1 /* infback.c -- inflate using a call-back interface 2 * Copyright (C) 1995-2016 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 /* function prototypes */ 19 local void fixedtables OF((struct inflate_state FAR *state)); 20 21 /* 22 strm provides memory allocation functions in zalloc and zfree, or 23 Z_NULL to use the library memory allocation functions. 24 25 windowBits is in the range 8..15, and window is a user-supplied 26 window and output buffer that is 2**windowBits bytes. 27 */ 28 int ZEXPORT inflateBackInit_(z_streamp strm, int windowBits, 29 unsigned char FAR *window, const char *version, int stream_size) 30 { 31 struct inflate_state FAR *state; 32 33 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] || 34 stream_size != (int)(sizeof(z_stream))) 35 return Z_VERSION_ERROR; 36 if (strm == Z_NULL || window == Z_NULL || 37 windowBits < 8 || windowBits > 15) 38 return Z_STREAM_ERROR; 39 strm->msg = Z_NULL; /* in case we return an error */ 40 if (strm->zalloc == (alloc_func)0) { 41 #ifdef Z_SOLO 42 return Z_STREAM_ERROR; 43 #else 44 strm->zalloc = zcalloc; 45 strm->opaque = (voidpf)0; 46 #endif 47 } 48 if (strm->zfree == (free_func)0) 49 #ifdef Z_SOLO 50 return Z_STREAM_ERROR; 51 #else 52 strm->zfree = zcfree; 53 #endif 54 state = (struct inflate_state FAR *)ZALLOC(strm, 1, 55 sizeof(struct inflate_state)); 56 if (state == Z_NULL) return Z_MEM_ERROR; 57 Tracev((stderr, "inflate: allocated\n")); 58 strm->state = (struct internal_state FAR *)state; 59 state->dmax = 32768U; 60 state->wbits = (uInt)windowBits; 61 state->wsize = 1U << windowBits; 62 state->window = window; 63 state->wnext = 0; 64 state->whave = 0; 65 return Z_OK; 66 } 67 68 /* 69 Return state with length and distance decoding tables and index sizes set to 70 fixed code decoding. Normally this returns fixed tables from inffixed.h. 71 If BUILDFIXED is defined, then instead this routine builds the tables the 72 first time it's called, and returns those tables the first time and 73 thereafter. This reduces the size of the code by about 2K bytes, in 74 exchange for a little execution time. However, BUILDFIXED should not be 75 used for threaded applications, since the rewriting of the tables and virgin 76 may not be thread-safe. 77 */ 78 local void fixedtables(struct inflate_state FAR *state) 79 { 80 #ifdef BUILDFIXED 81 static int virgin = 1; 82 static code *lenfix, *distfix; 83 static code fixed[544]; 84 85 /* build fixed huffman tables if first call (may not be thread safe) */ 86 if (virgin) { 87 unsigned sym, bits; 88 static code *next; 89 90 /* literal/length table */ 91 sym = 0; 92 while (sym < 144) state->lens[sym++] = 8; 93 while (sym < 256) state->lens[sym++] = 9; 94 while (sym < 280) state->lens[sym++] = 7; 95 while (sym < 288) state->lens[sym++] = 8; 96 next = fixed; 97 lenfix = next; 98 bits = 9; 99 inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); 100 101 /* distance table */ 102 sym = 0; 103 while (sym < 32) state->lens[sym++] = 5; 104 distfix = next; 105 bits = 5; 106 inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); 107 108 /* do this just once */ 109 virgin = 0; 110 } 111 #else /* !BUILDFIXED */ 112 # include "inffixed.h" 113 #endif /* BUILDFIXED */ 114 state->lencode = lenfix; 115 state->lenbits = 9; 116 state->distcode = distfix; 117 state->distbits = 5; 118 } 119 120 /* Macros for inflateBack(): */ 121 122 /* Load returned state from inflate_fast() */ 123 #define LOAD() \ 124 do { \ 125 put = strm->next_out; \ 126 left = strm->avail_out; \ 127 next = strm->next_in; \ 128 have = strm->avail_in; \ 129 hold = state->hold; \ 130 bits = state->bits; \ 