| 1 | /* infback.c -- inflate using a call-back interface |
| 2 | * Copyright (C) 1995-2011 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, unsigned char FAR *window, const char *version, int stream_size) |
| 29 | { |
| 30 | struct inflate_state FAR *state; |
| 31 | |
| 32 | if (version == Z_NULL || version[0] != ZLIB_VERSION[0] || |
| 33 | stream_size != (int)(sizeof(z_stream))) |
| 34 | return Z_VERSION_ERROR; |
| 35 | if (strm == Z_NULL || window == Z_NULL || |
| 36 | windowBits < 8 || windowBits > 15) |
| 37 | return Z_STREAM_ERROR; |
| 38 | strm->msg = Z_NULL; /* in case we return an error */ |
| 39 | if (strm->zalloc == (alloc_func)0) { |
| 40 | #ifdef Z_SOLO |
| 41 | return Z_STREAM_ERROR; |
| 42 | #else |
| 43 | strm->zalloc = zcalloc; |
| 44 | strm->opaque = (voidpf)0; |
| 45 | #endif |
| 46 | } |
| 47 | if (strm->zfree == Z_NULL) |
| 48 | #ifdef Z_SOLO |
| 49 | return Z_STREAM_ERROR; |
| 50 | #else |
| 51 | strm->zfree = zcfree; |
| 52 | #endif |
| 53 | state = (struct inflate_state FAR *)ZALLOC(strm, 1, |
| 54 | sizeof(struct inflate_state)); |
| 55 | if (state == Z_NULL) return Z_MEM_ERROR; |
| 56 | Tracev((stderr, "inflate: allocated\n")); |
| 57 | strm->state = (struct internal_state FAR *)state; |
| 58 | state->dmax = 32768U; |
| 59 | state->wbits = windowBits; |
| 60 | state->wsize = 1U << windowBits; |
| 61 | state->window = window; |
| 62 | state->wnext = 0; |
| 63 | state->whave = 0; |
| 64 | return Z_OK; |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | Return state with length and distance decoding tables and index sizes set to |
| 69 | fixed code decoding. Normally this returns fixed tables from inffixed.h. |
| 70 | If BUILDFIXED is defined, then instead this routine builds the tables the |
| 71 | first time it's called, and returns those tables the first time and |
| 72 | thereafter. This reduces the size of the code by about 2K bytes, in |
| 73 | exchange for a little execution time. However, BUILDFIXED should not be |
| 74 | used for threaded applications, since the rewriting of the tables and virgin |
| 75 | may not be thread-safe. |
| 76 | */ |
| 77 | local void fixedtables(struct inflate_state FAR *state) |
| 78 | { |
| 79 | #ifdef BUILDFIXED |
| 80 | static int virgin = 1; |
| 81 | static code *lenfix, *distfix; |
| 82 | static code fixed[544]; |
| 83 | |
| 84 | /* build fixed huffman tables if first call (may not be thread safe) */ |
| 85 | if (virgin) { |
| 86 | unsigned sym, bits; |
| 87 | static code *next; |
| 88 | |
| 89 | /* literal/length table */ |
| 90 | sym = 0; |
| 91 | while (sym < 144) state->lens[sym++] = 8; |
| 92 | while (sym < 256) state->lens[sym++] = 9; |
| 93 | while (sym < 280) state->lens[sym++] = 7; |
| 94 | while (sym < 288) state->lens[sym++] = 8; |
| 95 | next = fixed; |
| 96 | lenfix = next; |
| 97 | bits = 9; |
| 98 | inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); |
| 99 | |
| 100 | /* distance table */ |
| 101 | sym = 0; |
| 102 | while (sym < 32) state->lens[sym++] = 5; |
| 103 | distfix = next; |
| 104 | bits = 5; |
| 105 | inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); |
| 106 | |
| 107 | /* do this just once */ |
| 108 | virgin = 0; |
| 109 | } |
| 110 | #else /* !BUILDFIXED */ |
| 111 | # include "inffixed.h" |
| 112 | #endif /* BUILDFIXED */ |
| 113 | state->lencode = lenfix; |
| 114 | state->lenbits = 9; |
| 115 | state->distcode = distfix; |
| 116 | state->distbits = 5; |
| 117 | } |
| 118 | |
| 119 | /* Macros for inflateBack(): */ |
| 120 | |
