1 // SPDX-License-Identifier: GPL-2.0 2 #define DEBG(x) 3 #define DEBG1(x) 4 /* inflate.c -- Not copyrighted 1992 by Mark Adler 5 version c10p1, 10 January 1993 */ 6 7 /* 8 * Adapted for booting Linux by Hannu Savolainen 1993 9 * based on gzip-1.0.3 10 * 11 * Nicolas Pitre <nico@fluxnic.net>, 1999/04/14 : 12 * Little mods for all variables to reside either into rodata or bss segments 13 * by marking constant variables with 'const' and initializing all the others 14 * at run-time only. This allows for the kernel uncompressor to run 15 * directly from Flash or ROM memory on embedded systems. 16 */ 17 18 /* 19 Inflate deflated (PKZIP's method 8 compressed) data. The compression 20 method searches for as much of the current string of bytes (up to a 21 length of 258) in the previous 32 K bytes. If it doesn't find any 22 matches (of at least length 3), it codes the next byte. Otherwise, it 23 codes the length of the matched string and its distance backwards from 24 the current position. There is a single Huffman code that codes both 25 single bytes (called "literals") and match lengths. A second Huffman 26 code codes the distance information, which follows a length code. Each 27 length or distance code actually represents a base value and a number 28 of "extra" (sometimes zero) bits to get to add to the base value. At 29 the end of each deflated block is a special end-of-block (EOB) literal/ 30 length code. The decoding process is basically: get a literal/length 31 code; if EOB then done; if a literal, emit the decoded byte; if a 32 length then get the distance and emit the referred-to bytes from the 33 sliding window of previously emitted data. 34 35 There are (currently) three kinds of inflate blocks: stored, fixed, and 36 dynamic. The compressor deals with some chunk of data at a time, and 37 decides which method to use on a chunk-by-chunk basis. A chunk might 38 typically be 32 K or 64 K. If the chunk is incompressible, then the 39 "stored" method is used. In this case, the bytes are simply stored as 40 is, eight bits per byte, with none of the above coding. The bytes are 41 preceded by a count, since there is no longer an EOB code. 42 43 If the data is compressible, then either the fixed or dynamic methods 44 are used. In the dynamic method, the compressed data is preceded by 45 an encoding of the literal/length and distance Huffman codes that are 46 to be used to decode this block. The representation is itself Huffman 47 coded, and so is preceded by a description of that code. These code 48 descriptions take up a little space, and so for small blocks, there is 49 a predefined set of codes, called the fixed codes. The fixed method is 50 used if the block codes up smaller that way (usually for quite small 51 chunks), otherwise the dynamic method is used. In the latter case, the 52 codes are customized to the probabilities in the current block, and so 53 can code it much better than the pre-determined fixed codes. 54 55 The Huffman codes themselves are decoded using a multi-level table 56 lookup, in order to maximize the speed of decoding plus the speed of 57 building the decoding tables. See the comments below that precede the 58 lbits and dbits tuning parameters. 59 */ 60 61 62 /* 63 Notes beyond the 1.93a appnote.txt: 64 65 1. Distance pointers never point before the beginning of the output 66 stream. 67 2. Distance pointers can point back across blocks, up to 32k away. 68 3. There is an implied maximum of 7 bits for the bit length table and 69 15 bits for the actual data. 70 4. If only one code exists, then it is encoded using one bit. (Zero 71 would be more efficient, but perhaps a little confusing.) If two 72 codes exist, they are coded using one bit each (0 and 1). 73 5. There is no way of sending zero distance codes--a dummy must be 74 sent if there are none. (History: a pre 2.0 version of PKZIP would 75 store blocks with no distance codes, but this was discovered to be 76 too harsh a criterion.) Valid only for 1.93a. 2.04c does allow 77 zero distance codes, which is sent as one code of zero bits in 78 length. 79 6. There are up to 286 literal/length codes. Code 256 represents the 80 end-of-block. Note however that the static length tree defines 81 288 codes just to fill out the Huffman codes. Codes 286 and 287 82 cannot be used though, since there is no length base or extra bits 83 defined for them. Similarly, there are up to 30 distance codes. 84 However, static trees define 32 codes (all 5 bits) to fill out the 85 Huffman codes, but the last two had better not show up in the data. 86 7. Unzip can check dynamic Huffman blocks for complete code sets. 87 The exception is that a single code would not be complete (see #4). 88 8. The five bits following the block type is really the number of 89 literal codes sent minus 257. 