131 } while (0) 132 133 /* Set state from registers for inflate_fast() */ 134 #define RESTORE() \ 135 do { \ 136 strm->next_out = put; \ 137 strm->avail_out = left; \ 138 strm->next_in = next; \ 139 strm->avail_in = have; \ 140 state->hold = hold; \ 141 state->bits = bits; \ 142 } while (0) 143 144 /* Clear the input bit accumulator */ 145 #define INITBITS() \ 146 do { \ 147 hold = 0; \ 148 bits = 0; \ 149 } while (0) 150 151 /* Assure that some input is available. If input is requested, but denied, 152 then return a Z_BUF_ERROR from inflateBack(). */ 153 #define PULL() \ 154 do { \ 155 if (have == 0) { \ 156 have = in(in_desc, &next); \ 157 if (have == 0) { \ 158 next = Z_NULL; \ 159 ret = Z_BUF_ERROR; \ 160 goto inf_leave; \ 161 } \ 162 } \ 163 } while (0) 164 165 /* Get a byte of input into the bit accumulator, or return from inflateBack() 166 with an error if there is no input available. */ 167 #define PULLBYTE() \ 168 do { \ 169 PULL(); \ 170 have--; \ 171 hold += (unsigned long)(*next++) << bits; \ 172 bits += 8; \ 173 } while (0) 174 175 /* Assure that there are at least n bits in the bit accumulator. If there is 176 not enough available input to do that, then return from inflateBack() with 177 an error. */ 178 #define NEEDBITS(n) \ 179 do { \ 180 while (bits < (unsigned)(n)) \ 181 PULLBYTE(); \ 182 } while (0) 183 184 /* Return the low n bits of the bit accumulator (n < 16) */ 185 #define BITS(n) \ 186 ((unsigned)hold & ((1U << (n)) - 1)) 187 188 /* Remove n bits from the bit accumulator */ 189 #define DROPBITS(n) \ 190 do { \ 191 hold >>= (n); \ 192 bits -= (unsigned)(n); \ 193 } while (0) 194 195 /* Remove zero to seven bits as needed to go to a byte boundary */ 196 #define BYTEBITS() \ 197 do { \ 198 hold >>= bits & 7; \ 199 bits -= bits & 7; \ 200 } while (0) 201 202 /* Assure that some output space is available, by writing out the window 203 if it's full. If the write fails, return from inflateBack() with a 204 Z_BUF_ERROR. */ 205 #define ROOM() \ 206 do { \ 207 if (left == 0) { \ 208 put = state->window; \ 209 left = state->wsize; \ 210 state->whave = left; \ 211 if (out(out_desc, put, left)) { \ 212 ret = Z_BUF_ERROR; \ 213 goto inf_leave; \ 214 } \ 215 } \ 216 } while (0) 217 218 /* 219 strm provides the memory allocation functions and window buffer on input, 220 and provides information on the unused input on return. For Z_DATA_ERROR 221 returns, strm will also provide an error message. 222 223 in() and out() are the call-back input and output functions. When 224 inflateBack() needs more input, it calls in(). When inflateBack() has 225 filled the window with output, or when it completes with data in the 226 window, it calls out() to write out the data. The application must not 227 change the provided input until in() is called again or inflateBack() 228 returns. The application must not change the window/output buffer until 229 inflateBack() returns. 230 231 in() and out() are called with a descriptor parameter provided in the 232 inflateBack() call. This parameter can be a structure that provides the 233 information required to do the read or write, as well as accumulated 234 information on the input and output such as totals and check values. 235 236 in() should return zero on failure. out() should return non-zero on 237 failure. If either in() or out() fails, than inflateBack() returns a 238 Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether it 239 was in() or out() that caused in the error. Otherwise, inflateBack() 240 returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format 241 error, or Z_MEM_ERROR if it could not allocate memory for the state. 