Annotation of sys/lib/libz/infback.c, Revision 1.1
1.1 ! nbrk 1: /* infback.c -- inflate using a call-back interface
! 2: * Copyright (C) 1995-2005 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_(strm, windowBits, window, version, stream_size)
! 29: z_streamp strm;
! 30: int windowBits;
! 31: unsigned char FAR *window;
! 32: const char *version;
! 33: int stream_size;
! 34: {
! 35: struct inflate_state FAR *state;
! 36:
! 37: if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
! 38: stream_size != (int)(sizeof(z_stream)))
! 39: return Z_VERSION_ERROR;
! 40: if (strm == Z_NULL || window == Z_NULL ||
! 41: windowBits < 8 || windowBits > 15)
! 42: return Z_STREAM_ERROR;
! 43: strm->msg = Z_NULL; /* in case we return an error */
! 44: if (strm->zalloc == (alloc_func)0) {
! 45: strm->zalloc = zcalloc;
! 46: strm->opaque = (voidpf)0;
! 47: }
! 48: if (strm->zfree == (free_func)0) strm->zfree = zcfree;
! 49: state = (struct inflate_state FAR *)ZALLOC(strm, 1,
! 50: sizeof(struct inflate_state));
! 51: if (state == Z_NULL) return Z_MEM_ERROR;
! 52: Tracev((stderr, "inflate: allocated\n"));
! 53: strm->state = (struct internal_state FAR *)state;
! 54: state->dmax = 32768U;
! 55: state->wbits = windowBits;
! 56: state->wsize = 1U << windowBits;
! 57: state->window = window;
! 58: state->write = 0;
! 59: state->whave = 0;
! 60: return Z_OK;
! 61: }
! 62:
! 63: /*
! 64: Return state with length and distance decoding tables and index sizes set to
! 65: fixed code decoding. Normally this returns fixed tables from inffixed.h.
! 66: If BUILDFIXED is defined, then instead this routine builds the tables the
! 67: first time it's called, and returns those tables the first time and
! 68: thereafter. This reduces the size of the code by about 2K bytes, in
! 69: exchange for a little execution time. However, BUILDFIXED should not be
! 70: used for threaded applications, since the rewriting of the tables and virgin
! 71: may not be thread-safe.
! 72: */
! 73: local void fixedtables(state)
! 74: struct inflate_state FAR *state;
! 75: {
! 76: #ifdef BUILDFIXED
! 77: static int virgin = 1;
! 78: static code *lenfix, *distfix;
! 79: static code fixed[544];
! 80:
! 81: /* build fixed huffman tables if first call (may not be thread safe) */
! 82: if (virgin) {
! 83: unsigned sym, bits;
! 84: static code *next;
! 85:
! 86: /* literal/length table */
! 87: sym = 0;
! 88: while (sym < 144) state->lens[sym++] = 8;
! 89: while (sym < 256) state->lens[sym++] = 9;
! 90: while (sym < 280) state->lens[sym++] = 7;
! 91: while (sym < 288) state->lens[sym++] = 8;
! 92: next = fixed;
! 93: lenfix = next;
! 94: bits = 9;
! 95: inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
! 96:
! 97: /* distance table */
! 98: sym = 0;
! 99: while (sym < 32) state->lens[sym++] = 5;
! 100: distfix = next;
! 101: bits = 5;
! 102: inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
! 103:
! 104: /* do this just once */
! 105: virgin = 0;
! 106: }
! 107: #else /* !BUILDFIXED */
! 108: # include "inffixed.h"
! 109: #endif /* BUILDFIXED */
! 110: state->lencode = lenfix;
! 111: state->lenbits = 9;
! 112: state->distcode = distfix;
! 113: state->distbits = 5;
! 114: }
! 115:
! 116: /* Macros for inflateBack(): */
! 117:
! 118: /* Load returned state from inflate_fast() */
! 119: #define LOAD() \
! 120: do { \
! 121: put = strm->next_out; \
! 122: left = strm->avail_out; \
! 123: next = strm->next_in; \
! 124: have = strm->avail_in; \
! 125: hold = state->hold; \
! 126: bits = state->bits; \
! 127: } while (0)
! 128:
! 129: /* Set state from registers for inflate_fast() */
! 130: #define RESTORE() \
! 131: do { \
! 132: strm->next_out = put; \
! 133: strm->avail_out = left; \
! 134: strm->next_in = next; \