| 121 | /* Load returned state from inflate_fast() */ |
| 122 | #define LOAD() \ |
| 123 | do { \ |
| 124 | put = strm->next_out; \ |
| 125 | left = strm->avail_out; \ |
| 126 | next = strm->next_in; \ |
| 127 | have = strm->avail_in; \ |
| 128 | hold = state->hold; \ |
| 129 | bits = state->bits; \ |
| 130 | } while (0) |
| 131 | |
| 132 | /* Set state from registers for inflate_fast() */ |
| 133 | #define RESTORE() \ |
| 134 | do { \ |
| 135 | strm->next_out = put; \ |
| 136 | strm->avail_out = left; \ |
| 137 | strm->next_in = next; \ |
| 138 | strm->avail_in = have; \ |
| 139 | state->hold = hold; \ |
| 140 | state->bits = bits; \ |
| 141 | } while (0) |
| 142 | |
| 143 | /* Clear the input bit accumulator */ |
| 144 | #define INITBITS() \ |
| 145 | do { \ |
| 146 | hold = 0; \ |
| 147 | bits = 0; \ |
| 148 | } while (0) |
| 149 | |
| 150 | /* Assure that some input is available. If input is requested, but denied, |
| 151 | then return a Z_BUF_ERROR from inflateBack(). */ |
| 152 | #define PULL() \ |
| 153 | do { \ |
| 154 | if (have == 0) { \ |
| 155 | have = in(in_desc, &next); \ |
| 156 | if (have == 0) { \ |
| 157 | next = Z_NULL; \ |
| 158 | ret = Z_BUF_ERROR; \ |
| 159 | goto inf_leave; \ |
| 160 | } \ |
| 161 | } \ |
| 162 | } while (0) |
| 163 | |
| 164 | /* Get a byte of input into the bit accumulator, or return from inflateBack() |
| 165 | with an error if there is no input available. */ |
| 166 | #define PULLBYTE() \ |
| 167 | do { \ |
| 168 | PULL(); \ |
| 169 | have--; \ |
| 170 | hold += (unsigned long)(*next++) << bits; \ |
| 171 | bits += 8; \ |
| 172 | } while (0) |
| 173 | |
| 174 | /* Assure that there are at least n bits in the bit accumulator. If there is |
| 175 | not enough available input to do that, then return from inflateBack() with |
| 176 | an error. */ |
| 177 | #define NEEDBITS(n) \ |
| 178 | do { \ |
| 179 | while (bits < (unsigned)(n)) \ |
| 180 | PULLBYTE(); \ |
| 181 | } while (0) |
| 182 | |
| 183 | /* Return the low n bits of the bit accumulator (n < 16) */ |
| 184 | #define BITS(n) \ |
| 185 | ((unsigned)hold & ((1U << (n)) - 1)) |
| 186 | |
| 187 | /* Remove n bits from the bit accumulator */ |
| 188 | #define DROPBITS(n) \ |
| 189 | do { \ |
| 190 | hold >>= (n); \ |
| 191 | bits -= (unsigned)(n); \ |
| 192 | } while (0) |
| 193 | |
| 194 | /* Remove zero to seven bits as needed to go to a byte boundary */ |
| 195 | #define BYTEBITS() \ |
| 196 | do { \ |
| 197 | hold >>= bits & 7; \ |
| 198 | bits -= bits & 7; \ |
| 199 | } while (0) |
| 200 | |
| 201 | /* Assure that some output space is available, by writing out the window |
| 202 | if it's full. If the write fails, return from inflateBack() with a |
| 203 | Z_BUF_ERROR. */ |
| 204 | #define ROOM() \ |
| 205 | do { \ |
| 206 | if (left == 0) { \ |
| 207 | put = state->window; \ |
| 208 | left = state->wsize; \ |
| 209 | state->whave = left; \ |
| 210 | if (out(out_desc, put, left)) { \ |
| 211 | ret = Z_BUF_ERROR; \ |
| 212 | goto inf_leave; \ |
| 213 | } \ |
| 214 | } \ |
| 215 | } while (0) |
| 216 | |
| 217 | /* |
| 218 | strm provides the memory allocation functions and window buffer on input, |
| 219 | and provides information on the unused input on return. For Z_DATA_ERROR |
| 220 | returns, strm will also provide an error message. |
| 221 | |
| 222 | in() and out() are the call-back input and output functions. When |
| 223 | inflateBack() needs more input, it calls in(). When inflateBack() has |
| 224 | filled the window with output, or when it completes with data in the |
