1 /* infback.c -- inflate using a call-back interface 2 * Copyright (C) 1995-2022 Mark Adler 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 6 /* 7 This code is largely copied from inflate.c. Normally either infback.o or 8 inflate.o would be linked into an application--not both. The interface 9 with inffast.c is retained so that optimized assembler-coded versions of 10 inflate_fast() can be used with either inflate.c or infback.c. 11 */ 12 13 #include "zutil.h" 14 #include "inftrees.h" 15 #include "inflate.h" 16 #include "inffast.h" 17 18 /* 19 strm provides memory allocation functions in zalloc and zfree, or 20 Z_NULL to use the library memory allocation functions. 21 22 windowBits is in the range 8..15, and window is a user-supplied 23 window and output buffer that is 2**windowBits bytes. 24 */ 25 int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits, 26 unsigned char FAR *window, const char *version, 27 int stream_size) { 28 struct inflate_state FAR *state; 29 30 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] || 31 stream_size != (int)(sizeof(z_stream))) 32 return Z_VERSION_ERROR; 33 if (strm == Z_NULL || window == Z_NULL || 34 windowBits < 8 || windowBits > 15) 35 return Z_STREAM_ERROR; 36 strm->msg = Z_NULL; /* in case we return an error */ 37 if (strm->zalloc == (alloc_func)0) { 38 #if defined(Z_SOLO) && !defined(_KERNEL) 39 return Z_STREAM_ERROR; 40 #else 41 strm->zalloc = zcalloc; 42 strm->opaque = (voidpf)0; 43 #endif 44 } 45 if (strm->zfree == (free_func)0) 46 #if defined(Z_SOLO) && !defined(_KERNEL) 47 return Z_STREAM_ERROR; 48 #else 49 strm->zfree = zcfree; 50 #endif 51 state = (struct inflate_state FAR *)ZALLOC(strm, 1, 52 sizeof(struct inflate_state)); 53 if (state == Z_NULL) return Z_MEM_ERROR; 54 Tracev((stderr, "inflate: allocated\n")); 55 strm->state = (struct internal_state FAR *)state; 56 state->dmax = 32768U; 57 state->wbits = (uInt)windowBits; 58 state->wsize = 1U << windowBits; 59 state->window = window; 60 state->wnext = 0; 61 state->whave = 0; 62 state->sane = 1; 63 return Z_OK; 64 } 65 66 /* 67 Return state with length and distance decoding tables and index sizes set to 68 fixed code decoding. Normally this returns fixed tables from inffixed.h. 69 If BUILDFIXED is defined, then instead this routine builds the tables the 70 first time it's called, and returns those tables the first time and 71 thereafter. This reduces the size of the code by about 2K bytes, in 72 exchange for a little execution time. However, BUILDFIXED should not be 73 used for threaded applications, since the rewriting of the tables and virgin 74 may not be thread-safe. 75 */ 76 local void fixedtables(struct inflate_state FAR *state) { 77 #ifdef BUILDFIXED 78 static int virgin = 1; 79 static code *lenfix, *distfix; 80 static code fixed[544]; 81 82 /* build fixed huffman tables if first call (may not be thread safe) */ 83 if (virgin) { 84 unsigned sym, bits; 85 static code *next; 86 87 /* literal/length table */ 88 sym = 0; 89 while (sym < 144) state->lens[sym++] = 8; 90 while (sym < 256) state->lens[sym++] = 9; 91 while (sym < 280) state->lens[sym++] = 7; 92 while (sym < 288) state->lens[sym++] = 8; 93 next = fixed; 94 lenfix = next; 95 bits = 9; 96 inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); 97 98 /* distance table */ 99 sym = 0; 100 while (sym < 32) state->lens[sym++] = 5; 101 distfix = next; 102 bits = 5; 103 inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); 104 105 /* do this just once */ 106 virgin = 0; 107 } 108 #else /* !BUILDFIXED */ 109 # include "inffixed.h" 110 #endif /* BUILDFIXED */ 111 state->lencode = lenfix; 112 state->lenbits = 9; 113 state->distcode = distfix; 114 state->distbits = 