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1.1.1.5 ! root 1: /* inflate.c -- Not copyrighted 1992 by Mark Adler ! 2: version c4, 15 April 1992 */ ! 3: ! 4: ! 5: /* You can do whatever you like with this source file, though I would ! 6: prefer that if you modify it and redistribute it that you include ! 7: comments to that effect with your name and the date. Thank you. ! 8: ! 9: History: ! 10: vers date who what ! 11: ---- --------- -------------- ------------------------------------ ! 12: a ~~ Feb 92 M. Adler used full (large, one-step) lookup table ! 13: b1 21 Mar 92 M. Adler first version with partial lookup tables ! 14: b2 21 Mar 92 M. Adler fixed bug in fixed-code blocks ! 15: b3 22 Mar 92 M. Adler sped up match copies, cleaned up some ! 16: b4 25 Mar 92 M. Adler added prototypes; removed window[] (now ! 17: is the responsibility of unzip.h--also ! 18: changed name to slide[]), so needs diffs ! 19: for unzip.c and unzip.h (this allows ! 20: compiling in the small model on MSDOS); ! 21: fixed cast of q in huft_build(); ! 22: b5 26 Mar 92 M. Adler got rid of unintended macro recursion. ! 23: b6 27 Mar 92 M. Adler got rid of nextbyte() routine. fixed ! 24: bug in inflate_fixed(). ! 25: c1 30 Mar 92 M. Adler removed lbits, dbits environment variables. ! 26: changed BMAX to 16 for explode. Removed ! 27: OUTB usage, and replaced it with flush()-- ! 28: this was a 20% speed improvement! Added ! 29: an explode.c (to replace unimplode.c) that ! 30: uses the huft routines here. Removed ! 31: register union. ! 32: c2 4 Apr 92 M. Adler fixed bug for file sizes a multiple of 32k. ! 33: c3 10 Apr 92 M. Adler reduced memory of code tables made by ! 34: huft_build significantly (factor of two to ! 35: three). ! 36: c4 15 Apr 92 M. Adler added NOMEMCPY do kill use of memcpy(). ! 37: worked around a Turbo C optimization bug. ! 38: c5 21 Apr 92 M. Adler added the WSIZE #define to allow reducing ! 39: the 32K window size for specialized ! 40: applications. ! 41: c6 27 May 92 J.loup Gailly Adapted for pgp ! 42: */ ! 43: ! 44: ! 45: /* ! 46: Inflate deflated (PKZIP's method 8 compressed) data. The compression ! 47: method searches for as much of the current string of bytes (up to a ! 48: length of 258) in the previous 32K bytes. If it doesn't find any ! 49: matches (of at least length 3), it codes the next byte. Otherwise, it ! 50: codes the length of the matched string and its distance backwards from ! 51: the current position. There is a single Huffman code that codes both ! 52: single bytes (called "literals") and match lengths. A second Huffman ! 53: code codes the distance information, which follows a length code. Each ! 54: length or distance code actually represents a base value and a number ! 55: of "extra" (sometimes zero) bits to get to add to the base value. At ! 56: the end of each deflated block is a special end-of-block (EOB) literal/ ! 57: length code. The decoding process is basically: get a literal/length ! 58: code; if EOB then done; if a literal, emit the decoded byte; if a ! 59: length then get the distance and emit the referred-to bytes from the ! 60: sliding window of previously emitted data. ! 61: ! 62: There are (currently) three kinds of inflate blocks: stored, fixed, and ! 63: dynamic. The compressor deals with some chunk of data at a time, and ! 64: decides which method to use on a chunk-by-chunk basis. A chunk might ! 65: typically be 32K or 64K. If the chunk is uncompressible, then the ! 66: "stored" method is used. In this case, the bytes are simply stored as ! 67: is, eight bits per byte, with none of the above coding. The bytes are ! 68: preceded by a count, since there is no longer an EOB code. ! 69: ! 70: If the data is compressible, then either the fixed or dynamic methods ! 71: are used. In the dynamic method, the compressed data is preceded by ! 72: an encoding of the literal/length and distance Huffman codes that are ! 73: to be used to decode this block. The representation is itself Huffman ! 74: coded, and so is preceded by a description of that code. These code ! 75: descriptions take up a little space, and so for small blocks, there is ! 76: a predefined set of codes, called the fixed codes. The fixed method is ! 77: used if the block codes up smaller that way (usually for quite small ! 