90 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits 91 (1+6+6). Therefore, to output three times the length, you output 92 three codes (1+1+1), whereas to output four times the same length, 93 you only need two codes (1+3). Hmm. 94 10. In the tree reconstruction algorithm, Code = Code + Increment 95 only if BitLength(i) is not zero. (Pretty obvious.) 96 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) 97 12. Note: length code 284 can represent 227-258, but length code 285 98 really is 258. The last length deserves its own, short code 99 since it gets used a lot in very redundant files. The length 100 258 is special since 258 - 3 (the min match length) is 255. 101 13. The literal/length and distance code bit lengths are read as a 102 single stream of lengths. It is possible (and advantageous) for 103 a repeat code (16, 17, or 18) to go across the boundary between 104 the two sets of lengths. 105 */ 106 #include <linux/compiler.h> 107 #ifdef NO_INFLATE_MALLOC 108 #include <linux/slab.h> 109 #endif 110 111 #ifdef RCSID 112 static char rcsid[] = "#Id: inflate.c,v 0.14 1993/06/10 13:27:04 jloup Exp #"; 113 #endif 114 115 #ifndef STATIC 116 117 #if defined(STDC_HEADERS) || defined(HAVE_STDLIB_H) 118 # include <sys/types.h> 119 # include <stdlib.h> 120 #endif 121 122 #include "gzip.h" 123 #define STATIC 124 #endif /* !STATIC */ 125 126 #ifndef INIT 127 #define INIT 128 #endif 129 130 #define slide window 131 132 /* Huffman code lookup table entry--this entry is four bytes for machines 133 that have 16-bit pointers (e.g. PC's in the small or medium model). 134 Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16 135 means that v is a literal, 16 < e < 32 means that v is a pointer to 136 the next table, which codes e - 16 bits, and lastly e == 99 indicates 137 an unused code. If a code with e == 99 is looked up, this implies an 138 error in the data. */ 139 struct huft { 140 uch e; /* number of extra bits or operation */ 141 uch b; /* number of bits in this code or subcode */ 142 union { 143 ush n; /* literal, length base, or distance base */ 144 struct huft *t; /* pointer to next level of table */ 145 } v; 146 }; 147 148 149 /* Function prototypes */ 150 STATIC int INIT huft_build OF((unsigned *, unsigned, unsigned, 151 const ush *, const ush *, struct huft **, int *)); 152 STATIC int INIT huft_free OF((struct huft *)); 153 STATIC int INIT inflate_codes OF((struct huft *, struct huft *, int, int)); 154 STATIC int INIT inflate_stored OF((void)); 155 STATIC int INIT inflate_fixed OF((void)); 156 STATIC int INIT inflate_dynamic OF((void)); 157 STATIC int INIT inflate_block OF((int *)); 158 STATIC int INIT inflate OF((void)); 159 160 161 /* The inflate algorithm uses a sliding 32 K byte window on the uncompressed 162 stream to find repeated byte strings. This is implemented here as a 163 circular buffer. The index is updated simply by incrementing and then 164 ANDing with 0x7fff (32K-1). */ 165 /* It is left to other modules to supply the 32 K area. It is assumed 166 to be usable as if it were declared "uch slide[32768];" or as just 167 "uch *slide;" and then malloc'ed in the latter case. The definition 168 must be in unzip.h, included above. */ 169 /* unsigned wp; current position in slide */ 170 #define wp outcnt 171 #define flush_output(w) (wp=(w),flush_window()) 172 173 /* Tables for deflate from PKZIP's appnote.txt. */ 174 static const unsigned border[] = { /* Order of the bit length code lengths */ 175 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; 176 static const ush cplens[] = { /* Copy lengths for literal codes 257..285 */ 177 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 178 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; 179 /* note: see note #13 above about the 258 in this list. */ 180 static const ush cplext[] = { /* Extra bits for literal codes 257..285 */ 181 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 182 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */ 183 static const ush cpdist[] = { /* Copy offsets for distance codes 0..29 */ 184 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 185 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 186 8193, 12289, 16385, 24577}; 187 static const ush cpdext[] = { /* Extra bits for distance codes */ 188 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 189 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 190 12, 12, 13, 13}; 191 192 193 194 /* Macros for inflate() bit peeking and grabbing. 195 The usage is: 196 197 NEEDBITS(j) 198 x = b & mask_bits[j]; 199 DUMPBITS(j) 200 201 where NEEDBITS makes sure that b has at least j bits in it, and 202 DUMPBITS removes the bits from b. The macros use the variable k 203 for the number of bits in b. Normally, b and k are register 204 variables for speed, and are initialized at the beginning of a 205 routine that uses these macros from a global bit buffer and count. 