! 135: strm->avail_in = have; \
! 136: state->hold = hold; \
! 137: state->bits = bits; \
! 138: } while (0)
! 139:
! 140: /* Clear the input bit accumulator */
! 141: #define INITBITS() \
! 142: do { \
! 143: hold = 0; \
! 144: bits = 0; \
! 145: } while (0)
! 146:
! 147: /* Assure that some input is available. If input is requested, but denied,
! 148: then return a Z_BUF_ERROR from inflateBack(). */
! 149: #define PULL() \
! 150: do { \
! 151: if (have == 0) { \
! 152: have = in(in_desc, &next); \
! 153: if (have == 0) { \
! 154: next = Z_NULL; \
! 155: ret = Z_BUF_ERROR; \
! 156: goto inf_leave; \
! 157: } \
! 158: } \
! 159: } while (0)
! 160:
! 161: /* Get a byte of input into the bit accumulator, or return from inflateBack()
! 162: with an error if there is no input available. */
! 163: #define PULLBYTE() \
! 164: do { \
! 165: PULL(); \
! 166: have--; \
! 167: hold += (unsigned long)(*next++) << bits; \
! 168: bits += 8; \
! 169: } while (0)
! 170:
! 171: /* Assure that there are at least n bits in the bit accumulator. If there is
! 172: not enough available input to do that, then return from inflateBack() with
! 173: an error. */
! 174: #define NEEDBITS(n) \
! 175: do { \
! 176: while (bits < (unsigned)(n)) \
! 177: PULLBYTE(); \
! 178: } while (0)
! 179:
! 180: /* Return the low n bits of the bit accumulator (n < 16) */
! 181: #define BITS(n) \
! 182: ((unsigned)hold & ((1U << (n)) - 1))
! 183:
! 184: /* Remove n bits from the bit accumulator */
! 185: #define DROPBITS(n) \
! 186: do { \
! 187: hold >>= (n); \
! 188: bits -= (unsigned)(n); \
! 189: } while (0)
! 190:
! 191: /* Remove zero to seven bits as needed to go to a byte boundary */
! 192: #define BYTEBITS() \
! 193: do { \
! 194: hold >>= bits & 7; \
! 195: bits -= bits & 7; \
! 196: } while (0)
! 197:
! 198: /* Assure that some output space is available, by writing out the window
! 199: if it's full. If the write fails, return from inflateBack() with a
! 200: Z_BUF_ERROR. */
! 201: #define ROOM() \
! 202: do { \
! 203: if (left == 0) { \
! 204: put = state->window; \
! 205: left = state->wsize; \
! 206: state->whave = left; \
! 207: if (out(out_desc, put, left)) { \
! 208: ret = Z_BUF_ERROR; \
! 209: goto inf_leave; \
! 210: } \
! 211: } \
! 212: } while (0)
! 213:
! 214: /*
! 215: strm provides the memory allocation functions and window buffer on input,
! 216: and provides information on the unused input on return. For Z_DATA_ERROR
! 217: returns, strm will also provide an error message.
! 218:
! 219: in() and out() are the call-back input and output functions. When
! 220: inflateBack() needs more input, it calls in(). When inflateBack() has
! 221: filled the window with output, or when it completes with data in the
! 222: window, it calls out() to write out the data. The application must not
! 223: change the provided input until in() is called again or inflateBack()
! 224: returns. The application must not change the window/output buffer until
! 225: inflateBack() returns.
! 226:
! 227: in() and out() are called with a descriptor parameter provided in the
! 228: inflateBack() call. This parameter can be a structure that provides the
! 229: information required to do the read or write, as well as accumulated
! 230: information on the input and output such as totals and check values.
! 231:
! 232: in() should return zero on failure. out() should return non-zero on
! 233: failure. If either in() or out() fails, than inflateBack() returns a
! 234: Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether it
! 235: was in() or out() that caused in the error. Otherwise, inflateBack()
! 236: returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format
! 237: error, or Z_MEM_ERROR if it could not allocate memory for the state.