78: chunks), otherwise the dynamic method is used. In the latter case, the ! 79: codes are customized to the probabilities in the current block, and so ! 80: can code it much better than the pre-determined fixed codes. ! 81: ! 82: The Huffman codes themselves are decoded using a mutli-level table ! 83: lookup, in order to maximize the speed of decoding plus the speed of ! 84: building the decoding tables. See the comments below that precede the ! 85: lbits and dbits tuning parameters. ! 86: */ ! 87: ! 88: ! 89: /* ! 90: Notes beyond the 1.93a appnote.txt: ! 91: ! 92: 1. Distance pointers never point before the beginning of the output ! 93: stream. ! 94: 2. Distance pointers can point back across blocks, up to 32k away. ! 95: 3. There is an implied maximum of 7 bits for the bit length table and ! 96: 15 bits for the actual data. ! 97: 4. If only one code exists, then it is encoded using one bit. (Zero ! 98: would be more efficient, but perhaps a little confusing.) If two ! 99: codes exist, they are coded using one bit each (0 and 1). ! 100: 5. There is no way of sending zero distance codes--a dummy must be ! 101: sent if there are none. (History: a pre 2.0 version of PKZIP would ! 102: store blocks with no distance codes, but this was discovered to be ! 103: too harsh a criterion.) ! 104: 6. There are up to 286 literal/length codes. Code 256 represents the ! 105: end-of-block. Note however that the static length tree defines ! 106: 288 codes just to fill out the Huffman codes. Codes 286 and 287 ! 107: cannot be used though, since there is no length base or extra bits ! 108: defined for them. Similarily, there are up to 30 distance codes. ! 109: However, static trees define 32 codes (all 5 bits) to fill out the ! 110: Huffman codes, but the last two had better not show up in the data. ! 111: 7. Unzip can check dynamic huffman blocks for complete code sets. ! 112: The exception is that a single code would not be complete (see #4). ! 113: 8. The five bits following the block type is really the number of ! 114: literal codes sent minus 257. ! 115: 9. Length codes 8,16,16 are interpreted as 13 length codes of 8 bits ! 116: (1+6+6). Therefore, to output three times the length, you output ! 117: three codes (1+1+1), whereas to output four times the same length, ! 118: you only need two codes (1+3). Hmm. ! 119: 10. In the tree reconstruction algorithm, Code = Code + Increment ! 120: only if BitLength(i) is not zero. (Pretty obvious.) ! 121: 11. Correction: 4 Bits: # of Bit Length codes - 4 (4 - 19) ! 122: 12. Note: length code 284 can represent 227-258, but length code 285 ! 123: really is 258. The last length deserves its own, short code ! 124: since it gets used a lot in very redundant files. The length ! 125: 258 is special since 258 - 3 (the min match length) is 255. ! 126: 13. The literal/length and distance code bit lengths are read as a ! 127: single stream of lengths. It is possible (and advantageous) for ! 128: a repeat code (16, 17, or 18) to go across the boundary between ! 129: the two sets of lengths. ! 130: */ ! 131: ! 132: #include "zunzip.h" ! 133: #include "exitpgp.h" ! 134: #define OF __ ! 135: ! 136: #ifndef WSIZE ! 137: # define WSIZE 8192 ! 138: /* window size--must be a power of two, <= 32K, and equal to that of zip. ! 139: * On 16 bit machines (MSDOS), WSIZE must be <= 16K (32K is possible ! 140: * with a few hacks, see the zip archiver. ! 141: */ ! 142: #endif ! 143: ! 144: #ifdef DYN_ALLOC ! 145: extern char *window; ! 146: #else ! 147: extern char window[]; ! 148: #endif ! 149: #define slide window ! 150: ! 151: /* Huffman code lookup table entry--this entry is four bytes for machines ! 152: that have 16-bit pointers (e.g. PC's in the small or medium model). ! 153: Valid extra bits are 0..13. e == 15 is EOB (end of block), e == 16 ! 154: means that v is a literal, 16 < e < 32 means that v is a pointer to ! 155: the next table, which codes e - 16 bits, and lastly e == 99 indicates ! 156: an unused code. If a code with e == 99 is looked up, this implies an ! 157: error in the data. */ ! 158: struct huft { ! 159: byte e; /* number of extra bits or operation */ ! 160: byte b; /* number of bits in this code or subcode */ ! 161: union { ! 162: UWORD n; /* literal, length base, or distance base */ ! 163: struct huft *t; /* pointer to next level of table */ ! 