5; 115 } 116 117 /* Macros for inflateBack(): */ 118 119 /* Load returned state from inflate_fast() */ 120 #define LOAD() \ 121 do { \ 122 put = strm->next_out; \ 123 left = strm->avail_out; \ 124 next = strm->next_in; \ 125 have = strm->avail_in; \ 126 hold = state->hold; \ 127 bits = state->bits; \ 128 } while (0) 129 130 /* Set state from registers for inflate_fast() */ 131 #define RESTORE() \ 132 do { \ 133 strm->next_out = put; \ 134 strm->avail_out = left; \ 135 strm->next_in = next; \ 136 strm->avail_in = have; \ 137 state->hold = hold; \ 138 state->bits = bits; \ 139 } while (0) 140 141 /* Clear the input bit accumulator */ 142 #define INITBITS() \ 143 do { \ 144 hold = 0; \ 145 bits = 0; \ 146 } while (0) 147 148 /* Assure that some input is available. If input is requested, but denied, 149 then return a Z_BUF_ERROR from inflateBack(). */ 150 #define PULL() \ 151 do { \ 152 if (have == 0) { \ 153 have = in(in_desc, &next); \ 154 if (have == 0) { \ 155 next = Z_NULL; \ 156 ret = Z_BUF_ERROR; \ 157 goto inf_leave; \ 158 } \ 159 } \ 160 } while (0) 161 162 /* Get a byte of input into the bit accumulator, or return from inflateBack() 163 with an error if there is no input available. */ 164 #define PULLBYTE() \ 165 do { \ 166 PULL(); \ 167 have--; \ 168 hold += (unsigned long)(*next++) << bits; \ 169 bits += 8; \ 170 } while (0) 171 172 /* Assure that there are at least n bits in the bit accumulator. If there is 173 not enough available input to do that, then return from inflateBack() with 174 an error. */ 175 #define NEEDBITS(n) \ 176 do { \ 177 while (bits < (unsigned)(n)) \ 178 PULLBYTE(); \ 179 } while (0) 180 181 /* Return the low n bits of the bit accumulator (n < 16) */ 182 #define BITS(n) \ 183 ((unsigned)hold & ((1U << (n)) - 1)) 184 185 /* Remove n bits from the bit accumulator */ 186 #define DROPBITS(n) \ 187 do { \ 188 hold >>= (n); \ 189 bits -= (unsigned)(n); \ 190 } while (0) 191 192 /* Remove zero to seven bits as needed to go to a byte boundary */ 193 #define BYTEBITS() \ 194 do { \ 195 hold >>= bits & 7; \ 196 bits -= bits & 7; \ 197 } while (0) 198 199 /* Assure that some output space is available, by writing out the window 200 if it's full. If the write fails, return from inflateBack() with a 201 Z_BUF_ERROR. */ 202 #define ROOM() \ 203 do { \ 204 if (left == 0) { \ 205 put = state->window; \ 206 left = state->wsize; \ 207 state->whave = left; \ 208 if (out(out_desc, put, left)) { \ 209 ret = Z_BUF_ERROR; \ 210 goto inf_leave; \ 211 } \ 212 } \ 213 } while (0) 214 215 /* 216 strm provides the memory allocation functions and window buffer on input, 217 and provides information on the unused input on return. For Z_DATA_ERROR 218 returns, strm will also provide an error message. 219 220 in() and out() are the call-back input and output functions. When 221 inflateBack() needs more input, it calls in(). When inflateBack() has 222 filled the window with output, or when it completes with data in the 223 window, it calls out() to write out the data. The application must not 224 change the provided input until in() is called again or inflateBack() 225 returns. The application must not change the window/output buffer until 226 inflateBack() returns. 227 228 in() and out() are called with a descriptor parameter provided in the 229 inflateBack() call. This parameter can be a structure that provides the 230 information required to do the read or write, as well as accumulated 231 information on the input and output such as totals and check values. 