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Diffstat (limited to 'source/unzip/explode.c')
| -rw-r--r-- | source/unzip/explode.c | 1120 |
1 files changed, 1120 insertions, 0 deletions
diff --git a/source/unzip/explode.c b/source/unzip/explode.c new file mode 100644 index 0000000..6558a7b --- /dev/null +++ b/source/unzip/explode.c @@ -0,0 +1,1120 @@ +/* explode.c -- Not copyrighted 1992 by Mark Adler + version c7, 27 June 1992 */ + + +/* 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 + ---- --------- -------------- ------------------------------------ + c1 30 Mar 92 M. Adler explode that uses huft_build from inflate + (this gives over a 70% speed improvement + over the original unimplode.c, which + decoded a bit at a time) + c2 4 Apr 92 M. Adler fixed bug for file sizes a multiple of 32k. + c3 10 Apr 92 M. Adler added a little memory tracking if DEBUG + c4 11 Apr 92 M. Adler added NOMEMCPY do kill use of memcpy() + 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 typecasts to eliminate some warnings + c7 27 Jun 92 G. Roelofs added more typecasts + */ + + +/* + Explode imploded (PKZIP method 6 compressed) data. This compression + method searches for as much of the current string of bytes (up to a length + of ~320) in the previous 4K or 8K bytes. If it doesn't find any matches + (of at least length 2 or 3), it codes the next byte. Otherwise, it codes + the length of the matched string and its distance backwards from the + current position. Single bytes ("literals") are preceded by a one (a + single bit) and are either uncoded (the eight bits go directly into the + compressed stream for a total of nine bits) or Huffman coded with a + supplied literal code tree. If literals are coded, then the minimum match + length is three, otherwise it is two. + + There are therefore four kinds of imploded streams: 8K search with coded + literals (min match = 3), 4K search with coded literals (min match = 3), + 8K with uncoded literals (min match = 2), and 4K with uncoded literals + (min match = 2). The kind of stream is identified in two bits of a + general purpose bit flag that is outside of the compressed stream. + + Distance-length pairs are always coded. Distance-length pairs for matched + strings are preceded by a zero bit (to distinguish them from literals) and + are always coded. The distance comes first and is either the low six (4K) + or low seven (8K) bits of the distance (uncoded), followed by the high six + bits of the distance coded. Then the length is six bits coded (0..63 + + min match length), and if the maximum such length is coded, then it's + followed by another eight bits (uncoded) to be added to the coded length. + This gives a match length range of 2..320 or 3..321 bytes. + + The literal, length, and distance codes are all represented in a slightly + compressed form themselves. What is sent are the lengths of the codes for + each value, which is sufficient to construct the codes. Each byte of the + code representation is the code length (the low four bits representing + 1..16), and the number of values sequentially with that length (the high + four bits also representing 1..16). There are 256 literal code values (if + literals are coded), 64 length code values, and 64 distance code values, + in that order at the beginning of the compressed stream. Each set of code + values is preceded (redundantly) with a byte indicating how many bytes are + in the code description that follows, in the range 1..256. + + The codes themselves are decoded using tables made by huft_build() from + the bit lengths. That routine and its comments are in the inflate.c + module. + */ + +#include "unz.h" /* this must supply the slide[] (byte) array */ +#include "unzipP.h" +//#include <stdlib.h> +#include "ds2_malloc.h" + +#ifndef WSIZE +# define WSIZE 0x8000 /* window size--must be a power of two, and at least + 8K for zip's implode method */ +#endif /* !WSIZE */ + + +struct huft { + byte e; /* number of extra bits or operation */ + byte b; /* number of bits in this code or subcode */ + union { + UWORD n; /* literal, length base, or distance base */ + struct huft *t; /* pointer to next level of table */ + } v; +}; + +/* Function prototypes */ +/* routines from inflate.c */ +extern unsigned hufts; +int huft_build OF((unsigned *, unsigned, unsigned, UWORD *, UWORD *, + struct huft **, int *)); +int huft_free OF((struct huft *)); +void flush OF((unsigned)); + +/* routines here */ +int get_tree OF((unsigned *, unsigned)); +int explode_lit8 OF((struct huft *, struct huft *, struct huft *, + int, int, int)); +int explode_lit4 OF((struct huft *, struct huft *, struct huft *, + int, int, int)); +int explode_nolit8 OF((struct huft *, struct huft *, int, int)); +int explode_nolit4 OF((struct huft *, struct huft *, int, int)); +int explode (); + +extern file_in_zip_read_info_s *pfile_in_zip_read_info; +extern unz_s *pUnzip; + +/* The implode algorithm uses a sliding 4K or 8K byte window on the + uncompressed stream to find repeated byte strings. This is implemented + here as a circular buffer. The index is updated simply by incrementing + and then and'ing with 0x0fff (4K-1) or 0x1fff (8K-1). Here, the 32K + buffer of inflate is used, and it works just as well to always have + a 32K circular buffer, so the index is anded with 0x7fff. This is + done to allow the window to also be used as the output buffer. */ +/* This must be supplied in an external module useable like "byte slide[8192];" + or "byte *slide;", where the latter would be malloc'ed. In unzip, slide[] + is actually a 32K area for use by inflate, which uses a 32K sliding window. + */ + + +/* Tables for length and distance */ +UWORD cplen2[] = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, + 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, + 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, + 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65}; +UWORD cplen3[] = {3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, + 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, + 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, + 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66}; +UWORD extra[] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 8}; +UWORD cpdist4[] = {1, 65, 129, 193, 257, 321, 385, 449, 513, 577, 641, 705, + 769, 833, 897, 961, 1025, 1089, 1153, 1217, 1281, 1345, 1409, 1473, + 1537, 1601, 1665, 1729, 1793, 1857, 1921, 1985, 2049, 2113, 2177, + 2241, 2305, 2369, 2433, 2497, 2561, 2625, 2689, 2753, 2817, 2881, + 2945, 3009, 3073, 3137, 3201, 3265, 3329, 3393, 3457, 3521, 3585, + 3649, 3713, 3777, 3841, 3905, 3969, 4033}; +UWORD cpdist8[] = {1, 129, 257, 385, 513, 641, 769, 897, 1025, 1153, 1281, + 1409, 1537, 1665, 1793, 1921, 2049, 2177, 2305, 2433, 2561, 2689, + 2817, 2945, 3073, 3201, 3329, 3457, 3585, 3713, 3841, 3969, 4097, + 4225, 4353, 4481, 4609, 4737, 4865, 4993, 5121, 5249, 5377, 5505, + 5633, 5761, 5889, 6017, 6145, 6273, 6401, 6529, 6657, 6785, 6913, + 7041, 7169, 7297, 7425, 7553, 7681, 7809, 7937, 8065}; + + +/* Macros for inflate() bit peeking and grabbing. + The usage is: + + NEEDBITS(j) + x = b & mask_bits[j]; + DUMPBITS(j) + + where NEEDBITS makes sure that b has at least j bits in it, and + DUMPBITS removes the