164: } v; ! 165: }; ! 166: ! 167: ! 168: /* Function prototypes */ ! 169: int huft_build OF((unsigned *, unsigned, unsigned, UWORD *, UWORD *, ! 170: struct huft **, int *)); ! 171: int huft_free OF((struct huft *)); ! 172: void flush OF((unsigned)); ! 173: int inflate_codes OF((struct huft *, struct huft *, int, int)); ! 174: int inflate_stored OF((void)); ! 175: int inflate_fixed OF((void)); ! 176: int inflate_dynamic OF((void)); ! 177: int inflate_block OF((int *)); ! 178: int inflate_entry OF((void)); ! 179: int inflate OF((void)); ! 180: ! 181: ! 182: /* The inflate algorithm uses a sliding 32K byte window on the uncompressed ! 183: stream to find repeated byte strings. This is implemented here as a ! 184: circular buffer. The index is updated simply by incrementing and then ! 185: and'ing with 0x7fff (32K-1). */ ! 186: /* It is left to other modules to supply the 32K area. It is assumed ! 187: to be usable as if it were declared "byte slide[32768];" or as just ! 188: "byte *slide;" and then malloc'ed in the latter case. The definition ! 189: must be in unzip.h, included above. */ ! 190: unsigned wp; /* current position in slide */ ! 191: ! 192: ! 193: /* Tables for deflate from PKZIP's appnote.txt. */ ! 194: static unsigned border[] = { /* Order of the bit length code lengths */ ! 195: 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; ! 196: static UWORD cplens[] = { /* Copy lengths for literal codes 257..285 */ ! 197: 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, ! 198: 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0}; ! 199: /* note: see note #13 above about the 258 in this list. */ ! 200: static UWORD cplext[] = { /* Extra bits for literal codes 257..285 */ ! 201: 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, ! 202: 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99}; /* 99==invalid */ ! 203: static UWORD cpdist[] = { /* Copy offsets for distance codes 0..29 */ ! 204: 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, ! 205: 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, ! 206: 8193, 12289, 16385, 24577}; ! 207: static UWORD cpdext[] = { /* Extra bits for distance codes */ ! 208: 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, ! 209: 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, ! 210: 12, 12, 13, 13}; ! 211: ! 212: ! 213: ! 214: /* Macros for inflate() bit peeking and grabbing. ! 215: The usage is: ! 216: ! 217: NEEDBITS(j) ! 218: x = b & mask_bits[j]; ! 219: DUMPBITS(j) ! 220: ! 221: where NEEDBITS makes sure that b has at least j bits in it, and ! 222: DUMPBITS removes the bits from b. The macros use the variable k ! 223: for the number of bits in b. Normally, b and k are register ! 224: variables for speed, and are initialized at the begining of a ! 225: routine that uses these macros from a global bit buffer and count. ! 226: ! 227: If we assume that EOB will be the longest code, then we will never ! 228: ask for bits with NEEDBITS that are beyond the end of the stream. ! 229: So, NEEDBITS should not read any more bytes than are needed to ! 230: meet the request. Then no bytes need to be "returned" to the buffer ! 231: at the end of the last block. ! 232: ! 233: However, this assumption is not true for fixed blocks--the EOB code ! 234: is 7 bits, but the other literal/length codes can be 8 or 9 bits. ! 235: (Why PK made the EOB code, which can only occur once in a block, ! 236: the *shortest* code in the set, I'll never know.) However, by ! 237: making the first table have a lookup of seven bits, the EOB code ! 238: will be found in that first lookup, and so will not require that too ! 239: many bits be pulled from the stream. ! 240: */ ! 241: ! 242: ULONG bb; /* bit buffer */ ! 243: unsigned bk; /* bits in bit buffer */ ! 244: ! 245: UWORD bytebuf; ! 246: #if 0 ! 247: #define NEXTBYTE (ReadByte(&bytebuf), bytebuf) ! 248: #define NEEDBITS(n) {while(k<(n)){b|=((ULONG)NEXTBYTE)<<k;k+=8;}} ! 249: #else ! 250: #define NEEDBITS(n) \ ! 251: { while (k < (n)) { \ ! 252: if (--incnt < 0 && FillInBuf()) return 1; \ ! 253: b |= (ULONG)*inptr++ << k; \ ! 254: k += 8; \ ! 255: } } ! 256: #endif ! 257: ! 258: #define DUMPBITS(n) {b>>=(n);k-=(n);} ! 259: ! 260: ! 261: /* ! 262: Huffman code decoding is performed using a multi-level table lookup. ! 