| 225 | window, it calls out() to write out the data. The application must not |
| 226 | change the provided input until in() is called again or inflateBack() |
| 227 | returns. The application must not change the window/output buffer until |
| 228 | inflateBack() returns. |
| 229 | |
| 230 | in() and out() are called with a descriptor parameter provided in the |
| 231 | inflateBack() call. This parameter can be a structure that provides the |
| 232 | information required to do the read or write, as well as accumulated |
| 233 | information on the input and output such as totals and check values. |
| 234 | |
| 235 | in() should return zero on failure. out() should return non-zero on |
| 236 | failure. If either in() or out() fails, than inflateBack() returns a |
| 237 | Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether it |
| 238 | was in() or out() that caused in the error. Otherwise, inflateBack() |
| 239 | returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format |
| 240 | error, or Z_MEM_ERROR if it could not allocate memory for the state. |
| 241 | inflateBack() can also return Z_STREAM_ERROR if the input parameters |
| 242 | are not correct, i.e. strm is Z_NULL or the state was not initialized. |
| 243 | */ |
| 244 | int ZEXPORT inflateBack(z_streamp strm, in_func in, void FAR *in_desc, out_func out, void FAR *out_desc) |
| 245 | { |
| 246 | struct inflate_state FAR *state; |
| 247 | z_const unsigned char FAR *next; /* next input */ |
| 248 | unsigned char FAR *put; /* next output */ |
| 249 | unsigned have, left; /* available input and output */ |
| 250 | unsigned long hold; /* bit buffer */ |
| 251 | unsigned bits; /* bits in bit buffer */ |
| 252 | unsigned copy; /* number of stored or match bytes to copy */ |
| 253 | unsigned char FAR *from; /* where to copy match bytes from */ |
| 254 | code here; /* current decoding table entry */ |
| 255 | code last; /* parent table entry */ |
| 256 | unsigned len; /* length to copy for repeats, bits to drop */ |
| 257 | int ret; /* return code */ |
| 258 | static const unsigned short order[19] = /* permutation of code lengths */ |
| 259 | {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; |
| 260 | |
| 261 | /* Check that the strm exists and that the state was initialized */ |
| 262 | if (strm == Z_NULL || strm->state == Z_NULL) |
| 263 | return Z_STREAM_ERROR; |
| 264 | state = (struct inflate_state FAR *)strm->state; |
| 265 | |
| 266 | /* Reset the state */ |
| 267 | strm->msg = Z_NULL; |
| 268 | state->mode = TYPE; |
| 269 | state->last = 0; |
| 270 | state->whave = 0; |
| 271 | next = strm->next_in; |
| 272 | have = next != Z_NULL ? strm->avail_in : 0; |
| 273 | hold = 0; |
| 274 | bits = 0; |
| 275 | put = state->window; |
| 276 | left = state->wsize; |
| 277 | |
| 278 | /* Inflate until end of block marked as last */ |
| 279 | for (;;) |
| 280 | switch (state->mode) { |
| 281 | case TYPE: |
| 282 | /* determine and dispatch block type */ |
| 283 | if (state->last) { |
| 284 | BYTEBITS(); |
| 285 | state->mode = DONE; |
| 286 | break; |
| 287 | } |
| 288 | NEEDBITS(3); |
| 289 | state->last = BITS(1); |
| 290 | DROPBITS(1); |
| 291 | switch (BITS(2)) { |
| 292 | case 0: /* stored block */ |
| 293 | Tracev((stderr, "inflate: stored block%s\n", |
| 294 | state->last ? " (last)" : "")); |
| 295 | state->mode = STORED; |
| 296 | break; |
| 297 | case 1: /* fixed block */ |
| 298 | fixedtables(state); |
| 299 | Tracev((stderr, "inflate: fixed codes block%s\n", |
| 300 | state->last ? " (last)" : "")); |
