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sys/kern/inflate.c
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1 /* 2 * Most parts of this file are not covered by: 3 * ---------------------------------------------------------------------------- 4 * "THE BEER-WARE LICENSE" (Revision 42): 5 * <phk@login.dknet.dk> wrote this file. As long as you retain this notice you 6 * can do whatever you want with this stuff. If we meet some day, and you think 7 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp 8 * ---------------------------------------------------------------------------- 9 * 10 * $FreeBSD: src/sys/kern/inflate.c,v 1.14 1999/12/29 04:54:39 peter Exp $ 11 * $DragonFly: src/sys/kern/inflate.c,v 1.8 2008/01/06 16:55:51 swildner Exp $ 12 * 13 * 14 */ 15 16 #include <sys/param.h> 17 #include <sys/inflate.h> 18 #ifdef _KERNEL 19 #include <sys/systm.h> 20 #include <sys/kernel.h> 21 #endif 22 #include <sys/malloc.h> 23 24 #ifdef _KERNEL 25 static MALLOC_DEFINE(M_GZIP, "Gzip trees", "Gzip trees"); 26 #endif 27 28 /* needed to make inflate() work */ 29 #define uch u_char 30 #define ush u_short 31 #define ulg u_long 32 33 /* Stuff to make inflate() work */ 34 #ifdef _KERNEL 35 #define memzero(dest,len) bzero(dest,len) 36 #endif 37 #define NOMEMCPY 38 #ifdef _KERNEL 39 #define FPRINTF kprintf 40 #else 41 extern void putstr (char *); 42 #define FPRINTF putstr 43 #endif 44 45 #define FLUSH(x,y) { \ 46 int foo = (*x->gz_output)(x->gz_private,x->gz_slide,y); \ 47 if (foo) \ 48 return foo; \ 49 } 50 51 static const int qflag = 0; 52 53 #ifndef _KERNEL /* want to use this file in kzip also */ 54 extern unsigned char *kzipmalloc (int); 55 extern void kzipfree (void*); 56 #define kmalloc(x, y, z) kzipmalloc((x)) 57 #define kfree(x, y) kzipfree((x)) 58 #endif 59 60 /* 61 * This came from unzip-5.12. I have changed it the flow to pass 62 * a structure pointer around, thus hopefully making it re-entrant. 63 * Poul-Henning 64 */ 65 66 /* inflate.c -- put in the public domain by Mark Adler 67 version c14o, 23 August 1994 */ 68 69 /* You can do whatever you like with this source file, though I would 70 prefer that if you modify it and redistribute it that you include 71 comments to that effect with your name and the date. Thank you. 72 73 History: 74 vers date who what 75 ---- --------- -------------- ------------------------------------ 76 a ~~ Feb 92 M. Adler used full (large, one-step) lookup table 77 b1 21 Mar 92 M. Adler first version with partial lookup tables 78 b2 21 Mar 92 M. Adler fixed bug in fixed-code blocks 79 b3 22 Mar 92 M. Adler sped up match copies, cleaned up some 80 b4 25 Mar 92 M. Adler added prototypes; removed window[] (now 81 is the responsibility of unzip.h--also 82 changed name to slide[]), so needs diffs 83 for unzip.c and unzip.h (this allows 84 compiling in the small model on MSDOS); 85 fixed cast of q in huft_build(); 86 b5 26 Mar 92 M. Adler got rid of unintended macro recursion. 87 b6 27 Mar 92 M. Adler got rid of nextbyte() routine. fixed 88 bug in inflate_fixed(). 89 c1 30 Mar 92 M. Adler removed lbits, dbits environment variables. 90 changed BMAX to 16 for explode. Removed 91 OUTB usage, and replaced it with flush()-- 92 this was a 20% speed improvement! Added 93 an explode.c (to replace unimplod.c) that 94 uses the huft routines here. Removed 95 register union. 96 c2 4 Apr 92 M. Adler fixed bug for file sizes a multiple of 32k. 97 c3 10 Apr 92 M. Adler reduced memory of code tables made by 98 huft_build significantly (factor of two to 99 three). 100 c4 15 Apr 92 M. Adler added NOMEMCPY do kill use of memcpy(). 101 worked around a Turbo C optimization bug. 102 c5 21 Apr 92 M. Adler added the GZ_WSIZE #define to allow reducing 103 the 32K window size for specialized 104 applications. 105 c6 31 May 92 M. Adler added some typecasts to eliminate warnings 106 c7 27 Jun 92 G. Roelofs added some more typecasts (444: MSC bug). 107 c8 5 Oct 92 J-l. Gailly added ifdef'd code to deal with PKZIP bug. 108 c9 9 Oct 92 M. Adler removed a memory error message (~line 416). 109 c10 17 Oct 92 G. Roelofs changed ULONG/UWORD/byte to ulg/ush/uch, 110 removed old inflate, renamed inflate_entry 111 to inflate, added Mark's fix to a comment. 112 c10.5 14 Dec 92 M. Adler fix up error messages for incomplete trees. 113 c11 2 Jan 93 M. Adler fixed bug in detection of incomplete 114 tables, and removed assumption that EOB is 115 the longest code (bad assumption). 116 c12 3 Jan 93 M. Adler make tables for fixed blocks only once. 117 c13 5 Jan 93 M. Adler allow all zero length codes (pkzip 2.04c 118 outputs one zero length code for an empty 119 distance tree). 