! 238: inflateBack() can also return Z_STREAM_ERROR if the input parameters
! 239: are not correct, i.e. strm is Z_NULL or the state was not initialized.
! 240: */
! 241: int ZEXPORT inflateBack(strm, in, in_desc, out, out_desc)
! 242: z_streamp strm;
! 243: in_func in;
! 244: void FAR *in_desc;
! 245: out_func out;
! 246: void FAR *out_desc;
! 247: {
! 248: struct inflate_state FAR *state;
! 249: 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 this; /* 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: #ifdef SMALL
! 312: strm->msg = "error";
! 313: #else
! 314: strm->msg = (char *)"invalid block type";
! 315: #endif
! 316: state->mode = BAD;
! 317: }
! 318: DROPBITS(2);
! 319: break;
! 320:
! 321: case STORED:
! 322: /* get and verify stored block length */
! 323: BYTEBITS(); /* go to byte boundary */
! 324: NEEDBITS(32);
! 325: if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
! 326: #ifdef SMALL
! 327: strm->msg = "error";
! 328: #else
! 329: strm->msg = (char *)"invalid stored block lengths";
! 330: #endif
! 331: state->mode = BAD;
! 332: break;
! 333: }
! 334: state->length = (unsigned)hold & 0xffff;
! 335: Tracev((stderr, "inflate: stored length %u\n",
! 336: state->length));
! 337: INITBITS();
! 338:
! 339: /* copy stored block from input to output */
! 340: while (state->length != 0) {
! 341: copy = state->length;
! 342: PULL();
! 343: ROOM();
! 344: if (copy > have) copy = have;
! 345: if (copy > left) copy = left;
! 346: zmemcpy(put, next, copy);
! 347: have -= copy;
! 348: next += copy;
! 349: left -= copy;
! 350: put += copy;
! 351: state->length -= copy;
! 352: }
! 353: Tracev((stderr, "inflate: stored end\n"));
! 354: state->mode = TYPE;
! 355: break;
! 356:
! 357: case TABLE:
! 358: /* get dynamic table entries descriptor */
! 359: NEEDBITS(14);
! 360: state->nlen = BITS(5) + 257;
! 361: DROPBITS(5);
! 362: state->ndist = BITS(5) + 1;
! 363: DROPBITS(5);
! 364: state->ncode = BITS(4) + 4;
! 365: DROPBITS(4);
! 366: #ifndef PKZIP_BUG_WORKAROUND
! 367: if (state->nlen > 286 || state->ndist > 30) {
! 368: #ifdef SMALL
! 369: strm->msg = "error";
! 370: #else
! 371: strm->msg = (char *)"too many length or distance symbols";
! 372: #endif
! 373: state->mode = BAD;
! 374: break;
! 375: }
! 376: #endif
! 377: Tracev((stderr, "inflate: table sizes ok\n"));
! 378:
! 379: /* get code length code lengths (not a typo) */
! 380: state->have = 0;
! 381: while (state->have < state->ncode) {
! 382: NEEDBITS(3);
! 383: state->lens[order[state->have++]] = (unsigned short)BITS(3);
! 384: DROPBITS(3);
! 385: }
! 386: while (state->have < 19)
! 387: state->lens[order[state->have++]] = 0;
! 388: state->next = state->codes;
! 389: state->lencode = (code const FAR *)(state->next);
! 390: state->lenbits = 7;
! 391: ret = inflate_table(CODES, state->lens, 19, &(state->next),
! 392: &(state->lenbits), state->work);
! 393: if (ret) {
! 394: strm->msg = (char *)"invalid code lengths set";
! 395: state->mode = BAD;
! 396: break;
! 397: }
! 398: Tracev((stderr, "inflate: code lengths ok\n"));
! 399:
! 400: /* get length and distance code code lengths */
! 401: state->have = 0;
