state *s, tree_desc *desc));
  static void gen_codes      OF((ct_data *tree, int max_code, ushf *bl_count));
  static void build_tree     OF((deflate_state *s, tree_desc *desc));
  static void scan_tree      OF((deflate_state *s, ct_data *tree, int max_code));
  static void send_tree      OF((deflate_state *s, ct_data *tree, int max_code));
  static int  build_bl_tree  OF((deflate_state *s));
  static void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
                                int blcodes));
  static void compress_block OF((deflate_state *s, ct_data *ltree,
                                ct_data *dtree));
  static void set_data_type  OF((deflate_state *s));
  static unsigned bi_reverse OF((unsigned value, int length));
  static void bi_windup      OF((deflate_state *s));
  static void bi_flush       OF((deflate_state *s));
  static void copy_block     OF((deflate_state *s, charf *buf, unsigned len,
                                int header));
  
  #ifdef GEN_TREES_H
  static void gen_trees_header OF((void));
  #endif
  
  #ifndef DEBUG_ZLIB
  #  define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
     /* Send a code of the given tree. c and tree must not have side effects */
  
  #else /* DEBUG_ZLIB */
  #  define send_code(s, c, tree) \
       { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
         send_bits(s, tree[c].Code, tree[c].Len); }
  #endif
  
  /* ===========================================================================
   * Output a short LSB first on the stream.
   * IN assertion: there is enough room in pendingBuf.
   */
  #define put_short(s, w) { \
      put_byte(s, (uch)((w) & 0xff)); \
      put_byte(s, (uch)((ush)(w) >> 8)); \
  }
  
  /* ===========================================================================
   * Send a value on a given number of bits.
   * IN assertion: length <= 16 and value fits in length bits.
   */
  #ifdef DEBUG_ZLIB
  static void send_bits      OF((deflate_state *s, int value, int length));
  
  static void send_bits(deflate_state *s, int value, int length)
  {
      Tracevv((stderr," l %2d v %4x ", length, value));
      Assert(length > 0 && length <= 15, "invalid length");
      s->bits_sent += (ulg)length;
  
      /* If not enough room in bi_buf, use (valid) bits from bi_buf and
       * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
       * unused bits in value.
       */
      if (s->bi_valid > (int)Buf_size - length) {
          s->bi_buf |= (value << s->bi_valid);
          put_short(s, s->bi_buf);
          s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
          s->bi_valid += length - Buf_size;
      } else {
          s->bi_buf |= value << s->bi_valid;
          s->bi_valid += length;
      }
  }
  #else /* !DEBUG_ZLIB */
  
  #define send_bits(s, value, length) \
  { int len = length;\
    if (s->bi_valid > (int)Buf_size - len) {\
      int val = value;\
      s->bi_buf |= (val << s->bi_valid);\
      put_short(s, s->bi_buf);\
      s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
      s->bi_valid += len - Buf_size;\
    } else {\
      s->bi_buf |= (value) << s->bi_valid;\
      s->bi_valid += len;\
    }\
  }
  #endif /* DEBUG_ZLIB */
  
  
  #ifndef MAX
  #define MAX(a,b) (a >= b ? a : b)
  #endif
  /* the arguments must not have side effects */
  
  typedef struct {
          ct_data static_ltree[L_CODES+2];
          ct_data static_dtree[D_CODES];
          uch             _dist_code[DIST_CODE_LEN];
          uch             _length_code[MAX_MATCH-MIN_MATCH+1];
          int             base_length[LENGTH_CODES];
          int             base_dist[D_CODES];
  } __used_to_be_static;
  
  #if defined(GEN_TREES_H) || !defined(STDC)
  static __used_to_be_static      *static_storage = Z_NULL;
  #endif /* defined(GEN_TREES_H) || !defined(STDC) */
  
  /* ===========================================================================
   * Initialize the various 'constant' tables.
   */
  static int tr_static_init(
          z_streamp       z)
  {
  #if defined(GEN_TREES_H) || !defined(STDC)
      static int static_init_done = 0;
      int n;        /* iterates over tree elements */
      int bits;     /* bit counter */
      int length;   /* length value */
      int code;     /* code value */
      int dist;     /* distance index */
      ush bl_count[MAX_BITS+1];
      /* number of codes at each bit length for an optimal tree */
  
      if (static_init_done) return Z_OK;
      
      /* allocate storage for static structures */
      if (static_storage == Z_NULL) {
          static_storage = (__used_to_be_static*)ZALLOC(z, 1, sizeof(__used_to_be_static));
          if (static_storage == Z_NULL)
                  return Z_MEM_ERROR;
      }
      
      static_ltree = static_storage->static_ltree;
      static_dtree = static_storage->static_dtree;
      _dist_code = static_storage->_dist_code;
      _length_code = static_storage->_length_code;
      base_length = static_storage->base_length;
      base_dist = static_storage->base_dist;
      
      /* For some embedded targets, global variables are not initialized: */
      static_l_desc.static_tree = static_ltree;
      static_l_desc.extra_bits = extra_lbits;
      static_d_desc.static_tree = static_dtree;
      static_d_desc.extra_bits = extra_dbits;
      static_bl_desc.extra_bits = extra_blbits;
  
      /* Initialize the mapping length (0..255) -> length code (0..28) */
      length = 0;
      for (code = 0; code < LENGTH_CODES-1; code++) {
          base_length[code] = length;
          for (n = 0; n < (1<<extra_lbits[code]); n++) {
              _length_code[length++] = (uch)code;
          }
      }
      Assert (length == 256, "tr_static_init: length != 256");
      /* Note that the length 255 (match length 258) can be represented
       * in two different ways: code 284 + 5 bits or code 285, so we
       * overwrite length_code[255] to use the best encoding:
       */
      _length_code[length-1] = (uch)code;
  
      /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
      dist = 0;
      for (code = 0 ; code < 16; code++) {
          base_dist[code] = dist;
          for (n = 0; n < (1<<extra_dbits[code]); n++) {
              _dist_code[dist++] = (uch)code;
          }
      }
      Assert (dist == 256, "tr_static_init: dist != 256");
      dist >>= 7; /* from now on, all distances are divided by 128 */
      for ( ; code < D_CODES; code++) {
          base_dist[code] = dist << 7;
          for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
              _dist_code[256 + dist++] = (uch)code;
          }
      }
      Assert (dist == 256, "tr_static_init: 256+dist != 512");
  
      /* Construct the codes of the static literal tree */
      for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
      n = 0;
      while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
      while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
      while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
      while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
      /* Codes 286 and 287 do not exist, but we must include them in the
       * tree construction to get a canonical Huffman tree (longest code
       * all ones)
       */
      gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
  
      /* The static distance tree is trivial: */
      for (n = 0; n < D_CODES; n++) {
          static_dtree[n].Len = 5;
          static_dtree[n].Code = bi_reverse((unsigned)n, 5);
      }
      static_init_done = 1;
  
  #  ifdef GEN_TREES_H
      gen_trees_header();
  #  endif
  #endif /* defined(GEN_TREES_H) || !defined(STDC) */
      return Z_OK;
  }
  
  /* ===========================================================================
   * Genererate the file trees.h describing the static trees.
   */
  #ifdef GEN_TREES_H
  #  ifndef DEBUG_ZLIB
  #    include <stdio.h>
  #  endif
  
  #  define SEPARATOR(i, last, width) \
        ((i) == (last)? "\n};\n\n" :    \
         ((i) % (width) == (width)-1 ? ",\n" : ", "))
  
  void gen_trees_header()
  {
      FILE *header = fopen("trees.h", "w");
      int i;
  
      Assert (header != NULL, "Can't open trees.h");
      fprintf(header,
              "/* header created automatically with -DGEN_TREES_H */\n\n");
  
      fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
      for (i = 0; i < L_CODES+2; i++) {
          fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
                  static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
      }
  
      fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
      for (i = 0; i < D_CODES; i++) {
          fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
                  static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
      }
  
      fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n");
      for (i = 0; i < DIST_CODE_LEN; i++) {
          fprintf(header, "%2u%s", _dist_code[i],
                  SEPARATOR(i, DIST_CODE_LEN-1, 20));
      }
  
      fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
      for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
          fprintf(header, "%2u%s", _length_code[i],
                  SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
      }
  
      fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
      for (i = 0; i < LENGTH_CODES; i++) {
          fprintf(header, "%1u%s", base_length[i],
                  SEPARATOR(i, LENGTH_CODES-1, 20));
      }
  
      fprintf(header, "local const int base_dist[D_CODES] = {\n");
      for (i = 0; i < D_CODES; i++) {
          fprintf(header, "%5u%s", base_dist[i],
                  SEPARATOR(i, D_CODES-1, 10));
      }
  
      fclose(header);
  }
  #endif /* GEN_TREES_H */
  
  /* ===========================================================================
   * Initialize the tree data structures for a new zlib stream.
   */
  static void
  _tr_init(deflate_state *s)
  {
      tr_static_init(s->strm);
  
      s->l_desc.dyn_tree = s->dyn_ltree;
      s->l_desc.stat_desc = &static_l_desc;
  
      s->d_desc.dyn_tree = s->dyn_dtree;
      s->d_desc.stat_desc = &static_d_desc;
  
      s->bl_desc.dyn_tree = s->bl_tree;
      s->bl_desc.stat_desc = &static_bl_desc;
  
      s->bi_buf = 0;
      s->bi_valid = 0;
      s->last_eob_len = 8; /* enough lookahead for inflate */
  #ifdef DEBUG_ZLIB
      s->compressed_len = 0L;
      s->bits_sent = 0L;
  #endif
  
      /* Initialize the first block of the first file: */
      init_block(s);
  }
  
  /* ===========================================================================
   * Initialize a new block.
   */
  static void
  init_block(deflate_state *s)
  {
      int n; /* iterates over tree elements */
  
      /* Initialize the trees. */
      for (n = 0; n < L_CODES;  n++) s->dyn_ltree[n].Freq = 0;
      for (n = 0; n < D_CODES;  n++) s->dyn_dtree[n].Freq = 0;
      for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
  
      s->dyn_ltree[END_BLOCK].Freq = 1;
      s->opt_len = s->static_len = 0L;
      s->last_lit = s->matches = 0;
  }
  
  #define SMALLEST 1
  /* Index within the heap array of least frequent node in the Huffman tree */
  
  
  /* ===========================================================================
   * Remove the smallest element from the heap and recreate the heap with
   * one less element. Updates heap and heap_len.
   */
  #define pqremove(s, tree, top) \
  {\
      top = s->heap[SMALLEST]; \
      s->heap[SMALLEST] = s->heap[s->heap_len--]; \
      pqdownheap(s, tree, SMALLEST); \
  }
  
  /* ===========================================================================
   * Compares to subtrees, using the tree depth as tie breaker when
   * the subtrees have equal frequency. This minimizes the worst case length.
   */
  #define smaller(tree, n, m, depth) \
     (tree[n].Freq < tree[m].Freq || \
     (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
  
  /* ===========================================================================
   * Restore the heap property by moving down the tree starting at node k,
   * exchanging a node with the smallest of its two sons if necessary, stopping
   * when the heap property is re-established (each father smaller than its
   * two sons).
   * ct_data *tree;  the tree to restore
   * int k;               node to move down
   */
  static void
  pqdownheap(deflate_state *s, ct_data *tree, int k)
  {
      int v = s->heap[k];
      int j = k << 1;  /* left son of k */
      while (j <= s->heap_len) {
          /* Set j to the smallest of the two sons: */
          if (j < s->heap_len &&
              smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
              j++;
          }
          /* Exit if v is smaller than both sons */
          if (smaller(tree, v, s->heap[j], s->depth)) break;
  
          /* Exchange v with the smallest son */
          s->heap[k] = s->heap[j];  k = j;
  
          /* And continue down the tree, setting j to the left son of k */
          j <<= 1;
      }
      s->heap[k] = v;
  }
  
  /* ===========================================================================
   * Compute the optimal bit lengths for a tree and update the total bit length
   * for the current block.
   * IN assertion: the fields freq and dad are set, heap[heap_max] and
   *    above are the tree nodes sorted by increasing frequency.
   * OUT assertions: the field len is set to the optimal bit length, the
   *     array bl_count contains the frequencies for each bit length.
   *     The length opt_len is updated; static_len is also updated if stree is
   *     not null.
   */
  static void
  gen_bitlen(deflate_state *s, tree_desc *desc)
  {
      ct_data *tree        = desc->dyn_tree;
      int max_code         = desc->max_code;
      const ct_data *stree = desc->stat_desc->static_tree;
      const intf *extra    = desc->stat_desc->extra_bits;
      int base             = desc->stat_desc->extra_base;
      int max_length       = desc->stat_desc->max_length;
      int h;              /* heap index */
      int n, m;           /* iterate over the tree elements */
      int bits;           /* bit length */
      int xbits;          /* extra bits */
      ush f;              /* frequency */
      int overflow = 0;   /* number of elements with bit length too large */
  
      for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
  
      /* In a first pass, compute the optimal bit lengths (which may
       * overflow in the case of the bit length tree).
       */
      tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
  
      for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
          n = s->heap[h];
          bits = tree[tree[n].Dad].Len + 1;
          if (bits > max_length) bits = max_length, overflow++;
          tree[n].Len = (ush)bits;
          /* We overwrite tree[n].Dad which is no longer needed */
  
          if (n > max_code) continue; /* not a leaf node */
  
          s->bl_count[bits]++;
          xbits = 0;
          if (n >= base) xbits = extra[n-base];
          f = tree[n].Freq;
          s->opt_len += (ulg)f * (bits + xbits);
          if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
      }
      if (overflow == 0) return;
  
      Trace((stderr,"\nbit length overflow\n"));
      /* This happens for example on obj2 and pic of the Calgary corpus */
  
      /* Find the first bit length which could increase: */
      do {
          bits = max_length-1;
          while (s->bl_count[bits] == 0) bits--;
          s->bl_count[bits]--;      /* move one leaf down the tree */
          s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
          s->bl_count[max_length]--;
          /* The brother of the overflow item also moves one step up,
           * but this does not affect bl_count[max_length]
           */
          overflow -= 2;
      } while (overflow > 0);
  
      /* Now recompute all bit lengths, scanning in increasing frequency.
       * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
       * lengths instead of fixing only the wrong ones. This idea is taken
       * from 'ar' written by Haruhiko Okumura.)
       */
      for (bits = max_length; bits != 0; bits--) {
          n = s->bl_count[bits];
          while (n != 0) {
              m = s->heap[--h];
              if (m > max_code) continue;
              if (tree[m].Len != (unsigned) bits) {
                  Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
                  s->opt_len += ((long)bits - (long)tree[m].Len)
                                *(long)tree[m].Freq;
                  tree[m].Len = (ush)bits;
              }
              n--;
          }
      }
  }
  
  /* ===========================================================================
   * Generate the codes for a given tree and bit counts (which need not be
   * optimal).
   * IN assertion: the array bl_count contains the bit length statistics for
   * the given tree and the field len is set for all tree elements.
   * OUT assertion: the field code is set for all tree elements of non
   *     zero code length.
   *
   * ct_data *tree;             the tree to decorate
   * int max_code;              largest code with non zero frequency
   * ushf *bl_count;            number of codes at each bit length
   */
  static void
  gen_codes(ct_data *tree, int max_code, ushf *bl_count)
  {
      ush next_code[MAX_BITS+1]; /* next code value for each bit length */
      ush code = 0;              /* running code value */
      int bits;                  /* bit index */
      int n;                     /* code index */
  