120 c14 12 Mar 93 M. Adler made inflate.c standalone with the 121 introduction of inflate.h. 122 c14b 16 Jul 93 G. Roelofs added (unsigned) typecast to w at 470. 123 c14c 19 Jul 93 J. Bush changed v[N_MAX], l[288], ll[28x+3x] arrays 124 to static for Amiga. 125 c14d 13 Aug 93 J-l. Gailly de-complicatified Mark's c[*p++]++ thing. 126 c14e 8 Oct 93 G. Roelofs changed memset() to memzero(). 127 c14f 22 Oct 93 G. Roelofs renamed quietflg to qflag; made Trace() 128 conditional; added inflate_free(). 129 c14g 28 Oct 93 G. Roelofs changed l/(lx+1) macro to pointer (Cray bug) 130 c14h 7 Dec 93 C. Ghisler huft_build() optimizations. 131 c14i 9 Jan 94 A. Verheijen set fixed_t{d,l} to NULL after freeing; 132 G. Roelofs check NEXTBYTE macro for GZ_EOF. 133 c14j 23 Jan 94 G. Roelofs removed Ghisler "optimizations"; ifdef'd 134 GZ_EOF check. 135 c14k 27 Feb 94 G. Roelofs added some typecasts to avoid warnings. 136 c14l 9 Apr 94 G. Roelofs fixed split comments on preprocessor lines 137 to avoid bug in Encore compiler. 138 c14m 7 Jul 94 P. Kienitz modified to allow assembler version of 139 inflate_codes() (define ASM_INFLATECODES) 140 c14n 22 Jul 94 G. Roelofs changed fprintf to FPRINTF for DLL versions 141 c14o 23 Aug 94 C. Spieler added a newline to a debug statement; 142 G. Roelofs added another typecast to avoid MSC warning 143 */ 144 145 146 /* 147 Inflate deflated (PKZIP's method 8 compressed) data. The compression 148 method searches for as much of the current string of bytes (up to a 149 length of 258) in the previous 32K bytes. If it doesn't find any 150 matches (of at least length 3), it codes the next byte. Otherwise, it 151 codes the length of the matched string and its distance backwards from 152 the current position. There is a single Huffman code that codes both 153 single bytes (called "literals") and match lengths. A second Huffman 154 code codes the distance information, which follows a length code. Each 155 length or distance code actually represents a base value and a number 156 of "extra" (sometimes zero) bits to get to add to the base value. At 157 the end of each deflated block is a special end-of-block (EOB) literal/ 158 length code. The decoding process is basically: get a literal/length 159 code; if EOB then done; if a literal, emit the decoded byte; if a 160 length then get the distance and emit the referred-to bytes from the 161 sliding window of previously emitted data. 162 163 There are (currently) three kinds of inflate blocks: stored, fixed, and 164 dynamic. The compressor outputs a chunk of data at a time and decides 165 which method to use on a chunk-by-chunk basis. A chunk might typically 166 be 32K to 64K, uncompressed. If the chunk is uncompressible, then the 167 "stored" method is used. In this case, the bytes are simply stored as 168 is, eight bits per byte, with none of the above coding. The bytes are 169 preceded by a count, since there is no longer an EOB code. 170 171 If the data is compressible, then either the fixed or dynamic methods 172 are used. In the dynamic method, the compressed data is preceded by 173 an encoding of the literal/length and distance Huffman codes that are 174 to be used to decode this block. The representation is itself Huffman 175 coded, and so is preceded by a description of that code. These code 176 descriptions take up a little space, and so for small blocks, there is 177 a predefined set of codes, called the fixed codes. The fixed method is 178 used if the block ends up smaller that way (usually for quite small 179 chunks); otherwise the dynamic method is used. In the latter case, the 180 codes are customized to the probabilities in the current block and so 181 can code it much better than the pre-determined fixed codes can. 182 183 The Huffman codes themselves are decoded using a mutli-level table 184 lookup, in order to maximize the speed of decoding plus the speed of 185 building the decoding tables. See the comments below that precede the 186 lbits and dbits tuning parameters. 187 */ 188 189 190 /* 191 Notes beyond the 1.93a appnote.txt: 192 193 1. Distance pointers never point before the beginning of the output 194 stream. 195 2. Distance pointers can point back across blocks, up to 32k away. 196 3. There is an implied maximum of 7 bits for the bit length table and 197 15 bits for the actual data. 198 4. If only one code exists, then it is encoded using one bit. (Zero 199 would be more efficient, but perhaps a little confusing.) If two 200 codes exist, they are coded using one bit each (0 and 1). 201 5. There is no way of sending zero distance codes--a dummy must be 202 sent if there are none. (History: a pre 2.0 version of PKZIP would 203 store blocks with no distance codes, but this was discovered to be 204 too harsh a criterion.) Valid only for 1.93a. 2.04c does allow 205 zero distance codes, which is sent as one code of zero bits in 206 length. 