bits from b. The macros use the variable k + for the number of bits in b. Normally, b and k are register + variables for speed. + */ + +extern UWORD bytebuf; /* (use the one in inflate.c) */ +#define NEXTBYTE (ReadByte(&bytebuf), bytebuf) +#define NEEDBITS(n) {while(k<(n)){b|=((ULONG)NEXTBYTE)<<k;k+=8;}} +#define DUMPBITS(n) {b>>=(n);k-=(n);} + +/* HERE */ +UWORD mask_bits[] = { + 0x0000, + 0x0001, 0x0003, 0x0007, 0x000f, 0x001f, 0x003f, 0x007f, 0x00ff, + 0x01ff, 0x03ff, 0x07ff, 0x0fff, 0x1fff, 0x3fff, 0x7fff, 0xffff +}; +union work area; /* see unzip.h for the definition of work */ +ULONG crc32val; +ush bytebuf; +ULONG bitbuf; +int bits_left; +boolean zipeof; + +int get_tree(l, n) +unsigned *l; /* bit lengths */ +unsigned n; /* number expected */ +/* Get the bit lengths for a code representation from the compressed + stream. If get_tree() returns 4, then there is an error in the data. + Otherwise zero is returned. */ +{ + unsigned i; /* bytes remaining in list */ + unsigned k; /* lengths entered */ + unsigned j; /* number of codes */ + unsigned b; /* bit length for those codes */ + + + /* get bit lengths */ + ReadByte(&bytebuf); + i = bytebuf + 1; /* length/count pairs to read */ + k = 0; /* next code */ + do { + ReadByte(&bytebuf); + b = ((j = bytebuf) & 0xf) + 1; /* bits in code (1..16) */ + j = ((j & 0xf0) >> 4) + 1; /* codes with those bits (1..16) */ + if (k + j > n) + return 4; /* don't overflow l[] */ + do { + l[k++] = b; + } while (--j); + } while (--i); + return k != n ? 4 : 0; /* should have read n of them */ +} + + + +int explode_lit8(tb, tl, td, bb, bl, bd) +struct huft *tb, *tl, *td; /* literal, length, and distance tables */ +int bb, bl, bd; /* number of bits decoded by those */ +/* Decompress the imploded data using coded literals and an 8K sliding + window. */ +{ + longint s; /* bytes to decompress */ + register unsigned e; /* table entry flag/number of extra bits */ + unsigned n, d; /* length and index for copy */ + unsigned w; /* current window position */ + struct huft *t; /* pointer to table entry */ + unsigned mb, ml, md; /* masks for bb, bl, and bd bits */ + register ULONG b; /* bit buffer */ + register unsigned k; /* number of bits in bit buffer */ + unsigned u; /* true if unflushed */ + + + /* explode the coded data */ + b = k = w = 0; /* initialize bit buffer, window */ + u = 1; /* buffer unflushed */ + mb = mask_bits[bb]; /* precompute masks for speed */ + ml = mask_bits[bl]; + md = mask_bits[bd]; + s = pUnzip->pfile_in_zip_read->rest_read_uncompressed; + while (s > 0) /* do until ucsize bytes uncompressed */ + { + NEEDBITS(1) + if (b & 1) /* then literal--decode it */ + { + DUMPBITS(1) + s--; + NEEDBITS((unsigned)bb) /* get coded literal */ + if ((e = (t = tb + ((~(unsigned)b) & mb))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + slide[w++] = (byte)t->v.n; + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + } + else /* else distance/length */ + { + DUMPBITS(1) + NEEDBITS(7) /* get distance low bits */ + d = (unsigned)b & 0x7f; + DUMPBITS(7) + NEEDBITS((unsigned)bd) /* get coded distance high bits */ + if ((e = (t = td + ((~(unsigned)b) & md))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + d = w - d - t->v.n; /* construct offset */ + NEEDBITS((unsigned)bl) /* get coded length */ + if ((e = (t = tl + ((~(unsigned)b) & ml))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + n = t->v.n; + if (e) /* get length extra bits */ + { + NEEDBITS(8) + n += (unsigned)b & 0xff; + DUMPBITS(8) + } + + /* do the copy */ + s -= n; + do { + n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); + if (u && w <= d) + { + memset(slide + w, 0, e); + w += e; + d += e; + } + else +#ifndef NOMEMCPY + if (w - d >= e) /* (this test assumes unsigned comparison) */ + { + memcpy(slide + w, slide + d, e); + w += e; + d += e; + } + else /* do it slow to avoid memcpy() overlap */ +#endif /* !NOMEMCPY */ + do { + slide[w++] = slide[d++]; + } while (--e); + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + } while (n); + } + } + + /* flush out slide */ + flush(w); + return pfile_in_zip_read_info->rest_read_compressed ? 