232 233 in() should return zero on failure. out() should return non-zero on 234 failure. If either in() or out() fails, than inflateBack() returns a 235 Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether it 236 was in() or out() that caused in the error. Otherwise, inflateBack() 237 returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format 238 error, or Z_MEM_ERROR if it could not allocate memory for the state. 239 inflateBack() can also return Z_STREAM_ERROR if the input parameters 240 are not correct, i.e. strm is Z_NULL or the state was not initialized. 241 */ 242 int ZEXPORT inflateBack(z_streamp strm, in_func in, void FAR *in_desc, 243 out_func out, void FAR *out_desc) { 244 struct inflate_state FAR *state; 245 z_const unsigned char FAR *next; /* next input */ 246 unsigned char FAR *put; /* next output */ 247 unsigned have, left; /* available input and output */ 248 unsigned long hold; /* bit buffer */ 249 unsigned bits; /* bits in bit buffer */ 250 unsigned copy; /* number of stored or match bytes to copy */ 251 unsigned char FAR *from; /* where to copy match bytes from */ 252 code here; /* current decoding table entry */ 253 code last; /* parent table entry */ 254 unsigned len; /* length to copy for repeats, bits to drop */ 255 int ret; /* return code */ 256 static const unsigned short order[19] = /* permutation of code lengths */ 257 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; 258 259 /* Check that the strm exists and that the state was initialized */ 260 if (strm == Z_NULL || strm->state == Z_NULL) 261 return Z_STREAM_ERROR; 262 state = (struct inflate_state FAR *)strm->state; 263 264 /* Reset the state */ 265 strm->msg = Z_NULL; 266 state->mode = TYPE; 267 state->last = 0; 268 state->whave = 0; 269 next = strm->next_in; 270 have = next != Z_NULL ? strm->avail_in : 0; 271 hold = 0; 272 bits = 0; 273 put = state->window; 274 left = state->wsize; 275 276 /* Inflate until end of block marked as last */ 277 for (;;) 278 switch (state->mode) { 279 case TYPE: 280 /* determine and dispatch block type */ 281 if (state->last) { 282 BYTEBITS(); 283 state->mode = DONE; 284 break; 285 } 286 NEEDBITS(3); 287 state->last = BITS(1); 288 DROPBITS(1); 289 switch (BITS(2)) { 290 case 0: /* stored block */ 291 Tracev((stderr, "inflate: stored block%s\n", 292 state->last ? " (last)" : "")); 293 state->mode = STORED; 294 break; 295 case 1: /* fixed block */ 296 fixedtables(state); 297 Tracev((stderr, "inflate: fixed codes block%s\n", 298 state->last ? " (last)" : "")); 299 state->mode = LEN; /* decode codes */ 300 break; 301 case 2: /* dynamic block */ 302 Tracev((stderr, "inflate: dynamic codes block%s\n", 303 state->last ? " (last)" : "")); 304 state->mode = TABLE; 305 break; 306 case 3: 307 strm->msg = (char *)"invalid block type"; 308 state->mode = BAD; 309 } 310 DROPBITS(2); 311 break; 312 313 case STORED: 314 /* get and verify stored block length */ 315 BYTEBITS(); /* go to byte boundary */ 316 NEEDBITS(32); 317 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) { 318 strm->msg = (char *)"invalid stored block lengths"; 319 state->mode = BAD; 320 break; 321 } 322 state->length = (unsigned)hold & 0xffff; 323 Tracev((stderr, "inflate: stored length %u\n", 324 state->length)); 325 INITBITS(); 326 327 /* copy stored block from input to output */ 328 while (state->length != 0) { 329 copy = state->length; 330 PULL(); 331 ROOM(); 332 if (copy > have) copy = have; 333 if (copy > left) copy = left; 334 zmemcpy(put, next, copy); 335 have -= copy; 336 next += copy; 337 left -= copy; 338 put += copy; 339 state->length -= copy; 340 } 341 Tracev((stderr, "inflate: stored end\n")); 342 state->mode = TYPE; 343 break; 344 345 case TABLE: 346 /* get dynamic table entries descriptor */ 347 NEEDBITS(14); 348 state->nlen = BITS(5) + 257; 349 DROPBITS(5); 350 state->ndist = BITS(5) + 1; 351 DROPBITS(5); 352 