263: The fastest way to decode is to simply build a lookup table whose ! 264: size is determined by the longest code. However, the time it takes ! 265: to build this table can also be a factor if the data being decoded ! 266: is not very long. The most common codes are necessarily the ! 267: shortest codes, so those codes dominate the decoding time, and hence ! 268: the speed. The idea is you can have a shorter table that decodes the ! 269: shorter, more probable codes, and then point to subsidiary tables for ! 270: the longer codes. The time it costs to decode the longer codes is ! 271: then traded against the time it takes to make longer tables. ! 272: ! 273: This results of this trade are in the variables lbits and dbits ! 274: below. lbits is the number of bits the first level table for literal/ ! 275: length codes can decode in one step, and dbits is the same thing for ! 276: the distance codes. Subsequent tables are also less than or equal to ! 277: those sizes. These values may be adjusted either when all of the ! 278: codes are shorter than that, in which case the longest code length in ! 279: bits is used, or when the shortest code is *longer* than the requested ! 280: table size, in which case the length of the shortest code in bits is ! 281: used. ! 282: ! 283: There are two different values for the two tables, since they code a ! 284: different number of possibilities each. The literal/length table ! 285: codes 286 possible values, or in a flat code, a little over eight ! 286: bits. The distance table codes 30 possible values, or a little less ! 287: than five bits, flat. The optimum values for speed end up being ! 288: about one bit more than those, so lbits is 8+1 and dbits is 5+1. ! 289: The optimum values may differ though from machine to machine, and ! 290: possibly even between compilers. Your mileage may vary. ! 291: */ ! 292: ! 293: ! 294: int lbits = 9; /* bits in base literal/length lookup table */ ! 295: int dbits = 6; /* bits in base distance lookup table */ ! 296: ! 297: ! 298: /* If BMAX needs to be larger than 16, then h and x[] should be ULONG. */ ! 299: #define BMAX 16 /* maximum bit length of any code (16 for explode) */ ! 300: #define NMAX 288 /* maximum number of codes in any set */ ! 301: ! 302: ! 303: unsigned hufts; /* track memory usage */ ! 304: ! 305: ! 306: int huft_build(b, n, s, d, e, t, m) ! 307: unsigned *b; /* code lengths in bits (all assumed <= BMAX) */ ! 308: unsigned n; /* number of codes (assumed <= NMAX) */ ! 309: unsigned s; /* number of simple-valued codes (0..s-1) */ ! 310: UWORD *d; /* list of base values for non-simple codes */ ! 311: UWORD *e; /* list of extra bits for non-simple codes */ ! 312: struct huft **t; /* result: starting table */ ! 313: int *m; /* maximum lookup bits, returns actual */ ! 314: /* Given a list of code lengths and a maximum table size, make a set of ! 315: tables to decode that set of codes. Return zero on success, one if ! 316: the given code set is incomplete (the tables are still built in this ! 317: case), two if the input is invalid (all zero length codes or an ! 318: oversubscribed set of lengths), and three if not enough memory. */ ! 319: { ! 320: unsigned a; /* counter for codes of length k */ ! 321: unsigned c[BMAX+1]; /* bit length count table */ ! 322: unsigned f; /* i repeats in table every f entries */ ! 323: int g; /* maximum code length */ ! 324: int h; /* table level */ ! 325: register unsigned i; /* counter, current code */ ! 326: register unsigned j; /* counter */ ! 327: register int k; /* number of bits in current code */ ! 328: int l; /* bits per table (returned in m) */ ! 329: register unsigned *p; /* pointer into c[], b[], or v[] */ ! 330: register struct huft *q; /* points to current table */ ! 331: struct huft r; /* table entry for structure assignment */ ! 332: struct huft *u[BMAX]; /* table stack */ ! 333: unsigned v[NMAX]; /* values in order of bit length */ ! 334: register int w; /* bits before this table == (l * h) */ ! 335: unsigned x[BMAX+1]; /* bit offsets, then code stack */ ! 336: unsigned *xp; /* pointer into x */ ! 337: int y; /* number of dummy codes added */ ! 338: unsigned z; /* number of entries in current table */ ! 339: ! 340: ! 341: /* Generate counts for each bit length */ ! 342: memset(c, 0, sizeof(c)); ! 343: p = b; i = n; ! 344: do { ! 