207 6. There are up to 286 literal/length codes. Code 256 represents the 208 end-of-block. Note however that the static length tree defines 209 288 codes just to fill out the Huffman codes. Codes 286 and 287 210 cannot be used though, since there is no length base or extra bits 211 defined for them. Similarily, there are up to 30 distance codes. 212 However, static trees define 32 codes (all 5 bits) to fill out the 213 Huffman codes, but the last two had better not show up in the data. 214 7. Unzip can check dynamic Huffman blocks for complete code sets. 215 The exception is that a single code would not be complete (see #4). 216 8. The five bits following the block type is really the number of 217 literal codes sent minus 257. 218 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits 219 (1+6+6). Therefore, to output three times the length, you output 220 three codes (1+1+1), whereas to output four times the same length, 221 you only need two codes (1+3). Hmm. 222 10. In the tree reconstruction algorithm, Code = Code + Increment 223 only if BitLength(i) is not zero. (Pretty obvious.) 224 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) 225 12. Note: length code 284 can represent 227-258, but length code 285 226 really is 258. The last length deserves its own, short code 227 since it gets used a lot in very redundant files. The length 228 258 is special since 258 - 3 (the min match length) is 255. 229 13. The literal/length and distance code bit lengths are read as a 230 single stream of lengths. It is possible (and advantageous) for 231 a repeat code (16, 17, or 18) to go across the boundary between 232 the two sets of lengths. 233 */ 234 235 236 #define PKZIP_BUG_WORKAROUND /* PKZIP 1.93a problem--live with it */ 237 238 /* 239 inflate.h must supply the uch slide[GZ_WSIZE] array and the NEXTBYTE, 240 FLUSH() and memzero macros. If the window size is not 32K, it 241 should also define GZ_WSIZE. If INFMOD is defined, it can include 242 compiled functions to support the NEXTBYTE and/or FLUSH() macros. 243 There are defaults for NEXTBYTE and FLUSH() below for use as 244 examples of what those functions need to do. Normally, you would 245 also want FLUSH() to compute a crc on the data. inflate.h also 246 needs to provide these typedefs: 247 248 typedef unsigned char uch; 249 typedef unsigned short ush; 250 typedef unsigned long ulg; 251 252 This module uses the external functions malloc() and free() (and 253 probably memset() or bzero() in the memzero() macro). Their 254 prototypes are normally found in <string.h> and <stdlib.h>. 255 */ 256 #define INFMOD /* tell inflate.h to include code to be 257 * compiled */ 258 259 /* Huffman code lookup table entry--this entry is four bytes for machines 260 that have 16-bit pointers (e.g. PC's in the small or medium model). 261 Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16 262 means that v is a literal, 16 < e < 32 means that v is a pointer to 263 the next table, which codes e - 16 bits, and lastly e == 99 indicates 264 an unused code. If a code with e == 99 is looked up, this implies an 265 error in the data. */ 266 struct huft { 267 uch e; /* number of extra bits or operation */ 268 uch b; /* number of bits in this code or subcode */ 269 union { 270 ush n; /* literal, length base, or distance 271 * base */ 272 struct huft *t; /* pointer to next level of table */ 273 } v; 274 }; 275 276 277 /* Function prototypes */ 278 static int huft_build (struct inflate *, unsigned *, unsigned, unsigned, const ush *, const ush *, struct huft **, int *); 279 static int huft_free (struct inflate *, struct huft *); 280 static int inflate_codes (struct inflate *, struct huft *, struct huft *, int, int); 281 static int inflate_stored (struct inflate *); 282 static int xinflate (struct inflate *); 283 static int inflate_fixed (struct inflate *); 284 static int inflate_dynamic (struct inflate *); 285 static int inflate_block (struct inflate *, int *); 286 287 /* The inflate algorithm uses a sliding 32K byte window on the uncompressed 288 stream to find repeated byte strings. This is implemented here as a 289 circular buffer. The index is updated simply by incrementing and then 290 and'ing with 0x7fff (32K-1). */ 291 /* It is left to other modules to supply the 32K area. It is assumed 292 to be usable as if it were declared "uch slide[32768];" or as just 293 "uch *slide;" and then malloc'ed in the latter case. The definition 294 must be in unzip.h, included above. */ 295 296 297 /* Tables for deflate from PKZIP's appnote.txt. */ 298 299 /* Order of the bit length code