state->ncode = BITS(4) + 4; 353 DROPBITS(4); 354 #ifndef PKZIP_BUG_WORKAROUND 355 if (state->nlen > 286 || state->ndist > 30) { 356 strm->msg = (char *)"too many length or distance symbols"; 357 state->mode = BAD; 358 break; 359 } 360 #endif 361 Tracev((stderr, "inflate: table sizes ok\n")); 362 363 /* get code length code lengths (not a typo) */ 364 state->have = 0; 365 while (state->have < state->ncode) { 366 NEEDBITS(3); 367 state->lens[order[state->have++]] = (unsigned short)BITS(3); 368 DROPBITS(3); 369 } 370 while (state->have < 19) 371 state->lens[order[state->have++]] = 0; 372 state->next = state->codes; 373 state->lencode = (code const FAR *)(state->next); 374 state->lenbits = 7; 375 ret = inflate_table(CODES, state->lens, 19, &(state->next), 376 &(state->lenbits), state->work); 377 if (ret) { 378 strm->msg = (char *)"invalid code lengths set"; 379 state->mode = BAD; 380 break; 381 } 382 Tracev((stderr, "inflate: code lengths ok\n")); 383 384 /* get length and distance code code lengths */ 385 state->have = 0; 386 while (state->have < state->nlen + state->ndist) { 387 for (;;) { 388 here = state->lencode[BITS(state->lenbits)]; 389 if ((unsigned)(here.bits) <= bits) break; 390 PULLBYTE(); 391 } 392 if (here.val < 16) { 393 DROPBITS(here.bits); 394 state->lens[state->have++] = here.val; 395 } 396 else { 397 if (here.val == 16) { 398 NEEDBITS(here.bits + 2); 399 DROPBITS(here.bits); 400 if (state->have == 0) { 401 strm->msg = (char *)"invalid bit length repeat"; 402 state->mode = BAD; 403 break; 404 } 405 len = (unsigned)(state->lens[state->have - 1]); 406 copy = 3 + BITS(2); 407 DROPBITS(2); 408 } 409 else if (here.val == 17) { 410 NEEDBITS(here.bits + 3); 411 DROPBITS(here.bits); 412 len = 0; 413 copy = 3 + BITS(3); 414 DROPBITS(3); 415 } 416 else { 417 NEEDBITS(here.bits + 7); 418 DROPBITS(here.bits); 419 len = 0; 420 copy = 11 + BITS(7); 421 DROPBITS(7); 422 } 423 if (state->have + copy > state->nlen + state->ndist) { 424 strm->msg = (char *)"invalid bit length repeat"; 425 state->mode = BAD; 426 break; 427 } 428 while (copy--) 429 state->lens[state->have++] = (unsigned short)len; 430 } 431 } 432 433 /* handle error breaks in while */ 434 if (state->mode == BAD) break; 435 436 /* check for end-of-block code (better have one) */ 437 if (state->lens[256] == 0) { 438 strm->msg = (char *)"invalid code -- missing end-of-block"; 439 state->mode = BAD; 440 break; 441 } 442 443 /* build code tables -- note: do not change the lenbits or distbits 444 values here (9 and 6) without reading the comments in inftrees.h 445 concerning the ENOUGH constants, which depend on those values */ 446 state->next = state->codes; 447 state->lencode = (code const FAR *)(state->next); 448 state->lenbits = 9; 449 ret = inflate_table(LENS, state->lens, state->nlen, &(state->next), 450 &(state->lenbits), state->work); 451 if (ret) { 452 strm->msg = (char *)"invalid literal/lengths set"; 453 state->mode = BAD; 454 break; 455 } 456 state->distcode = (code const FAR *)(state->next); 457 state->distbits = 6; 458 ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist, 459 &(state->next), &(state->distbits), state->work); 460 if (ret) { 461 strm->msg = (char *)"invalid distances set"; 462 state->mode = BAD; 463 break; 464 } 465 Tracev((stderr, "inflate: codes ok\n")); 466 state->mode = LEN; 467 /* fallthrough */ 468 469 case LEN: 470 /* use inflate_fast() if we have enough input and output */ 471 if (have >= 6 && left >= 258) { 472 RESTORE(); 473 if (state->whave < state->wsize) 474 state->whave = state->wsize - left; 475 inflate_fast(strm, state->wsize); 476 LOAD(); 477 break; 478 } 479 480 /* get a literal, length, or end-of-block code */ 481 for (;;) { 482 here = state->lencode[BITS(state->lenbits)]; 483 if ((unsigned)(here.bits) <= bits) break; 484 PULLBYTE(); 485 } 486 if (here.op && (here.op & 0xf0) == 0) { 487 last = here; 488 for (;;) { 489 here = state->lencode[last.val + 490 (BITS(last.bits + last.op) >> last.bits)]; 491 if ((unsigned)(last.bits + here.bits) <= bits) break; 492 PULLBYTE(); 493 } 494 DROPBITS(last.bits); 495 } 496 DROPBITS(here.bits); 497 state->length = (unsigned)here.val; 498 499 /* process literal */ 500 if (here.op == 0) { 501 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? 502 "inflate: literal '%c'\n" : 503 "inflate: literal 0x%02x\n", here.val)); 504 ROOM(); 505 *put++ = (unsigned char)(state->length); 506 left--; 507 state->mode = LEN; 508 break; 509 } 510 511 /* process end of block */ 512 if (here.op & 32) { 513 Tracevv((stderr, "inflate: end of block\n")); 514 state->mode = TYPE; 515 break; 516 } 517 518 /* invalid code */ 519 if (here.op & 64) { 520 strm->msg = (char *)"invalid literal/length code"; 521 state->mode = BAD; 522 break; 523 } 524 525 /* length code -- get extra bits, if any */ 526 state->extra = (unsigned)(here.op) & 15; 527 if (state->extra != 0) { 528 NEEDBITS(state->extra); 529 state->length += BITS(state->extra); 530 DROPBITS(state->extra); 531 } 532 Tracevv((stderr, "inflate: length %u\n", state->length)); 533 534 /* get distance code */ 535 for (;;) { 536 here = state->distcode[BITS(state->distbits)]; 537 if ((unsigned)(here.bits) <= bits) break; 538 PULLBYTE(); 539 } 540 if ((here.op & 0xf0) == 0) { 541 last = here; 542 for (;;) { 543 here = state->distcode[last.val + 544 (BITS(last.bits + last.op) >> last.bits)]; 545 if ((unsigned)(last.bits + here.bits) <= bits) break; 546 PULLBYTE(); 547 } 548 DROPBITS(last.bits); 549 } 550 DROPBITS(here.bits); 551 if (here.op & 64) { 552 strm->msg = (char *)"invalid distance code"; 553 state->mode = BAD; 554 break; 555 } 556 state->offset = (unsigned)here.val; 557 558 /* get distance extra bits, if any */ 559 state->extra = (unsigned)(here.op) & 15; 560 if (state->extra != 0) { 561 NEEDBITS(state->extra); 562 state->offset += BITS(state->extra); 563 DROPBITS(state->extra); 564 } 565 if (state->offset > state->wsize - (state->whave < state->wsize ? 566 left : 0)) { 567 strm->msg = (char *)"invalid distance too far back"; 568 state->mode = BAD; 569 break; 570 } 571 Tracevv((stderr, "inflate: distance %u\n", state->offset)); 572 573 /* copy match from window to output */ 574 do { 575 ROOM(); 576 copy = state->wsize - state->offset; 577 if (copy < left) { 578 from = put + copy; 579 copy = left - copy; 580 } 581 else { 582 from = put - state->offset; 583 copy = left; 584 } 585 if (copy > state->length) copy = state->length; 586 state->length -= copy; 587 left -= copy; 588 do { 589 *put++ = *from++; 590 } while (--copy); 591 } while (state->length != 0); 592 break; 593 594 case DONE: 595 /* inflate stream terminated properly */ 596 ret = Z_STREAM_END; 597 goto inf_leave; 598 599 case BAD: 600 ret = Z_DATA_ERROR; 601 goto inf_leave; 602 603 default: 604 /* can't happen, but makes compilers happy */ 605 ret = Z_STREAM_ERROR; 606 goto inf_leave; 607 } 608 609 /* Write leftover output and return unused input */ 610 inf_leave: 611 if (left < state->wsize) { 612 if (out(out_desc, state->window, state->wsize - left) && 613 ret == Z_STREAM_END) 614 ret = Z_BUF_ERROR; 615 } 616 strm->next_in = next; 617 strm->avail_in = have; 618 return ret; 619 } 620 621 int ZEXPORT inflateBackEnd(z_streamp strm) { 622 if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0) 623 return Z_STREAM_ERROR; 624 ZFREE(strm, strm->state); 625 strm->state = Z_NULL; 626 Tracev((stderr, "inflate: end\n")); 627 return Z_OK; 628 } 629