242 inflateBack() can also return Z_STREAM_ERROR if the input parameters 243 are not correct, i.e. strm is Z_NULL or the state was not initialized. 244 */ 245 int ZEXPORT inflateBack(z_streamp strm, in_func in, void FAR *in_desc, 246 out_func out, void FAR *out_desc) 247 { 248 struct inflate_state FAR *state; 249 z_const unsigned char FAR *next; /* next input */ 250 unsigned char FAR *put; /* next output */ 251 unsigned have, left; /* available input and output */ 252 unsigned long hold; /* bit buffer */ 253 unsigned bits; /* bits in bit buffer */ 254 unsigned copy; /* number of stored or match bytes to copy */ 255 unsigned char FAR *from; /* where to copy match bytes from */ 256 code here; /* current decoding table entry */ 257 code last; /* parent table entry */ 258 unsigned len; /* length to copy for repeats, bits to drop */ 259 int ret; /* return code */ 260 static const unsigned short order[19] = /* permutation of code lengths */ 261 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; 262 263 /* Check that the strm exists and that the state was initialized */ 264 if (strm == Z_NULL || strm->state == Z_NULL) 265 return Z_STREAM_ERROR; 266 state = (struct inflate_state FAR *)strm->state; 267 268 /* Reset the state */ 269 strm->msg = Z_NULL; 270 state->mode = TYPE; 271 state->last = 0; 272 state->whave = 0; 273 next = strm->next_in; 274 have = next != Z_NULL ? strm->avail_in : 0; 275 hold = 0; 276 bits = 0; 277 put = state->window; 278 left = state->wsize; 279 280 /* Inflate until end of block marked as last */ 281 for (;;) 282 switch (state->mode) { 283 case TYPE: 284 /* determine and dispatch block type */ 285 if (state->last) { 286 BYTEBITS(); 287 state->mode = DONE; 288 break; 289 } 290 NEEDBITS(3); 291 state->last = BITS(1); 292 DROPBITS(1); 293 switch (BITS(2)) { 294 case 0: /* stored block */ 295 Tracev((stderr, "inflate: stored block%s\n", 296 state->last ? " (last)" : "")); 297 state->mode = STORED; 298 break; 299 case 1: /* fixed block */ 300 fixedtables(state); 301 Tracev((stderr, "inflate: fixed codes block%s\n", 302 state->last ? " (last)" : "")); 303 state->mode = LEN; /* decode codes */ 304 break; 305 case 2: /* dynamic block */ 306 Tracev((stderr, "inflate: dynamic codes block%s\n", 307 state->last ? " (last)" : "")); 308 state->mode = TABLE; 309 break; 310 case 3: 311 strm->msg = (char *)"invalid block type"; 312 state->mode = BAD; 313 } 314 DROPBITS(2); 315 break; 316 317 case STORED: 318 /* get and verify stored block length */ 319 BYTEBITS(); /* go to byte boundary */ 320 NEEDBITS(32); 321 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) { 322 strm->msg = (char *)"invalid stored block lengths"; 323 state->mode = BAD; 324 break; 325 } 326 state->length = (unsigned)hold & 0xffff; 327 Tracev((stderr, "inflate: stored length %u\n", 328 state->length)); 329 INITBITS(); 330 331 /* copy stored block from input to output */ 332 while (state->length != 0) { 333 copy = state->length; 334 PULL(); 335 ROOM(); 336 if (copy > have) copy = have; 337 if (copy > left) copy = left; 338 zmemcpy(put, next, copy); 339 have -= copy; 340 next += copy; 341 left -= copy; 342 put += copy; 343 state->length -= copy; 344 } 345 Tracev((stderr, "inflate: stored end\n")); 346 state->mode = TYPE; 347 break; 348 349 case TABLE: 350 /* get dynamic table entries descriptor */ 351 NEEDBITS(14); 352 state->nlen = BITS(5) + 257; 353 DROPBITS(5); 354 state->ndist = BITS(5) + 1; 355 DROPBITS(5); 356 state->ncode = BITS(4) + 4; 357 DROPBITS(4); 358 #ifndef PKZIP_BUG_WORKAROUND 359 if (state->nlen > 286 || state->ndist > 30) { 360 