/* inflate.c -- put in the public domain by Mark Adler */ /* Decompresses raw data compressed using the DEFLATE algorithm (RFC 1951) */ /* You can do whatever you like with this source file, though I would prefer that if you modify it and redistribute it that you include comments to that effect with your name and the date. Thank you. History: vers date who what ---- --------- -------------- ------------------------------------ a ~~ Feb 92 M. Adler used full (large, one-step) lookup table b1 21 Mar 92 M. Adler first version with partial lookup tables b2 21 Mar 92 M. Adler fixed bug in fixed-code blocks b3 22 Mar 92 M. Adler sped up match copies, cleaned up some b4 25 Mar 92 M. Adler added prototypes; removed window[] (now is the responsibility of unzip.h--also changed name to slide[]), so needs diffs for unzip.c and unzip.h (this allows compiling in the small model on MSDOS); fixed cast of q in huft_build(); b5 26 Mar 92 M. Adler got rid of unintended macro recursion. b6 27 Mar 92 M. Adler got rid of nextbyte() routine. fixed bug in inflate_fixed(). c1 30 Mar 92 M. Adler removed lbits, dbits environment variables. changed BMAX to 16 for explode. Removed OUTB usage, and replaced it with flush()-- this was a 20% speed improvement! Added an explode.c (to replace unimplod.c) that uses the huft routines here. Removed register union. c2 4 Apr 92 M. Adler fixed bug for file sizes a multiple of 32k. c3 10 Apr 92 M. Adler reduced memory of code tables made by huft_build significantly (factor of two to three). c4 15 Apr 92 M. Adler added NOMEMCPY do kill use of memcpy(). worked around a Turbo C optimization bug. c5 21 Apr 92 M. Adler added the WSIZE #define to allow reducing the 32K window size for specialized applications. c6 31 May 92 M. Adler added some typecasts to eliminate warnings c7 27 Jun 92 G. Roelofs added some more typecasts (444: MSC bug). c8 5 Oct 92 J-l. Gailly added ifdef'd code to deal with PKZIP bug. c9 9 Oct 92 M. Adler removed a memory error message (~line 416). c10 17 Oct 92 G. Roelofs changed ULONG/UWORD/byte to ulg/ush/uch, removed old inflate, renamed inflate_entry to inflate, added Mark's fix to a comment. c10.5 14 Dec 92 M. Adler fix up error messages for incomplete trees. c11 2 Jan 93 M. Adler fixed bug in detection of incomplete tables, and removed assumption that EOB is the longest code (bad assumption). c12 3 Jan 93 M. Adler make tables for fixed blocks only once. c13 5 Jan 93 M. Adler allow all zero length codes (pkzip 2.04c outputs one zero length code for an empty distance tree). c14 12 Mar 93 M. Adler made inflate.c standalone with the introduction of inflate.h. c14b 16 Jul 93 G. Roelofs added (unsigned) typecast to w at 470. c14c 19 Jul 93 J. Bush changed v[N_MAX], l[288], ll[28x+3x] arrays to static for Amiga. c14d 13 Aug 93 J-l. Gailly de-complicatified Mark's c[*p++]++ thing. c14e 8 Oct 93 G. Roelofs changed memset() to memzero(). c14f 22 Oct 93 G. Roelofs renamed quietflg to qflag; made Trace() conditional; added inflate_free(). c14g 28 Oct 93 G. Roelofs changed l/(lx+1) macro to pointer (Cray bug) c14h 7 Dec 93 C. Ghisler huft_build() optimizations. c14i 9 Jan 94 A. Verheijen set fixed_t{d,l} to NULL after freeing; G. Roelofs check NEXTBYTE macro for EOF. c14j 23 Jan 94 G. Roelofs removed Ghisler "optimizations"; ifdef'd EOF check. c14k 27 Feb 94 G. Roelofs added some typecasts to avoid warnings. c14l 9 Apr 94 G. Roelofs fixed split comments on preprocessor lines to avoid bug in Encore compiler. c14m 7 Jul 94 P. Kienitz modified to allow assembler version of inflate_codes() (define ASM_INFLATECODES) c14n 22 Jul 94 G. Roelofs changed fprintf to macro for DLL versions c14o 23 Aug 94 C. Spieler added a newline to a debug statement; G. Roelofs added another typecast to avoid MSC warning c14p 4 Oct 94 G. Roelofs added (voidp *) cast to free() argument c14q 30 Oct 94 G. Roelofs changed fprintf macro to MESSAGE() c14