345: c[*p++]++; /* assume all entries <= BMAX */ ! 346: } while (--i); ! 347: if (c[0] == n) ! 348: return 2; /* bad input--all zero length codes */ ! 349: ! 350: ! 351: /* Find minimum and maximum length, bound *m by those */ ! 352: l = *m; ! 353: for (j = 1; j <= BMAX; j++) ! 354: if (c[j]) ! 355: break; ! 356: k = j; /* minimum code length */ ! 357: if (l < j) ! 358: l = j; ! 359: for (i = BMAX; i; i--) ! 360: if (c[i]) ! 361: break; ! 362: g = i; /* maximum code length */ ! 363: if (l > i) ! 364: l = i; ! 365: *m = l; ! 366: ! 367: ! 368: /* Adjust last length count to fill out codes, if needed */ ! 369: for (y = 1 << j; j < i; j++, y <<= 1) ! 370: if ((y -= c[j]) < 0) ! 371: return 2; /* bad input: more codes than bits */ ! 372: if ((y -= c[i]) < 0) ! 373: return 2; ! 374: c[i] += y; ! 375: ! 376: ! 377: /* Generate starting offsets into the value table for each length */ ! 378: x[1] = j = 0; ! 379: p = c + 1; xp = x + 2; ! 380: while (--i) { /* note that i == g from above */ ! 381: *xp++ = (j += *p++); ! 382: } ! 383: ! 384: ! 385: /* Make a table of values in order of bit lengths */ ! 386: p = b; i = 0; ! 387: do { ! 388: if ((j = *p++) != 0) ! 389: v[x[j]++] = i; ! 390: } while (++i < n); ! 391: ! 392: ! 393: /* Generate the Huffman codes and for each, make the table entries */ ! 394: x[0] = i = 0; /* first Huffman code is zero */ ! 395: p = v; /* grab values in bit order */ ! 396: h = -1; /* no tables yet--level -1 */ ! 397: w = -l; /* bits decoded == (l * h) */ ! 398: u[0] = NULL; q = NULL; z = 0; /* just to keep compilers happy */ ! 399: ! 400: /* go through the bit lengths (k already is bits in shortest code) */ ! 401: for (; k <= g; k++) ! 402: { ! 403: a = c[k]; ! 404: while (a--) ! 405: { ! 406: /* here i is the Huffman code of length k bits for value *p */ ! 407: /* make tables up to required level */ ! 408: while (k > w + l) ! 409: { ! 410: h++; ! 411: w += l; /* previous table always l bits */ ! 412: ! 413: /* compute minimum size table less than or equal to l bits */ ! 414: z = (z = g - w) > l ? l : z; /* upper limit on table size */ ! 415: if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */ ! 416: { /* too few codes for k-w bit table */ ! 417: f -= a + 1; /* deduct codes from patterns left */ ! 418: xp = c + k; ! 419: while (++j < z) /* try smaller tables up to z bits */ ! 420: { ! 421: if ((f <<= 1) <= *++xp) ! 422: break; /* enough codes to use up j bits */ ! 423: f -= *xp; /* else deduct codes from patterns */ ! 424: } ! 425: } ! 426: z = 1 << j; /* table entries for j-bit table */ ! 427: ! 428: /* allocate and link in new table */ ! 429: if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) == NULL) ! 430: { ! 431: if (h) ! 432: huft_free(u[0]); ! 433: fprintf(stderr, "\n*** inflate out of memory *** "); ! 434: return 3; /* not enough memory */ ! 435: } ! 436: hufts += z + 1; /* track memory usage */ ! 437: *t = q + 1; /* link to list for huft_free() */ ! 438: *(t = &(q->v.t)) = NULL; ! 439: u[h] = ++q; /* table starts after link */ ! 440: ! 441: /* connect to last table, if there is one */ ! 442: if (h) ! 443: { ! 444: x[h] = i; /* save pattern for backing up */ ! 445: r.b = l; /* bits to dump before this table */ ! 446: r.e = 16 + j; /* bits in this table */ ! 447: r.v.t = q; /* pointer to this table */ ! 448: j = i >> (w - l); /* (get around Turbo C bug) */ ! 449: u[h-1][j] = r; /* connect to last table */ ! 450: } ! 451: } ! 452: ! 453: /* set up table entry in r */ ! 454: r.b = k - w; ! 455: if (p >= v + n) ! 456: r.e = 99; /* out of values--invalid code */ ! 457: else if (*p < s) ! 458: { ! 459: r.e = *p < 256 ? 16 : 15; /* 256 is end-of-block code */ ! 460: r.v.n = *p++; /* simple code is just the value */ ! 461: } ! 462: else ! 463: { ! 464: r.e = e[*p - s]; /* non-simple--look up in lists */ ! 465: r.v.n = d[*p++ - s]; ! 466: } ! 467: ! 468: /* fill code-like entries with r */ ! 469: f = 1 << (k - w); ! 470: for (j = i >> w; j < z; j += f) ! 471: q[j] = r; ! 472: ! 473: /* backwards increment the k-bit code i */ ! 474: for (j = 1 << (k - 1); i & j; j >>= 1) ! 475: i ^= j; ! 476: i ^= j; ! 477: ! 478: /* backup over finished tables */ ! 479: while ((i & ((1 << w) - 1)) != x[h]) ! 480: { ! 481: h--; /* don't need to update q */ ! 482: w -= l; ! 483: } ! 484: } ! 485: } ! 486: ! 487: ! 488: /* Return true (1) if we were given an incomplete table */ ! 