lengths */ 300 static const unsigned border[] = { 301 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; 302 303 static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */ 304 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 305 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; 306 /* note: see note #13 above about the 258 in this list. */ 307 308 static const ush cplext[] = { /* Extra bits for literal codes 257..285 */ 309 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 310 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */ 311 312 static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */ 313 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 314 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 315 8193, 12289, 16385, 24577}; 316 317 static const ush cpdext[] = { /* Extra bits for distance codes */ 318 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 319 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 320 12, 12, 13, 13}; 321 322 /* And'ing with mask[n] masks the lower n bits */ 323 static const ush mask[] = { 324 0x0000, 325 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, 326 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff 327 }; 328 329 330 /* Macros for inflate() bit peeking and grabbing. 331 The usage is: 332 333 NEEDBITS(glbl,j) 334 x = b & mask[j]; 335 DUMPBITS(j) 336 337 where NEEDBITS makes sure that b has at least j bits in it, and 338 DUMPBITS removes the bits from b. The macros use the variable k 339 for the number of bits in b. Normally, b and k are register 340 variables for speed, and are initialized at the begining of a 341 routine that uses these macros from a global bit buffer and count. 342 343 In order to not ask for more bits than there are in the compressed 344 stream, the Huffman tables are constructed to only ask for just 345 enough bits to make up the end-of-block code (value 256). Then no 346 bytes need to be "returned" to the buffer at the end of the last 347 block. See the huft_build() routine. 348 */ 349 350 /* 351 * The following 2 were global variables. 352 * They are now fields of the inflate structure. 353 */ 354 355 #define NEEDBITS(glbl,n) { \ 356 while(k<(n)) { \ 357 int c=(*glbl->gz_input)(glbl->gz_private); \ 358 if(c==GZ_EOF) \ 359 return 1; \ 360 b|=((ulg)c)<<k; \ 361 k+=8; \ 362 } \ 363 } 364 365 #define DUMPBITS(n) {b>>=(n);k-=(n);} 366 367 /* 368 Huffman code decoding is performed using a multi-level table lookup. 369 The fastest way to decode is to simply build a lookup table whose 370 size is determined by the longest code. However, the time it takes 371 to build this table can also be a factor if the data being decoded 372 is not very long. The most common codes are necessarily the 373 shortest codes, so those codes dominate the decoding time, and hence 374 the speed. The idea is you can have a shorter table that decodes the 375 shorter, more probable codes, and then point to subsidiary tables for 376 the longer codes. The time it costs to decode the longer codes is 377 then traded against the time it takes to make longer tables. 378 379 This results of this trade are in the variables lbits and dbits 380 below. lbits is the number of bits the first level table for literal/ 381 length codes can decode in one step, and dbits is the same thing for 382 the distance codes. Subsequent tables are also less than or equal to 383 those sizes. These values may be adjusted either when all of the 384 codes are shorter than that, in which case the longest code length in 385 bits is used, or when the shortest code is *longer* than the requested 386 table size, in which case the length of the shortest code in bits is 387 used. 388 389 There are two different values for the two tables, since they code a 390 different number of possibilities each. The literal/length table 391 codes 286 possible values, or in a flat code, a little over eight 392 bits. The distance table codes 30 possible values, or a little less 393 than five bits, flat. The optimum values for speed end up being 394 about one bit more than those, so lbits is 8+1 and dbits is 5+1. 395 The optimum values may differ though from machine to machine, and 396 possibly even between compilers. Your mileage may vary. 397 */ 398 399 static const int lbits = 9; /* bits in base literal/length lookup table */ 400 static const int dbits = 6; /* bits in base distance lookup table */ 401 402 403 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */ 404 #define BMAX 16 /* maximum bit length of any code (16 for 405 * explode) */ 406 #define N_MAX 288 /* maximum number of codes in any set */ 407 408 /* Given a list of code lengths and a maximum table size, make a set of 409 tables to decode that set of codes. Return zero on success, one if 410 the given code set is incomplete (the tables are still built in this 411 case), two if the input is invalid (all zero length codes or an 412 oversubscribed set of lengths), and three if not enough memory. 