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<h1>Wear-Leveling</h1>
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/* restore global bit buffer */ G.bk = k; /* done */ return 0; } #endif /* ASM_INFLATECODES */ static int inflate_stored(__G) __GDEF /* "decompress" an inflated type 0 (stored) block. */ { unsigned n; /* number of bytes in block */ unsigned w; /* current window position */ register ulg b; /* bit buffer */ register unsigned k; /* number of bits in bit buffer */ /* make local copies of globals */ Trace((stderr, "\nstored block")); b = G.bb; /* initialize bit buffer */ k = G.bk; w = G.wp; /* initialize window position */ /* go to byte boundary */ n = k & 7; DUMPBITS(n); /* get the length and its complement */ NEEDBITS(16) n = ((unsigned)b & 0xffff); DUMPBITS(16) NEEDBITS(16) if (n != (unsigned)((~b) & 0xffff)) return 1; /* error in compressed data */ DUMPBITS(16) /* read and output the compressed data */ while (n--) { NEEDBITS(8) redirSlide[w++] = (uch)b; if (w == wsize) { FLUSH(w); w = 0; } DUMPBITS(8) } /* restore the globals from the locals */ G.wp = w; /* restore global window pointer */ G.bb = b; /* restore global bit buffer */ G.bk = k; return 0; } /* Globals for literal tables (built once) */ /* Moved to globals.h */ #if 0 struct huft *fixed_tl = (struct huft *)NULL; struct huft *fixed_td; int fixed_bl, fixed_bd; #endif static int inflate_fixed(__G) __GDEF /* decompress an inflated type 1 (fixed Huffman codes) block. We should either replace this with a custom decoder, or at least precompute the Huffman tables. */ { /* if first time, set up tables for fixed blocks */ Trace((stderr, "\nliteral block")); if (G.fixed_tl == (struct huft *)NULL) { int i; /* temporary variable */ unsigned l[288]; /* length list for huft_build */ /* literal table */ for (i = 0; i < 144; i++) l[i] = 8; for (; i < 256; i++) l[i] = 9; for (; i < 280; i++) l[i] = 7; for (; i < 288; i++) /* make a complete, but wrong code set */ l[i] = 8; G.fixed_bl = 7; if ((i = huft_build(__G__ l, 288, 257, cplens, cplext, &G.fixed_tl, &G.fixed_bl)) != 0) { G.fixed_tl = (struct huft *)NULL; return i; } /* distance table */ for (i = 0; i < 30; i++) /* make an incomplete code set */ l[i] = 5; G.fixed_bd = 5; if ((i = huft_build(__G__ l, 30, 0, cpdist, cpdext, &G.fixed_td, &G.fixed_bd)) > 1) { huft_free(G.fixed_tl); G.fixed_tl = (struct huft *)NULL; return i; } } /* decompress until an end-of-block code */ return inflate_codes(__G__ G.fixed_tl, G.fixed_td, G.fixed_bl, G.fixed_bd) != 0; } static int inflate_dynamic(__G) __GDEF /* decompress an inflated type 2 (dynamic Huffman codes) block. */ { int i; /* temporary variables */ unsigned j; unsigned l; /* last length */ unsigned m; /* mask for bit lengths table */ unsigned n; /* number of lengths to get */ struct huft *tl; /* literal/length code table */ struct huft *td; /* distance code table */ int bl; /* lookup bits for tl */ int bd; /* lookup bits for td */ unsigned nb; /* number of bit length codes */ unsigned nl; /* number of literal/length codes */ unsigned nd; /* number of distance codes */ #ifdef PKZIP_BUG_WORKAROUND unsigned ll[288+32]; /* literal/length and distance code lengths */ #else unsigned ll[286+30]; /* literal/length and distance code lengths */ #endif register ulg b; /* bit buffer */ register unsigned k; /* number of bits in bit buffer */ /* make local bit buffer */ Trace((stderr, "\ndynamic block")); b = G.bb; k = G.bk; /* read in table lengths */ NEEDBITS(5) nl = 257 + ((unsigned)b & 0x1f); /* number of literal/length codes */ DUMPBITS(5) NEEDBITS(5) nd = 1 + ((unsigned)b & 0x1f); /* number of distance codes */ DUMPBITS(5) NEEDBITS(4) nb = 4 + ((unsigned)b & 0xf); /* number of bit length codes */ DUMPBITS(4) #ifdef PKZIP_BUG_WORKAROUND if (nl > 288 || nd > 32) #else if (nl > 286 || nd > 30) #endif return 1; /* bad lengths */ /* read in bit-length-code lengths */ for (j = 0; j < nb; j++) { NEEDBITS(3) ll[border[j]] = (unsigned)b & 7; DUMPBITS(3) } for (; j < 19; j++) ll[border[j]] = 0; /* build decoding table for trees--single level, 7 bit lookup */ bl = 7; i = huft_build(__G__ ll, 19, 19, NULL, NULL, &tl, &bl); if (bl == 0) /* no bit lengths */ i = 1; if (i) { if (i == 1) huft_free(tl); return i; /* incomplete code set */ } /* read in literal and distance code lengths */ n = nl + nd; m = mask_bits[bl]; i = l = 0; while ((unsigned)i < n) { NEEDBITS((unsigned)bl) j = (td = tl + ((unsigned)b & m))->b; DUMPBITS(j) j = td->v.n; if (j < 16) /* length of code in bits (0..15) */ ll[i++] = l = j; /* save last length in l */ else if (j == 16) /* repeat last length 3 to 6 times */ { NEEDBITS(2) j = 3 + ((unsigned)b & 3); DUMPBITS(2) if ((unsigned)i + j > n) { huft_free(tl); return 1; } while (j--) ll[i++] = l; } else if (j == 17) /* 3 to 10 zero length codes */ { NEEDBITS(3) j = 3 + ((unsigned)b & 7); DUMPBITS(3) if ((unsigned)i + j > n) { huft_free(tl); return 1; } while (j--) ll[i++] = 0; l = 0; } else /* j == 18: 11 to 138 zero length codes */ { NEEDBITS(7) j = 11 + ((unsigned)b & 0x7f); DUMPBITS(7) if ((unsigned)i + j > n) { huft_free(tl); return 1; } while (j--) ll[i++] = 0; l = 0; } } /* free decoding table for trees */ huft_free(tl); /* restore the global bit buffer */ G.bb = b; G.bk = k; /* build the decoding tables for literal/length and distance codes */ bl = lbits; i = huft_build(__G__ ll, nl, 257, cplens, cplext, &tl, &bl); if (bl == 0) /* no literals or lengths */ i = 1; if (i) { if (i == 1) { //if (!uO.qflag) MESSAGE((uch *)"(incomplete l-tree) ", 21L, 1); huft_free(tl); } return i; /* incomplete code set */ } bd = dbits; i = huft_build(__G__ ll + nl, nd, 0, cpdist, cpdext, &td, &bd); if (bd == 0 && nl > 257) /* lengths but no distances */ { //if (!uO.qflag) MESSAGE((uch *)"(incomplete d-tree) ", 21L, 1); huft_free(tl); huft_free(td); return 1; } if (i == 1) { #ifdef PKZIP_BUG_WORKAROUND i = 0; #else //if (!uO.qflag) MESSAGE((uch *)"(incomplete d-tree) ", 21L, 1); huft_free(td); td = NULL; #endif } if (i) { huft_free(tl); return i; } /* decompress until an end-of-block code */ i = inflate_codes(__G__ tl, td, bl, bd); /* free the decoding tables, return */ huft_free(tl); huft_free(td); if (i) return 1; return 0; } static int inflate_block(__G__ e) __GDEF int *e; /* last block flag */ /* decompress an inflated block */ { unsigned t; /* block type */ register ulg b; /* bit buffer */ register unsigned k; /* number of bits in bit buffer */ /* make local bit buffer */ b = G.bb; k = G.bk; /* read in last block bit */ NEEDBITS(1) *e = (int)b & 1; DUMPBITS(1) /* read in block type */ NEEDBITS(2) t = (unsigned)b & 3; DUMPBITS(2) /* restore the global bit buffer */ G.bb = b; G.bk = k; /* inflate that block type */ if (t == 2) return inflate_dynamic(__G); if (t == 0) return inflate_stored(__G); if (t == 1) return inflate_fixed(__G); /* bad block type */ return 2; } int inflate(__G) __GDEF /* decompress an inflated entry */ { int e; /* last block flag */ int r; /* result code */ //#ifdef DEBUG // unsigned h = 0; /* maximum struct huft's malloc'ed */ //#endif #if (defined(DLL) && !defined(NO_SLIDE_REDIR)) if (G.redirect_slide) wsize = G.redirect_size, redirSlide = G.redirect_buffer; else wsize = WSIZE, redirSlide = slide; /* how they're #defined if !DLL */ #endif /* initialize window, bit buffer */ G.wp = 0; G.bk = 0; G.bb = 0; /* decompress until the last block */ do { //#ifdef DEBUG // G.hufts = 0; //#endif if ((r = inflate_block(__G__ &e)) != 0) return r; //#ifdef DEBUG // if (G.hufts > h) // h = G.hufts; //#endif } while (!e); /* flush out redirSlide */ FLUSH(G.wp); /* return success */ //Trace((stderr, "\n%u bytes in Huffman tables (%d/entry)\n", // h * sizeof(struct huft), sizeof(struct huft))); return 0; } int inflate_free(__G) __GDEF { if (G.fixed_tl != (struct huft *)NULL) { huft_free(G.fixed_td); huft_free(G.fixed_tl); G.fixed_td = G.fixed_tl = (struct huft *)NULL; } return 0; } #endif /* ?USE_ZLIB */ /* * GRR: moved huft_build() and huft_free() down here; used by explode() * and fUnZip regardless of whether USE_ZLIB defined or not */ /* If BMAX needs to be larger than 16, then h and x[] should be ulg. */ #define BMAX 16 /* maximum bit length of any code (16 for explode) */ #define N_MAX 288 /* maximum number of codes in any set */ int huft_build( __GDEF ZCONST unsigned *b, /* code lengths in bits (all assumed <= BMAX) */ unsigned n, /* number of codes (assumed <= N_MAX) */ unsigned s, /* number of simple-valued codes (0..s-1) */ ZCONST ush *d, /* list of base values for non-simple codes */ ZCONST ush *e, /* list of extra bits for non-simple codes */ struct huft **t, /* result: starting table */ int *m /* maximum lookup bits, returns actual */ ) /* Given a list of code lengths and a maximum table size, make a set of tables to decode that set of codes. Return zero on success, one if the given code set is incomplete (the tables are still built in this case), two if the input is invalid (all zero length codes or an oversubscribed set of lengths), and three if not enough memory. The code with value 256 is special, and the tables are constructed so that no bits beyond that code are fetched when that code is decoded. */ { unsigned a; /* counter for codes of length k */ unsigned c[BMAX+1]; /* bit length count table */ unsigned el; /* length of EOB code (value 256) */ unsigned f; /* i repeats in table every f entries */ int g; /* maximum code length */ int h; /* table level */ register unsigned i; /* counter, current code */ register unsigned j; /* counter */ register int k; /* number of bits in current code */ int lx[BMAX+1]; /* memory for l[-1..BMAX-1] */ int *l = lx+1; /* stack of bits per table */ register unsigned *p; /* pointer into c[], b[], or v[] */ register struct huft *q; /* points to current table */ struct huft r; /* table entry for structure assignment */ struct huft *u[BMAX]; /* table stack */ unsigned v[N_MAX]; /* values in order of bit length */ register int w; /* bits before this table == (l * h) */ unsigned x[BMAX+1]; /* bit offsets, then code stack */ unsigned *xp; /* pointer into x */ int y; /* number of dummy codes added */ unsigned z; /* number of entries in current table */ /* Generate counts for each bit length */ el = n > 256 ? b[256] : BMAX; /* set length of EOB code, if any */ memset(c, 0, sizeof(c)); p = (unsigned *)b; i = n; do { c[*p]++; p++; /* assume all entries <= BMAX */ } while (--i); if (c[0] == n) /* null input--all zero length codes */ { *t = (struct huft *)NULL; *m = 0; return 0; } /* Find minimum and maximum length, bound *m by those */ for (j = 1; j <= BMAX; j++) if (c[j]) break; k = j; /* minimum code length */ if ((unsigned)*m < j) *m = j; for (i = BMAX; i; i--) if (c[i]) break; g = i; /* maximum code length */ if ((unsigned)*m > i) *m = i; /* Adjust last length count to fill out codes, if needed */ for (y = 1 << j; j < i; j++, y <<= 1) if ((y -= c[j]) < 0) return 2; /* bad input: more codes than bits */ if ((y -= c[i]) < 0) return 2; c[i] += y; /* Generate starting offsets into the value table for each length */ x[1] = j = 0; p = c + 1; xp = x + 2; while (--i) { /* note that i == g from above */ *xp++ = (j += *p++); } /* Make a table of values in order of bit