5 : 0; /* should have read csize bytes */ +} + + + +int explode_lit4(tb, tl, td, bb, bl, bd) +struct huft *tb, *tl, *td; /* literal, length, and distance tables */ +int bb, bl, bd; /* number of bits decoded by those */ +/* Decompress the imploded data using coded literals and a 4K sliding + window. */ +{ + longint s; /* bytes to decompress */ + register unsigned e; /* table entry flag/number of extra bits */ + unsigned n, d; /* length and index for copy */ + unsigned w; /* current window position */ + struct huft *t; /* pointer to table entry */ + unsigned mb, ml, md; /* masks for bb, bl, and bd bits */ + register ULONG b; /* bit buffer */ + register unsigned k; /* number of bits in bit buffer */ + unsigned u; /* true if unflushed */ + + + /* explode the coded data */ + b = k = w = 0; /* initialize bit buffer, window */ + u = 1; /* buffer unflushed */ + mb = mask_bits[bb]; /* precompute masks for speed */ + ml = mask_bits[bl]; + md = mask_bits[bd]; + s = pUnzip->pfile_in_zip_read->rest_read_uncompressed; + while (s > 0) /* do until ucsize bytes uncompressed */ + { + NEEDBITS(1) + if (b & 1) /* then literal--decode it */ + { + DUMPBITS(1) + s--; + NEEDBITS((unsigned)bb) /* get coded literal */ + if ((e = (t = tb + ((~(unsigned)b) & mb))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + slide[w++] = (byte)t->v.n; + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + } + else /* else distance/length */ + { + DUMPBITS(1) + NEEDBITS(6) /* get distance low bits */ + d = (unsigned)b & 0x3f; + DUMPBITS(6) + NEEDBITS((unsigned)bd) /* get coded distance high bits */ + if ((e = (t = td + ((~(unsigned)b) & md))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + d = w - d - t->v.n; /* construct offset */ + NEEDBITS((unsigned)bl) /* get coded length */ + if ((e = (t = tl + ((~(unsigned)b) & ml))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + n = t->v.n; + if (e) /* get length extra bits */ + { + NEEDBITS(8) + n += (unsigned)b & 0xff; + DUMPBITS(8) + } + + /* do the copy */ + s -= n; + do { + n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); + if (u && w <= d) + { + memset(slide + w, 0, e); + w += e; + d += e; + } + else +#ifndef NOMEMCPY + if (w - d >= e) /* (this test assumes unsigned comparison) */ + { + memcpy(slide + w, slide + d, e); + w += e; + d += e; + } + else /* do it slow to avoid memcpy() overlap */ +#endif /* !NOMEMCPY */ + do { + slide[w++] = slide[d++]; + } while (--e); + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + } while (n); + } + } + + /* flush out slide */ + flush(w); + return pfile_in_zip_read_info->rest_read_compressed ? 