413 The code with value 256 is special, and the tables are constructed 414 so that no bits beyond that code are fetched when that code is 415 decoded. 416 417 Parameters: 418 b: code lengths in bits (all assumed <= BMAX) 419 n: number of codes (assumed <= N_MAX) 420 s: number of simple-valued codes (0..s-1) 421 d: list of base values for non-simple codes 422 e: list of extra bits for non-simple codes 423 t: result: starting table 424 m: maximum lookup bits, returns actual */ 425 static int 426 huft_build(struct inflate *glbl, unsigned *b, unsigned n, unsigned s, 427 const ush *d, const ush *e, struct huft **t, int *m) 428 { 429 unsigned a; /* counter for codes of length k */ 430 unsigned c[BMAX + 1]; /* bit length count table */ 431 unsigned el; /* length of EOB code (value 256) */ 432 unsigned f; /* i repeats in table every f entries */ 433 int g; /* maximum code length */ 434 int h; /* table level */ 435 unsigned i; /* counter, current code */ 436 unsigned j; /* counter */ 437 int k; /* number of bits in current code */ 438 int lx[BMAX + 1]; /* memory for l[-1..BMAX-1] */ 439 int *l = lx + 1; /* stack of bits per table */ 440 unsigned *p; /* pointer into c[], b[], or v[] */ 441 struct huft *q;/* points to current table */ 442 struct huft r; /* table entry for structure assignment */ 443 struct huft *u[BMAX];/* table stack */ 444 unsigned v[N_MAX]; /* values in order of bit length */ 445 int w; /* bits before this table == (l * h) */ 446 unsigned x[BMAX + 1]; /* bit offsets, then code stack */ 447 unsigned *xp; /* pointer into x */ 448 int y; /* number of dummy codes added */ 449 unsigned z; /* number of entries in current table */ 450 451 /* Generate counts for each bit length */ 452 el = n > 256 ? b[256] : BMAX; /* set length of EOB code, if any */ 453 #ifdef _KERNEL 454 memzero((char *) c, sizeof(c)); 455 #else 456 for (i = 0; i < BMAX+1; i++) 457 c [i] = 0; 458 #endif 459 p = b; 460 i = n; 461 do { 462 c[*p]++; 463 p++; /* assume all entries <= BMAX */ 464 } while (--i); 465 if (c[0] == n) { /* null input--all zero length codes */ 466 *t = NULL; 467 *m = 0; 468 return 0; 469 } 470 /* Find minimum and maximum length, bound *m by those */ 471 for (j = 1; j <= BMAX; j++) 472 if (c[j]) 473 break; 474 k = j; /* minimum code length */ 475 if ((unsigned) *m < j) 476 *m = j; 477 for (i = BMAX; i; i--) 478 if (c[i]) 479 break; 480 g = i; /* maximum code length */ 481 if ((unsigned) *m > i) 482 *m = i; 483 484 /* Adjust last length count to fill out codes, if needed */ 485 for (y = 1 << j; j < i; j++, y <<= 1) 486 if ((y -= c[j]) < 0) 487 return 2; /* bad input: more codes than bits */ 488 if ((y -= c[i]) < 0) 489 return 2; 490 c[i] += y; 491 492 /* Generate starting offsets into the value table for each length */ 493 x[1] = j = 0; 494 p = c + 1; 495 xp = x + 2; 496 while (--i) { /* note that i == g from above */ 497 *xp++ = (j += *p++); 498 } 499 500 /* Make a table of values in order of bit lengths */ 501 p = b; 502 i = 0; 503 do { 504 if ((j = *p++) != 0) 505 v[x[j]++] = i; 506 } while (++i < n); 507 508 /* Generate the Huffman codes and for each, make the table entries */ 509 x[0] = i = 0; /* first Huffman code is zero */ 510 p = v; /* grab values in bit order */ 511 h = -1; /* no tables yet--level -1 */ 512 w = l[-1] = 0; /* no bits decoded yet */ 513 u[0] = NULL; /* just to keep compilers happy */ 514 q = NULL; /* ditto */ 515 z = 0; /* ditto */ 516 517 /* go through the bit lengths (k already is bits in shortest code) */ 518 for (; k <= g; k++) { 519 a = c[k]; 520 while (a--) { 521 /* 522 * here i is the Huffman code of length k bits for 523 * value *p 524 */ 525 /* make tables up to required level */ 526 while (k > w + l[h]) { 527 w += l[h++]; /* add bits already decoded */ 528 529 /* 530 * compute minimum size table less than or 531 * equal to *m bits 532 */ 533 z = (z = g - w) > (unsigned) *m ? *m : z; /* upper limit */ 534 if ((f = 1 << (j = k - w)) > a + 1) { /* try a k-w bit table *//* t 535 * oo few codes for k-w 536 * bit table */ 537 f -= a + 1; /* deduct codes from 538 * patterns left */ 539 xp = c + k; 540 while (++j < z) { /* try smaller tables up 541 * to z bits */ 542 if ((f <<= 1) <= *++xp) 543 break; /* enough codes to use 544 * up j bits */ 545 f -= *xp; /* else deduct codes 546 * from patterns */ 547 } 548 } 549 if ((unsigned) w + j > el && (unsigned) w < el) 550 j = el - w; /* make EOB code end at 551 * table */ 552 z = 1 << j; /* table entries