| 301 | state->mode = LEN; /* decode codes */ |
| 302 | break; |
| 303 | case 2: /* dynamic block */ |
| 304 | Tracev((stderr, "inflate: dynamic codes block%s\n", |
| 305 | state->last ? " (last)" : "")); |
| 306 | state->mode = TABLE; |
| 307 | break; |
| 308 | case 3: |
| 309 | strm->msg = (char *)"invalid block type"; |
| 310 | state->mode = BAD; |
| 311 | } |
| 312 | DROPBITS(2); |
| 313 | break; |
| 314 | |
| 315 | case STORED: |
| 316 | /* get and verify stored block length */ |
| 317 | BYTEBITS(); /* go to byte boundary */ |
| 318 | NEEDBITS(32); |
| 319 | if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) { |
| 320 | strm->msg = (char *)"invalid stored block lengths"; |
| 321 | state->mode = BAD; |
| 322 | break; |
| 323 | } |
| 324 | state->length = (unsigned)hold & 0xffff; |
| 325 | Tracev((stderr, "inflate: stored length %u\n", |
| 326 | state->length)); |
| 327 | INITBITS(); |
| 328 | |
| 329 | /* copy stored block from input to output */ |
| 330 | while (state->length != 0) { |
| 331 | copy = state->length; |
| 332 | PULL(); |
| 333 | ROOM(); |
| 334 | if (copy > have) copy = have; |
| 335 | if (copy > left) copy = left; |
| 336 | zmemcpy(put, next, copy); |
| 337 | have -= copy; |
| 338 | next += copy; |
| 339 | left -= copy; |
| 340 | put += copy; |
| 341 | state->length -= copy; |
| 342 | } |
| 343 | Tracev((stderr, "inflate: stored end\n")); |
| 344 | state->mode = TYPE; |
| 345 | break; |
| 346 | |
| 347 | case TABLE: |
| 348 | /* get dynamic table entries descriptor */ |
| 349 | NEEDBITS(14); |
| 350 | state->nlen = BITS(5) + 257; |
| 351 | DROPBITS(5); |
| 352 | state->ndist = BITS(5) + 1; |
| 353 | DROPBITS(5); |
| 354 | state->ncode = BITS(4) + 4; |
| 355 | DROPBITS(4); |
| 356 | #ifndef PKZIP_BUG_WORKAROUND |
| 357 | if (state->nlen > 286 || state->ndist > 30) { |
| 358 | strm->msg = (char *)"too many length or distance symbols"; |
| 359 | state->mode = BAD; |
| 360 | break; |
| 361 | } |
| 362 | #endif |
| 363 | Tracev((stderr, "inflate: table sizes ok\n")); |
| 364 | |
| 365 | /* get code length code lengths (not a typo) */ |
| 366 | state->have = 0; |
| 367 | while (state->have < state->ncode) { |
| 368 | NEEDBITS(3); |
| 369 | state->lens[order[state->have++]] = (unsigned short)BITS(3); |
| 370 | DROPBITS(3); |
| 371 | } |
| 372 | while (state->have < 19) |
| 373 | state->lens[order[state->have++]] = 0; |
| 374 | state->next = state->codes; |
| 375 | state->lencode = (code const FAR *)(state->next); |
| 376 | state->lenbits = 7; |
| 377 | ret = inflate_table(CODES, state->lens, 19, &(state->next), |
| 378 | &(state->lenbits), state->work); |
| 379 | if (ret) { |
| 380 | strm->msg = (char *)"invalid code lengths set"; |
| 381 | state->mode = BAD; |
| 382 | break; |
| 383 | } |
| 384 | Tracev((stderr, "inflate: code lengths ok\n")); |
| 385 | |
| 386 | /* get length and distance code code lengths */ |
| 387 | state->have = 0; |
| 388 | while (state->have < state->nlen + state->ndist) { |
| 389 | for (;;) { |
| 390 | here = state->lencode[BITS(state->lenbits)]; |
| 391 | if ((unsigned)(here.bits) <= bits) break; |
| 392 | PULLBYTE(); |
| 393 | } |
| 394 | if (here.val < 16) { |
| 395 | DROPBITS(here.bits); |
| 396 | state->lens[state->have++] = here.val; |
| 397 | } |
| 398 | else { |
| 399 | if (here.val == 16) { |
| 400 | NEEDBITS(here.bits + 2); |
| 401 | DROPBITS(here.bits); |
| 402 | if (state->have == 0) { |
| 403 | strm->msg = (char *)"invalid bit length repeat"; |
| 404 | state->mode = BAD; |
| 405 | break; |