206 207 If we assume that EOB will be the longest code, then we will never 208 ask for bits with NEEDBITS that are beyond the end of the stream. 209 So, NEEDBITS should not read any more bytes than are needed to 210 meet the request. Then no bytes need to be "returned" to the buffer 211 at the end of the last block. 212 213 However, this assumption is not true for fixed blocks--the EOB code 214 is 7 bits, but the other literal/length codes can be 8 or 9 bits. 215 (The EOB code is shorter than other codes because fixed blocks are 216 generally short. So, while a block always has an EOB, many other 217 literal/length codes have a significantly lower probability of 218 showing up at all.) However, by making the first table have a 219 lookup of seven bits, the EOB code will be found in that first 220 lookup, and so will not require that too many bits be pulled from 221 the stream. 222 */ 223 224 STATIC ulg bb; /* bit buffer */ 225 STATIC unsigned bk; /* bits in bit buffer */ 226 227 STATIC const ush mask_bits[] = { 228 0x0000, 229 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, 230 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff 231 }; 232 233 #define NEXTBYTE() ({ int v = get_byte(); if (v < 0) goto underrun; (uch)v; }) 234 #define NEEDBITS(n) {while(k<(n)){b|=((ulg)NEXTBYTE())<<k;k+=8;}} 235 #define DUMPBITS(n) {b>>=(n);k-=(n);} 236 237 #ifndef NO_INFLATE_MALLOC 238 /* A trivial malloc implementation, adapted from 239 * malloc by Hannu Savolainen 1993 and Matthias Urlichs 1994 240 */ 241 242 static unsigned long malloc_ptr; 243 static int malloc_count; 244 245 static void *malloc(int size) 246 { 247 void *p; 248 249 if (size < 0) 250 error("Malloc error"); 251 if (!malloc_ptr) 252 malloc_ptr = free_mem_ptr; 253 254 malloc_ptr = (malloc_ptr + 3) & ~3; /* Align */ 255 256 p = (void *)malloc_ptr; 257 malloc_ptr += size; 258 259 if (free_mem_end_ptr && malloc_ptr >= free_mem_end_ptr) 260 error("Out of memory"); 261 262 malloc_count++; 263 return p; 264 } 265 266 static void free(void *where) 267 { 268 malloc_count--; 269 if (!malloc_count) 270 malloc_ptr = free_mem_ptr; 271 } 272 #else 273 #define malloc(a) kmalloc(a, GFP_KERNEL) 274 #define free(a) kfree(a) 275 #endif 276 277 /* 278 Huffman code decoding is performed using a multi-level table lookup. 279 The fastest way to decode is to simply build a lookup table whose 280 size is determined by the longest code. However, the time it takes 281 to build this table can also be a factor if the data being decoded 282 is not very long. The most common codes are necessarily the 283 shortest codes, so those codes dominate the decoding time, and hence 284 the speed. The idea is you can have a shorter table that decodes the 285 shorter, more probable codes, and then point to subsidiary tables for 286 the longer codes. The time it costs to decode the longer codes is 287 then traded against the time it takes to make longer tables. 288 289 The results of this trade are in the variables lbits and dbits 290 below. lbits is the number of bits the first level table for literal/ 291 length codes can decode in one step, and dbits is the same thing for 292 the distance codes. Subsequent tables are also less than or equal to 293 those sizes. These values may be adjusted either when all of the 294 codes are shorter than that, in which case the longest code length in 295 bits is used, or when the shortest code is *longer* than the requested 296 table size, in which case the length of the shortest code in bits is 297 used. 298 299 There are two different values for the two tables, since they code a 300 different number of possibilities each. The literal/length table 301 codes 286 possible values, or in a flat code, a little over eight 302 bits. The distance table codes 30 possible values, or a little less 303 than five bits, flat. The optimum values for speed end up being 304 about one bit more than those, so lbits is 8+1 and dbits is 5+1. 305 The optimum values may differ though from machine to machine, and 306 possibly even between compilers. Your mileage may vary. 307 */ 308 309 310 STATIC const int lbits = 9; /* bits in base literal/length lookup table */ 311 STATIC const int dbits = 6; /* bits in base distance lookup table */ 312 313 314 /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */ 315 #define BMAX 16 /* maximum bit length of any code (16 for explode) */ 316 #define N_MAX 288 /* maximum number of codes in any set */ 317 318 319 STATIC unsigned hufts; /* track memory usage */ 320 321 322 STATIC int INIT huft_build( 323 unsigned *b, /* code lengths in bits (all assumed <= BMAX) */ 324 unsigned n, /* number of codes (assumed <= N_MAX) */ 325 unsigned s, /* number of simple-valued codes (0..s-1) */ 326 const ush *d, /* list of base values for non-simple codes */ 327 const ush *e, /* list of extra bits for non-simple codes */ 328 struct huft **t, /* result: starting table */ 329 int *m /* maximum lookup bits, returns actual */ 330 ) 331 /* Given a list of code lengths and a maximum table size, make a set of 332 tables to decode that set of codes. Return zero on success, one if 333 the given code set is incomplete (the tables are still built in this 334 case), two if the input is invalid (all zero length codes or an 335 oversubscribed set of lengths), and three if not enough memory. */ 336 { 337 unsigned a; /* counter for codes of length k */ 338 unsigned f; /* i repeats in table every f entries */ 339 int g; /* maximum code length */ 340 int h; /* table level */ 341 register unsigned i; /* counter, current code */ 342 register unsigned j; /* counter */ 343 register int k; /* number of bits in current code */ 344 int l; /* bits per table (returned in m) */ 345 register unsigned *p; /* pointer into c[], b[], or v[] */ 346 register struct huft *q; /* points to current table */ 347 struct huft r; /* table entry for structure assignment */ 348 register int w; /* bits before this table == (l * h) */ 349 unsigned *xp; /* pointer into x */ 350 int y; /* number of dummy codes added */ 351 unsigned z; /* number of entries in current table */ 352 struct { 353 unsigned c[BMAX+1]; /* bit length count table */ 354 struct huft *u[BMAX]; /* table stack */ 355 unsigned v[N_MAX]; /* values in order of bit length */ 356 unsigned x[BMAX+1]; /* bit offsets, then code stack */ 357 } *stk; 358 unsigned *c, *v, *x; 359 struct huft **u; 360 int ret; 361 362 DEBG("huft1 "); 363 364 stk = malloc(sizeof(*stk)); 365 if (stk == NULL) 366 return 3; /* out of memory */ 367 368 c = stk->c; 369 v = stk->v; 370 x = stk->x; 371 u = stk->u; 372 373 /* Generate counts for each bit length */ 374 memzero(stk->c, sizeof(stk->c)); 375 p = b; i = n; 376 do { 377 Tracecv(*p, (stderr, (n-i >= ' ' && n-i <= '~' ? "%c %d\n" : "0x%x %d\n"), 378 n-i, *p)); 379 c[*p]++; /* assume all entries <= BMAX */ 380 p++; /* Can't combine with above line (Solaris bug) */ 381 } while (--i); 382 if (c[0] == n) /* null input--all zero length codes */ 383 { 384 *t = (struct huft *)NULL; 385 *m = 0; 386 ret = 2; 387 goto out; 388 } 389 390 DEBG("huft2 "); 391 392 /* Find minimum and maximum length, bound *m by those */ 393 l = *m; 394 for (j = 1; j <= BMAX; j++) 395 if (c[j]) 396 break; 397 k = j; /* minimum code length */ 398 if ((unsigned)l < j) 399 l = j; 400 for (i = BMAX; i; i--) 401 if (c[i]) 402 break; 403 g = i; /* maximum code length */ 404 if ((unsigned)l > i) 405 l = i; 406 *m = l; 407 408 DEBG("huft3 "); 409 410 /* Adjust last length count to fill out codes, if needed */ 411 for (y = 1 << j; j < i; j++, y <<= 1) 412 if ((y -= c[j]) < 0) { 413 ret = 2; /* bad input: more codes than bits */ 414 goto out; 415 } 416 if ((y -= c[i]) < 0) { 417 ret = 2; 418 goto out; 419 } 420 c[i] += y; 421 422 DEBG("huft4 "); 423 424 /* Generate starting offsets into the value table for each length */ 425 x[1] = j = 0; 426 p = c + 1; xp = x + 2; 427 while (--i) { /* note that i == g from above */ 428 *xp++ = (j += *p++); 429 } 430 431 DEBG("huft5 "); 432 433 /* Make a table of values in order of bit lengths */ 434 p = b; i = 0; 435 do { 436 if ((j = *p++) != 0) 437 v[x[j]++] = i; 438 } while (++i < n); 439 n = x[g]; /* set n to length of v */ 440 441 DEBG("h6 "); 442 443 /* Generate the Huffman codes and for each, make the table entries */ 444 x[0] = i = 0; /* first Huffman code is zero */ 445 p = v; /* grab values in bit order */ 446 h = -1; /* no tables yet--level -1 */ 447 w = -l; /* bits decoded == (l * h) */ 448 u[0] = (struct huft *)NULL; /* just to keep compilers happy */ 449 q = (struct huft *)NULL; /* ditto */ 450 z = 0; /* ditto */ 451 DEBG("h6a "); 452 453 /* go through the bit lengths (k already is bits in shortest code) */ 454 for (; k <= g; k++) 455 { 456 DEBG("h6b "); 457 a = c[k]; 458 while (a--) 459 { 460 DEBG("h6b1 "); 461 /* here i is the Huffman code of length k bits for value *p */ 462 /* make tables up to required level */ 463 while (k > w + l) 464 { 465 DEBG1("1 "); 466 h++; 467 w += l; /* previous table always l bits */ 468 469 /* compute minimum size table less than or equal to l bits */ 470 z = (z = g - w) > (unsigned)l ? l : z; /* upper limit on table size */ 471 if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */ 472 { /* too few codes for k-w bit table */ 473 DEBG1("2 "); 474 f -= a + 1; /* deduct codes from patterns left */ 475 xp = c + k; 476 if (j < z) 477 while (++j < z) /* try smaller tables up to z bits */ 478 { 479 if ((f <<= 1) <= *++xp) 480 break; /* enough codes to use up j bits */ 481 f -= *xp; /* else deduct codes from patterns */ 482 } 483 } 484 DEBG1("3 "); 485 z = 1 << j; /* table entries for j-bit table */ 486 487 /* allocate and link in new table */ 488 if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) == 489 (struct huft *)NULL) 490 { 491 if (h) 492 