      /* The distribution counts are first used to generate the code values
       * without bit reversal.
       */
      for (bits = 1; bits <= MAX_BITS; bits++) {
          next_code[bits] = code = (code + bl_count[bits-1]) << 1;
      }
      /* Check that the bit counts in bl_count are consistent. The last code
       * must be all ones.
       */
      Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
              "inconsistent bit counts");
      Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
  
      for (n = 0;  n <= max_code; n++) {
          int len = tree[n].Len;
          if (len == 0) continue;
          /* Now reverse the bits */
          tree[n].Code = bi_reverse(next_code[len]++, len);
  
          Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
               n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
      }
  }
  
  /* ===========================================================================
   * Construct one Huffman tree and assigns the code bit strings and lengths.
   * Update the total bit length for the current block.
   * IN assertion: the field freq is set for all tree elements.
   * OUT assertions: the fields len and code are set to the optimal bit length
   *     and corresponding code. The length opt_len is updated; static_len is
   *     also updated if stree is not null. The field max_code is set.
   */
  static void
  build_tree(deflate_state *s, tree_desc *desc)
  {
      ct_data *tree         = desc->dyn_tree;
      const ct_data *stree  = desc->stat_desc->static_tree;
      int elems             = desc->stat_desc->elems;
      int n, m;          /* iterate over heap elements */
      int max_code = -1; /* largest code with non zero frequency */
      int node;          /* new node being created */
  
      /* Construct the initial heap, with least frequent element in
       * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
       * heap[0] is not used.
       */
      s->heap_len = 0, s->heap_max = HEAP_SIZE;
  
      for (n = 0; n < elems; n++) {
          if (tree[n].Freq != 0) {
              s->heap[++(s->heap_len)] = max_code = n;
              s->depth[n] = 0;
          } else {
              tree[n].Len = 0;
          }
      }
  
      /* The pkzip format requires that at least one distance code exists,
       * and that at least one bit should be sent even if there is only one
       * possible code. So to avoid special checks later on we force at least
       * two codes of non zero frequency.
       */
      while (s->heap_len < 2) {
          node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
          tree[node].Freq = 1;
          s->depth[node] = 0;
          s->opt_len--; if (stree) s->static_len -= stree[node].Len;
          /* node is 0 or 1 so it does not have extra bits */
      }
      desc->max_code = max_code;
  
      /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
       * establish sub-heaps of increasing lengths:
       */
      for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
  
      /* Construct the Huffman tree by repeatedly combining the least two
       * frequent nodes.
       */
      node = elems;              /* next internal node of the tree */
      do {
          pqremove(s, tree, n);  /* n = node of least frequency */
          m = s->heap[SMALLEST]; /* m = node of next least frequency */
  
          s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
          s->heap[--(s->heap_max)] = m;
  
          /* Create a new node father of n and m */
          tree[node].Freq = tree[n].Freq + tree[m].Freq;
          s->depth[node] = (uch) (MAX(s->depth[n], s->depth[m]) + 1);
          tree[n].Dad = tree[m].Dad = (ush)node;
  #ifdef DUMP_BL_TREE
          if (tree == s->bl_tree) {
              fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
                      node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
          }
  #endif
          /* and insert the new node in the heap */
          s->heap[SMALLEST] = node++;
          pqdownheap(s, tree, SMALLEST);
  
      } while (s->heap_len >= 2);
  
      s->heap[--(s->heap_max)] = s->heap[SMALLEST];
  
      /* At this point, the fields freq and dad are set. We can now
       * generate the bit lengths.
       */
      gen_bitlen(s, (tree_desc *)desc);
  
      /* The field len is now set, we can generate the bit codes */
      gen_codes ((ct_data *)tree, max_code, s->bl_count);
  }
  
  /* ===========================================================================
   * Scan a literal or distance tree to determine the frequencies of the codes
   * in the bit length tree.
   *
   * ct_data *tree;   the tree to be scanned
   * int max_code;    and its largest code of non zero frequency
   */
  static void
  scan_tree(deflate_state *s, ct_data *tree, int max_code)
  {
      int n;                     /* iterates over all tree elements */
      int prevlen = -1;          /* last emitted length */
      int curlen;                /* length of current code */
      int nextlen = tree[0].Len; /* length of next code */
      int count = 0;             /* repeat count of the current code */
      int max_count = 7;         /* max repeat count */
      int min_count = 4;         /* min repeat count */
  
      if (nextlen == 0) max_count = 138, min_count = 3;
      tree[max_code+1].Len = (ush)0xffff; /* guard */
  
      for (n = 0; n <= max_code; n++) {
          curlen = nextlen; nextlen = tree[n+1].Len;
          if (++count < max_count && curlen == nextlen) {
              continue;
          } else if (count < min_count) {
              s->bl_tree[curlen].Freq += count;
          } else if (curlen != 0) {
              if (curlen != prevlen) s->bl_tree[curlen].Freq++;
              s->bl_tree[REP_3_6].Freq++;
          } else if (count <= 10) {
              s->bl_tree[REPZ_3_10].Freq++;
          } else {
              s->bl_tree[REPZ_11_138].Freq++;
          }
          count = 0; prevlen = curlen;
          if (nextlen == 0) {
              max_count = 138, min_count = 3;
          } else if (curlen == nextlen) {
              max_count = 6, min_count = 3;
          } else {
              max_count = 7, min_count = 4;
          }
      }
  }
  
  /* ===========================================================================
   * Send a literal or distance tree in compressed form, using the codes in
   * bl_tree.
   *
   * ct_data *tree; the tree to be scanned
   * int max_code;       and its largest code of non zero frequency
   */
  static void
  send_tree(deflate_state *s, ct_data *tree, int max_code)
  {
      int n;                     /* iterates over all tree elements */
      int prevlen = -1;          /* last emitted length */
      int curlen;                /* length of current code */
      int nextlen = tree[0].Len; /* length of next code */
      int count = 0;             /* repeat count of the current code */
      int max_count = 7;         /* max repeat count */
      int min_count = 4;         /* min repeat count */
  
      /* tree[max_code+1].Len = -1; */  /* guard already set */
      if (nextlen == 0) max_count = 138, min_count = 3;
  
      for (n = 0; n <= max_code; n++) {
          curlen = nextlen; nextlen = tree[n+1].Len;
          if (++count < max_count && curlen == nextlen) {
              continue;
          } else if (count < min_count) {
              do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
  
          } else if (curlen != 0) {
              if (curlen != prevlen) {
                  send_code(s, curlen, s->bl_tree); count--;
              }
              Assert(count >= 3 && count <= 6, " 3_6?");
              send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
  
          } else if (count <= 10) {
              send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
  
          } else {
              send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
          }
          count = 0; prevlen = curlen;
          if (nextlen == 0) {
              max_count = 138, min_count = 3;
          } else if (curlen == nextlen) {
              max_count = 6, min_count = 3;
          } else {
              max_count = 7, min_count = 4;
          }
      }
  }
  
  /* ===========================================================================
   * Construct the Huffman tree for the bit lengths and return the index in
   * bl_order of the last bit length code to send.
   */
  static int
  build_bl_tree(deflate_state *s)
  {
      int max_blindex;  /* index of last bit length code of non zero freq */
  
      /* Determine the bit length frequencies for literal and distance trees */
      scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
      scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
  
      /* Build the bit length tree: */
      build_tree(s, (tree_desc *)(&(s->bl_desc)));
      /* opt_len now includes the length of the tree representations, except
       * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
       */
  
      /* Determine the number of bit length codes to send. The pkzip format
       * requires that at least 4 bit length codes be sent. (appnote.txt says
       * 3 but the actual value used is 4.)
       */
      for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
          if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
      }
      /* Update opt_len to include the bit length tree and counts */
      s->opt_len += 3*(max_blindex+1) + 5+5+4;
      Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
              s->opt_len, s->static_len));
  
      return max_blindex;
  }
  
  /* ===========================================================================
   * Send the header for a block using dynamic Huffman trees: the counts, the
   * lengths of the bit length codes, the literal tree and the distance tree.
   * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
   */
  static void
  send_all_trees(deflate_state *s, int lcodes, int dcodes, int blcodes)
  {
      int rank;                    /* index in bl_order */
  
      Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
      Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
              "too many codes");
      Tracev((stderr, "\nbl counts: "));
      send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
      send_bits(s, dcodes-1,   5);
      send_bits(s, blcodes-4,  4); /* not -3 as stated in appnote.txt */
      for (rank = 0; rank < blcodes; rank++) {
          Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
          send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
      }
      Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
  
      send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
      Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
  
      send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
      Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
  }
  
  /* ===========================================================================
   * Send a stored block
   *
   * charf *buf;       input block
   * ulg stored_len;   length of input block
   * int eof;          true if this is the last block for a file
   */
  static void
  _tr_stored_block(deflate_state *s, charf *buf, ulg stored_len, int eof)
  {
      send_bits(s, (STORED_BLOCK<<1)+eof, 3);  /* send block type */
  #ifdef DEBUG_ZLIB
      s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
      s->compressed_len += (stored_len + 4) << 3;
  #endif
      copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
  }
  
  /* ===========================================================================
   * Send one empty static block to give enough lookahead for inflate.
   * This takes 10 bits, of which 7 may remain in the bit buffer.
   * The current inflate code requires 9 bits of lookahead. If the
   * last two codes for the previous block (real code plus EOB) were coded
   * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
   * the last real code. In this case we send two empty static blocks instead
   * of one. (There are no problems if the previous block is stored or fixed.)
   * To simplify the code, we assume the worst case of last real code encoded
   * on one bit only.
   */
  static void
  _tr_align(deflate_state *s)
  {
      send_bits(s, STATIC_TREES<<1, 3);
      send_code(s, END_BLOCK, static_ltree);
  #ifdef DEBUG_ZLIB
      s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
  #endif
      bi_flush(s);
      /* Of the 10 bits for the empty block, we have already sent
       * (10 - bi_valid) bits. The lookahead for the last real code (before
       * the EOB of the previous block) was thus at least one plus the length
       * of the EOB plus what we have just sent of the empty static block.
       */
      if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
          send_bits(s, STATIC_TREES<<1, 3);
          send_code(s, END_BLOCK, static_ltree);
  #ifdef DEBUG_ZLIB
          s->compressed_len += 10L;
  #endif
          bi_flush(s);
      }
      s->last_eob_len = 7;
  }
  
  /* ===========================================================================
   * Determine the best encoding for the current block: dynamic trees, static
   * trees or store, and output the encoded block to the zip file.
   *
   * charf *buf;       input block, or NULL if too old
   * ulg stored_len;   length of input block
   * int eof;          true if this is the last block for a file
   */
  static void
  _tr_flush_block(deflate_state *s, charf *buf, ulg stored_len, int eof)
  {
      ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
      int max_blindex = 0;  /* index of last bit length code of non zero freq */
  
      /* Build the Huffman trees unless a stored block is forced */
      if (s->level > 0) {
  
           /* Check if the file is ascii or binary */
          if (s->data_type == Z_UNKNOWN) set_data_type(s);
  
          /* Construct the literal and distance trees */
          build_tree(s, (tree_desc *)(&(s->l_desc)));
          Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
                  s->static_len));
  
          build_tree(s, (tree_desc *)(&(s->d_desc)));
          Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
                  s->static_len));
          /* At this point, opt_len and static_len are the total bit lengths of
           * the compressed block data, excluding the tree representations.
           */
  
          /* Build the bit length tree for the above two trees, and get the index
           * in bl_order of the last bit length code to send.
           */
          max_blindex = build_bl_tree(s);
  
          /* Determine the best encoding. Compute first the block length in bytes*/
          opt_lenb = (s->opt_len+3+7)>>3;
          static_lenb = (s->static_len+3+7)>>3;
  
          Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
                  opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
                  s->last_lit));
  
          if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
  
      } else {
          Assert(buf != (char*)0, "lost buf");
          opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
      }
  
  #ifdef FORCE_STORED
      if (buf != (char*)0) { /* force stored block */
  #else
      if (stored_len+4 <= opt_lenb && buf != (char*)0) {
                         /* 4: two words for the lengths */
  #endif
          /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
           * Otherwise we can't have processed more than WSIZE input bytes since
           * the last block flush, because compression would have been
           * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
           * transform a block into a stored block.
           */
          _tr_stored_block(s, buf, stored_len, eof);
  
  #ifdef FORCE_STATIC
      } else if (static_lenb >= 0) { /* force static trees */
  #else
      } else if (static_lenb == opt_lenb) {
  #endif
          send_bits(s, (STATIC_TREES<<1)+eof, 3);
          compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
  #ifdef DEBUG_ZLIB
          s->compressed_len += 3 + s->static_len;
  #endif
      } else {
          send_bits(s, (DYN_TREES<<1)+eof, 3);
          send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
                         max_blindex+1);
          compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
  #ifdef DEBUG_ZLIB
          s->compressed_len += 3 + s->opt_len;
  #endif
      }
      Assert (s->compressed_len == s->bits_sent, "bad compressed size");
      /* The above check is made mod 2^32, for files larger than 512 MB
       * and uLong implemented on 32 bits.
       */
      init_block(s);
  
      if (eof) {
          bi_windup(s);
  #ifdef DEBUG_ZLIB
          s->compressed_len += 7;  /* align on byte boundary */
  #endif
      }
      Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
             s->compressed_len-7*eof));
  }
  
  /* ===========================================================================
   * Save the match info and tally the frequency counts. Return true if
   * the current block must be flushed.
   *
   * unsigned dist;  distance of matched string
   * unsigned lc;    match length-MIN_MATCH or unmatched char (if dist==0)
   */
  static int
  _tr_tally(deflate_state *s, unsigned int dist, unsigned int lc)
  {
      s->d_buf[s->last_lit] = (ush)dist;
      s->l_buf[s->last_lit++] = (uch)lc;
      if (dist == 0) {
          /* lc is the unmatched char */
          s->dyn_ltree[lc].Freq++;
      } else {
          s->matches++;
          /* Here, lc is the match length - MIN_MATCH */
          dist--;             /* dist = match distance - 1 */
          Assert((ush)dist < (ush)MAX_DIST(s) &&
                 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
                 (ush)d_code(dist) < (ush)D_CODES,  "_tr_tally: bad match");
  
          s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
          s->dyn_dtree[d_code(dist)].Freq++;
      }
  
  #ifdef TRUNCATE_BLOCK
      /* Try to guess if it is profitable to stop the current block here */
      if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
          /* Compute an upper bound for the compressed length */
          ulg out_length = (ulg)s->last_lit*8L;
          ulg in_length = (ulg)((long)s->strstart - s->block_start);
          int dcode;
          for (dcode = 0; dcode < D_CODES; dcode++) {
              out_length += (ulg)s->dyn_dtree[dcode].Freq *
                  (5L+extra_dbits[dcode]);
          }
          out_length >>= 3;
          Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
                 s->last_lit, in_length, out_length,
                 100L - out_length*100L/in_length));
          if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
      }
  #endif
      return (s->last_lit == s->lit_bufsize-1);
      /* We avoid equality with lit_bufsize because of wraparound at 64K
       * on 16 bit machines and because stored blocks are restricted to
       * 64K-1 bytes.
       */
  }
  