lengths */ memset(v, 0, sizeof(v)); p = (unsigned *)b; i = 0; do { if ((j = *p++) != 0) v[x[j]++] = i; } while (++i < n); n = x[g]; /* set n to length of v */ /* Generate the Huffman codes and for each, make the table entries */ x[0] = i = 0; /* first Huffman code is zero */ p = v; /* grab values in bit order */ h = -1; /* no tables yet--level -1 */ w = l[-1] = 0; /* no bits decoded yet */ u[0] = (struct huft *)NULL; /* just to keep compilers happy */ q = (struct huft *)NULL; /* ditto */ z = 0; /* ditto */ /* go through the bit lengths (k already is bits in shortest code) */ for (; k <= g; k++) { a = c[k]; while (a--) { /* here i is the Huffman code of length k bits for value *p */ /* make tables up to required level */ while (k > w + l[h]) { w += l[h++]; /* add bits already decoded */ /* compute minimum size table less than or equal to *m bits */ z = (z = g - w) > (unsigned)*m ? *m : z; /* upper limit */ if ((f = 1 << (j = k - w)) > a + 1) /* try a k-w bit table */ { /* too few codes for k-w bit table */ f -= a + 1; /* deduct codes from patterns left */ xp = c + k; while (++j < z) /* try smaller tables up to z bits */ { if ((f <<= 1) <= *++xp) break; /* enough codes to use up j bits */ f -= *xp; /* else deduct codes from patterns */ } } if ((unsigned)w + j > el && (unsigned)w < el) j = el - w; /* make EOB code end at table */ z = 1 << j; /* table entries for j-bit table */ l[h] = j; /* set table size in stack */ /* allocate and link in new table */ if ((q = (struct huft *)malloc((z + 1)*sizeof(struct huft))) == (struct huft *)NULL) { if (h) huft_free(u[0]); return 3; /* not enough memory */ } //#ifdef DEBUG // G.hufts += z + 1; /* track memory usage */ //#endif *t = q + 1; /* link to list for huft_free() */ *(t = &(q->v.t)) = (struct huft *)NULL; u[h] = ++q; /* table starts after link */ /* connect to last table, if there is one */ if (h) { x[h] = i; /* save pattern for backing up */ r.b = (uch)l[h-1]; /* bits to dump before this table */ r.e = (uch)(16 + j); /* bits in this table */ r.v.t = q; /* pointer to this table */ j = (i & ((1 << w) - 1)) >> (w - l[h-1]); u[h-1][j] = r; /* connect to last table */ } } /* set up table entry in r */ r.b = (uch)(k - w); if (p >= v + n) r.e = 99; /* out of values--invalid code */ else if (*p < s) { r.e = (uch)(*p < 256 ? 16 : 15); /* 256 is end-of-block code */ r.v.n = (ush)*p++; /* simple code is just the value */ } else { r.e = (uch)e[*p - s]; /* non-simple--look up in lists */ r.v.n = d[*p++ - s]; } /* fill code-like entries with r */ f = 1 << (k - w); for (j = i >> w; j < z; j += f) q[j] = r; /* backwards increment the k-bit code i */ for (j = 1 << (k - 1); i & j; j >>= 1) i ^= j; i ^= j; /* backup over finished tables */ while ((i & ((1 << w) - 1)) != x[h]) w -= l[--h]; /* don't need to update q */ } } /* return actual size of base table */ *m = l[0]; /* Return true (1) if we were given an incomplete table */ return y != 0 && g != 1; } int huft_free (struct huft *t) /* table to free */ /* Free the malloc'ed tables built by huft_build(), which makes a linked list of the tables it made, with the links in a dummy first entry of each table. */ { register struct huft *p, *q; /* Go through linked list, freeing from the malloced (t[-1]) address. */ p = t; while (p != (struct huft *)NULL) { q = (--p)->v.t; free((zvoid *)p); p = q; } return 0; } // Main public function. Decompresses raw data compressed using the DEFLATE algorithm (RFC 1951 - e.g. zlib, gzip). // Returns 0 if decompression fails or, if successful, returns the size of the decompressed data. int DecompressDeflatedData (char *out, char *in, int inLength) { G.outbufptr = out; G.inptr = in; G.incnt = inLength; G.outCounter = 0; if (inflate(__G) != 0) { // Error decompressing return 0; } return G.outCounter; }