strm->msg = (char *)"too many length or distance symbols"; 361 state->mode = BAD; 362 break; 363 } 364 #endif 365 Tracev((stderr, "inflate: table sizes ok\n")); 366 367 /* get code length code lengths (not a typo) */ 368 state->have = 0; 369 while (state->have < state->ncode) { 370 NEEDBITS(3); 371 state->lens[order[state->have++]] = (unsigned short)BITS(3); 372 DROPBITS(3); 373 } 374 while (state->have < 19) 375 state->lens[order[state->have++]] = 0; 376 state->next = state->codes; 377 state->lencode = (code const FAR *)(state->next); 378 state->lenbits = 7; 379 ret = inflate_table(CODES, state->lens, 19, &(state->next), 380 &(state->lenbits), state->work); 381 if (ret) { 382 strm->msg = (char *)"invalid code lengths set"; 383 state->mode = BAD; 384 break; 385 } 386 Tracev((stderr, "inflate: code lengths ok\n")); 387 388 /* get length and distance code code lengths */ 389 state->have = 0; 390 while (state->have < state->nlen + state->ndist) { 391 for (;;) { 392 here = state->lencode[BITS(state->lenbits)]; 393 if ((unsigned)(here.bits) <= bits) break; 394 PULLBYTE(); 395 } 396 if (here.val < 16) { 397 DROPBITS(here.bits); 398 state->lens[state->have++] = here.val; 399 } 400 else { 401 if (here.val == 16) { 402 NEEDBITS(here.bits + 2); 403 DROPBITS(here.bits); 404 if (state->have == 0) { 405 strm->msg = (char *)"invalid bit length repeat"; 406 state->mode = BAD; 407 break; 408 } 409 len = (unsigned)(state->lens[state->have - 1]); 410 copy = 3 + BITS(2); 411 DROPBITS(2); 412 } 413 else if (here.val == 17) { 414 NEEDBITS(here.bits + 3); 415 DROPBITS(here.bits); 416 len = 0; 417 copy = 3 + BITS(3); 418 DROPBITS(3); 419 } 420 else { 421 NEEDBITS(here.bits + 7); 422 DROPBITS(here.bits); 423 len = 0; 424 copy = 11 + BITS(7); 425 DROPBITS(7); 426 } 427 if (state->have + copy > state->nlen + state->ndist) { 428 strm->msg = (char *)"invalid bit length repeat"; 429 state->mode = BAD; 430 break; 431 } 432 while (copy--) 433 state->lens[state->have++] = (unsigned short)len; 434 } 435 } 436 437 /* handle error breaks in while */ 438 if (state->mode == BAD) break; 439 440 /* check for end-of-block code (better have one) */ 441 if (state->lens[256] == 0) { 442 strm->msg = (char *)"invalid code -- missing end-of-block"; 443 state->mode = BAD; 444 break; 445 } 446 447 /* build code tables -- note: do not change the lenbits or distbits 448 values here (9 and 6) without reading the comments in inftrees.h 449 concerning the ENOUGH constants, which depend on those values */ 450 state->next = state->codes; 451 state->lencode = (code const FAR *)(state->next); 452 state->lenbits = 9; 453 ret = inflate_table(LENS, state->lens, state->nlen, &(state->next), 454 &(state->lenbits), state->work); 455 if (ret) { 456 strm->msg = (char *)"invalid literal/lengths set"; 457 state->mode = BAD; 458 break; 459 } 460 state->distcode = (code const FAR *)(state->next); 461 state->distbits = 6; 462 ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist, 463 &(state->next), &(state->distbits), state->work); 464 if (ret) { 465 strm->msg = (char *)"invalid distances set"; 466 state->mode = BAD; 467 break; 468 } 469 Tracev((stderr, "inflate: codes ok\n")); 470 state->mode = LEN; 471 /* FALLTHROUGH */ 472 case LEN: 473 /* use inflate_fast() if we have enough input and output */ 474 if (have >= 6 && left >= 258) { 475 RESTORE(); 476 if (state->whave < state->wsize) 477 state->whave = state->wsize - left; 478 inflate_fast(strm, state->wsize); 479 LOAD(); 480 break; 481 } 482 483 /* get a literal, length, or end-of-block code */ 484 for (;;) { 485 here = state->lencode[BITS(state->lenbits)]; 486 if ((unsigned)(here.bits) <= bits) break; 487 PULLBYTE(); 488 } 489 if (here.op && (here.op & 0xf0) == 0) { 490 last = here; 491 for (;;) { 492 here = state->lencode[last.val + 493 (BITS(last.bits + last.op) >> last.bits)]; 494 if ((unsigned)(last.bits + here.bits) <= bits) break; 495 PULLBYTE(); 496 } 497 DROPBITS(last.bits); 498 } 499 DROPBITS(here.bits); 500 state->length = (unsigned)here.val; 501 502 /* process literal */ 503 if (here.op == 0) { 504 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? 