  /* ===========================================================================
   * Send the block data compressed using the given Huffman trees
   *
   * ct_data *ltree; literal tree
   * ct_data *dtree; distance tree
   */
  static void
  compress_block(deflate_state *s, ct_data *ltree, ct_data *dtree)
  {
      unsigned dist;      /* distance of matched string */
      int lc;             /* match length or unmatched char (if dist == 0) */
      unsigned lx = 0;    /* running index in l_buf */
      unsigned code;      /* the code to send */
      int extra;          /* number of extra bits to send */
  
      if (s->last_lit != 0) do {
          dist = s->d_buf[lx];
          lc = s->l_buf[lx++];
          if (dist == 0) {
              send_code(s, lc, ltree); /* send a literal byte */
              Tracecv(isgraph(lc), (stderr," '%c' ", lc));
          } else {
              /* Here, lc is the match length - MIN_MATCH */
              code = _length_code[lc];
              send_code(s, code+LITERALS+1, ltree); /* send the length code */
              extra = extra_lbits[code];
              if (extra != 0) {
                  lc -= base_length[code];
                  send_bits(s, lc, extra);       /* send the extra length bits */
              }
              dist--; /* dist is now the match distance - 1 */
              code = d_code(dist);
              Assert (code < D_CODES, "bad d_code");
  
              send_code(s, code, dtree);       /* send the distance code */
              extra = extra_dbits[code];
              if (extra != 0) {
                  dist -= base_dist[code];
                  send_bits(s, dist, extra);   /* send the extra distance bits */
              }
          } /* literal or match pair ? */
  
          /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
          Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow");
  
      } while (lx < s->last_lit);
  
      send_code(s, END_BLOCK, ltree);
      s->last_eob_len = ltree[END_BLOCK].Len;
  }
  
  /* ===========================================================================
   * Set the data type to ASCII or BINARY, using a crude approximation:
   * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
   * IN assertion: the fields freq of dyn_ltree are set and the total of all
   * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
   */
  static void
  set_data_type(deflate_state *s)
  {
      int n = 0;
      unsigned ascii_freq = 0;
      unsigned bin_freq = 0;
      while (n < 7)        bin_freq += s->dyn_ltree[n++].Freq;
      while (n < 128)    ascii_freq += s->dyn_ltree[n++].Freq;
      while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq;
      s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII);
  }
  
  /* ===========================================================================
   * Reverse the first len bits of a code, using straightforward code (a faster
   * method would use a table)
   * IN assertion: 1 <= len <= 15
   */
  static unsigned
  bi_reverse(unsigned code, int len)
  {
      unsigned res = 0;
      do {
          res |= code & 1;
          code >>= 1, res <<= 1;
      } while (--len > 0);
      return res >> 1;
  }
  
  /* ===========================================================================
   * Flush the bit buffer, keeping at most 7 bits in it.
   */
  static void
  bi_flush(deflate_state *s)
  {
      if (s->bi_valid == 16) {
          put_short(s, s->bi_buf);
          s->bi_buf = 0;
          s->bi_valid = 0;
      } else if (s->bi_valid >= 8) {
          put_byte(s, (Byte)s->bi_buf);
          s->bi_buf >>= 8;
          s->bi_valid -= 8;
      }
  }
  
  /* ===========================================================================
   * Flush the bit buffer and align the output on a byte boundary
   */
  static void
  bi_windup(deflate_state *s)
  {
      if (s->bi_valid > 8) {
          put_short(s, s->bi_buf);
      } else if (s->bi_valid > 0) {
          put_byte(s, (Byte)s->bi_buf);
      }
      s->bi_buf = 0;
      s->bi_valid = 0;
  #ifdef DEBUG_ZLIB
      s->bits_sent = (s->bits_sent+7) & ~7;
  #endif
  }
  
  /* ===========================================================================
   * Copy a stored block, storing first the length and its
   * one's complement if requested.
   *
   * charf    *buf;    the input data
   * unsigned len;     its length
   * int      header;  true if block header must be written
   */
  static void
  copy_block(deflate_state *s, charf *buf, unsigned int len, int header)
  {
      bi_windup(s);        /* align on byte boundary */
      s->last_eob_len = 8; /* enough lookahead for inflate */
  
      if (header) {
          put_short(s, (ush)len);   
          put_short(s, (ush)~len);
  #ifdef DEBUG_ZLIB
          s->bits_sent += 2*16;
  #endif
      }
  #ifdef DEBUG_ZLIB
      s->bits_sent += (ulg)len<<3;
  #endif
      while (len--) {
          put_byte(s, *buf++);
      }
  }
  /* --- trees.c */
  
  /* +++ inflate.c */
  /* inflate.c -- zlib interface to inflate modules
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zutil.h" */
  
  /* +++ infblock.h */
  /* infblock.h -- header to use infblock.c
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* WARNING: this file should *not* be used by applications. It is
     part of the implementation of the compression library and is
     subject to change. Applications should only use zlib.h.
   */
  
  struct inflate_blocks_state;
  typedef struct inflate_blocks_state FAR inflate_blocks_statef;
  
  static inflate_blocks_statef * inflate_blocks_new OF((
      z_streamp z,
      check_func c,               /* check function */
      uInt w));                   /* window size */
  
  static int inflate_blocks OF((
      inflate_blocks_statef *,
      z_streamp ,
      int));                      /* initial return code */
  
  static void inflate_blocks_reset OF((
      inflate_blocks_statef *,
      z_streamp ,
      uLongf *));                  /* check value on output */
  
  static int inflate_blocks_free OF((
      inflate_blocks_statef *,
      z_streamp));
  
  static void inflate_set_dictionary OF((
      inflate_blocks_statef *s,
      const Bytef *d,  /* dictionary */
      uInt  n));       /* dictionary length */
  
  static int inflate_blocks_sync_point OF((
      inflate_blocks_statef *s));
  /* --- infblock.h */
  
  #ifndef NO_DUMMY_DECL
  struct inflate_blocks_state {int dummy;}; /* for buggy compilers */
  #endif
  
  /* inflate private state */
  typedef struct inflate_state {
  
    /* mode */
    enum {
        METHOD,   /* waiting for method byte */
        FLAG,     /* waiting for flag byte */
        DICT4,    /* four dictionary check bytes to go */
        DICT3,    /* three dictionary check bytes to go */
        DICT2,    /* two dictionary check bytes to go */
        DICT1,    /* one dictionary check byte to go */
        DICT0,    /* waiting for inflateSetDictionary */
        BLOCKS,   /* decompressing blocks */
        CHECK4,   /* four check bytes to go */
        CHECK3,   /* three check bytes to go */
        CHECK2,   /* two check bytes to go */
        CHECK1,   /* one check byte to go */
        DONE,     /* finished check, done */
        BAD}      /* got an error--stay here */
      mode;               /* current inflate mode */
  
    /* mode dependent information */
    union {
      uInt method;        /* if FLAGS, method byte */
      struct {
        uLong was;                /* computed check value */
        uLong need;               /* stream check value */
      } check;            /* if CHECK, check values to compare */
      uInt marker;        /* if BAD, inflateSync's marker bytes count */
    } sub;        /* submode */
  
    /* mode independent information */
    int  nowrap;          /* flag for no wrapper */
    uInt wbits;           /* log2(window size)  (8..15, defaults to 15) */
    inflate_blocks_statef 
      *blocks;            /* current inflate_blocks state */
  
  }inflate_state;
  
  
  int ZEXPORT
  inflateReset(z_streamp z)
  {
          inflate_state* s;
          if (z == Z_NULL || z->state == Z_NULL)
                  return Z_STREAM_ERROR;
  
          s = (inflate_state*)z->state;
          z->total_in = z->total_out = 0;
          z->msg = Z_NULL;
          s->mode = s->nowrap ? BLOCKS : METHOD;
          inflate_blocks_reset(s->blocks, z, Z_NULL);
          Tracev((stderr, "inflate: reset\n"));
          return Z_OK;
  }
  
  
  int ZEXPORT
  inflateEnd(z_streamp z)
  {
    if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL)
      return Z_STREAM_ERROR;
    if (((inflate_state*)z->state)->blocks != Z_NULL)
      inflate_blocks_free(((inflate_state*)z->state)->blocks, z);
    ZFREE(z, z->state);
    z->state = Z_NULL;
    Tracev((stderr, "inflate: end\n"));
    return Z_OK;
  }
  
  
  int ZEXPORT
  inflateInit2_(z_streamp z, int w, const char *ver, int stream_size)
  {
          inflate_state*  s;
    if (ver == Z_NULL || ver[0] != ZLIB_VERSION[0] ||
        stream_size != sizeof(z_stream))
        return Z_VERSION_ERROR;
  
    /* initialize state */
    if (z == Z_NULL)
      return Z_STREAM_ERROR;
    z->msg = Z_NULL;
  #ifndef NO_ZCFUNCS
    if (z->zalloc == Z_NULL)
    {
      z->zalloc = zcalloc;
      z->opaque = (voidpf)0;
    }
    if (z->zfree == Z_NULL) z->zfree = zcfree;
  #endif
    if ((z->state = (struct internal_state FAR *)
         ZALLOC(z,1,sizeof(struct inflate_state))) == Z_NULL)
      return Z_MEM_ERROR;
    s = (inflate_state*)z->state;
    s->blocks = Z_NULL;
  
    /* handle undocumented nowrap option (no zlib header or check) */
    s->nowrap = 0;
    if (w < 0)
    {
      w = - w;
      s->nowrap = 1;
    }
  
    /* set window size */
    if (w < 8 || w > 15)
    {
      inflateEnd(z);
      return Z_STREAM_ERROR;
    }
    s->wbits = (uInt)w;
  
    /* create inflate_blocks state */
    if ((s->blocks =
        inflate_blocks_new(z, s->nowrap ? Z_NULL : adler32, (uInt)1 << w))
        == Z_NULL)
    {
      inflateEnd(z);
      return Z_MEM_ERROR;
    }
    Tracev((stderr, "inflate: allocated\n"));
  
    /* reset state */
    inflateReset(z);
    return Z_OK;
  }
  
  
  int ZEXPORT
  inflateInit_(z_streamp z, const char *ver, int stream_size)
  {
    return inflateInit2_(z, DEF_WBITS, ver, stream_size);
  }
  
  
  #define NEEDBYTE {if(z->avail_in==0)return r;r=f;}
  #define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)
  
  int ZEXPORT
  inflate(z_streamp z, int f)
  {
    int r;
    uInt b;
    inflate_state* s;
  
    if (z == Z_NULL || z->state == Z_NULL || z->next_in == Z_NULL)
      return Z_STREAM_ERROR;
    f = f == Z_FINISH ? Z_BUF_ERROR : Z_OK;
    r = Z_BUF_ERROR;
    s = (inflate_state*)z->state;
    while (1) switch (s->mode)
    {
      case METHOD:
        NEEDBYTE
        if (((s->sub.method = NEXTBYTE) & 0xf) != Z_DEFLATED)
        {
          s->mode = BAD;
          z->msg = (char*)"unknown compression method";
          s->sub.marker = 5;       /* can't try inflateSync */
          break;
        }
        if ((s->sub.method >> 4) + 8 > s->wbits)
        {
          s->mode = BAD;
          z->msg = (char*)"invalid window size";
          s->sub.marker = 5;       /* can't try inflateSync */
          break;
        }
        s->mode = FLAG;
      case FLAG:
        NEEDBYTE
        b = NEXTBYTE;
        if (((s->sub.method << 8) + b) % 31)
        {
          s->mode = BAD;
          z->msg = (char*)"incorrect header check";
          s->sub.marker = 5;       /* can't try inflateSync */
          break;
        }
        Tracev((stderr, "inflate: zlib header ok\n"));
        if (!(b & PRESET_DICT))
        {
          s->mode = BLOCKS;
          break;
        }
        s->mode = DICT4;
      case DICT4:
        NEEDBYTE
        s->sub.check.need = (uLong)NEXTBYTE << 24;
        s->mode = DICT3;
      case DICT3:
        NEEDBYTE
        s->sub.check.need += (uLong)NEXTBYTE << 16;
        s->mode = DICT2;
      case DICT2:
        NEEDBYTE
        s->sub.check.need += (uLong)NEXTBYTE << 8;
        s->mode = DICT1;
      case DICT1:
        NEEDBYTE
        s->sub.check.need += (uLong)NEXTBYTE;
        z->adler = s->sub.check.need;
        s->mode = DICT0;
        return Z_NEED_DICT;
      case DICT0:
        s->mode = BAD;
        z->msg = (char*)"need dictionary";
        s->sub.marker = 0;       /* can try inflateSync */
        return Z_STREAM_ERROR;
      case BLOCKS:
        r = inflate_blocks(s->blocks, z, r);
        if (r == Z_DATA_ERROR)
        {
          s->mode = BAD;
          s->sub.marker = 0;       /* can try inflateSync */
          break;
        }
        if (r == Z_OK)
          r = f;
        if (r != Z_STREAM_END)
          return r;
        r = f;
        inflate_blocks_reset(s->blocks, z, &s->sub.check.was);
        if (s->nowrap)
        {
          s->mode = DONE;
          break;
        }
        s->mode = CHECK4;
      case CHECK4:
        NEEDBYTE
        s->sub.check.need = (uLong)NEXTBYTE << 24;
        s->mode = CHECK3;
      case CHECK3:
        NEEDBYTE
        s->sub.check.need += (uLong)NEXTBYTE << 16;
        s->mode = CHECK2;
      case CHECK2:
        NEEDBYTE
        s->sub.check.need += (uLong)NEXTBYTE << 8;
        s->mode = CHECK1;
      case CHECK1:
        NEEDBYTE
        s->sub.check.need += (uLong)NEXTBYTE;
  
        if (s->sub.check.was != s->sub.check.need)
        {
          s->mode = BAD;
          z->msg = (char*)"incorrect data check";
          s->sub.marker = 5;       /* can't try inflateSync */
          break;
        }
        Tracev((stderr, "inflate: zlib check ok\n"));
        s->mode = DONE;
      case DONE:
        return Z_STREAM_END;
      case BAD:
        return Z_DATA_ERROR;
      default:
        return Z_STREAM_ERROR;
    }
  #ifdef NEED_DUMMY_RETURN
    return Z_STREAM_ERROR;  /* Some dumb compilers complain without this */
  #endif
  }
  
  
  int ZEXPORT inflateSetDictionary(z, dictionary, dictLength)
  z_streamp z;
  const Bytef *dictionary;
  uInt  dictLength;
  {
    uInt length = dictLength;
    inflate_state* s;
  
    if (z == Z_NULL || z->state == Z_NULL || ((inflate_state*)z->state)->mode != DICT0)
      return Z_STREAM_ERROR;
    s = (inflate_state*)z->state;
  
    if (adler32(1L, dictionary, dictLength) != z->adler) return Z_DATA_ERROR;
    z->adler = 1L;
  
    if (length >= ((uInt)1<<s->wbits))
    {
      length = (1<<s->wbits)-1;
      dictionary += dictLength - length;
    }
    inflate_set_dictionary(s->blocks, dictionary, length);
    s->mode = BLOCKS;
    return Z_OK;
  }
  
  
  int ZEXPORT inflateSync(z)
  z_streamp z;
  {
    uInt n;       /* number of bytes to look at */
    Bytef *p;     /* pointer to bytes */
    uInt m;       /* number of marker bytes found in a row */
    uLong r, w;   /* temporaries to save total_in and total_out */
    inflate_state* s;
  
    /* set up */
    if (z == Z_NULL || z->state == Z_NULL)
      return Z_STREAM_ERROR;
    s = (inflate_state*)z->state;
    if (s->mode != BAD)
    {
      s->mode = BAD;
      s->sub.marker = 0;
    }
    if ((n = z->avail_in) == 0)
      return Z_BUF_ERROR;
    p = z->next_in;
    m = s->sub.marker;
  
    /* search */
    while (n && m < 4)
    {
      static const Byte mark[4] = {0, 0, 0xff, 0xff};
      if (*p == mark[m])
        m++;
      else if (*p)
        m = 0;
      else
        m = 4 - m;
      p++, n--;
    }
  