| 406 | } |
| 407 | len = (unsigned)(state->lens[state->have - 1]); |
| 408 | copy = 3 + BITS(2); |
| 409 | DROPBITS(2); |
| 410 | } |
| 411 | else if (here.val == 17) { |
| 412 | NEEDBITS(here.bits + 3); |
| 413 | DROPBITS(here.bits); |
| 414 | len = 0; |
| 415 | copy = 3 + BITS(3); |
| 416 | DROPBITS(3); |
| 417 | } |
| 418 | else { |
| 419 | NEEDBITS(here.bits + 7); |
| 420 | DROPBITS(here.bits); |
| 421 | len = 0; |
| 422 | copy = 11 + BITS(7); |
| 423 | DROPBITS(7); |
| 424 | } |
| 425 | if (state->have + copy > state->nlen + state->ndist) { |
| 426 | strm->msg = (char *)"invalid bit length repeat"; |
| 427 | state->mode = BAD; |
| 428 | break; |
| 429 | } |
| 430 | while (copy--) |
| 431 | state->lens[state->have++] = (unsigned short)len; |
| 432 | } |
| 433 | } |
| 434 | |
| 435 | /* handle error breaks in while */ |
| 436 | if (state->mode == BAD) break; |
| 437 | |
| 438 | /* check for end-of-block code (better have one) */ |
| 439 | if (state->lens[256] == 0) { |
| 440 | strm->msg = (char *)"invalid code -- missing end-of-block"; |
| 441 | state->mode = BAD; |
| 442 | break; |
| 443 | } |
| 444 | |
| 445 | /* build code tables -- note: do not change the lenbits or distbits |
| 446 | values here (9 and 6) without reading the comments in inftrees.h |
| 447 | concerning the ENOUGH constants, which depend on those values */ |
| 448 | state->next = state->codes; |
| 449 | state->lencode = (code const FAR *)(state->next); |
| 450 | state->lenbits = 9; |
| 451 | ret = inflate_table(LENS, state->lens, state->nlen, &(state->next), |
| 452 | &(state->lenbits), state->work); |
| 453 | if (ret) { |
| 454 | strm->msg = (char *)"invalid literal/lengths set"; |
| 455 | state->mode = BAD; |
| 456 | break; |
| 457 | } |
| 458 | state->distcode = (code const FAR *)(state->next); |
| 459 | state->distbits = 6; |
| 460 | ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist, |
| 461 | &(state->next), &(state->distbits), state->work); |
| 462 | if (ret) { |
| 463 | strm->msg = (char *)"invalid distances set"; |
| 464 | state->mode = BAD; |
| 465 | break; |
| 466 | } |
| 467 | Tracev((stderr, "inflate: codes ok\n")); |
| 468 | state->mode = LEN; |
| 469 | |
| 470 | case LEN: |
| 471 | /* use inflate_fast() if we have enough input and output */ |
| 472 | if (have >= 6 && left >= 258) { |
| 473 | RESTORE(); |
| 474 | if (state->whave < state->wsize) |
| 475 | state->whave = state->wsize - left; |
| 476 | inflate_fast(strm, state->wsize); |
| 477 | LOAD(); |
| 478 | break; |
| 479 | } |
| 480 | |
| 481 | /* get a literal, length, or end-of-block code */ |
| 482 | for (;;) { |
| 483 | here = state->lencode[BITS(state->lenbits)]; |
| 484 | if ((unsigned)(here.bits) <= bits) break; |
| 485 | PULLBYTE(); |
| 486 | } |
| 487 | if (here.op && (here.op & 0xf0) == 0) { |
| 488 | last = here; |
| 489 | for (;;) { |
| 490 | here = state->lencode[last.val + |
| 491 | (BITS(last.bits + last.op) >> last.bits)]; |
| 492 | if ((unsigned)(last.bits + here.bits) <= bits) break; |
| 493 | PULLBYTE(); |
| 494 | } |
| 495 | DROPBITS(last.bits); |
| 496 | } |
| 497 | DROPBITS(here.bits); |
| 498 | state->length = (unsigned)here.val; |
| 499 | |
| 500 | /* process literal */ |
| 501 | if (here.op == 0) { |
| 502 | Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? |
| 503 | "inflate: literal '%c'\n" : |
| 504 | "inflate: literal 0x%02x\n", here.val)); |
| 505 | ROOM(); |
| 506 | *put++ = (unsigned char)(state->length); |
| 507 | left--; |
| 508 | state->mode = LEN; |
| 509 | break; |
| 510 | } |