505 "inflate: literal '%c'\n" : 506 "inflate: literal 0x%02x\n", here.val)); 507 ROOM(); 508 *put++ = (unsigned char)(state->length); 509 left--; 510 state->mode = LEN; 511 break; 512 } 513 514 /* process end of block */ 515 if (here.op & 32) { 516 Tracevv((stderr, "inflate: end of block\n")); 517 state->mode = TYPE; 518 break; 519 } 520 521 /* invalid code */ 522 if (here.op & 64) { 523 strm->msg = (char *)"invalid literal/length code"; 524 state->mode = BAD; 525 break; 526 } 527 528 /* length code -- get extra bits, if any */ 529 state->extra = (unsigned)(here.op) & 15; 530 if (state->extra != 0) { 531 NEEDBITS(state->extra); 532 state->length += BITS(state->extra); 533 DROPBITS(state->extra); 534 } 535 Tracevv((stderr, "inflate: length %u\n", state->length)); 536 537 /* get distance code */ 538 for (;;) { 539 here = state->distcode[BITS(state->distbits)]; 540 if ((unsigned)(here.bits) <= bits) break; 541 PULLBYTE(); 542 } 543 if ((here.op & 0xf0) == 0) { 544 last = here; 545 for (;;) { 546 here = state->distcode[last.val + 547 (BITS(last.bits + last.op) >> last.bits)]; 548 if ((unsigned)(last.bits + here.bits) <= bits) break; 549 PULLBYTE(); 550 } 551 DROPBITS(last.bits); 552 } 553 DROPBITS(here.bits); 554 if (here.op & 64) { 555 strm->msg = (char *)"invalid distance code"; 556 state->mode = BAD; 557 break; 558 } 559 state->offset = (unsigned)here.val; 560 561 /* get distance extra bits, if any */ 562 state->extra = (unsigned)(here.op) & 15; 563 if (state->extra != 0) { 564 NEEDBITS(state->extra); 565 state->offset += BITS(state->extra); 566 DROPBITS(state->extra); 567 } 568 if (state->offset > state->wsize - (state->whave < state->wsize ? 569 left : 0)) { 570 strm->msg = (char *)"invalid distance too far back"; 571 state->mode = BAD; 572 break; 573 } 574 Tracevv((stderr, "inflate: distance %u\n", state->offset)); 575 576 /* copy match from window to output */ 577 do { 578 ROOM(); 579 copy = state->wsize - state->offset; 580 if (copy < left) { 581 from = put + copy; 582 copy = left - copy; 583 } 584 else { 585 from = put - state->offset; 586 copy = left; 587 } 588 if (copy > state->length) copy = state->length; 589 state->length -= copy; 590 left -= copy; 591 do { 592 *put++ = *from++; 593 } while (--copy); 594 } while (state->length != 0); 595 break; 596 597 case DONE: 598 /* inflate stream terminated properly -- write leftover output */ 599 ret = Z_STREAM_END; 600 if (left < state->wsize) { 601 if (out(out_desc, state->window, state->wsize - left)) 602 ret = Z_BUF_ERROR; 603 } 604 goto inf_leave; 605 606 case BAD: 607 ret = Z_DATA_ERROR; 608 goto inf_leave; 609 610 default: /* can't happen, but makes compilers happy */ 611 ret = Z_STREAM_ERROR; 612 goto inf_leave; 613 } 614 615 /* Return unused input */ 616 inf_leave: 617 strm->next_in = next; 618 strm->avail_in = have; 619 return ret; 620 } 621 622 int ZEXPORT inflateBackEnd(z_streamp strm) 623 { 624 if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0) 625 return Z_STREAM_ERROR; 626 ZFREE(strm, strm->state); 627 strm->state = Z_NULL; 628 Tracev((stderr, "inflate: end\n")); 629 return Z_OK; 630 } 631