    /* restore */
    z->total_in += p - z->next_in;
    z->next_in = p;
    z->avail_in = n;
    s->sub.marker = m;
  
    /* return no joy or set up to restart on a new block */
    if (m != 4)
      return Z_DATA_ERROR;
    r = z->total_in;  w = z->total_out;
    inflateReset(z);
    z->total_in = r;  z->total_out = w;
    s->mode = BLOCKS;
    return Z_OK;
  }
  
  
  /* Returns true if inflate is currently at the end of a block generated
   * by Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
   * implementation to provide an additional safety check. PPP uses Z_SYNC_FLUSH
   * but removes the length bytes of the resulting empty stored block. When
   * decompressing, PPP checks that at the end of input packet, inflate is
   * waiting for these length bytes.
   */
  int ZEXPORT inflateSyncPoint(z)
  z_streamp z;
  {
    if (z == Z_NULL || z->state == Z_NULL || ((inflate_state*)z->state)->blocks == Z_NULL)
      return Z_STREAM_ERROR;
    return inflate_blocks_sync_point(((inflate_state*)z->state)->blocks);
  }
  #undef NEEDBYTE
  #undef NEXTBYTE
  /* --- inflate.c */
  
  /* +++ infblock.c */
  /* infblock.c -- interpret and process block types to last block
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zutil.h" */
  /* #include "infblock.h" */
  
  /* +++ inftrees.h */
  /* inftrees.h -- header to use inftrees.c
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* WARNING: this file should *not* be used by applications. It is
     part of the implementation of the compression library and is
     subject to change. Applications should only use zlib.h.
   */
  
  /* Huffman code lookup table entry--this entry is four bytes for machines
     that have 16-bit pointers (e.g. PC's in the small or medium model). */
  
  typedef struct inflate_huft_s FAR inflate_huft;
  
  struct inflate_huft_s {
    union {
      struct {
        Byte Exop;        /* number of extra bits or operation */
        Byte Bits;        /* number of bits in this code or subcode */
      } what;
      uInt pad;           /* pad structure to a power of 2 (4 bytes for */
    } word;               /*  16-bit, 8 bytes for 32-bit int's) */
    uInt base;            /* literal, length base, distance base,
                             or table offset */
  };
  
  /* Maximum size of dynamic tree.  The maximum found in a long but non-
     exhaustive search was 1004 huft structures (850 for length/literals
     and 154 for distances, the latter actually the result of an
     exhaustive search).  The actual maximum is not known, but the
     value below is more than safe. */
  #define MANY 1440
  
  static int inflate_trees_bits OF((
      uIntf *,                    /* 19 code lengths */
      uIntf *,                    /* bits tree desired/actual depth */
      inflate_huft * FAR *,       /* bits tree result */
      inflate_huft *,             /* space for trees */
      z_streamp));                /* for messages */
  
  static int inflate_trees_dynamic OF((
      uInt,                       /* number of literal/length codes */
      uInt,                       /* number of distance codes */
      uIntf *,                    /* that many (total) code lengths */
      uIntf *,                    /* literal desired/actual bit depth */
      uIntf *,                    /* distance desired/actual bit depth */
      inflate_huft * FAR *,       /* literal/length tree result */
      inflate_huft * FAR *,       /* distance tree result */
      inflate_huft *,             /* space for trees */
      z_streamp));                /* for messages */
  
  static int inflate_trees_fixed OF((
      uIntf *,                    /* literal desired/actual bit depth */
      uIntf *,                    /* distance desired/actual bit depth */
      inflate_huft * FAR *,       /* literal/length tree result */
      inflate_huft * FAR *,       /* distance tree result */
      z_streamp));                /* for memory allocation */
  /* --- inftrees.h */
  
  /* +++ infcodes.h */
  /* infcodes.h -- header to use infcodes.c
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* WARNING: this file should *not* be used by applications. It is
     part of the implementation of the compression library and is
     subject to change. Applications should only use zlib.h.
   */
  
  struct inflate_codes_state;
  typedef struct inflate_codes_state FAR inflate_codes_statef;
  
  static inflate_codes_statef *inflate_codes_new OF((
      uInt, uInt,
      inflate_huft *, inflate_huft *,
      z_streamp ));
  
  static int inflate_codes OF((
      inflate_blocks_statef *,
      z_streamp ,
      int));
  
  static void inflate_codes_free OF((
      inflate_codes_statef *,
      z_streamp ));
  
  /* --- infcodes.h */
  
  /* +++ infutil.h */
  /* infutil.h -- types and macros common to blocks and codes
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* WARNING: this file should *not* be used by applications. It is
     part of the implementation of the compression library and is
     subject to change. Applications should only use zlib.h.
   */
  
  #ifndef _INFUTIL_H
  #define _INFUTIL_H
  
  typedef enum {
        TYPE,     /* get type bits (3, including end bit) */
        LENS,     /* get lengths for stored */
        STORED,   /* processing stored block */
        TABLE,    /* get table lengths */
        BTREE,    /* get bit lengths tree for a dynamic block */
        DTREE,    /* get length, distance trees for a dynamic block */
        CODES,    /* processing fixed or dynamic block */
        DRY,      /* output remaining window bytes */
        DONEB,     /* finished last block, done */
        BADB}      /* got a data error--stuck here */
  inflate_block_mode;
  
  /* inflate blocks semi-private state */
  struct inflate_blocks_state {
  
    /* mode */
    inflate_block_mode  mode;     /* current inflate_block mode */
  
    /* mode dependent information */
    union {
      uInt left;          /* if STORED, bytes left to copy */
      struct {
        uInt table;               /* table lengths (14 bits) */
        uInt index;               /* index into blens (or border) */
        uIntf *blens;             /* bit lengths of codes */
        uInt bb;                  /* bit length tree depth */
        inflate_huft *tb;         /* bit length decoding tree */
      } trees;            /* if DTREE, decoding info for trees */
      struct {
        inflate_codes_statef 
           *codes;
      } decode;           /* if CODES, current state */
    } sub;                /* submode */
    uInt last;            /* true if this block is the last block */
  
    /* mode independent information */
    uInt bitk;            /* bits in bit buffer */
    uLong bitb;           /* bit buffer */
    inflate_huft *hufts;  /* single malloc for tree space */
    Bytef *window;        /* sliding window */
    Bytef *end;           /* one byte after sliding window */
    Bytef *read;          /* window read pointer */
    Bytef *write;         /* window write pointer */
    check_func checkfn;   /* check function */
    uLong check;          /* check on output */
  
  };
  
  
  /* defines for inflate input/output */
  /*   update pointers and return */
  #define UPDBITS {s->bitb=b;s->bitk=k;}
  #define UPDIN {z->avail_in=n;z->total_in+=p-z->next_in;z->next_in=p;}
  #define UPDOUT {s->write=q;}
  #define UPDATE {UPDBITS UPDIN UPDOUT}
  #define LEAVE {UPDATE return inflate_flush(s,z,r);}
  /*   get bytes and bits */
  #define LOADIN {p=z->next_in;n=z->avail_in;b=s->bitb;k=s->bitk;}
  #define NEEDBYTE {if(n)r=Z_OK;else LEAVE}
  #define NEXTBYTE (n--,*p++)
  #define NEEDBITS(j) {while(k<(j)){NEEDBYTE;b|=((uLong)NEXTBYTE)<<k;k+=8;}}
  #define DUMPBITS(j) {b>>=(j);k-=(j);}
  /*   output bytes */
  #define WAVAIL (uInt)(q<s->read?s->read-q-1:s->end-q)
  #define LOADOUT {q=s->write;m=(uInt)WAVAIL;}
  #define WRAP {if(q==s->end&&s->read!=s->window){q=s->window;m=(uInt)WAVAIL;}}
  #define FLUSH {UPDOUT r=inflate_flush(s,z,r); LOADOUT}
  #define NEEDOUT {if(m==0){WRAP if(m==0){FLUSH WRAP if(m==0) LEAVE}}r=Z_OK;}
  #define OUTBYTE(a) {*q++=(Byte)(a);m--;}
  /*   load local pointers */
  #define LOAD {LOADIN LOADOUT}
  
  /* masks for lower bits (size given to avoid silly warnings with Visual C++) */
  /* And'ing with mask[n] masks the lower n bits */
  static uInt inflate_mask[17] = {
      0x0000,
      0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff,
      0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff
  };
  
  /* copy as much as possible from the sliding window to the output area */
  static int inflate_flush OF((
      inflate_blocks_statef *,
      z_streamp ,
      int));
  
  #ifndef NO_DUMMY_DECL
  struct internal_state      {int dummy;}; /* for buggy compilers */
  #endif
  
  #endif
  /* --- infutil.h */
  
  #ifndef NO_DUMMY_DECL
  struct inflate_codes_state {int dummy;}; /* for buggy compilers */
  #endif
  
  /* simplify the use of the inflate_huft type with some defines */
  #define exop word.what.Exop
  #define bits word.what.Bits
  
  /* Table for deflate from PKZIP's appnote.txt. */
  static const uInt border[] = { /* Order of the bit length code lengths */
          16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
  
  /*
     Notes beyond the 1.93a appnote.txt:
  
     1. Distance pointers never point before the beginning of the output
        stream.
     2. Distance pointers can point back across blocks, up to 32k away.
     3. There is an implied maximum of 7 bits for the bit length table and
        15 bits for the actual data.
     4. If only one code exists, then it is encoded using one bit.  (Zero
        would be more efficient, but perhaps a little confusing.)  If two
        codes exist, they are coded using one bit each (0 and 1).
     5. There is no way of sending zero distance codes--a dummy must be
        sent if there are none.  (History: a pre 2.0 version of PKZIP would
        store blocks with no distance codes, but this was discovered to be
        too harsh a criterion.)  Valid only for 1.93a.  2.04c does allow
        zero distance codes, which is sent as one code of zero bits in
        length.
     6. There are up to 286 literal/length codes.  Code 256 represents the
        end-of-block.  Note however that the static length tree defines
        288 codes just to fill out the Huffman codes.  Codes 286 and 287
        cannot be used though, since there is no length base or extra bits
        defined for them.  Similarily, there are up to 30 distance codes.
        However, static trees define 32 codes (all 5 bits) to fill out the
        Huffman codes, but the last two had better not show up in the data.
     7. Unzip can check dynamic Huffman blocks for complete code sets.
        The exception is that a single code would not be complete (see #4).
     8. The five bits following the block type is really the number of
        literal codes sent minus 257.
     9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits
        (1+6+6).  Therefore, to output three times the length, you output
        three codes (1+1+1), whereas to output four times the same length,
        you only need two codes (1+3).  Hmm.
    10. In the tree reconstruction algorithm, Code = Code + Increment
        only if BitLength(i) is not zero.  (Pretty obvious.)
    11. Correction: 4 Bits: # of Bit Length codes - 4     (4 - 19)
    12. Note: length code 284 can represent 227-258, but length code 285
        really is 258.  The last length deserves its own, short code
        since it gets used a lot in very redundant files.  The length
        258 is special since 258 - 3 (the min match length) is 255.
    13. The literal/length and distance code bit lengths are read as a
        single stream of lengths.  It is possible (and advantageous) for
        a repeat code (16, 17, or 18) to go across the boundary between
        the two sets of lengths.
   */
  
  
  static void inflate_blocks_reset(s, z, c)
  inflate_blocks_statef *s;
  z_streamp z;
  uLongf *c;
  {
    if (c != Z_NULL)
      *c = s->check;
    if (s->mode == BTREE || s->mode == DTREE)
      ZFREE(z, s->sub.trees.blens);
    if (s->mode == CODES)
      inflate_codes_free(s->sub.decode.codes, z);
    s->mode = TYPE;
    s->bitk = 0;
    s->bitb = 0;
    s->read = s->write = s->window;
    if (s->checkfn != Z_NULL)
      z->adler = s->check = (*s->checkfn)(0L, (const Bytef *)Z_NULL, 0);
    Tracev((stderr, "inflate:   blocks reset\n"));
  }
  
  
  static inflate_blocks_statef *inflate_blocks_new(z, c, w)
  z_streamp z;
  check_func c;
  uInt w;
  {
    inflate_blocks_statef *s;
  
    if ((s = (inflate_blocks_statef *)ZALLOC
         (z,1,sizeof(struct inflate_blocks_state))) == Z_NULL)
      return s;
    if ((s->hufts =
         (inflate_huft *)ZALLOC(z, sizeof(inflate_huft), MANY)) == Z_NULL)
    {
      ZFREE(z, s);
      return Z_NULL;
    }
    if ((s->window = (Bytef *)ZALLOC(z, 1, w)) == Z_NULL)
    {
      ZFREE(z, s->hufts);
      ZFREE(z, s);
      return Z_NULL;
    }
    s->end = s->window + w;
    s->checkfn = c;
    s->mode = TYPE;
    Tracev((stderr, "inflate:   blocks allocated\n"));
    inflate_blocks_reset(s, z, Z_NULL);
    return s;
  }
  
  
  static int inflate_blocks(s, z, r)
  inflate_blocks_statef *s;
  z_streamp z;
  int r;
  {
    uInt t;               /* temporary storage */
    uLong b;              /* bit buffer */
    uInt k;               /* bits in bit buffer */
    Bytef *p;             /* input data pointer */
    uInt n;               /* bytes available there */
    Bytef *q;             /* output window write pointer */
    uInt m;               /* bytes to end of window or read pointer */
  