for j-bit 553 * table */ 554 l[h] = j; /* set table size in stack */ 555 556 /* allocate and link in new table */ 557 q = (struct huft *) kmalloc((z + 1) * sizeof(struct huft), M_GZIP, M_WAITOK); 558 glbl->gz_hufts += z + 1; /* track memory usage */ 559 *t = q + 1; /* link to list for 560 * huft_free() */ 561 *(t = &(q->v.t)) = NULL; 562 u[h] = ++q; /* table starts after link */ 563 564 /* connect to last table, if there is one */ 565 if (h) { 566 x[h] = i; /* save pattern for 567 * backing up */ 568 r.b = (uch) l[h - 1]; /* bits to dump before 569 * this table */ 570 r.e = (uch) (16 + j); /* bits in this table */ 571 r.v.t = q; /* pointer to this table */ 572 j = (i & ((1 << w) - 1)) >> (w - l[h - 1]); 573 u[h - 1][j] = r; /* connect to last table */ 574 } 575 } 576 577 /* set up table entry in r */ 578 r.b = (uch) (k - w); 579 if (p >= v + n) 580 r.e = 99; /* out of values--invalid 581 * code */ 582 else if (*p < s) { 583 r.e = (uch) (*p < 256 ? 16 : 15); /* 256 is end-of-block 584 * code */ 585 r.v.n = *p++; /* simple code is just the 586 * value */ 587 } else { 588 r.e = (uch) e[*p - s]; /* non-simple--look up 589 * in lists */ 590 r.v.n = d[*p++ - s]; 591 } 592 593 /* fill code-like entries with r */ 594 f = 1 << (k - w); 595 for (j = i >> w; j < z; j += f) 596 q[j] = r; 597 598 /* backwards increment the k-bit code i */ 599 for (j = 1 << (k - 1); i & j; j >>= 1) 600 i ^= j; 601 i ^= j; 602 603 /* backup over finished tables */ 604 while ((i & ((1 << w) - 1)) != x[h]) 605 w -= l[--h]; /* don't need to update q */ 606 } 607 } 608 609 /* return actual size of base table */ 610 *m = l[0]; 611 612 /* Return true (1) if we were given an incomplete table */ 613 return y != 0 && g != 1; 614 } 615 616 /* 617 * Parameters: 618 * t: table to free 619 */ 620 static int 621 huft_free(struct inflate *glbl, struct huft *t) 622 /* Free the malloc'ed tables built by huft_build(), which makes a linked 623 list of the tables it made, with the links in a dummy first entry of 624 each table. */ 625 { 626 struct huft *p, *q; 627 628 /* Go through linked list, freeing from the malloced (t[-1]) address. */ 629 p = t; 630 while (p != NULL) { 631 q = (--p)->v.t; 632 kfree(p, M_GZIP); 633 p = q; 634 } 635 return 0; 636 } 637 638 /* inflate (decompress) the codes in a deflated (compressed) block. 639 Return an error code or zero if it all goes ok. 640 641 tl, td - literal/length and distance decoder tables 642 bl, bd - number of bits decoded by tl[] and td[] */ 643 static int 644 inflate_codes(struct inflate *glbl, struct huft *tl, struct huft *td, 645 int bl, int bd) 646 { 647 unsigned e; /* table entry flag/number of extra bits */ 648 unsigned n, d; /* length and index for copy */ 649 unsigned w; /* current window position */ 650 struct huft *t; /* pointer to table entry */ 651 unsigned ml, md; /* masks for bl and bd bits */ 652 ulg b; /* bit buffer */ 653 unsigned k; /* number of bits in bit buffer */ 654 655 /* make local copies of globals */ 656 b = glbl->gz_bb; /* initialize bit buffer */ 657 k = glbl->gz_bk; 658 w = glbl->gz_wp; /* initialize window position */ 659 660 /* inflate the coded data */ 661 ml = mask[bl]; /* precompute masks for speed */ 662 md = mask[bd]; 663 while (1) { /* do until end of block */ 664 NEEDBITS(glbl, (unsigned) bl) 665 if ((e = (t = tl + ((unsigned) b & ml))->e) > 16) 666 do { 667 if (e == 99) 668 return 1; 669 DUMPBITS(t->b) 670 e -= 16; 671 NEEDBITS(glbl, e) 672 } while ((e = (t = t->v.t + ((unsigned) b & mask[e]))->e) > 16); 673 DUMPBITS(t->b) 674 if (e == 16) { /* then it's a literal */ 675 glbl->gz_slide[w++] = (uch) t->v.n; 676 if (w == GZ_WSIZE) { 677 FLUSH(glbl, w); 678 w = 0; 679 } 680 } else { /* it's an EOB or a length */ 681 /* exit if end of block */ 682 if (e == 15) 683 break; 684 685 /* get length of block to copy */ 686 NEEDBITS(glbl, e) 687 n = t->v.n + ((unsigned) b & mask[e]); 688 DUMPBITS(e); 689 690 /* decode distance of block to copy */ 691 NEEDBITS(glbl, (unsigned) bd) 692 if ((e = (t = td + ((unsigned) b & md))->e) > 16) 693 do { 694 if (e == 99) 695 return 1; 696 DUMPBITS(t->b) 697 e -= 16; 698 NEEDBITS(glbl, e) 699 } while ((e = (t = t->v.t + ((unsigned) b & mask[e]))->e) > 16); 700 DUMPBITS(t->b) 701 NEEDBITS(glbl, e) 702 d = w - t->v.n - ((unsigned) b & mask[e]); 703 DUMPBITS(e) 704 /* do the copy */ 705 do { 706 n -= (e = (e = GZ_WSIZE - ((d &= GZ_WSIZE - 1) > w ? d : w)) > n ? n : e); 707 #ifndef NOMEMCPY 708 if (w - d >= e) { /* (this test assumes 709 * unsigned comparison) */ 710 memcpy(glbl->gz_slide + w, glbl->gz_slide + d, e); 711 w += e; 712 d += e; 713 } else /* do it slow to avoid memcpy() 714 * overlap */ 715 #endif /* !NOMEMCPY */ 716 do { 717 glbl->gz_slide[w++] = glbl->gz_slide[d++]; 