! 402: while (state->have < state->nlen + state->ndist) {
! 403: for (;;) {
! 404: this = state->lencode[BITS(state->lenbits)];
! 405: if ((unsigned)(this.bits) <= bits) break;
! 406: PULLBYTE();
! 407: }
! 408: if (this.val < 16) {
! 409: NEEDBITS(this.bits);
! 410: DROPBITS(this.bits);
! 411: state->lens[state->have++] = this.val;
! 412: }
! 413: else {
! 414: if (this.val == 16) {
! 415: NEEDBITS(this.bits + 2);
! 416: DROPBITS(this.bits);
! 417: if (state->have == 0) {
! 418: strm->msg = (char *)"invalid bit length repeat";
! 419: state->mode = BAD;
! 420: break;
! 421: }
! 422: len = (unsigned)(state->lens[state->have - 1]);
! 423: copy = 3 + BITS(2);
! 424: DROPBITS(2);
! 425: }
! 426: else if (this.val == 17) {
! 427: NEEDBITS(this.bits + 3);
! 428: DROPBITS(this.bits);
! 429: len = 0;
! 430: copy = 3 + BITS(3);
! 431: DROPBITS(3);
! 432: }
! 433: else {
! 434: NEEDBITS(this.bits + 7);
! 435: DROPBITS(this.bits);
! 436: len = 0;
! 437: copy = 11 + BITS(7);
! 438: DROPBITS(7);
! 439: }
! 440: if (state->have + copy > state->nlen + state->ndist) {
! 441: strm->msg = (char *)"invalid bit length repeat";
! 442: state->mode = BAD;
! 443: break;
! 444: }
! 445: while (copy--)
! 446: state->lens[state->have++] = (unsigned short)len;
! 447: }
! 448: }
! 449:
! 450: /* handle error breaks in while */
! 451: if (state->mode == BAD) break;
! 452:
! 453: /* build code tables */
! 454: state->next = state->codes;
! 455: state->lencode = (code const FAR *)(state->next);
! 456: state->lenbits = 9;
! 457: ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
! 458: &(state->lenbits), state->work);
! 459: if (ret) {
! 460: strm->msg = (char *)"invalid literal/lengths set";
! 461: state->mode = BAD;
! 462: break;
! 463: }
! 464: state->distcode = (code const FAR *)(state->next);
! 465: state->distbits = 6;
! 466: ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
! 467: &(state->next), &(state->distbits), state->work);
! 468: if (ret) {
! 469: strm->msg = (char *)"invalid distances set";
! 470: state->mode = BAD;
! 471: break;
! 472: }
! 473: Tracev((stderr, "inflate: codes ok\n"));
! 474: state->mode = LEN;
! 475:
! 476: case LEN:
! 477: #ifndef SLOW
! 478: /* use inflate_fast() if we have enough input and output */
! 479: if (have >= 6 && left >= 258) {
! 480: RESTORE();
! 481: if (state->whave < state->wsize)
! 482: state->whave = state->wsize - left;
! 483: inflate_fast(strm, state->wsize);
! 484: LOAD();
! 485: break;
! 486: }
! 487: #endif
! 488:
! 489: /* get a literal, length, or end-of-block code */
! 490: for (;;) {
! 491: this = state->lencode[BITS(state->lenbits)];
! 492: if ((unsigned)(this.bits) <= bits) break;
! 493: PULLBYTE();
! 494: }
! 495: if (this.op && (this.op & 0xf0) == 0) {
! 496: last = this;
! 497: for (;;) {
! 498: this = state->lencode[last.val +
! 499: (BITS(last.bits + last.op) >> last.bits)];
! 500: if ((unsigned)(last.bits + this.bits) <= bits) break;
! 501: PULLBYTE();
! 502: }
! 503: DROPBITS(last.bits);
! 504: }
! 505: DROPBITS(this.bits);
! 506: state->length = (unsigned)this.val;
! 507:
! 508: /* process literal */
! 509: if (this.op == 0) {
! 510: Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ?