    /* copy input/output information to locals (UPDATE macro restores) */
    LOAD
  
    /* process input based on current state */
    while (1) switch (s->mode)
    {
      case TYPE:
        NEEDBITS(3)
        t = (uInt)b & 7;
        s->last = t & 1;
        switch (t >> 1)
        {
          case 0:                         /* stored */
            Tracev((stderr, "inflate:     stored block%s\n",
                   s->last ? " (last)" : ""));
            DUMPBITS(3)
            t = k & 7;                    /* go to byte boundary */
            DUMPBITS(t)
            s->mode = LENS;               /* get length of stored block */
            break;
          case 1:                         /* fixed */
            Tracev((stderr, "inflate:     fixed codes block%s\n",
                   s->last ? " (last)" : ""));
            {
              uInt bl, bd;
              inflate_huft *tl, *td;
  
              inflate_trees_fixed(&bl, &bd, &tl, &td, z);
              s->sub.decode.codes = inflate_codes_new(bl, bd, tl, td, z);
              if (s->sub.decode.codes == Z_NULL)
              {
                r = Z_MEM_ERROR;
                LEAVE
              }
            }
            DUMPBITS(3)
            s->mode = CODES;
            break;
          case 2:                         /* dynamic */
            Tracev((stderr, "inflate:     dynamic codes block%s\n",
                   s->last ? " (last)" : ""));
            DUMPBITS(3)
            s->mode = TABLE;
            break;
          case 3:                         /* illegal */
            DUMPBITS(3)
            s->mode = BADB;
            z->msg = (char*)"invalid block type";
            r = Z_DATA_ERROR;
            LEAVE
        }
        break;
      case LENS:
        NEEDBITS(32)
        if ((((~b) >> 16) & 0xffff) != (b & 0xffff))
        {
          s->mode = BADB;
          z->msg = (char*)"invalid stored block lengths";
          r = Z_DATA_ERROR;
          LEAVE
        }
        s->sub.left = (uInt)b & 0xffff;
        b = k = 0;                      /* dump bits */
        Tracev((stderr, "inflate:       stored length %u\n", s->sub.left));
        s->mode = s->sub.left ? STORED : (s->last ? DRY : TYPE);
        break;
      case STORED:
        if (n == 0)
          LEAVE
        NEEDOUT
        t = s->sub.left;
        if (t > n) t = n;
        if (t > m) t = m;
        zmemcpy(q, p, t);
        p += t;  n -= t;
        q += t;  m -= t;
        if ((s->sub.left -= t) != 0)
          break;
        Tracev((stderr, "inflate:       stored end, %lu total out\n",
                z->total_out + (q >= s->read ? q - s->read :
                (s->end - s->read) + (q - s->window))));
        s->mode = s->last ? DRY : TYPE;
        break;
      case TABLE:
        NEEDBITS(14)
        s->sub.trees.table = t = (uInt)b & 0x3fff;
  #ifndef PKZIP_BUG_WORKAROUND
        if ((t & 0x1f) > 29 || ((t >> 5) & 0x1f) > 29)
        {
          s->mode = BADB;
          z->msg = (char*)"too many length or distance symbols";
          r = Z_DATA_ERROR;
          LEAVE
        }
  #endif
        t = 258 + (t & 0x1f) + ((t >> 5) & 0x1f);
        if ((s->sub.trees.blens = (uIntf*)ZALLOC(z, t, sizeof(uInt))) == Z_NULL)
        {
          r = Z_MEM_ERROR;
          LEAVE
        }
        DUMPBITS(14)
        s->sub.trees.index = 0;
        Tracev((stderr, "inflate:       table sizes ok\n"));
        s->mode = BTREE;
      case BTREE:
        while (s->sub.trees.index < 4 + (s->sub.trees.table >> 10))
        {
          NEEDBITS(3)
          s->sub.trees.blens[border[s->sub.trees.index++]] = (uInt)b & 7;
          DUMPBITS(3)
        }
        while (s->sub.trees.index < 19)
          s->sub.trees.blens[border[s->sub.trees.index++]] = 0;
        s->sub.trees.bb = 7;
        t = inflate_trees_bits(s->sub.trees.blens, &s->sub.trees.bb,
                               &s->sub.trees.tb, s->hufts, z);
        if (t != Z_OK)
        {
          r = t;
          if (r == Z_DATA_ERROR)
          {
            ZFREE(z, s->sub.trees.blens);
            s->mode = BADB;
          }
          LEAVE
        }
        s->sub.trees.index = 0;
        Tracev((stderr, "inflate:       bits tree ok\n"));
        s->mode = DTREE;
      case DTREE:
        while (t = s->sub.trees.table,
               s->sub.trees.index < 258 + (t & 0x1f) + ((t >> 5) & 0x1f))
        {
          inflate_huft *h;
          uInt i, j, c;
  
          t = s->sub.trees.bb;
          NEEDBITS(t)
          h = s->sub.trees.tb + ((uInt)b & inflate_mask[t]);
          t = h->bits;
          c = h->base;
          if (c < 16)
          {
            DUMPBITS(t)
            s->sub.trees.blens[s->sub.trees.index++] = c;
          }
          else /* c == 16..18 */
          {
            i = c == 18 ? 7 : c - 14;
            j = c == 18 ? 11 : 3;
            NEEDBITS(t + i)
            DUMPBITS(t)
            j += (uInt)b & inflate_mask[i];
            DUMPBITS(i)
            i = s->sub.trees.index;
            t = s->sub.trees.table;
            if (i + j > 258 + (t & 0x1f) + ((t >> 5) & 0x1f) ||
                (c == 16 && i < 1))
            {
              ZFREE(z, s->sub.trees.blens);
              s->mode = BADB;
              z->msg = (char*)"invalid bit length repeat";
              r = Z_DATA_ERROR;
              LEAVE
            }
            c = c == 16 ? s->sub.trees.blens[i - 1] : 0;
            do {
              s->sub.trees.blens[i++] = c;
            } while (--j);
            s->sub.trees.index = i;
          }
        }
        s->sub.trees.tb = Z_NULL;
        {
          uInt bl, bd;
          inflate_huft *tl, *td;
          inflate_codes_statef *c;
  
          bl = 9;         /* must be <= 9 for lookahead assumptions */
          bd = 6;         /* must be <= 9 for lookahead assumptions */
          t = s->sub.trees.table;
          t = inflate_trees_dynamic(257 + (t & 0x1f), 1 + ((t >> 5) & 0x1f),
                                    s->sub.trees.blens, &bl, &bd, &tl, &td,
                                    s->hufts, z);
          if (t != Z_OK)
          {
            if (t == (uInt)Z_DATA_ERROR)
            {
              ZFREE(z, s->sub.trees.blens);
              s->mode = BADB;
            }
            r = t;
            LEAVE
          }
          Tracev((stderr, "inflate:       trees ok\n"));
          if ((c = inflate_codes_new(bl, bd, tl, td, z)) == Z_NULL)
          {
            r = Z_MEM_ERROR;
            LEAVE
          }
          s->sub.decode.codes = c;
        }
        ZFREE(z, s->sub.trees.blens);
        s->mode = CODES;
      case CODES:
        UPDATE
        if ((r = inflate_codes(s, z, r)) != Z_STREAM_END)
          return inflate_flush(s, z, r);
        r = Z_OK;
        inflate_codes_free(s->sub.decode.codes, z);
        LOAD
        Tracev((stderr, "inflate:       codes end, %lu total out\n",
                z->total_out + (q >= s->read ? q - s->read :
                (s->end - s->read) + (q - s->window))));
        if (!s->last)
        {
          s->mode = TYPE;
          break;
        }
        s->mode = DRY;
      case DRY:
        FLUSH
        if (s->read != s->write)
          LEAVE
        s->mode = DONEB;
      case DONEB:
        r = Z_STREAM_END;
        LEAVE
      case BADB:
        r = Z_DATA_ERROR;
        LEAVE
      default:
        r = Z_STREAM_ERROR;
        LEAVE
    }
  }
  
  
  static int inflate_blocks_free(s, z)
  inflate_blocks_statef *s;
  z_streamp z;
  {
    inflate_blocks_reset(s, z, Z_NULL);
    ZFREE(z, s->window);
    ZFREE(z, s->hufts);
    ZFREE(z, s);
    Tracev((stderr, "inflate:   blocks freed\n"));
    return Z_OK;
  }
  
  
  static void inflate_set_dictionary(s, d, n)
  inflate_blocks_statef *s;
  const Bytef *d;
  uInt  n;
  {
    zmemcpy(s->window, d, n);
    s->read = s->write = s->window + n;
  }
  
  
  /* Returns true if inflate is currently at the end of a block generated
   * by Z_SYNC_FLUSH or Z_FULL_FLUSH. 
   * IN assertion: s != Z_NULL
   */
  static int inflate_blocks_sync_point(s)
  inflate_blocks_statef *s;
  {
    return s->mode == LENS;
  }
  /* --- infblock.c */
  
  /* +++ inftrees.c */
  /* inftrees.c -- generate Huffman trees for efficient decoding
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zutil.h" */
  /* #include "inftrees.h" */
  
  #if !defined(BUILDFIXED) && !defined(STDC)
  #  define BUILDFIXED   /* non ANSI compilers may not accept inffixed.h */
  #endif
  
  const char inflate_copyright[] =
     " inflate 1.1.4 Copyright 1995-2002 Mark Adler ";
  /*
    If you use the zlib library in a product, an acknowledgment is welcome
    in the documentation of your product. If for some reason you cannot
    include such an acknowledgment, I would appreciate that you keep this
    copyright string in the executable of your product.
   */
   
  #ifndef NO_DUMMY_DECL
  struct internal_state  {int dummy;}; /* for buggy compilers */
  #endif
  
  /* simplify the use of the inflate_huft type with some defines */
  #define exop word.what.Exop
  #define bits word.what.Bits
  
  
  static int
  huft_build OF((
      uIntf *,            /* code lengths in bits */
      uInt,               /* number of codes */
      uInt,               /* number of "simple" codes */
      const uIntf *,      /* list of base values for non-simple codes */
      const uIntf *,      /* list of extra bits for non-simple codes */
      inflate_huft * FAR*,/* result: starting table */
      uIntf *,            /* maximum lookup bits (returns actual) */
      inflate_huft *,     /* space for trees */
      uInt *,             /* hufts used in space */
      uIntf * ));         /* space for values */
  
  /* Tables for deflate from PKZIP's appnote.txt. */
  static const uInt cplens[31] = { /* Copy lengths for literal codes 257..285 */
          3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
          35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0};
          /* see note #13 above about 258 */
  static const uInt cplext[31] = { /* Extra bits for literal codes 257..285 */
          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, 112, 112}; /* 112==invalid */
  static const uInt cpdist[30] = { /* Copy offsets for distance codes 0..29 */
          1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
          257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
          8193, 12289, 16385, 24577};
  static const uInt cpdext[30] = { /* Extra bits for distance codes */
          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};
  
  /*
     Huffman code decoding is performed using a multi-level table lookup.
     The fastest way to decode is to simply build a lookup table whose
     size is determined by the longest code.  However, the time it takes
     to build this table can also be a factor if the data being decoded
     is not very long.  The most common codes are necessarily the
     shortest codes, so those codes dominate the decoding time, and hence
     the speed.  The idea is you can have a shorter table that decodes the
     shorter, more probable codes, and then point to subsidiary tables for
     the longer codes.  The time it costs to decode the longer codes is
     then traded against the time it takes to make longer tables.
  
     This results of this trade are in the variables lbits and dbits
     below.  lbits is the number of bits the first level table for literal/
     length codes can decode in one step, and dbits is the same thing for
     the distance codes.  Subsequent tables are also less than or equal to
     those sizes.  These values may be adjusted either when all of the
     codes are shorter than that, in which case the longest code length in
     bits is used, or when the shortest code is *longer* than the requested
     table size, in which case the length of the shortest code in bits is
     used.
  
     There are two different values for the two tables, since they code a
     different number of possibilities each.  The literal/length table
     codes 286 possible values, or in a flat code, a little over eight
     bits.  The distance table codes 30 possible values, or a little less
     than five bits, flat.  The optimum values for speed end up being
     about one bit more than those, so lbits is 8+1 and dbits is 5+1.
     The optimum values may differ though from machine to machine, and
     possibly even between compilers.  Your mileage may vary.
   */
  
  
  /* If BMAX needs to be larger than 16, then h and x[] should be uLong. */
  #define BMAX 15         /* maximum bit length of any code */
  
  /* Given a list of code lengths and a maximum table size, make a set of
     tables to decode that set of codes.  Return Z_OK on success, Z_BUF_ERROR
     if the given code set is incomplete (the tables are still built in this
     case), or Z_DATA_ERROR if the input is invalid. */
  #if 0
  uIntf *b;               /* code lengths in bits (all assumed <= BMAX) */
  uInt n;                 /* number of codes (assumed <= 288) */
  uInt s;                 /* number of simple-valued codes (0..s-1) */
  const uIntf *d;         /* list of base values for non-simple codes */
  const uIntf *e;         /* list of extra bits for non-simple codes */
  inflate_huft * FAR *t;  /* result: starting table */
  uIntf *m;               /* maximum lookup bits, returns actual */
  inflate_huft *hp;       /* space for trees */
  uInt *hn;               /* hufts used in space */
  uIntf *v;               /* working area: values in order of bit length */
  #endif
  
  static int
  huft_build(uIntf *b, uInt n, uInt s, const uIntf *d, const uIntf *e,
             inflate_huft * FAR *t, uIntf *m, inflate_huft *hp, uInt *hn,
             uIntf *v)
  {
    uInt a;                       /* counter for codes of length k */
    uInt c[BMAX+1];               /* bit length count table */
    uInt f;                       /* i repeats in table every f entries */
    int g;                        /* maximum code length */
    int h;                        /* table level */
    uInt i;              /* counter, current code */
    uInt j;              /* counter */
    int k;               /* number of bits in current code */
    int l;                        /* bits per table (returned in m) */
    uInt mask;                    /* (1 << w) - 1, to avoid cc -O bug on HP */
    uIntf *p;            /* pointer into c[], b[], or v[] */
    inflate_huft *q;              /* points to current table */
    struct inflate_huft_s r;      /* table entry for structure assignment */
    inflate_huft *u[BMAX];        /* table stack */
    int w;               /* bits before this table == (l * h) */
    uInt x[BMAX+1];               /* bit offsets, then code stack */
    uIntf *xp;                    /* pointer into x */
    int y;                        /* number of dummy codes added */
    uInt z;                       /* number of entries in current table */
  
  
    /* Generate counts for each bit length */
    p = c;
  #define C0 *p++ = 0;
  #define C2 C0 C0 C0 C0
  #define C4 C2 C2 C2 C2
    C4                            /* clear c[]--assume BMAX+1 is 16 */
    p = b;  i = n;
    do {
      c[*p++]++;                  /* assume all entries <= BMAX */
    } while (--i);
    if (c[0] == n)                /* null input--all zero length codes */
    {
      *t = (inflate_huft *)Z_NULL;
      *m = 0;
      return Z_OK;
    }
  
  
    /* Find minimum and maximum length, bound *m by those */
    l = *m;
    for (j = 1; j <= BMAX; j++)
      if (c[j])
        break;
    k = j;                        /* minimum code length */
    if ((uInt)l < j)
      l = j;
    for (i = BMAX; i; i--)
      if (c[i])
        break;
    g = i;                        /* maximum code length */
    if ((uInt)l > i)
      l = i;
    *m = l;
  
  
    /* Adjust last length count to fill out codes, if needed */
    for (y = 1 << j; j < i; j++, y <<= 1)
      if ((y -= c[j]) < 0)
        return Z_DATA_ERROR;
    if ((y -= c[i]) < 0)
      return Z_DATA_ERROR;
    c[i] += y;
  
  
    /* Generate starting offsets into the value table for each length */
    x[1] = j = 0;
    p = c + 1;  xp = x + 2;
    while (--i) {                 /* note that i == g from above */
      *xp++ = (j += *p++);
    }
  
  
    /* Make a table of values in order of bit lengths */
    p = b;  i = 0;
    do {
      if ((j = *p++) != 0)
        v[x[j]++] = i;
    } while (++i < n);
    n = x[g];                     /* set n to length of v */
  
  
    /* Generate the Huffman codes and for each, make the table entries */
    x[0] = i = 0;                 /* first Huffman code is zero */
    p = v;                        /* grab values in bit order */
    h = -1;                       /* no tables yet--level -1 */
    w = -l;                       /* bits decoded == (l * h) */
    u[0] = (inflate_huft *)Z_NULL;        /* just to keep compilers happy */
    q = (inflate_huft *)Z_NULL;   /* ditto */
    z = 0;                        /* ditto */
  
    /* go through the bit lengths (k already is bits in shortest code) */
    for (; k <= g; k++)
    {
      a = c[k];
      while (a--)
      {
        /* here i is the Huffman code of length k bits for value *p */
        /* make tables up to required level */
        while (k > w + l)
        {
          h++;
          w += l;                 /* previous table always l bits */
  
          /* compute minimum size table less than or equal to l bits */
          z = g - w;
          z = z > (uInt)l ? l : z;        /* table size upper limit */
          if ((f = 1 << (j = k - w)) > a + 1)     /* try a k-w bit table */
          {                       /* too few codes for k-w bit table */
            f -= a + 1;           /* deduct codes from patterns left */
            xp = c + k;
            if (j < z)
              while (++j < z)     /* try smaller tables up to z bits */
              {
                if ((f <<= 1) <= *++xp)
                  break;          /* enough codes to use up j bits */
                f -= *xp;         /* else deduct codes from patterns */
              }
          }
          z = 1 << j;             /* table entries for j-bit table */
  
          /* allocate new table */
          if (*hn + z > MANY)     /* (note: doesn't matter for fixed) */
            return Z_DATA_ERROR;  /* overflow of MANY */
          u[h] = q = hp + *hn;
          *hn += z;
  