489: return y != 0 && n != 1; ! 490: } ! 491: ! 492: ! 493: ! 494: int huft_free(t) ! 495: struct huft *t; /* table to free */ ! 496: /* Free the malloc'ed tables built by huft_build(), which makes a linked ! 497: list of the tables it made, with the links in a dummy first entry of ! 498: each table. */ ! 499: { ! 500: register struct huft *p, *q; ! 501: ! 502: ! 503: /* Go through linked list, freeing from the malloced (t[-1]) address. */ ! 504: p = t; ! 505: while (p != NULL) ! 506: { ! 507: q = (--p)->v.t; ! 508: free(p); ! 509: p = q; ! 510: } ! 511: return 0; ! 512: } ! 513: ! 514: ! 515: ! 516: void flush(w) ! 517: unsigned w; /* number of bytes to flush */ ! 518: /* Do the equivalent of OUTB for the bytes slide[0..w-1]. */ ! 519: { ! 520: unsigned n; ! 521: byte *p; ! 522: ! 523: p = (byte*)slide; ! 524: while (w) ! 525: { ! 526: n = (n = OUTBUFSIZ - outcnt) < w ? n : w; ! 527: memcpy(outptr, p, n); /* try to fill up buffer */ ! 528: outptr += n; ! 529: if ((outcnt += n) == OUTBUFSIZ) ! 530: if (FlushOutput()) /* if full, empty */ ! 531: { ! 532: fprintf(stderr, "\nWrite error.\n"); ! 533: exitPGP(1); ! 534: } ! 535: p += n; ! 536: w -= n; ! 537: } ! 538: } ! 539: ! 540: ! 541: ! 542: int inflate_codes(tl, td, bl, bd) ! 543: struct huft *tl, *td; /* literal/length and distance decoder tables */ ! 544: int bl, bd; /* number of bits decoded by tl[] and td[] */ ! 545: /* inflate (decompress) the codes in a deflated (compressed) block. ! 546: Return an error code or zero if it all goes ok. */ ! 547: { ! 548: register unsigned e; /* table entry flag/number of extra bits */ ! 549: unsigned n, d; /* length and index for copy */ ! 550: unsigned w; /* current window position */ ! 551: struct huft *t; /* pointer to table entry */ ! 552: ULONG ml, md; /* masks for bl and bd bits */ ! 553: register ULONG b; /* bit buffer */ ! 554: register unsigned k; /* number of bits in bit buffer */ ! 555: ! 556: ! 557: /* make local copies of globals */ ! 558: b = bb; /* initialize bit buffer */ ! 559: k = bk; ! 560: w = wp; /* initialize window position */ ! 561: ! 562: ! 563: /* inflate the coded data */ ! 564: ml = mask_bits[bl]; /* precompute masks for speed */ ! 565: md = mask_bits[bd]; ! 566: while (1) /* do until end of block */ ! 567: { ! 568: NEEDBITS(bl) ! 569: if ((e = (t = tl + (b & ml))->e) > 16) ! 570: do { ! 571: if (e == 99) ! 572: return 1; ! 573: DUMPBITS(t->b) ! 574: e -= 16; ! 575: NEEDBITS(e) ! 576: } while ((e = (t = t->v.t + (b & mask_bits[e]))->e) > 16); ! 577: DUMPBITS(t->b) ! 578: if (e == 16) /* then it's a literal */ ! 579: { ! 580: slide[w++] = t->v.n; ! 581: if (w == WSIZE) ! 582: { ! 583: flush(w); ! 584: w = 0; ! 585: } ! 586: } ! 587: else /* it's an EOB or a length */ ! 588: { ! 589: /* exit if end of block */ ! 590: if (e == 15) ! 591: break; ! 592: ! 593: /* get length of block to copy */ ! 594: NEEDBITS(e) ! 595: n = t->v.n + (b & mask_bits[e]); ! 596: DUMPBITS(e); ! 597: ! 598: /* decode distance of block to copy */ ! 599: NEEDBITS(bd) ! 600: if ((e = (t = td + (b & md))->e) > 16) ! 601: do { ! 602: if (e == 99) ! 603: return 1; ! 604: DUMPBITS(t->b) ! 605: e -= 16; ! 606: NEEDBITS(e) ! 607: } while ((e = (t = t->v.t + (b & mask_bits[e]))->e) > 16); ! 608: DUMPBITS(t->b) ! 609: NEEDBITS(e) ! 610: d = w - t->v.n - (b & mask_bits[e]); ! 611: DUMPBITS(e) ! 612: ! 613: /* do the copy */ ! 614: do { ! 615: n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); ! 616: #ifndef NOMEMCPY ! 617: if (w - d >= e) /* (this test assumes unsigned comparison) */ ! 618: { ! 619: memcpy(slide + w, slide + d, e); ! 620: w += e; ! 621: d += e; ! 622: } ! 623: else /* do it slow to avoid memcpy() overlap */ ! 624: #endif /* !NOMEMCPY */ ! 625: do { ! 626: slide[w++] = slide[d++]; ! 627: } while (--e); ! 628: if (w == WSIZE) ! 629: { ! 630: flush(w); ! 631: w = 0; ! 632: } ! 633: } while (n); ! 634: } ! 635: } ! 636: ! 637: ! 638: /* restore the globals from the locals */ ! 639: wp = w; /* restore global window pointer */ ! 640: bb = b; /* restore global bit buffer */ ! 641: bk = k; ! 642: ! 643: ! 644: /* done */ ! 645: return 0; ! 646: } ! 647: ! 648: ! 649: ! 650: int inflate_stored() ! 651: /* "decompress" an inflated type 0 (stored) block. */ ! 652: { ! 653: unsigned n; /* number of bytes in block */ ! 