! 511: "inflate: literal '%c'\n" :
! 512: "inflate: literal 0x%02x\n", this.val));
! 513: ROOM();
! 514: *put++ = (unsigned char)(state->length);
! 515: left--;
! 516: state->mode = LEN;
! 517: break;
! 518: }
! 519:
! 520: /* process end of block */
! 521: if (this.op & 32) {
! 522: Tracevv((stderr, "inflate: end of block\n"));
! 523: state->mode = TYPE;
! 524: break;
! 525: }
! 526:
! 527: /* invalid code */
! 528: if (this.op & 64) {
! 529: strm->msg = (char *)"invalid literal/length code";
! 530: state->mode = BAD;
! 531: break;
! 532: }
! 533:
! 534: /* length code -- get extra bits, if any */
! 535: state->extra = (unsigned)(this.op) & 15;
! 536: if (state->extra != 0) {
! 537: NEEDBITS(state->extra);
! 538: state->length += BITS(state->extra);
! 539: DROPBITS(state->extra);
! 540: }
! 541: Tracevv((stderr, "inflate: length %u\n", state->length));
! 542:
! 543: /* get distance code */
! 544: for (;;) {
! 545: this = state->distcode[BITS(state->distbits)];
! 546: if ((unsigned)(this.bits) <= bits) break;
! 547: PULLBYTE();
! 548: }
! 549: if ((this.op & 0xf0) == 0) {
! 550: last = this;
! 551: for (;;) {
! 552: this = state->distcode[last.val +
! 553: (BITS(last.bits + last.op) >> last.bits)];
! 554: if ((unsigned)(last.bits + this.bits) <= bits) break;
! 555: PULLBYTE();
! 556: }
! 557: DROPBITS(last.bits);
! 558: }
! 559: DROPBITS(this.bits);
! 560: if (this.op & 64) {
! 561: strm->msg = (char *)"invalid distance code";
! 562: state->mode = BAD;
! 563: break;
! 564: }
! 565: state->offset = (unsigned)this.val;
! 566:
! 567: /* get distance extra bits, if any */
! 568: state->extra = (unsigned)(this.op) & 15;
! 569: if (state->extra != 0) {
! 570: NEEDBITS(state->extra);
! 571: state->offset += BITS(state->extra);
! 572: DROPBITS(state->extra);
! 573: }
! 574: if (state->offset > state->wsize - (state->whave < state->wsize ?
! 575: left : 0)) {
! 576: strm->msg = (char *)"invalid distance too far back";
! 577: state->mode = BAD;
! 578: break;
! 579: }
! 580: Tracevv((stderr, "inflate: distance %u\n", state->offset));
! 581:
! 582: /* copy match from window to output */
! 583: do {
! 584: ROOM();
! 585: copy = state->wsize - state->offset;
! 586: if (copy < left) {
! 587: from = put + copy;
! 588: copy = left - copy;
! 589: }
! 590: else {
! 591: from = put - state->offset;
! 592: copy = left;
! 593: }
! 594: if (copy > state->length) copy = state->length;
! 595: state->length -= copy;
! 596: left -= copy;
! 597: do {
! 598: *put++ = *from++;
! 599: } while (--copy);
! 600: } while (state->length != 0);
! 601: break;
! 602:
! 603: case DONE:
! 604: /* inflate stream terminated properly -- write leftover output */
! 605: ret = Z_STREAM_END;
! 606: if (left < state->wsize) {
! 607: if (out(out_desc, state->window, state->wsize - left))
! 608: ret = Z_BUF_ERROR;
! 609: }
! 610: goto inf_leave;
! 611:
! 612: case BAD:
! 613: ret = Z_DATA_ERROR;
! 614: goto inf_leave;
! 615:
! 616: default: /* can't happen, but makes compilers happy */
! 617: ret = Z_STREAM_ERROR;
! 618: goto inf_leave;
! 619: }
! 620:
! 621: /* Return unused input */
! 622: inf_leave:
! 623: strm->next_in = next;
! 624: strm->avail_in = have;
! 625: return ret;
! 626: }
! 627:
! 628: int ZEXPORT inflateBackEnd(strm)
! 629: z_streamp strm;
! 630: {
! 631: if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
! 632: return Z_STREAM_ERROR;
! 633: ZFREE(strm, strm->state);
! 634: strm->state = Z_NULL;
! 635: Tracev((stderr, "inflate: end\n"));
! 636: return Z_OK;
! 637: }
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