          /* connect to last table, if there is one */
          if (h)
          {
            x[h] = i;             /* save pattern for backing up */
            r.bits = (Byte)l;     /* bits to dump before this table */
            r.exop = (Byte)j;     /* bits in this table */
            j = i >> (w - l);
            r.base = (uInt)(q - u[h-1] - j);   /* offset to this table */
            u[h-1][j] = r;        /* connect to last table */
          }
          else
            *t = q;               /* first table is returned result */
        }
  
        /* set up table entry in r */
        r.bits = (Byte)(k - w);
        if (p >= v + n)
          r.exop = 128 + 64;      /* out of values--invalid code */
        else if (*p < s)
        {
          r.exop = (Byte)(*p < 256 ? 0 : 32 + 64);     /* 256 is end-of-block */
          r.base = *p++;          /* simple code is just the value */
        }
        else
        {
          r.exop = (Byte)(e[*p - s] + 16 + 64);/* non-simple--look up in lists */
          r.base = d[*p++ - s];
        }
  
        /* fill code-like entries with r */
        f = 1 << (k - w);
        for (j = i >> w; j < z; j += f)
          q[j] = r;
  
        /* backwards increment the k-bit code i */
        for (j = 1 << (k - 1); i & j; j >>= 1)
          i ^= j;
        i ^= j;
  
        /* backup over finished tables */
        mask = (1 << w) - 1;      /* needed on HP, cc -O bug */
        while ((i & mask) != x[h])
        {
          h--;                    /* don't need to update q */
          w -= l;
          mask = (1 << w) - 1;
        }
      }
    }
  
  
    /* Return Z_BUF_ERROR if we were given an incomplete table */
    return y != 0 && g != 1 ? Z_BUF_ERROR : Z_OK;
  }
  
  
  static int inflate_trees_bits(c, bb, tb, hp, z)
  uIntf *c;               /* 19 code lengths */
  uIntf *bb;              /* bits tree desired/actual depth */
  inflate_huft * FAR *tb; /* bits tree result */
  inflate_huft *hp;       /* space for trees */
  z_streamp z;            /* for messages */
  {
    int r;
    uInt hn = 0;          /* hufts used in space */
    uIntf *v;             /* work area for huft_build */
  
    if ((v = (uIntf*)ZALLOC(z, 19, sizeof(uInt))) == Z_NULL)
      return Z_MEM_ERROR;
    r = huft_build(c, 19, 19, (uIntf*)Z_NULL, (uIntf*)Z_NULL,
                   tb, bb, hp, &hn, v);
    if (r == Z_DATA_ERROR)
      z->msg = (char*)"oversubscribed dynamic bit lengths tree";
    else if (r == Z_BUF_ERROR || *bb == 0)
    {
      z->msg = (char*)"incomplete dynamic bit lengths tree";
      r = Z_DATA_ERROR;
    }
    ZFREE(z, v);
    return r;
  }
  
  
  static int inflate_trees_dynamic(nl, nd, c, bl, bd, tl, td, hp, z)
  uInt nl;                /* number of literal/length codes */
  uInt nd;                /* number of distance codes */
  uIntf *c;               /* that many (total) code lengths */
  uIntf *bl;              /* literal desired/actual bit depth */
  uIntf *bd;              /* distance desired/actual bit depth */
  inflate_huft * FAR *tl; /* literal/length tree result */
  inflate_huft * FAR *td; /* distance tree result */
  inflate_huft *hp;       /* space for trees */
  z_streamp z;            /* for messages */
  {
    int r;
    uInt hn = 0;          /* hufts used in space */
    uIntf *v;             /* work area for huft_build */
  
    /* allocate work area */
    if ((v = (uIntf*)ZALLOC(z, 288, sizeof(uInt))) == Z_NULL)
      return Z_MEM_ERROR;
  
    /* build literal/length tree */
    r = huft_build(c, nl, 257, cplens, cplext, tl, bl, hp, &hn, v);
    if (r != Z_OK || *bl == 0)
    {
      if (r == Z_DATA_ERROR)
        z->msg = (char*)"oversubscribed literal/length tree";
      else if (r != Z_MEM_ERROR)
      {
        z->msg = (char*)"incomplete literal/length tree";
        r = Z_DATA_ERROR;
      }
      ZFREE(z, v);
      return r;
    }
  
    /* build distance tree */
    r = huft_build(c + nl, nd, 0, cpdist, cpdext, td, bd, hp, &hn, v);
    if (r != Z_OK || (*bd == 0 && nl > 257))
    {
      if (r == Z_DATA_ERROR)
        z->msg = (char*)"oversubscribed distance tree";
      else if (r == Z_BUF_ERROR) {
  #ifdef PKZIP_BUG_WORKAROUND
        r = Z_OK;
      }
  #else
        z->msg = (char*)"incomplete distance tree";
        r = Z_DATA_ERROR;
      }
      else if (r != Z_MEM_ERROR)
      {
        z->msg = (char*)"empty distance tree with lengths";
        r = Z_DATA_ERROR;
      }
      ZFREE(z, v);
      return r;
  #endif
    }
  
    /* done */
    ZFREE(z, v);
    return Z_OK;
  }
  
  
  /* build fixed tables only once--keep them here */
  #ifdef BUILDFIXED
  static int fixed_built = 0;
  #define FIXEDH 544      /* number of hufts used by fixed tables */
  static inflate_huft *fixed_mem = NULL;
  static uInt fixed_bl;
  static uInt fixed_bd;
  static inflate_huft *fixed_tl;
  static inflate_huft *fixed_td;
  #else
  /* +++ inffixed.h */
  /* inffixed.h -- table for decoding fixed codes
   * Generated automatically by the maketree.c program
   */
  
  /* WARNING: this file should *not* be used by applications. It is
     part of the implementation of the compression library and is
     subject to change. Applications should only use zlib.h.
   */
  
  static uInt fixed_bl = 9;
  static uInt fixed_bd = 5;
  static inflate_huft fixed_tl[] = {
      {{{96,7}},256}, {{{0,8}},80}, {{{0,8}},16}, {{{84,8}},115},
      {{{82,7}},31}, {{{0,8}},112}, {{{0,8}},48}, {{{0,9}},192},
      {{{80,7}},10}, {{{0,8}},96}, {{{0,8}},32}, {{{0,9}},160},
      {{{0,8}},0}, {{{0,8}},128}, {{{0,8}},64}, {{{0,9}},224},
      {{{80,7}},6}, {{{0,8}},88}, {{{0,8}},24}, {{{0,9}},144},
      {{{83,7}},59}, {{{0,8}},120}, {{{0,8}},56}, {{{0,9}},208},
      {{{81,7}},17}, {{{0,8}},104}, {{{0,8}},40}, {{{0,9}},176},
      {{{0,8}},8}, {{{0,8}},136}, {{{0,8}},72}, {{{0,9}},240},
      {{{80,7}},4}, {{{0,8}},84}, {{{0,8}},20}, {{{85,8}},227},
      {{{83,7}},43}, {{{0,8}},116}, {{{0,8}},52}, {{{0,9}},200},
      {{{81,7}},13}, {{{0,8}},100}, {{{0,8}},36}, {{{0,9}},168},
      {{{0,8}},4}, {{{0,8}},132}, {{{0,8}},68}, {{{0,9}},232},
      {{{80,7}},8}, {{{0,8}},92}, {{{0,8}},28}, {{{0,9}},152},
      {{{84,7}},83}, {{{0,8}},124}, {{{0,8}},60}, {{{0,9}},216},
      {{{82,7}},23}, {{{0,8}},108}, {{{0,8}},44}, {{{0,9}},184},
      {{{0,8}},12}, {{{0,8}},140}, {{{0,8}},76}, {{{0,9}},248},
      {{{80,7}},3}, {{{0,8}},82}, {{{0,8}},18}, {{{85,8}},163},
      {{{83,7}},35}, {{{0,8}},114}, {{{0,8}},50}, {{{0,9}},196},
      {{{81,7}},11}, {{{0,8}},98}, {{{0,8}},34}, {{{0,9}},164},
      {{{0,8}},2}, {{{0,8}},130}, {{{0,8}},66}, {{{0,9}},228},
      {{{80,7}},7}, {{{0,8}},90}, {{{0,8}},26}, {{{0,9}},148},
      {{{84,7}},67}, {{{0,8}},122}, {{{0,8}},58}, {{{0,9}},212},
      {{{82,7}},19}, {{{0,8}},106}, {{{0,8}},42}, {{{0,9}},180},
      {{{0,8}},10}, {{{0,8}},138}, {{{0,8}},74}, {{{0,9}},244},
      {{{80,7}},5}, {{{0,8}},86}, {{{0,8}},22}, {{{192,8}},0},
      {{{83,7}},51}, {{{0,8}},118}, {{{0,8}},54}, {{{0,9}},204},
      {{{81,7}},15}, {{{0,8}},102}, {{{0,8}},38}, {{{0,9}},172},
      {{{0,8}},6}, {{{0,8}},134}, {{{0,8}},70}, {{{0,9}},236},
      {{{80,7}},9}, {{{0,8}},94}, {{{0,8}},30}, {{{0,9}},156},
      {{{84,7}},99}, {{{0,8}},126}, {{{0,8}},62}, {{{0,9}},220},
      {{{82,7}},27}, {{{0,8}},110}, {{{0,8}},46}, {{{0,9}},188},
      {{{0,8}},14}, {{{0,8}},142}, {{{0,8}},78}, {{{0,9}},252},
      {{{96,7}},256}, {{{0,8}},81}, {{{0,8}},17}, {{{85,8}},131},
      {{{82,7}},31}, {{{0,8}},113}, {{{0,8}},49}, {{{0,9}},194},
      {{{80,7}},10}, {{{0,8}},97}, {{{0,8}},33}, {{{0,9}},162},
      {{{0,8}},1}, {{{0,8}},129}, {{{0,8}},65}, {{{0,9}},226},
      {{{80,7}},6}, {{{0,8}},89}, {{{0,8}},25}, {{{0,9}},146},
      {{{83,7}},59}, {{{0,8}},121}, {{{0,8}},57}, {{{0,9}},210},
      {{{81,7}},17}, {{{0,8}},105}, {{{0,8}},41}, {{{0,9}},178},
      {{{0,8}},9}, {{{0,8}},137}, {{{0,8}},73}, {{{0,9}},242},
      {{{80,7}},4}, {{{0,8}},85}, {{{0,8}},21}, {{{80,8}},258},
      {{{83,7}},43}, {{{0,8}},117}, {{{0,8}},53}, {{{0,9}},202},
      {{{81,7}},13}, {{{0,8}},101}, {{{0,8}},37}, {{{0,9}},170},
      {{{0,8}},5}, {{{0,8}},133}, {{{0,8}},69}, {{{0,9}},234},
      {{{80,7}},8}, {{{0,8}},93}, {{{0,8}},29}, {{{0,9}},154},
      {{{84,7}},83}, {{{0,8}},125}, {{{0,8}},61}, {{{0,9}},218},
      {{{82,7}},23}, {{{0,8}},109}, {{{0,8}},45}, {{{0,9}},186},
      {{{0,8}},13}, {{{0,8}},141}, {{{0,8}},77}, {{{0,9}},250},
      {{{80,7}},3}, {{{0,8}},83}, {{{0,8}},19}, {{{85,8}},195},
      {{{83,7}},35}, {{{0,8}},115}, {{{0,8}},51}, {{{0,9}},198},
      {{{81,7}},11}, {{{0,8}},99}, {{{0,8}},35}, {{{0,9}},166},
      {{{0,8}},3}, {{{0,8}},131}, {{{0,8}},67}, {{{0,9}},230},
      {{{80,7}},7}, {{{0,8}},91}, {{{0,8}},27}, {{{0,9}},150},
      {{{84,7}},67}, {{{0,8}},123}, {{{0,8}},59}, {{{0,9}},214},
      {{{82,7}},19}, {{{0,8}},107}, {{{0,8}},43}, {{{0,9}},182},
      {{{0,8}},11}, {{{0,8}},139}, {{{0,8}},75}, {{{0,9}},246},
      {{{80,7}},5}, {{{0,8}},87}, {{{0,8}},23}, {{{192,8}},0},
      {{{83,7}},51}, {{{0,8}},119}, {{{0,8}},55}, {{{0,9}},206},
      {{{81,7}},15}, {{{0,8}},103}, {{{0,8}},39}, {{{0,9}},174},
      {{{0,8}},7}, {{{0,8}},135}, {{{0,8}},71}, {{{0,9}},238},
      {{{80,7}},9}, {{{0,8}},95}, {{{0,8}},31}, {{{0,9}},158},
      {{{84,7}},99}, {{{0,8}},127}, {{{0,8}},63}, {{{0,9}},222},
      {{{82,7}},27}, {{{0,8}},111}, {{{0,8}},47}, {{{0,9}},190},
      {{{0,8}},15}, {{{0,8}},143}, {{{0,8}},79}, {{{0,9}},254},
      {{{96,7}},256}, {{{0,8}},80}, {{{0,8}},16}, {{{84,8}},115},
      {{{82,7}},31}, {{{0,8}},112}, {{{0,8}},48}, {{{0,9}},193},
      {{{80,7}},10}, {{{0,8}},96}, {{{0,8}},32}, {{{0,9}},161},
      {{{0,8}},0}, {{{0,8}},128}, {{{0,8}},64}, {{{0,9}},225},
      {{{80,7}},6}, {{{0,8}},88}, {{{0,8}},24}, {{{0,9}},145},
      {{{83,7}},59}, {{{0,8}},120}, {{{0,8}},56}, {{{0,9}},209},
      {{{81,7}},17}, {{{0,8}},104}, {{{0,8}},40}, {{{0,9}},177},
      {{{0,8}},8}, {{{0,8}},136}, {{{0,8}},72}, {{{0,9}},241},
      {{{80,7}},4}, {{{0,8}},84}, {{{0,8}},20}, {{{85,8}},227},
      {{{83,7}},43}, {{{0,8}},116}, {{{0,8}},52}, {{{0,9}},201},
      {{{81,7}},13}, {{{0,8}},100}, {{{0,8}},36}, {{{0,9}},169},
      {{{0,8}},4}, {{{0,8}},132}, {{{0,8}},68}, {{{0,9}},233},
      {{{80,7}},8}, {{{0,8}},92}, {{{0,8}},28}, {{{0,9}},153},
      {{{84,7}},83}, {{{0,8}},124}, {{{0,8}},60}, {{{0,9}},217},
      {{{82,7}},23}, {{{0,8}},108}, {{{0,8}},44}, {{{0,9}},185},
      {{{0,8}},12}, {{{0,8}},140}, {{{0,8}},76}, {{{0,9}},249},
      {{{80,7}},3}, {{{0,8}},82}, {{{0,8}},18}, {{{85,8}},163},
      {{{83,7}},35}, {{{0,8}},114}, {{{0,8}},50}, {{{0,9}},197},
      {{{81,7}},11}, {{{0,8}},98}, {{{0,8}},34}, {{{0,9}},165},
      {{{0,8}},2}, {{{0,8}},130}, {{{0,8}},66}, {{{0,9}},229},
      {{{80,7}},7}, {{{0,8}},90}, {{{0,8}},26}, {{{0,9}},149},
      {{{84,7}},67}, {{{0,8}},122}, {{{0,8}},58}, {{{0,9}},213},
      {{{82,7}},19}, {{{0,8}},106}, {{{0,8}},42}, {{{0,9}},181},
      {{{0,8}},10}, {{{0,8}},138}, {{{0,8}},74}, {{{0,9}},245},
      {{{80,7}},5}, {{{0,8}},86}, {{{0,8}},22}, {{{192,8}},0},
      {{{83,7}},51}, {{{0,8}},118}, {{{0,8}},54}, {{{0,9}},205},
      {{{81,7}},15}, {{{0,8}},102}, {{{0,8}},38}, {{{0,9}},173},
      {{{0,8}},6}, {{{0,8}},134}, {{{0,8}},70}, {{{0,9}},237},
      {{{80,7}},9}, {{{0,8}},94}, {{{0,8}},30}, {{{0,9}},157},
      {{{84,7}},99}, {{{0,8}},126}, {{{0,8}},62}, {{{0,9}},221},
      {{{82,7}},27}, {{{0,8}},110}, {{{0,8}},46}, {{{0,9}},189},
      {{{0,8}},14}, {{{0,8}},142}, {{{0,8}},78}, {{{0,9}},253},
      {{{96,7}},256}, {{{0,8}},81}, {{{0,8}},17}, {{{85,8}},131},
      {{{82,7}},31}, {{{0,8}},113}, {{{0,8}},49}, {{{0,9}},195},
      {{{80,7}},10}, {{{0,8}},97}, {{{0,8}},33}, {{{0,9}},163},
      {{{0,8}},1}, {{{0,8}},129}, {{{0,8}},65}, {{{0,9}},227},
      {{{80,7}},6}, {{{0,8}},89}, {{{0,8}},25}, {{{0,9}},147},
      {{{83,7}},59}, {{{0,8}},121}, {{{0,8}},57}, {{{0,9}},211},
      {{{81,7}},17}, {{{0,8}},105}, {{{0,8}},41}, {{{0,9}},179},
      {{{0,8}},9}, {{{0,8}},137}, {{{0,8}},73}, {{{0,9}},243},
      {{{80,7}},4}, {{{0,8}},85}, {{{0,8}},21}, {{{80,8}},258},
      {{{83,7}},43}, {{{0,8}},117}, {{{0,8}},53}, {{{0,9}},203},
      {{{81,7}},13}, {{{0,8}},101}, {{{0,8}},37}, {{{0,9}},171},
      {{{0,8}},5}, {{{0,8}},133}, {{{0,8}},69}, {{{0,9}},235},
      {{{80,7}},8}, {{{0,8}},93}, {{{0,8}},29}, {{{0,9}},155},
      {{{84,7}},83}, {{{0,8}},125}, {{{0,8}},61}, {{{0,9}},219},
      {{{82,7}},23}, {{{0,8}},109}, {{{0,8}},45}, {{{0,9}},187},
      {{{0,8}},13}, {{{0,8}},141}, {{{0,8}},77}, {{{0,9}},251},
      {{{80,7}},3}, {{{0,8}},83}, {{{0,8}},19}, {{{85,8}},195},
      {{{83,7}},35}, {{{0,8}},115}, {{{0,8}},51}, {{{0,9}},199},
      {{{81,7}},11}, {{{0,8}},99}, {{{0,8}},35}, {{{0,9}},167},
      {{{0,8}},3}, {{{0,8}},131}, {{{0,8}},67}, {{{0,9}},231},
      {{{80,7}},7}, {{{0,8}},91}, {{{0,8}},27}, {{{0,9}},151},
      {{{84,7}},67}, {{{0,8}},123}, {{{0,8}},59}, {{{0,9}},215},
      {{{82,7}},19}, {{{0,8}},107}, {{{0,8}},43}, {{{0,9}},183},
      {{{0,8}},11}, {{{0,8}},139}, {{{0,8}},75}, {{{0,9}},247},
      {{{80,7}},5}, {{{0,8}},87}, {{{0,8}},23}, {{{192,8}},0},
      {{{83,7}},51}, {{{0,8}},119}, {{{0,8}},55}, {{{0,9}},207},
      {{{81,7}},15}, {{{0,8}},103}, {{{0,8}},39}, {{{0,9}},175},
      {{{0,8}},7}, {{{0,8}},135}, {{{0,8}},71}, {{{0,9}},239},
      {{{80,7}},9}, {{{0,8}},95}, {{{0,8}},31}, {{{0,9}},159},
      {{{84,7}},99}, {{{0,8}},127}, {{{0,8}},63}, {{{0,9}},223},
      {{{82,7}},27}, {{{0,8}},111}, {{{0,8}},47}, {{{0,9}},191},
      {{{0,8}},15}, {{{0,8}},143}, {{{0,8}},79}, {{{0,9}},255}
    };
  static inflate_huft fixed_td[] = {
      {{{80,5}},1}, {{{87,5}},257}, {{{83,5}},17}, {{{91,5}},4097},
      {{{81,5}},5}, {{{89,5}},1025}, {{{85,5}},65}, {{{93,5}},16385},
      {{{80,5}},3}, {{{88,5}},513}, {{{84,5}},33}, {{{92,5}},8193},
      {{{82,5}},9}, {{{90,5}},2049}, {{{86,5}},129}, {{{192,5}},24577},
      {{{80,5}},2}, {{{87,5}},385}, {{{83,5}},25}, {{{91,5}},6145},
      {{{81,5}},7}, {{{89,5}},1537}, {{{85,5}},97}, {{{93,5}},24577},
      {{{80,5}},4}, {{{88,5}},769}, {{{84,5}},49}, {{{92,5}},12289},
      {{{82,5}},13}, {{{90,5}},3073}, {{{86,5}},193}, {{{192,5}},24577}
    };
  /* --- inffixed.h */
  #endif
  