huft_free(u[0]); 493 ret = 3; /* not enough memory */ 494 goto out; 495 } 496 DEBG1("4 "); 497 hufts += z + 1; /* track memory usage */ 498 *t = q + 1; /* link to list for huft_free() */ 499 *(t = &(q->v.t)) = (struct huft *)NULL; 500 u[h] = ++q; /* table starts after link */ 501 502 DEBG1("5 "); 503 /* connect to last table, if there is one */ 504 if (h) 505 { 506 x[h] = i; /* save pattern for backing up */ 507 r.b = (uch)l; /* bits to dump before this table */ 508 r.e = (uch)(16 + j); /* bits in this table */ 509 r.v.t = q; /* pointer to this table */ 510 j = i >> (w - l); /* (get around Turbo C bug) */ 511 u[h-1][j] = r; /* connect to last table */ 512 } 513 DEBG1("6 "); 514 } 515 DEBG("h6c "); 516 517 /* set up table entry in r */ 518 r.b = (uch)(k - w); 519 if (p >= v + n) 520 r.e = 99; /* out of values--invalid code */ 521 else if (*p < s) 522 { 523 r.e = (uch)(*p < 256 ? 16 : 15); /* 256 is end-of-block code */ 524 r.v.n = (ush)(*p); /* simple code is just the value */ 525 p++; /* one compiler does not like *p++ */ 526 } 527 else 528 { 529 r.e = (uch)e[*p - s]; /* non-simple--look up in lists */ 530 r.v.n = d[*p++ - s]; 531 } 532 DEBG("h6d "); 533 534 /* fill code-like entries with r */ 535 f = 1 << (k - w); 536 for (j = i >> w; j < z; j += f) 537 q[j] = r; 538 539 /* backwards increment the k-bit code i */ 540 for (j = 1 << (k - 1); i & j; j >>= 1) 541 i ^= j; 542 i ^= j; 543 544 /* backup over finished tables */ 545 while ((i & ((1 << w) - 1)) != x[h]) 546 { 547 h--; /* don't need to update q */ 548 w -= l; 549 } 550 DEBG("h6e "); 551 } 552 DEBG("h6f "); 553 } 554 555 DEBG("huft7 "); 556 557 /* Return true (1) if we were given an incomplete table */ 558 ret = y != 0 && g != 1; 559 560 out: 561 free(stk); 562 return ret; 563 } 564 565 566 567 STATIC int INIT huft_free( 568 struct huft *t /* table to free */ 569 ) 570 /* Free the malloc'ed tables built by huft_build(), which makes a linked 571 list of the tables it made, with the links in a dummy first entry of 572 each table. */ 573 { 574 register struct huft *p, *q; 575 576 577 /* Go through linked list, freeing from the malloced (t[-1]) address. */ 578 p = t; 579 while (p != (struct huft *)NULL) 580 { 581 q = (--p)->v.t; 582 free((char*)p); 583 p = q; 584 } 585 return 0; 586 } 587 588 589 STATIC int INIT inflate_codes( 590 struct huft *tl, /* literal/length decoder tables */ 591 struct huft *td, /* distance decoder tables */ 592 int bl, /* number of bits decoded by tl[] */ 593 int bd /* number of bits decoded by td[] */ 594 ) 595 /* inflate (decompress) the codes in a deflated (compressed) block. 596 Return an error code or zero if it all goes ok. */ 597 { 598 register unsigned e; /* table entry flag/number of extra bits */ 599 unsigned n, d; /* length and index for copy */ 600 unsigned w; /* current window position */ 601 struct huft *t; /* pointer to table entry */ 602 unsigned ml, md; /* masks for bl and bd bits */ 603 register ulg b; /* bit buffer */ 604 register unsigned k; /* number of bits in bit buffer */ 605 606 607 /* make local copies of globals */ 608 b = bb; /* initialize bit buffer */ 609 k = bk; 610 w = wp; /* initialize window position */ 611 612 /* inflate the coded data */ 613 ml = mask_bits[bl]; /* precompute masks for speed */ 614 md = mask_bits[bd]; 615 for (;;) /* do until end of block */ 616 { 617 NEEDBITS((unsigned)bl) 618 if ((e = (t = tl + ((unsigned)b & ml))->e) > 16) 619 do { 620 if (e == 99) 621 return 1; 622 DUMPBITS(t->b) 623 e -= 16; 624 NEEDBITS(e) 625 } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16); 626 DUMPBITS(t->b) 627 if (e == 16) /* then it's a literal */ 628 { 629 slide[w++] = (uch)t->v.n; 630 Tracevv((stderr, "%c", slide[w-1])); 631 if (w == WSIZE) 632 { 633 flush_output(w); 634 w = 0; 635 } 636 } 637 else /* it's an EOB or a length */ 638 { 639 /* exit if end of block */ 640 if (e == 15) 641 break; 642 643 /* get length of block to copy */ 644 NEEDBITS(e) 645 n = t->v.n + ((unsigned)b & mask_bits[e]); 646 DUMPBITS(e); 647 648 /* decode distance of block to copy */ 649 NEEDBITS((unsigned)bd) 650 if ((e = (t = td + ((unsigned)b & md))->e) > 16) 651 do { 652 if (e == 99) 653 return 1; 654 DUMPBITS(t->b) 655 e -= 16; 656 NEEDBITS(e) 657 } while ((e = (t = t->v.t + ((unsigned)b & mask_bits[e]))->e) > 16); 658 DUMPBITS(t->b) 659 NEEDBITS(e) 660 d = w - t->v.n - ((unsigned)b & mask_bits[e]); 661 DUMPBITS(e) 662 Tracevv((stderr,"\\[%d,%d]", w-d, n)); 663 664 /* do the copy */ 665 do { 666 n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); 667 #if !defined(NOMEMCPY) && !defined(DEBUG) 668 if (w - d >= e) /* (this test assumes unsigned comparison) */ 669 { 670 memcpy(slide + w, slide + d, e); 671 w += e; 672 d += e; 673 } 674 else /* do it slow to avoid memcpy() overlap */ 675 #endif /* !NOMEMCPY */ 676 do { 677 slide[w++] = slide[d++]; 678 Tracevv((stderr, "%c", slide[w-1])); 679 } while (--e); 680 if (w == WSIZE) 681 { 682 flush_output(w); 683 w = 0; 684 } 685 } while (n); 686 } 687 } 688 689 690 /* restore the globals from the locals */ 691 wp = w; /* restore global window pointer */ 692 bb = b; /* restore global bit buffer */ 693 bk = k; 694 695 /* done */ 696 return 0; 697 698 underrun: 699 return 4; /* Input underrun */ 700 } 701 702 703 704 STATIC int INIT inflate_stored(void) 705 /* "decompress" an inflated type 0 (stored) block. */ 706 { 707 unsigned n; /* number of bytes in block */ 708 unsigned w; /* current window position */ 709 register ulg b; /* bit buffer */ 710 register unsigned k; /* number of bits in bit buffer */ 711 712 DEBG("<stor"); 713 714 /* make local copies of globals */ 715 b = bb; /* initialize bit buffer */ 716 k = bk; 717 w = wp; /* initialize window position */ 718 719 720 /* go to byte boundary */ 721 n = k & 7; 722 DUMPBITS(n); 723 724 725 /* get the length and its complement */ 726 NEEDBITS(16) 727 n = ((unsigned)b & 0xffff); 728 DUMPBITS(16) 729 NEEDBITS(16) 730 if (n != (unsigned)((~b) & 0xffff)) 731 return 1; /* error in compressed data */ 732 DUMPBITS(16) 733 734 735 /* read and output the compressed data */ 736 while (n--) 737 { 738 NEEDBITS(8) 739 slide[w++] = (uch)b; 740 if (w == WSIZE) 741 { 742 flush_output(w); 743 w = 0; 744 } 745 DUMPBITS(8) 746 } 747 748 749 /* restore the globals from the locals */ 750 wp = w; /* restore global window pointer */ 751 bb = b; /* restore global bit buffer */ 752 bk = k; 753 754 DEBG(">"); 755 return 0; 756 757 underrun: 758 return 4; /* Input underrun */ 759 } 760 761 762 /* 763 * We use `noinline' here to prevent gcc-3.5 from using too much stack space 764 */ 765 STATIC int noinline INIT inflate_fixed(void) 766 /* decompress an inflated type 1 (fixed Huffman codes) block. We should 767 either replace this with a custom decoder, or at least precompute the 768 Huffman tables. */ 769 { 770 int i; /* temporary variable */ 771 struct huft *tl; /* literal/length code table */ 772 struct huft *td; /* distance code table */ 773 int bl; /* lookup bits for tl */ 774 int bd; /* lookup bits for td */ 775 unsigned *l; /* length list for huft_build */ 776 777 DEBG("<fix"); 778 779 l = malloc(sizeof(*l) * 288); 780 if (l == NULL) 781 return 3; /* out of memory */ 782 783 /* set up literal table */ 784 for (i = 0; i < 144; i++) 785 l[i] = 8; 786 for (; i < 256; i++) 787 l[i] = 9; 788 for (; i < 280; i++) 789 l[i] = 7; 790 for (; i < 288; i++) /* make a complete, but wrong code set */ 791 l[i] = 8; 792 bl = 7; 793 if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) { 794 free(l); 795 return i; 796 } 797 798 /* set up distance table */ 799 for (i = 0; i < 30; i++) /* make an incomplete code set */ 800 l[i] = 5; 801 bd = 5; 802 if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) 803 { 804 huft_free(tl); 805 free(l); 806 807 DEBG(">"); 808 return i; 809 } 810 811 812 /* decompress until an end-of-block code */ 813 if (inflate_codes(tl, td, bl, bd)) { 814 huft_free(tl); 815 huft_free(td); 816 free(l); 817 return 1; 818 } 819 820 /* free the decoding tables, return */ 821 free(l); 822 huft_free(tl); 823 huft_free(td); 824 return 0; 825 } 826 827 828 /* 829 * We use `noinline' here to prevent gcc-3.5 from using too much stack space 830 */ 831 STATIC int noinline INIT inflate_dynamic(void) 832 /* decompress an inflated type 2 (dynamic Huffman codes) block. */ 833 { 834 int i; /* temporary variables */ 835 unsigned j; 836 unsigned l; /* last length */ 837 unsigned m; /* mask for bit lengths table */ 838 unsigned n; /* number of lengths to get */ 839 struct huft *tl; /* literal/length code table */ 840 struct huft *td; /* distance code table */ 841 int bl; /* lookup bits for tl */ 842 int bd; /* lookup bits for td */ 843 unsigned nb; /* number of bit length codes */ 844 unsigned nl; /* number of literal/length codes */ 845 unsigned nd; /* number of distance codes */ 846 unsigned *ll; /* literal/length and distance code lengths */ 847 register ulg b; /* bit buffer */ 848 register unsigned k; /* number of bits in bit buffer */ 849 int ret; 850 851 DEBG("<dyn"); 852 853 #ifdef PKZIP_BUG_WORKAROUND 854 ll = malloc(sizeof(*ll) * (288+32)); /* literal/length and distance code lengths */ 855 #else 856 ll = malloc(sizeof(*ll) * (286+30)); /* literal/length and distance code lengths */ 857 #endif 858 859 if (ll == NULL) 860 return 1; 861 862 /* make local bit buffer */ 863 b = bb; 864 k = bk; 865 866 867 /* read in table lengths */ 868 NEEDBITS(5) 869 nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */ 870 DUMPBITS(5) 871 NEEDBITS(5) 872 nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */ 873 DUMPBITS(5) 874 NEEDBITS(4) 875 nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */ 876 DUMPBITS(4) 877 #ifdef PKZIP_BUG_WORKAROUND 878 if (nl > 288 || nd > 32) 879 #else 880 if (nl > 286 || nd > 30) 881 #endif 882 { 883 ret = 1; /* bad lengths */ 884 goto out; 885 } 886 887 DEBG("dyn1 "); 888 889 /* read in bit-length-code lengths */ 890 for (j = 0; j < nb; j++) 891 { 892 NEEDBITS(3) 893 ll[border[j]] = (unsigned)b & 7; 894 DUMPBITS(3) 895 } 896 for (; j < 19; j++) 897 ll[border[j]] = 0; 898 899 DEBG("dyn2 "); 900 901 /* build decoding table for trees--single level, 7 bit lookup */ 902 bl = 7; 903 if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) 904 { 905 if (i == 1) 906 huft_free(tl); 907 ret = i; /* incomplete code set */ 908 goto out; 909 } 910 911 DEBG("dyn3 "); 912 913 /* read in literal and distance code lengths */ 914 n = nl + nd; 915 m = mask_bits[bl]; 916 i = l = 0; 917 while ((unsigned)i < n) 918 { 919 NEEDBITS((unsigned)bl) 920 j = (td = tl + ((unsigned)b & m))->b; 921 DUMPBITS(j) 922 j = td->v.n; 923 if (j < 16) /* length of code in bits (0..15) */ 924 ll[i++] = l = j; /* save last length in l */ 925 else if (j == 16) /* repeat last length 3 to 6 times */ 926 { 927 NEEDBITS(2) 928 j = 3 + ((unsigned)b & 3); 929 DUMPBITS(2) 930 if ((unsigned)i + j > n) { 931 ret = 1; 932 goto out; 933 } 934 while (j--) 935 ll[i++] = l; 936 } 937 else if (j == 17) /* 3 to 10 zero length codes */ 938 { 939 NEEDBITS(3) 940 j = 3 + ((unsigned)b & 7); 941 DUMPBITS(3) 942 if ((unsigned)i + j > n) { 943 ret = 1; 944 goto out; 945 } 946 while (j--) 947 ll[i++] = 0; 948 l = 0; 949 } 950 else /* j == 18: 11 to 138 zero length codes */ 951 { 952 NEEDBITS(7) 953 j = 11 + ((unsigned)b & 0x7f); 954 DUMPBITS(7) 955 if ((unsigned)i + j > n) { 956 ret = 1; 957 goto out; 958 } 959 while (j--) 960 ll[i++] = 0; 961 l = 0; 962 } 963 } 964 965 DEBG("dyn4 "); 966 967 /* free decoding table for trees */ 968 huft_free(tl); 969 970 DEBG("dyn5 "); 971 972 /* restore the global bit buffer */ 973 bb = b; 974 bk = k; 975 976 DEBG("dyn5a "); 977 978 /* build the decoding tables for literal/length and distance codes */ 979 bl = lbits; 980 if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) 981 { 982 DEBG("dyn5b "); 983 if (i == 1) { 984 error("incomplete literal tree"); 985 huft_free(tl); 986 } 987 ret = i; /* incomplete code set */ 988 goto out; 989 } 990 DEBG("dyn5c "); 991 bd = dbits; 992 if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) 993 { 994 DEBG("dyn5d "); 995 if (i == 1) { 996 error("incomplete distance tree"); 997 #ifdef PKZIP_BUG_WORKAROUND 998 i = 0; 999 } 1000 #else 1001 huft_free(td); 1002 } 1003 huft_free(tl); 1004 ret = i; /* incomplete code set */ 1005 goto out; 1006 #endif 1007 } 1008 1009 DEBG("dyn6 "); 1010 1011 /* decompress until an end-of-block code */ 1012 if (inflate_codes(tl, td, bl, bd)) 1013 ret = 1; 1014 else 1015 ret = 0; 1016 1017 DEBG("dyn7 "); 1018 1019 /* free the decoding tables, return */ 1020 huft_free(tl); 1021 huft_free(td); 1022 1023 DEBG(">"); 1024 out: 1025 free(ll); 1026 return ret; 1027 1028 underrun: 1029 ret = 4; /* Input underrun */ 1030 goto out; 1031 } 1032 1033 1034 1035 STATIC int INIT inflate_block( 1036 int *e /* last block flag */ 1037 ) 1038 /* decompress an inflated block */ 1039 { 1040 unsigned t; /* block type */ 1041 register ulg b; /* bit buffer */ 1042 register unsigned k; /* number of bits in bit buffer */ 1043 1044 DEBG("<blk"); 1045 1046 /* make local bit buffer */ 1047 b = bb; 1048 k = bk; 1049 1050 1051 /* read in last block bit */ 1052 NEEDBITS(1) 1053 *e = (int)b & 1; 1054 DUMPBITS(1) 1055 1056 1057 /* read in block type */ 1058 NEEDBITS(2) 1059 t = (unsigned)b & 3; 1060 DUMPBITS(2) 1061 1062 1063 /* restore the global bit buffer */ 1064 bb = b; 1065 bk = k; 1066 1067 /* inflate that block type */ 1068 if (t == 2) 1069 return inflate_dynamic(); 1070 if (t == 0) 1071 return inflate_stored(); 1072 if (t == 1) 1073 return inflate_fixed(); 1074 1075 DEBG(">"); 1076 1077 /* bad block type */ 1078 return 2; 1079 1080 underrun: 1081 return 4; /* Input underrun */ 1082 } 1083 1084 1085 1086 STATIC int INIT inflate(void) 1087 /* decompress an inflated entry */ 1088 { 1089 int e; /* last block flag */ 1090 int r; /* result code */ 1091 unsigned h; /* maximum struct huft's malloc'ed */ 1092 1093 /* initialize window, bit buffer */ 1094 wp = 0; 1095 bk = 0; 1096 bb = 0; 1097 1098 1099 /* decompress until the last block */ 1100 h = 0; 1101 do { 1102 hufts = 0; 1103 #ifdef ARCH_HAS_DECOMP_WDOG 1104 arch_decomp_wdog(); 1105 #endif 1106 r = inflate_block(&e); 1107 if (r) 1108 return r; 1109 if (hufts > h) 1110 h = hufts; 1111 } while (!e); 1112 1113 /* Undo too much lookahead. The next read will be byte aligned so we 1114 * can discard unused bits in the last meaningful byte. 1115 */ 1116 while (bk >= 8) { 1117 bk -= 8; 1118 inptr--; 1119 } 1120 1121 /* flush out slide */ 1122 flush_output(wp); 1123 1124 1125 /* return success */ 1126 #ifdef DEBUG 1127 fprintf(stderr, "<%u> ", h); 1128 #endif /* DEBUG */ 1129 return 0; 1130 } 1131 1132 /********************************************************************** 1133 * 1134 * The following are support routines for inflate.c 1135 * 1136 **********************************************************************/ 1137 1138 static ulg crc_32_tab[256]; 1139 static ulg crc; /* initialized in makecrc() so it'll reside in bss */ 1140 #define CRC_VALUE (crc ^ 0xffffffffUL) 1141 1142 /* 1143 * Code to compute the CRC-32 table. Borrowed from 1144 * gzip-1.0.3/makecrc.c. 1145 */ 1146 1147 static void INIT 1148 makecrc(void) 1149 { 1150 /* Not copyrighted 1990 Mark Adler */ 1151 1152 unsigned long c; /* crc shift register */ 1153 unsigned long e; /* polynomial exclusive-or pattern */ 1154 int i; /* counter for all possible eight bit values */ 1155 int k; /* byte being shifted into crc apparatus */ 1156 1157 /* terms of polynomial defining this crc (except x^32): */ 1158 static const int p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26}; 1159 1160 /* Make exclusive-or pattern from polynomial */ 1161 e = 0; 1162 for (i = 0; i < sizeof(p)/sizeof(int); i++) 1163 e |= 1L << (31 - p[i]); 1164 1165 crc_32_tab[0] = 0; 1166 1167 for (i = 1; i < 256; i++) 1168 { 1169 c = 0; 1170 for (k = i | 256; k != 1; k >>= 1) 1171 { 1172 c = c & 1 ? (c >> 1) ^ e : c >> 1; 1173 if (k & 1) 1174 c ^= e; 1175 } 1176 crc_32_tab[i] = c; 1177 } 1178 1179 /* this is initialized here so this code could reside in ROM */ 1180 crc = (ulg)0xffffffffUL; /* shift register contents */ 1181 } 1182 1183 /* gzip flag byte */ 1184 #define ASCII_FLAG 0x01 /* bit 0 set: file probably ASCII text */ 1185 #define CONTINUATION 0x02 /* bit 1 set: continuation of multi-part gzip file */ 1186 #define EXTRA_FIELD 0x04 /* bit 2 set: extra field present */ 1187 #define ORIG_NAME 0x08 /* bit 3 set: original file name present */ 1188 #define COMMENT 0x10 /* bit 4 set: file comment present */ 1189 #define ENCRYPTED 0x20 /* bit 5 set: file is encrypted */ 1190 #define RESERVED 0xC0 /* bit 6,7: reserved */ 1191 1192 /* 1193 * Do the uncompression! 1194 */ 1195 static int INIT gunzip(void) 1196 { 1197 uch flags; 1198 unsigned char magic[2]; /* magic header */ 1199 char method; 1200 ulg orig_crc = 0; /* original crc */ 1201 ulg orig_len = 0; /* original uncompressed length */ 1202 int res; 1203 1204 magic[0] = NEXTBYTE(); 1205 magic[1] = NEXTBYTE(); 1206 method = NEXTBYTE(); 1207 1208 if (magic[0] != 037 || 1209 ((magic[1] != 0213) && (magic[1] != 0236))) { 1210 error("bad gzip magic numbers"); 1211 return -1; 1212 } 1213 1214 /* We only support method #8, DEFLATED */ 1215 if (method != 8) { 1216 error("internal error, invalid method"); 1217 return -1; 1218 } 1219 1220 flags = (uch)get_byte(); 1221 if ((flags & ENCRYPTED) != 0) { 1222 error("Input is encrypted"); 1223 return -1; 1224 } 1225 if ((flags & CONTINUATION) != 0) { 1226 error("Multi part input"); 1227 return -1; 1228 } 1229 if ((flags & RESERVED) != 0) { 1230 error("Input has invalid flags"); 1231 return -1; 1232 } 1233 NEXTBYTE(); /* Get timestamp */ 1234 NEXTBYTE(); 1235 NEXTBYTE(); 1236 NEXTBYTE(); 1237 1238 (void)NEXTBYTE(); /* Ignore extra flags for the moment */ 1239 (void)NEXTBYTE(); /* Ignore OS type for the moment */ 1240 1241 if ((flags & EXTRA_FIELD) != 0) { 1242 unsigned len = (unsigned)NEXTBYTE(); 1243 len |= ((unsigned)NEXTBYTE())<<8; 1244 while (len--) (void)NEXTBYTE(); 1245 } 1246 1247 /* Get original file name if it was truncated */ 1248 if ((flags & ORIG_NAME) != 0) { 1249 /* Discard the old name */ 1250 while (NEXTBYTE() != 0) /* null */ ; 1251 } 1252 1253 /* Discard file comment if any */ 1254 if ((flags & COMMENT) != 0) { 1255 while (NEXTBYTE() != 0) /* null */ ; 1256 } 1257 1258 /* Decompress */ 1259 if ((res = inflate())) { 1260 switch (res) { 1261 case 1: 1262 error("invalid compressed format (err=1)"); 1263 break; 1264 case 2: 1265 error("invalid compressed format (err=2)"); 1266 break; 1267 case 3: 1268 error("out of memory"); 1269 break; 1270 case 4: 1271 error("out of input data"); 1272 break; 1273 default: 1274 error("invalid compressed format (other)"); 1275 } 1276 return -1; 1277 } 1278 1279 /* Get the crc and original length */ 1280 /* crc32 (see algorithm.doc) 1281 * uncompressed input size modulo 2^32 1282 */ 1283 orig_crc = (ulg) NEXTBYTE(); 1284 orig_crc |= (ulg) NEXTBYTE() << 8; 1285 orig_crc |= (ulg) NEXTBYTE() << 16; 1286 orig_crc |= (ulg) NEXTBYTE() << 24; 1287 1288 orig_len = (ulg) NEXTBYTE(); 1289 orig_len |= (ulg) NEXTBYTE() << 8; 1290 orig_len |= (ulg) NEXTBYTE() << 16; 1291 orig_len |= (ulg) NEXTBYTE() << 24; 1292 1293 /* Validate decompression */ 1294 if (orig_crc != CRC_VALUE) { 1295 error("crc error"); 1296 return -1; 1297 } 1298 if (orig_len != bytes_out) { 1299 error("length error"); 1300 return -1; 1301 } 1302 return 0; 1303 1304 underrun: /* NEXTBYTE() goto's here if needed */ 1305 error("out of input data"); 1306 return -1; 1307 } 1308 1309 1310