654: unsigned w; /* current window position */ ! 655: register ULONG b; /* bit buffer */ ! 656: register unsigned k; /* number of bits in bit buffer */ ! 657: ! 658: ! 659: /* make local copies of globals */ ! 660: b = bb; /* initialize bit buffer */ ! 661: k = bk; ! 662: w = wp; /* initialize window position */ ! 663: ! 664: ! 665: /* go to byte boundary */ ! 666: n = k & 7; ! 667: DUMPBITS(n); ! 668: ! 669: ! 670: /* get the length and its complement */ ! 671: NEEDBITS(16) ! 672: n = b & 0xffff; ! 673: DUMPBITS(16) ! 674: NEEDBITS(16) ! 675: if (n != ((~b) & 0xffff)) ! 676: return 1; /* error in compressed data */ ! 677: DUMPBITS(16) ! 678: ! 679: ! 680: /* read and output the compressed data */ ! 681: while (n--) ! 682: { ! 683: NEEDBITS(8) ! 684: slide[w++] = b; ! 685: if (w == WSIZE) ! 686: { ! 687: flush(w); ! 688: w = 0; ! 689: } ! 690: DUMPBITS(8) ! 691: } ! 692: ! 693: ! 694: /* restore the globals from the locals */ ! 695: wp = w; /* restore global window pointer */ ! 696: bb = b; /* restore global bit buffer */ ! 697: bk = k; ! 698: return 0; ! 699: } ! 700: ! 701: ! 702: ! 703: int inflate_fixed() ! 704: /* decompress an inflated type 1 (fixed Huffman codes) block. We should ! 705: either replace this with a custom decoder, or at least precompute the ! 706: Huffman tables. */ ! 707: { ! 708: int i; /* temporary variable */ ! 709: struct huft *tl; /* literal/length code table */ ! 710: struct huft *td; /* distance code table */ ! 711: int bl; /* lookup bits for tl */ ! 712: int bd; /* lookup bits for td */ ! 713: unsigned l[288]; /* length list for huft_build */ ! 714: ! 715: ! 716: /* set up literal table */ ! 717: for (i = 0; i < 144; i++) ! 718: l[i] = 8; ! 719: for (; i < 256; i++) ! 720: l[i] = 9; ! 721: for (; i < 280; i++) ! 722: l[i] = 7; ! 723: for (; i < 288; i++) /* make a complete, but wrong code set */ ! 724: l[i] = 8; ! 725: bl = 7; ! 726: if ((i = huft_build(l, 288, 257, cplens, cplext, &tl, &bl)) != 0) ! 727: return i; ! 728: ! 729: ! 730: /* set up distance table */ ! 731: for (i = 0; i < 30; i++) /* make an incomplete code set */ ! 732: l[i] = 5; ! 733: bd = 5; ! 734: if ((i = huft_build(l, 30, 0, cpdist, cpdext, &td, &bd)) > 1) ! 735: { ! 736: huft_free(tl); ! 737: return i; ! 738: } ! 739: ! 740: ! 741: /* decompress until an end-of-block code */ ! 742: if (inflate_codes(tl, td, bl, bd)) ! 743: return 1; ! 744: ! 745: ! 746: /* free the decoding tables, return */ ! 747: huft_free(tl); ! 748: huft_free(td); ! 749: return 0; ! 750: } ! 751: ! 752: ! 753: ! 754: int inflate_dynamic() ! 755: /* decompress an inflated type 2 (dynamic Huffman codes) block. */ ! 756: { ! 757: int i; /* temporary variables */ ! 758: unsigned j; ! 759: unsigned l; /* last length */ ! 760: unsigned m; /* mask for bit lengths table */ ! 761: unsigned n; /* number of lengths to get */ ! 762: struct huft *tl; /* literal/length code table */ ! 763: struct huft *td; /* distance code table */ ! 764: int bl; /* lookup bits for tl */ ! 765: int bd; /* lookup bits for td */ ! 766: unsigned nb; /* number of bit length codes */ ! 767: unsigned nl; /* number of literal/length codes */ ! 768: unsigned nd; /* number of distance codes */ ! 769: unsigned ll[286+30]; /* literal/length and distance code lengths */ ! 770: register ULONG b; /* bit buffer */ ! 771: register unsigned k; /* number of bits in bit buffer */ ! 772: ! 773: ! 774: /* make local bit buffer */ ! 775: b = bb; ! 776: k = bk; ! 777: ! 778: ! 779: /* read in table lengths */ ! 780: NEEDBITS(5) ! 781: nl = 257 + (b & 0x1f); /* number of literal/length codes */ ! 782: DUMPBITS(5) ! 783: NEEDBITS(5) ! 784: nd = 1 + (b & 0x1f); /* number of distance codes */ ! 785: DUMPBITS(5) ! 786: NEEDBITS(4) ! 787: nb = 4 + (b & 0xf); /* number of bit length codes */ ! 788: DUMPBITS(4) ! 789: if (nl > 286 || nd > 30) ! 790: return 1; /* bad lengths */ ! 791: ! 792: ! 793: /* read in bit-length-code lengths */ ! 794: for (i = 0; i < nb; i++) ! 795: { ! 796: NEEDBITS(3) ! 797: ll[border[i]] = b & 7; ! 798: DUMPBITS(3) ! 799: } ! 800: for (; i < 19; i++) ! 801: ll[border[i]] = 0; ! 802: ! 803: ! 804: /* build decoding table for trees--single level, 7 bit lookup */ ! 805: bl = 7; ! 806: if ((i = huft_build(ll, 19, 19, NULL, NULL, &tl, &bl)) != 0) ! 807: { ! 808: if (i == 1) ! 809: huft_free(tl); ! 810: return i; /* incomplete code set */ ! 