  
  static int inflate_trees_fixed(bl, bd, tl, td, z)
  uIntf *bl;               /* literal desired/actual bit depth */
  uIntf *bd;               /* distance desired/actual bit depth */
  inflate_huft * FAR *tl;  /* literal/length tree result */
  inflate_huft * FAR *td;  /* distance tree result */
  z_streamp z;             /* for memory allocation */
  {
  #ifdef BUILDFIXED
    /* build fixed tables if not already */
    if (!fixed_built)
    {
      int k;              /* temporary variable */
      uInt f = 0;         /* number of hufts used in fixed_mem */
      uIntf *c;           /* length list for huft_build */
      uIntf *v;           /* work area for huft_build */
  
      /* allocate memory */
      if ((c = (uIntf*)ZALLOC(z, 288, sizeof(uInt))) == Z_NULL)
        return Z_MEM_ERROR;
      if ((v = (uIntf*)ZALLOC(z, 288, sizeof(uInt))) == Z_NULL)
      {
        ZFREE(z, c);
        return Z_MEM_ERROR;
      }
      
      if ((fixed_mem = (inflate_huft*)ZALLOC(z, FIXEDH, sizeof(inflate_huft))) == Z_NULL)
      {
          ZFREE(z, c);
          ZFREE(z, v);
          return Z_MEM_ERROR;
      }
  
      /* literal table */
      for (k = 0; k < 144; k++)
        c[k] = 8;
      for (; k < 256; k++)
        c[k] = 9;
      for (; k < 280; k++)
        c[k] = 7;
      for (; k < 288; k++)
        c[k] = 8;
      fixed_bl = 9;
      huft_build(c, 288, 257, cplens, cplext, &fixed_tl, &fixed_bl,
                 fixed_mem, &f, v);
  
      /* distance table */
      for (k = 0; k < 30; k++)
        c[k] = 5;
      fixed_bd = 5;
      huft_build(c, 30, 0, cpdist, cpdext, &fixed_td, &fixed_bd,
                 fixed_mem, &f, v);
  
      /* done */
      ZFREE(z, v);
      ZFREE(z, c);
      fixed_built = 1;
    }
  #endif
    *bl = fixed_bl;
    *bd = fixed_bd;
    *tl = fixed_tl;
    *td = fixed_td;
    return Z_OK;
  }
  /* --- inftrees.c */
  
  /* +++ infcodes.c */
  /* infcodes.c -- process literals and length/distance pairs
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zutil.h" */
  /* #include "inftrees.h" */
  /* #include "infblock.h" */
  /* #include "infcodes.h" */
  /* #include "infutil.h" */
  
  /* +++ inffast.h */
  /* inffast.h -- header to use inffast.c
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* WARNING: this file should *not* be used by applications. It is
     part of the implementation of the compression library and is
     subject to change. Applications should only use zlib.h.
   */
  
  static int inflate_fast OF((
      uInt,
      uInt,
      inflate_huft *,
      inflate_huft *,
      inflate_blocks_statef *,
      z_streamp ));
  /* --- inffast.h */
  
  /* simplify the use of the inflate_huft type with some defines */
  #define exop word.what.Exop
  #define bits word.what.Bits
  
  typedef enum {        /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
        START,    /* x: set up for LEN */
        LEN,      /* i: get length/literal/eob next */
        LENEXT,   /* i: getting length extra (have base) */
        DIST,     /* i: get distance next */
        DISTEXT,  /* i: getting distance extra */
        COPY,     /* o: copying bytes in window, waiting for space */
        LIT,      /* o: got literal, waiting for output space */
        WASH,     /* o: got eob, possibly still output waiting */
        END,      /* x: got eob and all data flushed */
        BADCODE}  /* x: got error */
  inflate_codes_mode;
  
  /* inflate codes private state */
  struct inflate_codes_state {
  
    /* mode */
    inflate_codes_mode mode;      /* current inflate_codes mode */
  
    /* mode dependent information */
    uInt len;
    union {
      struct {
        inflate_huft *tree;       /* pointer into tree */
        uInt need;                /* bits needed */
      } code;             /* if LEN or DIST, where in tree */
      uInt lit;           /* if LIT, literal */
      struct {
        uInt get;                 /* bits to get for extra */
        uInt dist;                /* distance back to copy from */
      } copy;             /* if EXT or COPY, where and how much */
    } sub;                /* submode */
  
    /* mode independent information */
    Byte lbits;           /* ltree bits decoded per branch */
    Byte dbits;           /* dtree bits decoder per branch */
    inflate_huft *ltree;          /* literal/length/eob tree */
    inflate_huft *dtree;          /* distance tree */
  
  };
  
  
  static inflate_codes_statef *inflate_codes_new(bl, bd, tl, td, z)
  uInt bl, bd;
  inflate_huft *tl;
  inflate_huft *td; /* need separate declaration for Borland C++ */
  z_streamp z;
  {
    inflate_codes_statef *c;
  
    if ((c = (inflate_codes_statef *)
         ZALLOC(z,1,sizeof(struct inflate_codes_state))) != Z_NULL)
    {
      c->mode = START;
      c->lbits = (Byte)bl;
      c->dbits = (Byte)bd;
      c->ltree = tl;
      c->dtree = td;
      Tracev((stderr, "inflate:       codes new\n"));
    }
    return c;
  }
  
  
  static int inflate_codes(s, z, r)
  inflate_blocks_statef *s;
  z_streamp z;
  int r;
  {
    uInt j;               /* temporary storage */
    inflate_huft *t;      /* temporary pointer */
    uInt e;               /* extra bits or operation */
    uLong b;              /* bit buffer */
    uInt k;               /* bits in bit buffer */
    Bytef *p;             /* input data pointer */
    uInt n;               /* bytes available there */
    Bytef *q;             /* output window write pointer */
    uInt m;               /* bytes to end of window or read pointer */
    Bytef *f;             /* pointer to copy strings from */
    inflate_codes_statef *c = s->sub.decode.codes;  /* codes state */
  
    /* copy input/output information to locals (UPDATE macro restores) */
    LOAD
  
    /* process input and output based on current state */
    while (1) switch (c->mode)
    {             /* waiting for "i:"=input, "o:"=output, "x:"=nothing */
      case START:         /* x: set up for LEN */
  #ifndef SLOW
        if (m >= 258 && n >= 10)
        {
          UPDATE
          r = inflate_fast(c->lbits, c->dbits, c->ltree, c->dtree, s, z);
          LOAD
          if (r != Z_OK)
          {
            c->mode = r == Z_STREAM_END ? WASH : BADCODE;
            break;
          }
        }
  #endif /* !SLOW */
        c->sub.code.need = c->lbits;
        c->sub.code.tree = c->ltree;
        c->mode = LEN;
      case LEN:           /* i: get length/literal/eob next */
        j = c->sub.code.need;
        NEEDBITS(j)
        t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
        DUMPBITS(t->bits)
        e = (uInt)(t->exop);
        if (e == 0)               /* literal */
        {
          c->sub.lit = t->base;
          Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
                   "inflate:         literal '%c'\n" :
                   "inflate:         literal 0x%02x\n", t->base));
          c->mode = LIT;
          break;
        }
        if (e & 16)               /* length */
        {
          c->sub.copy.get = e & 15;
          c->len = t->base;
          c->mode = LENEXT;
          break;
        }
        if ((e & 64) == 0)        /* next table */
        {
          c->sub.code.need = e;
          c->sub.code.tree = t + t->base;
          break;
        }
        if (e & 32)               /* end of block */
        {
          Tracevv((stderr, "inflate:         end of block\n"));
          c->mode = WASH;
          break;
        }
        c->mode = BADCODE;        /* invalid code */
        z->msg = (char*)"invalid literal/length code";
        r = Z_DATA_ERROR;
        LEAVE
      case LENEXT:        /* i: getting length extra (have base) */
        j = c->sub.copy.get;
        NEEDBITS(j)
        c->len += (uInt)b & inflate_mask[j];
        DUMPBITS(j)
        c->sub.code.need = c->dbits;
        c->sub.code.tree = c->dtree;
        Tracevv((stderr, "inflate:         length %u\n", c->len));
        c->mode = DIST;
      case DIST:          /* i: get distance next */
        j = c->sub.code.need;
        NEEDBITS(j)
        t = c->sub.code.tree + ((uInt)b & inflate_mask[j]);
        DUMPBITS(t->bits)
        e = (uInt)(t->exop);
        if (e & 16)               /* distance */
        {
          c->sub.copy.get = e & 15;
          c->sub.copy.dist = t->base;
          c->mode = DISTEXT;
          break;
        }
        if ((e & 64) == 0)        /* next table */
        {
          c->sub.code.need = e;
          c->sub.code.tree = t + t->base;
          break;
        }
        c->mode = BADCODE;        /* invalid code */
        z->msg = (char*)"invalid distance code";
        r = Z_DATA_ERROR;
        LEAVE
      case DISTEXT:       /* i: getting distance extra */
        j = c->sub.copy.get;
        NEEDBITS(j)
        c->sub.copy.dist += (uInt)b & inflate_mask[j];
        DUMPBITS(j)
        Tracevv((stderr, "inflate:         distance %u\n", c->sub.copy.dist));
        c->mode = COPY;
      case COPY:          /* o: copying bytes in window, waiting for space */
        f = q - c->sub.copy.dist;
        while (f < s->window)             /* modulo window size-"while" instead */
          f += s->end - s->window;        /* of "if" handles invalid distances */
        while (c->len)
        {
          NEEDOUT
          OUTBYTE(*f++)
          if (f == s->end)
            f = s->window;
          c->len--;
        }
        c->mode = START;
        break;
      case LIT:           /* o: got literal, waiting for output space */
        NEEDOUT
        OUTBYTE(c->sub.lit)
        c->mode = START;
        break;
      case WASH:          /* o: got eob, possibly more output */
        if (k > 7)        /* return unused byte, if any */
        {
          Assert(k < 16, "inflate_codes grabbed too many bytes");
          k -= 8;
          n++;
          p--;            /* can always return one */
        }
        FLUSH
        if (s->read != s->write)
          LEAVE
        c->mode = END;
      case END:
        r = Z_STREAM_END;
        LEAVE
      case BADCODE:       /* x: got error */
        r = Z_DATA_ERROR;
        LEAVE
      default:
        r = Z_STREAM_ERROR;
        LEAVE
    }
  #ifdef NEED_DUMMY_RETURN
    return Z_STREAM_ERROR;  /* Some dumb compilers complain without this */
  #endif
  }
  
  
  static void inflate_codes_free(c, z)
  inflate_codes_statef *c;
  z_streamp z;
  {
    ZFREE(z, c);
    Tracev((stderr, "inflate:       codes free\n"));
  }
  /* --- infcodes.c */
  