| 511 | |
| 512 | /* process end of block */ |
| 513 | if (here.op & 32) { |
| 514 | Tracevv((stderr, "inflate: end of block\n")); |
| 515 | state->mode = TYPE; |
| 516 | break; |
| 517 | } |
| 518 | |
| 519 | /* invalid code */ |
| 520 | if (here.op & 64) { |
| 521 | strm->msg = (char *)"invalid literal/length code"; |
| 522 | state->mode = BAD; |
| 523 | break; |
| 524 | } |
| 525 | |
| 526 | /* length code -- get extra bits, if any */ |
| 527 | state->extra = (unsigned)(here.op) & 15; |
| 528 | if (state->extra != 0) { |
| 529 | NEEDBITS(state->extra); |
| 530 | state->length += BITS(state->extra); |
| 531 | DROPBITS(state->extra); |
| 532 | } |
| 533 | Tracevv((stderr, "inflate: length %u\n", state->length)); |
| 534 | |
| 535 | /* get distance code */ |
| 536 | for (;;) { |
| 537 | here = state->distcode[BITS(state->distbits)]; |
| 538 | if ((unsigned)(here.bits) <= bits) break; |
| 539 | PULLBYTE(); |
| 540 | } |
| 541 | if ((here.op & 0xf0) == 0) { |
| 542 | last = here; |
| 543 | for (;;) { |
| 544 | here = state->distcode[last.val + |
| 545 | (BITS(last.bits + last.op) >> last.bits)]; |
| 546 | if ((unsigned)(last.bits + here.bits) <= bits) break; |
| 547 | PULLBYTE(); |
| 548 | } |
| 549 | DROPBITS(last.bits); |
| 550 | } |
| 551 | DROPBITS(here.bits); |
| 552 | if (here.op & 64) { |
| 553 | strm->msg = (char *)"invalid distance code"; |
| 554 | state->mode = BAD; |
| 555 | break; |
| 556 | } |
| 557 | state->offset = (unsigned)here.val; |
| 558 | |
| 559 | /* get distance extra bits, if any */ |
| 560 | state->extra = (unsigned)(here.op) & 15; |
| 561 | if (state->extra != 0) { |
| 562 | NEEDBITS(state->extra); |
| 563 | state->offset += BITS(state->extra); |
| 564 | DROPBITS(state->extra); |
| 565 | } |
| 566 | if (state->offset > state->wsize - (state->whave < state->wsize ? |
| 567 | left : 0)) { |
| 568 | strm->msg = (char *)"invalid distance too far back"; |
| 569 | state->mode = BAD; |
| 570 | break; |
| 571 | } |
| 572 | Tracevv((stderr, "inflate: distance %u\n", state->offset)); |
| 573 | |
| 574 | /* copy match from window to output */ |
| 575 | do { |
| 576 | ROOM(); |
| 577 | copy = state->wsize - state->offset; |
| 578 | if (copy < left) { |
| 579 | from = put + copy; |
| 580 | copy = left - copy; |
| 581 | } |
| 582 | else { |
| 583 | from = put - state->offset; |
| 584 | copy = left; |
| 585 | } |
| 586 | if (copy > state->length) copy = state->length; |
| 587 | state->length -= copy; |
| 588 | left -= copy; |
| 589 | do { |
| 590 | *put++ = *from++; |
| 591 | } while (--copy); |
| 592 | } while (state->length != 0); |
| 593 | break; |
| 594 | |
| 595 | case DONE: |
| 596 | /* inflate stream terminated properly -- write leftover output */ |
| 597 | ret = Z_STREAM_END; |
| 598 | if (left < state->wsize) { |
| 599 | if (out(out_desc, state->window, state->wsize - left)) |
| 600 | ret = Z_BUF_ERROR; |
| 601 | } |
| 602 | goto inf_leave; |
| 603 | |
| 604 | case BAD: |
| 605 | ret = Z_DATA_ERROR; |
| 606 | goto inf_leave; |
| 607 | |
| 608 | default: /* can't happen, but makes compilers happy */ |
| 609 | ret = Z_STREAM_ERROR; |
| 610 | goto inf_leave; |
| 611 | } |
| 612 | |
| 613 | /* Return unused input */ |
| 614 | inf_leave: |
| 615 | strm->next_in = next; |
| 616 | strm->avail_in = have; |
| 617 | return ret; |
| 618 | } |
| 619 | |
| 620 | int ZEXPORT inflateBackEnd(z_streamp strm) |
| 621 | { |
| 622 | if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == Z_NULL) |
| 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 | } |