| 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 | #ifdef Z_SOLO |
| 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 | #ifdef Z_SOLO |
| 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 | } |