  /* +++ infutil.c */
  /* inflate_util.c -- data and routines common to blocks and codes
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zutil.h" */
  /* #include "infblock.h" */
  /* #include "inftrees.h" */
  /* #include "infcodes.h" */
  /* #include "infutil.h" */
  
  #ifndef NO_DUMMY_DECL
  struct inflate_codes_state {int dummy;}; /* for buggy compilers */
  #endif
  
  /* copy as much as possible from the sliding window to the output area */
  static int inflate_flush(s, z, r)
  inflate_blocks_statef *s;
  z_streamp z;
  int r;
  {
    uInt n;
    Bytef *p;
    Bytef *q;
  
    /* local copies of source and destination pointers */
    p = z->next_out;
    q = s->read;
  
    /* compute number of bytes to copy as far as end of window */
    n = (uInt)((q <= s->write ? s->write : s->end) - q);
    if (n > z->avail_out) n = z->avail_out;
    if (n && r == Z_BUF_ERROR) r = Z_OK;
  
    /* update counters */
    z->avail_out -= n;
    z->total_out += n;
  
    /* update check information */
    if (s->checkfn != Z_NULL)
      z->adler = s->check = (*s->checkfn)(s->check, q, n);
  
    /* copy as far as end of window */
    zmemcpy(p, q, n);
    p += n;
    q += n;
  
    /* see if more to copy at beginning of window */
    if (q == s->end)
    {
      /* wrap pointers */
      q = s->window;
      if (s->write == s->end)
        s->write = s->window;
  
      /* compute bytes to copy */
      n = (uInt)(s->write - q);
      if (n > z->avail_out) n = z->avail_out;
      if (n && r == Z_BUF_ERROR) r = Z_OK;
  
      /* update counters */
      z->avail_out -= n;
      z->total_out += n;
  
      /* update check information */
      if (s->checkfn != Z_NULL)
        z->adler = s->check = (*s->checkfn)(s->check, q, n);
  
      /* copy */
      zmemcpy(p, q, n);
      p += n;
      q += n;
    }
  
    /* update pointers */
    z->next_out = p;
    s->read = q;
  
    /* done */
    return r;
  }
  /* --- infutil.c */
  
  /* +++ inffast.c */
  /* inffast.c -- process literals and length/distance pairs fast
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zutil.h" */
  /* #include "inftrees.h" */
  /* #include "infblock.h" */
  /* #include "infcodes.h" */
  /* #include "infutil.h" */
  /* #include "inffast.h" */
  
  #ifndef NO_DUMMY_DECL
  struct inflate_codes_state {int dummy;}; /* for buggy compilers */
  #endif
  
  /* simplify the use of the inflate_huft type with some defines */
  #define exop word.what.Exop
  #define bits word.what.Bits
  
  /* macros for bit input with no checking and for returning unused bytes */
  #define GRABBITS(j) {while(k<(j)){b|=((uLong)NEXTBYTE)<<k;k+=8;}}
  #define UNGRAB {c=z->avail_in-n;c=(k>>3)<c?k>>3:c;n+=c;p-=c;k-=c<<3;}
  
  /* Called with number of bytes left to write in window at least 258
     (the maximum string length) and number of input bytes available
     at least ten.  The ten bytes are six bytes for the longest length/
     distance pair plus four bytes for overloading the bit buffer. */
  
  static int inflate_fast(bl, bd, tl, td, s, z)
  uInt bl, bd;
  inflate_huft *tl;
  inflate_huft *td; /* need separate declaration for Borland C++ */
  inflate_blocks_statef *s;
  z_streamp z;
  {
    inflate_huft *t;      /* temporary pointer */
    uInt e;               /* extra bits or operation */
    uLong b;              /* bit buffer */
    uInt k;               /* bits in bit buffer */
    Bytef *p;             /* input data pointer */
    uInt n;               /* bytes available there */
    Bytef *q;             /* output window write pointer */
    uInt m;               /* bytes to end of window or read pointer */
    uInt ml;              /* mask for literal/length tree */
    uInt md;              /* mask for distance tree */
    uInt c;               /* bytes to copy */
    uInt d;               /* distance back to copy from */
    Bytef *r;             /* copy source pointer */
  
    /* load input, output, bit values */
    LOAD
  
    /* initialize masks */
    ml = inflate_mask[bl];
    md = inflate_mask[bd];
  
    /* do until not enough input or output space for fast loop */
    do {                          /* assume called with m >= 258 && n >= 10 */
      /* get literal/length code */
      GRABBITS(20)                /* max bits for literal/length code */
      if ((e = (t = tl + ((uInt)b & ml))->exop) == 0)
      {
        DUMPBITS(t->bits)
        Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
                  "inflate:         * literal '%c'\n" :
                  "inflate:         * literal 0x%02x\n", t->base));
        *q++ = (Byte)t->base;
        m--;
        continue;
      }
      do {
        DUMPBITS(t->bits)
        if (e & 16)
        {
          /* get extra bits for length */
          e &= 15;
          c = t->base + ((uInt)b & inflate_mask[e]);
          DUMPBITS(e)
          Tracevv((stderr, "inflate:         * length %u\n", c));
  
          /* decode distance base of block to copy */
          GRABBITS(15);           /* max bits for distance code */
          e = (t = td + ((uInt)b & md))->exop;
          do {
            DUMPBITS(t->bits)
            if (e & 16)
            {
              /* get extra bits to add to distance base */
              e &= 15;
              GRABBITS(e)         /* get extra bits (up to 13) */
              d = t->base + ((uInt)b & inflate_mask[e]);
              DUMPBITS(e)
              Tracevv((stderr, "inflate:         * distance %u\n", d));
  
              /* do the copy */
              m -= c;
              r = q - d;
              if (r < s->window)                  /* wrap if needed */
              {
                do {
                  r += s->end - s->window;        /* force pointer in window */
                } while (r < s->window);          /* covers invalid distances */
                e = s->end - r;
                if (c > e)
                {
                  c -= e;                         /* wrapped copy */
                  do {
                      *q++ = *r++;
                  } while (--e);
                  r = s->window;
                  do {
                      *q++ = *r++;
                  } while (--c);
                }
                else                              /* normal copy */
                {
                  *q++ = *r++;  c--;
                  *q++ = *r++;  c--;
                  do {
                      *q++ = *r++;
                  } while (--c);
                }
              }
              else                                /* normal copy */
              {
                *q++ = *r++;  c--;
                *q++ = *r++;  c--;
                do {
                  *q++ = *r++;
                } while (--c);
              }
              break;
            }
            else if ((e & 64) == 0)
            {
              t += t->base;
              e = (t += ((uInt)b & inflate_mask[e]))->exop;
            }
            else
            {
              z->msg = (char*)"invalid distance code";
              UNGRAB
              UPDATE
              return Z_DATA_ERROR;
            }
          } while (1);
          break;
        }
        if ((e & 64) == 0)
        {
          t += t->base;
          if ((e = (t += ((uInt)b & inflate_mask[e]))->exop) == 0)
          {
            DUMPBITS(t->bits)
            Tracevv((stderr, t->base >= 0x20 && t->base < 0x7f ?
                      "inflate:         * literal '%c'\n" :
                      "inflate:         * literal 0x%02x\n", t->base));
            *q++ = (Byte)t->base;
            m--;
            break;
          }
        }
        else if (e & 32)
        {
          Tracevv((stderr, "inflate:         * end of block\n"));
          UNGRAB
          UPDATE
          return Z_STREAM_END;
        }
        else
        {
          z->msg = (char*)"invalid literal/length code";
          UNGRAB
          UPDATE
          return Z_DATA_ERROR;
        }
      } while (1);
    } while (m >= 258 && n >= 10);
  
    /* not enough input or output--restore pointers and return */
    UNGRAB
    UPDATE
    return Z_OK;
  }
  /* --- inffast.c */
  
  /* +++ zutil.c */
  /* zutil.c -- target dependent utility functions for the compression library
   * Copyright (C) 1995-2002 Jean-loup Gailly.
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zutil.h" */
  
  #ifndef NO_DUMMY_DECL
  struct internal_state      {int dummy;}; /* for buggy compilers */
  #endif
  
  #ifndef STDC
  extern void exit OF((int));
  #endif
  
  const char * ZEXPORT zlibVersion()
  {
      return ZLIB_VERSION;
  }
  
  #ifdef DEBUG_ZLIB
  
  #  ifndef verbose
  #    define verbose 0
  #  endif
  int z_verbose = verbose;
  
  void z_error (m)
      char *m;
  {
      fprintf(stderr, "%s\n", m);
      exit(1);
  }
  #endif
  
  /* exported to allow conversion of error code to string for compress() and
   * uncompress()
   */
  const char * ZEXPORT zError(err)
      int err;
  {
      return ERR_MSG(err);
  }
  
  
  #ifndef HAVE_MEMCPY
  
  void zmemcpy(dest, source, len)
      Bytef* dest;
      const Bytef* source;
      uInt  len;
  {
      if (len == 0) return;
      do {
          *dest++ = *source++; /* ??? to be unrolled */
      } while (--len != 0);
  }
  
  int zmemcmp(s1, s2, len)
      const Bytef* s1;
      const Bytef* s2;
      uInt  len;
  {
      uInt j;
  
      for (j = 0; j < len; j++) {
          if (s1[j] != s2[j]) return 2*(s1[j] > s2[j])-1;
      }
      return 0;
  }
  
  void zmemzero(dest, len)
      Bytef* dest;
      uInt  len;
  {
      if (len == 0) return;
      do {
          *dest++ = 0;  /* ??? to be unrolled */
      } while (--len != 0);
  }
  #endif
  
  #ifdef __TURBOC__
  #if (defined( __BORLANDC__) || !defined(SMALL_MEDIUM)) && !defined(__32BIT__)
  /* Small and medium model in Turbo C are for now limited to near allocation
   * with reduced MAX_WBITS and MAX_MEM_LEVEL
   */
  #  define MY_ZCALLOC
  
  /* Turbo C malloc() does not allow dynamic allocation of 64K bytes
   * and farmalloc(64K) returns a pointer with an offset of 8, so we
   * must fix the pointer. Warning: the pointer must be put back to its
   * original form in order to free it, use zcfree().
   */
  
  #define MAX_PTR 10
  /* 10*64K = 640K */
  
  static int next_ptr = 0;
  
  typedef struct ptr_table_s {
      voidpf org_ptr;
      voidpf new_ptr;
  } ptr_table;
  
  static ptr_table table[MAX_PTR];
  /* This table is used to remember the original form of pointers
   * to large buffers (64K). Such pointers are normalized with a zero offset.
   * Since MSDOS is not a preemptive multitasking OS, this table is not
   * protected from concurrent access. This hack doesn't work anyway on
   * a protected system like OS/2. Use Microsoft C instead.
   */
  
  voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
  {
      voidpf buf = opaque; /* just to make some compilers happy */
      ulg bsize = (ulg)items*size;
  
      /* If we allocate less than 65520 bytes, we assume that farmalloc
       * will return a usable pointer which doesn't have to be normalized.
       */
      if (bsize < 65520L) {
          buf = farmalloc(bsize);
          if (*(ush*)&buf != 0) return buf;
      } else {
          buf = farmalloc(bsize + 16L);
      }
      if (buf == NULL || next_ptr >= MAX_PTR) return NULL;
      table[next_ptr].org_ptr = buf;
  
      /* Normalize the pointer to seg:0 */
      *((ush*)&buf+1) += ((ush)((uch*)buf-0) + 15) >> 4;
      *(ush*)&buf = 0;
      table[next_ptr++].new_ptr = buf;
      return buf;
  }
  
  void  zcfree (voidpf opaque, voidpf ptr)
  {
      int n;
      if (*(ush*)&ptr != 0) { /* object < 64K */
          farfree(ptr);
          return;
      }
      /* Find the original pointer */
      for (n = 0; n < next_ptr; n++) {
          if (ptr != table[n].new_ptr) continue;
  
          farfree(table[n].org_ptr);
          while (++n < next_ptr) {
              table[n-1] = table[n];
          }
          next_ptr--;
          return;
      }
      ptr = opaque; /* just to make some compilers happy */
      Assert(0, "zcfree: ptr not found");
  }
  #endif
  #endif /* __TURBOC__ */
  
  
  #if defined(M_I86) && !defined(__32BIT__)
  /* Microsoft C in 16-bit mode */
  
  #  define MY_ZCALLOC
  
  #if (!defined(_MSC_VER) || (_MSC_VER <= 600))
  #  define _halloc  halloc
  #  define _hfree   hfree
  #endif
  
  voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
  {
      if (opaque) opaque = 0; /* to make compiler happy */
      return _halloc((long)items, size);
  }
  
  void  zcfree (voidpf opaque, voidpf ptr)
  {
      if (opaque) opaque = 0; /* to make compiler happy */
      _hfree(ptr);
  }
  
  #endif /* MSC */
  
  
  #ifndef MY_ZCALLOC /* Any system without a special alloc function */
  
  #ifndef STDC
  extern voidp  calloc OF((uInt items, uInt size));
  extern void   free   OF((voidpf ptr));
  #endif
  
  voidpf zcalloc (opaque, items, size)
      voidpf opaque;
      unsigned items;
      unsigned size;
  {
      if (opaque) items += size - size; /* make compiler happy */
      return (voidpf)calloc(items, size);
  }
  
  void  zcfree (opaque, ptr)
      voidpf opaque;
      voidpf ptr;
  {
      _FREE(ptr);
      if (opaque) return; /* make compiler happy */
  }
  
  #endif /* MY_ZCALLOC */
  /* --- zutil.c */
  
  /* +++ adler32.c */
  /* adler32.c -- compute the Adler-32 checksum of a data stream
   * Copyright (C) 1995-2002 Mark Adler
   * For conditions of distribution and use, see copyright notice in zlib.h 
   */
  
  /* #include "zlib.h" */
  
  #define BASE 65521L /* largest prime smaller than 65536 */
  #define NMAX 5552
  /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
  
  #define DO1(buf,i)  {s1 += buf[i]; s2 += s1;}
  #define DO2(buf,i)  DO1(buf,i); DO1(buf,i+1);
  #define DO4(buf,i)  DO2(buf,i); DO2(buf,i+2);
  #define DO8(buf,i)  DO4(buf,i); DO4(buf,i+4);
  #define DO16(buf)   DO8(buf,0); DO8(buf,8);
  
  /* ========================================================================= */
  uLong ZEXPORT
  adler32(uLong adler, const Bytef *buf, uInt len)
  {
      unsigned long s1 = adler & 0xffff;
      unsigned long s2 = (adler >> 16) & 0xffff;
      int k;
  
      if (buf == Z_NULL) return 1L;
  
      while (len > 0) {
          k = len < NMAX ? len : NMAX;
          len -= k;
          while (k >= 16) {
              DO16(buf);
              buf += 16;
              k -= 16;
          }
          if (k != 0) do {
              s1 += *buf++;
              s2 += s1;
          } while (--k);
          s1 %= BASE;
          s2 %= BASE;
      }
      return (s2 << 16) | s1;
  }
  /* --- adler32.c */