811: } ! 812: ! 813: ! 814: /* read in literal and distance code lengths */ ! 815: n = nl + nd; ! 816: m = mask_bits[bl]; ! 817: i = l = 0; ! 818: while (i < n) ! 819: { ! 820: NEEDBITS(bl) ! 821: j = (td = tl + (b & m))->b; ! 822: DUMPBITS(j) ! 823: j = td->v.n; ! 824: if (j < 16) /* length of code in bits (0..15) */ ! 825: ll[i++] = l = j; /* save last length in l */ ! 826: else if (j == 16) /* repeat last length 3 to 6 times */ ! 827: { ! 828: NEEDBITS(2) ! 829: j = 3 + (b & 3); ! 830: DUMPBITS(2) ! 831: if (i + j > n) ! 832: return 1; ! 833: while (j--) ! 834: ll[i++] = l; ! 835: } ! 836: else if (j == 17) /* 3 to 10 zero length codes */ ! 837: { ! 838: NEEDBITS(3) ! 839: j = 3 + (b & 7); ! 840: DUMPBITS(3) ! 841: if (i + j > n) ! 842: return 1; ! 843: while (j--) ! 844: ll[i++] = 0; ! 845: l = 0; ! 846: } ! 847: else /* j == 18: 11 to 138 zero length codes */ ! 848: { ! 849: NEEDBITS(7) ! 850: j = 11 + (b & 0x7f); ! 851: DUMPBITS(7) ! 852: if (i + j > n) ! 853: return 1; ! 854: while (j--) ! 855: ll[i++] = 0; ! 856: l = 0; ! 857: } ! 858: } ! 859: ! 860: ! 861: /* free decoding table for trees */ ! 862: huft_free(tl); ! 863: ! 864: ! 865: /* restore the global bit buffer */ ! 866: bb = b; ! 867: bk = k; ! 868: ! 869: ! 870: /* build the decoding tables for literal/length and distance codes */ ! 871: bl = lbits; ! 872: if ((i = huft_build(ll, nl, 257, cplens, cplext, &tl, &bl)) != 0) ! 873: { ! 874: if (i == 1) ! 875: huft_free(tl); ! 876: return i; /* incomplete code set */ ! 877: } ! 878: bd = dbits; ! 879: if ((i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &td, &bd)) != 0) ! 880: { ! 881: if (i == 1) ! 882: huft_free(td); ! 883: huft_free(tl); ! 884: return i; /* incomplete code set */ ! 885: } ! 886: ! 887: ! 888: /* decompress until an end-of-block code */ ! 889: if (inflate_codes(tl, td, bl, bd)) ! 890: return 1; ! 891: ! 892: ! 893: /* free the decoding tables, return */ ! 894: huft_free(tl); ! 895: huft_free(td); ! 896: return 0; ! 897: } ! 898: ! 899: ! 900: ! 901: int inflate_block(e) ! 902: int *e; /* last block flag */ ! 903: /* decompress an inflated block */ ! 904: { ! 905: unsigned t; /* block type */ ! 906: register ULONG b; /* bit buffer */ ! 907: register unsigned k; /* number of bits in bit buffer */ ! 908: ! 909: ! 910: /* make local bit buffer */ ! 911: b = bb; ! 912: k = bk; ! 913: ! 914: ! 915: /* read in last block bit */ ! 916: NEEDBITS(1) ! 917: *e = b & 1; ! 918: DUMPBITS(1) ! 919: ! 920: ! 921: /* read in block type */ ! 922: NEEDBITS(2) ! 923: t = b & 3; ! 924: DUMPBITS(2) ! 925: ! 926: ! 927: /* restore the global bit buffer */ ! 928: bb = b; ! 929: bk = k; ! 930: ! 931: ! 932: /* inflate that block type */ ! 933: if (t == 2) ! 934: return inflate_dynamic(); ! 935: if (t == 0) ! 936: return inflate_stored(); ! 937: if (t == 1) ! 938: return inflate_fixed(); ! 939: ! 940: ! 941: /* bad block type */ ! 942: return 2; ! 943: } ! 944: ! 945: ! 946: ! 947: int inflate_entry() ! 948: /* decompress an inflated entry */ ! 949: { ! 950: int e; /* last block flag */ ! 951: int r; /* result code */ ! 952: unsigned h; /* maximum struct huft's malloc'ed */ ! 953: ! 954: ! 955: /* initialize window, bit buffer */ ! 956: wp = 0; ! 957: bk = 0; ! 958: bb = 0; ! 959: ! 960: ! 961: /* decompress until the last block */ ! 962: h = 0; ! 963: do { ! 964: hufts = 0; ! 965: if ((r = inflate_block(&e)) != 0) ! 966: return r; ! 967: if (hufts > h) ! 968: h = hufts; ! 969: } while (!e); ! 970: ! 971: ! 972: /* flush out slide */ ! 973: flush(wp); ! 974: ! 975: ! 976: /* return success */ ! 977: #ifdef DEBUG ! 978: fprintf(stderr, "<%u> ", h); ! 979: #endif /* DEBUG */ ! 980: return 0; ! 981: } ! 982: ! 983: ! 984: int inflate() ! 985: /* ignore the return code for now ... */ ! 986: { ! 987: int status; ! 988: ! 989: #ifdef DYN_ALLOC ! 990: window = (char*) calloc((unsigned)WSIZE, 2*sizeof(char)); ! 991: /* Note that inflate only needs WSIZE bytes, but the window ! 992: * array is shared with deflate, which needs 2*WISZE bytes. ! 993: */ ! 994: if (window==NULL) err(4, ""); ! 995: #endif ! 996: ! 997: status = inflate_entry(); ! 998: ! 999: #ifdef DYN_ALLOC ! 1000: free(window); ! 1001: window = NULL; ! 1002: #endif ! 1003: ! 1004: return status; ! 1005: }
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