718 } while (--e); 719 if (w == GZ_WSIZE) { 720 FLUSH(glbl, w); 721 w = 0; 722 } 723 } while (n); 724 } 725 } 726 727 /* restore the globals from the locals */ 728 glbl->gz_wp = w; /* restore global window pointer */ 729 glbl->gz_bb = b; /* restore global bit buffer */ 730 glbl->gz_bk = k; 731 732 /* done */ 733 return 0; 734 } 735 736 /* "decompress" an inflated type 0 (stored) block. */ 737 static int 738 inflate_stored(struct inflate *glbl) 739 { 740 unsigned n; /* number of bytes in block */ 741 unsigned w; /* current window position */ 742 ulg b; /* bit buffer */ 743 unsigned k; /* number of bits in bit buffer */ 744 745 /* make local copies of globals */ 746 b = glbl->gz_bb; /* initialize bit buffer */ 747 k = glbl->gz_bk; 748 w = glbl->gz_wp; /* initialize window position */ 749 750 /* go to byte boundary */ 751 n = k & 7; 752 DUMPBITS(n); 753 754 /* get the length and its complement */ 755 NEEDBITS(glbl, 16) 756 n = ((unsigned) b & 0xffff); 757 DUMPBITS(16) 758 NEEDBITS(glbl, 16) 759 if (n != (unsigned) ((~b) & 0xffff)) 760 return 1; /* error in compressed data */ 761 DUMPBITS(16) 762 /* read and output the compressed data */ 763 while (n--) { 764 NEEDBITS(glbl, 8) 765 glbl->gz_slide[w++] = (uch) b; 766 if (w == GZ_WSIZE) { 767 FLUSH(glbl, w); 768 w = 0; 769 } 770 DUMPBITS(8) 771 } 772 773 /* restore the globals from the locals */ 774 glbl->gz_wp = w; /* restore global window pointer */ 775 glbl->gz_bb = b; /* restore global bit buffer */ 776 glbl->gz_bk = k; 777 return 0; 778 } 779 780 /* decompress an inflated type 1 (fixed Huffman codes) block. We should 781 either replace this with a custom decoder, or at least precompute the 782 Huffman tables. */ 783 static int 784 inflate_fixed(struct inflate *glbl) 785 { 786 /* if first time, set up tables for fixed blocks */ 787 if (glbl->gz_fixed_tl == NULL) { 788 int i; /* temporary variable */ 789 static unsigned l[288]; /* length list for huft_build */ 790 791 /* literal table */ 792 for (i = 0; i < 144; i++) 793 l[i] = 8; 794 for (; i < 256; i++) 795 l[i] = 9; 796 for (; i < 280; i++) 797 l[i] = 7; 798 for (; i < 288; i++) /* make a complete, but wrong code 799 * set */ 800 l[i] = 8; 801 glbl->gz_fixed_bl = 7; 802 if ((i = huft_build(glbl, l, 288, 257, cplens, cplext, 803 &glbl->gz_fixed_tl, &glbl->gz_fixed_bl)) != 0) { 804 glbl->gz_fixed_tl = NULL; 805 return i; 806 } 807 /* distance table */ 808 for (i = 0; i < 30; i++) /* make an incomplete code 809 * set */ 810 l[i] = 5; 811 glbl->gz_fixed_bd = 5; 812 if ((i = huft_build(glbl, l, 30, 0, cpdist, cpdext, 813 &glbl->gz_fixed_td, &glbl->gz_fixed_bd)) > 1) { 814 huft_free(glbl, glbl->gz_fixed_tl); 815 glbl->gz_fixed_tl = NULL; 816 return i; 817 } 818 } 819 /* decompress until an end-of-block code */ 820 return inflate_codes(glbl, glbl->gz_fixed_tl, glbl->gz_fixed_td, glbl->gz_fixed_bl, glbl->gz_fixed_bd) != 0; 821 } 822 823 /* decompress an inflated type 2 (dynamic Huffman codes) block. */ 824 static int 825 inflate_dynamic(struct inflate *glbl) 826 { 827 int i; /* temporary variables */ 828 unsigned j; 829 unsigned l; /* last length */ 830 unsigned m; /* mask for bit lengths table */ 831 unsigned n; /* number of lengths to get */ 832 struct huft *tl; /* literal/length code table */ 833 struct huft *td; /* distance code table */ 834 int bl; /* lookup bits for tl */ 835 int bd; /* lookup bits for td */ 836 unsigned nb; /* number of bit length codes */ 837 unsigned nl; /* number of literal/length codes */ 838 unsigned nd; /* number of distance codes */ 839 #ifdef PKZIP_BUG_WORKAROUND 840 unsigned ll[288 + 32]; /* literal/length and distance code 841 * lengths */ 842 #else 843 unsigned ll[286 + 30]; /* literal/length and distance code 844 * lengths */ 845 #endif 846 ulg b; /* bit buffer */ 847 unsigned k; /* number of bits in bit buffer */ 848 849 /* make local bit buffer */ 850 b = glbl->gz_bb; 851 k = glbl->gz_bk; 852 853 /* read in table lengths */ 854 NEEDBITS(glbl, 5) 855 nl = 257 + ((unsigned) b & 0x1f); /* number of 856 * literal/length codes */ 857 DUMPBITS(5) 858 NEEDBITS(glbl, 5) 859 nd = 1 + ((unsigned) b & 0x1f); /* number of distance codes */ 860 DUMPBITS(5) 861 NEEDBITS(glbl, 4) 862 nb = 4 + ((unsigned) b & 0xf); /* number of bit length codes */ 863 DUMPBITS(4) 864 #ifdef PKZIP_BUG_WORKAROUND 865 if (nl > 288 || nd > 32) 866 #else 867 if (nl > 286 || nd > 30) 868 #endif 869 return 1; /* bad lengths */ 870 /* read in bit-length-code lengths */ 871 for (j = 0; j < nb; j++) { 872 NEEDBITS(glbl, 3) 873 ll[border[j]] = (unsigned) b & 7; 874 DUMPBITS(3) 875 } 876 for (; j < 19; j++) 877 ll[border[j]] = 0; 878 879 /* build decoding table for trees--single level, 7 bit lookup */ 880 bl = 7; 881 if ((i = huft_build(glbl, ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) { 882 if (i == 1) 883 huft_free(glbl, tl); 884 return i; /* incomplete code set */ 885 } 886 /* read in literal and distance code lengths */ 887 n = nl + nd; 888 m = mask[bl]; 889 i = l = 0; 890 while ((unsigned) i < n) { 891 NEEDBITS(glbl, (unsigned) bl) 892 j = (td = tl + ((unsigned) b & m))->b; 893 DUMPBITS(j) 894 j = td->v.n; 895 if (j < 16) /* length of code in bits (0..15) */ 896 ll[i++] = l = j; /* save last length in l */ 897 else if (j == 16) { /* repeat last length 3 to 6 times */ 898 NEEDBITS(glbl, 2) 899 j = 3 + ((unsigned) b & 3); 900 DUMPBITS(2) 901 if ((unsigned) i + j > n) 902 return 1; 903 while (j--) 904 ll[i++] = l; 905 } else if (j == 17) { /* 3 to 10 zero length codes */ 906 NEEDBITS(glbl, 3) 907 j = 3 + ((unsigned) b & 7); 908 DUMPBITS(3) 909 if ((unsigned) i + j > n) 910 return 1; 911 while (j--) 912 ll[i++] = 0; 913 l = 0; 914 } else { /* j == 18: 11 to 138 zero length codes */ 915 NEEDBITS(glbl, 7) 916 j = 11 + ((unsigned) b & 0x7f); 917 DUMPBITS(7) 918 if ((unsigned) i + j > n) 919 return 1; 920 while (j--) 921 ll[i++] = 0; 922 l = 0; 923 } 924 } 925 926 /* free decoding table for trees */ 927 huft_free(glbl, tl); 928 929 /* restore the global bit buffer */ 930 glbl->gz_bb = b; 931 glbl->gz_bk = k; 932 933 /* build the decoding tables for literal/length and distance codes */ 934 bl = lbits; 935 i = huft_build(glbl, ll, nl, 257, cplens, cplext, &tl, &bl); 936 if (i != 0) { 937 if (i == 1 && !qflag) { 938 FPRINTF("(incomplete l-tree) "); 939 huft_free(glbl, tl); 940 } 941 return i; /* incomplete code set */ 942 } 943 bd = dbits; 944 i = huft_build(glbl, ll + nl, nd, 0, cpdist, cpdext, &td, &bd); 945 if (i != 0) { 946 if (i == 1 && !qflag) { 947 FPRINTF("(incomplete d-tree) "); 948 #ifdef PKZIP_BUG_WORKAROUND 949 i = 0; 950 } 951 #else 952 huft_free(glbl, td); 953 } 954 huft_free(glbl, tl); 955 return i; /* incomplete code set */ 956 #endif 957 } 958 /* decompress until an end-of-block code */ 959 if (inflate_codes(glbl, tl, td, bl, bd)) 960 return 1; 961 962 /* free the decoding tables, return */ 963 huft_free(glbl, tl); 964 huft_free(glbl, td); 965 return 0; 966 } 967 968 /* decompress an inflated block 969 970 e - last block flag */ 971 static int 972 inflate_block(struct inflate *glbl, int *e) 973 { 974 unsigned t; /* block type */ 975 ulg b; /* bit buffer */ 976 unsigned k; /* number of bits in bit buffer */ 977 978 /* make local bit buffer */ 979 b = glbl->gz_bb; 980 k = glbl->gz_bk; 981 982 /* read in last block bit */ 983 NEEDBITS(glbl, 1) 984 * e = (int) b & 1; 985 DUMPBITS(1) 986 /* read in block type */ 987 NEEDBITS(glbl, 2) 988 t = (unsigned) b & 3; 989 DUMPBITS(2) 990 /* restore the global bit buffer */ 991 glbl->gz_bb = b; 992 glbl->gz_bk = k; 993 994 /* inflate that block type */ 995 if (t == 2) 996 return inflate_dynamic(glbl); 997 if (t == 0) 998 return inflate_stored(glbl); 999 if (t == 1) 1000 return inflate_fixed(glbl); 1001 /* bad block type */ 1002 return 2; 1003 } 1004 1005 1006 1007 /* decompress an inflated entry */ 1008 static int 1009 xinflate(struct inflate *glbl) 1010 { 1011 int e; /* last block flag */ 1012 int r; /* result code */ 1013 unsigned h; /* maximum struct huft's malloc'ed */ 1014 1015 glbl->gz_fixed_tl = NULL; 1016 1017 /* initialize window, bit buffer */ 1018 glbl->gz_wp = 0; 1019 glbl->gz_bk = 0; 1020 glbl->gz_bb = 0; 1021 1022 /* decompress until the last block */ 1023 h = 0; 1024 do { 1025 glbl->gz_hufts = 0; 1026 if ((r = inflate_block(glbl, &e)) != 0) 1027 return r; 1028 if (glbl->gz_hufts > h) 1029 h = glbl->gz_hufts; 1030 } while (!e); 1031 1032 /* flush out slide */ 1033 FLUSH(glbl, glbl->gz_wp); 1034 1035 /* return success */ 1036 return 0; 1037 } 1038 1039 /* Nobody uses this - why not? */ 1040 int 1041 inflate(struct inflate *glbl) 1042 { 1043 int i; 1044 #ifdef _KERNEL 1045 u_char *p = NULL; 1046 1047 if (!glbl->gz_slide) 1048 p = glbl->gz_slide = kmalloc(GZ_WSIZE, M_GZIP, M_WAITOK); 1049 #endif 1050 if (!glbl->gz_slide) 1051 #ifdef _KERNEL 1052 return(ENOMEM); 1053 #else 1054 return 3; /* kzip expects 3 */ 1055 #endif 1056 i = xinflate(glbl); 1057 1058 if (glbl->gz_fixed_td != NULL) { 1059 huft_free(glbl, glbl->gz_fixed_td); 1060 glbl->gz_fixed_td = NULL; 1061 } 1062 if (glbl->gz_fixed_tl != NULL) { 1063 huft_free(glbl, glbl->gz_fixed_tl); 1064 glbl->gz_fixed_tl = NULL; 1065 } 1066 #ifdef _KERNEL 1067 if (p == glbl->gz_slide) { 1068 kfree(glbl->gz_slide, M_GZIP); 1069 glbl->gz_slide = NULL; 1070 } 1071 #endif 1072 return i; 1073 } 1074 /* ----------------------- END INFLATE.C */
Cache object: dc7d2ae696a18c79a495f98033dac53c
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