5 : 0; /* should have read csize bytes */ +} + + + +int explode_nolit8(tl, td, bl, bd) +struct huft *tl, *td; /* length and distance decoder tables */ +int bl, bd; /* number of bits decoded by tl[] and td[] */ +/* Decompress the imploded data using uncoded literals and an 8K sliding + window. */ +{ + longint s; /* bytes to decompress */ + register unsigned e; /* table entry flag/number of extra bits */ + unsigned n, d; /* length and index for copy */ + unsigned w; /* current window position */ + struct huft *t; /* pointer to table entry */ + unsigned ml, md; /* masks for bl and bd bits */ + register ULONG b; /* bit buffer */ + register unsigned k; /* number of bits in bit buffer */ + unsigned u; /* true if unflushed */ + + + /* explode the coded data */ + b = k = w = 0; /* initialize bit buffer, window */ + u = 1; /* buffer unflushed */ + ml = mask_bits[bl]; /* precompute masks for speed */ + md = mask_bits[bd]; + s = pUnzip->pfile_in_zip_read->rest_read_uncompressed; + while (s > 0) /* do until ucsize bytes uncompressed */ + { + NEEDBITS(1) + if (b & 1) /* then literal--get eight bits */ + { + DUMPBITS(1) + s--; + NEEDBITS(8) + slide[w++] = (byte)b; + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + DUMPBITS(8) + } + else /* else distance/length */ + { + DUMPBITS(1) + NEEDBITS(7) /* get distance low bits */ + d = (unsigned)b & 0x7f; + DUMPBITS(7) + NEEDBITS((unsigned)bd) /* get coded distance high bits */ + if ((e = (t = td + ((~(unsigned)b) & md))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + d = w - d - t->v.n; /* construct offset */ + NEEDBITS((unsigned)bl) /* get coded length */ + if ((e = (t = tl + ((~(unsigned)b) & ml))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + n = t->v.n; + if (e) /* get length extra bits */ + { + NEEDBITS(8) + n += (unsigned)b & 0xff; + DUMPBITS(8) + } + + /* do the copy */ + s -= n; + do { + n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); + if (u && w <= d) + { + memset(slide + w, 0, e); + w += e; + d += e; + } + else +#ifndef NOMEMCPY + if (w - d >= e) /* (this test assumes unsigned comparison) */ + { + memcpy(slide + w, slide + d, e); + w += e; + d += e; + } + else /* do it slow to avoid memcpy() overlap */ +#endif /* !NOMEMCPY */ + do { + slide[w++] = slide[d++]; + } while (--e); + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + } while (n); + } + } + + /* flush out slide */ + flush(w); + return pfile_in_zip_read_info->rest_read_compressed ? 5 : 0; /* should have read csize bytes */ +} + + + +int explode_nolit4(tl, td, bl, bd) +struct huft *tl, *td; /* length and distance decoder tables */ +int bl, bd; /* number of bits decoded by tl[] and td[] */ +/* Decompress the imploded data using uncoded literals and a 4K sliding + window. */ +{ + longint s; /* bytes to decompress */ + register unsigned e; /* table entry flag/number of extra bits */ + unsigned n, d; /* length and index for copy */ + unsigned w; /* current window position */ + struct huft *t; /* pointer to table entry */ + unsigned ml, md; /* masks for bl and bd bits */ + register ULONG b; /* bit buffer */ + register unsigned k; /* number of bits in bit buffer */ + unsigned u; /* true if unflushed */ + + + /* explode the coded data */ + b = k = w = 0; /* initialize bit buffer, window */ + u = 1; /* buffer unflushed */ + ml = mask_bits[bl]; /* precompute masks for speed */ + md = mask_bits[bd]; + s = pUnzip->pfile_in_zip_read->rest_read_uncompressed; + while (s > 0) /* do until ucsize bytes uncompressed */ + { + NEEDBITS(1) + if (b & 1) /* then literal--get eight bits */ + { + DUMPBITS(1) + s--; + NEEDBITS(8) + slide[w++] = (byte)b; + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + DUMPBITS(8) + } + else /* else distance/length */ + { + DUMPBITS(1) + NEEDBITS(6) /* get distance low bits */ + d = (unsigned)b & 0x3f; + DUMPBITS(6) + NEEDBITS((unsigned)bd) /* get coded distance high bits */ + if ((e = (t = td + ((~(unsigned)b) & md))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + d = w - d - t->v.n; /* construct offset */ + NEEDBITS((unsigned)bl) /* get coded length */ + if ((e = (t = tl + ((~(unsigned)b) & ml))->e) > 16) + do { + if (e == 99) + return 1; + DUMPBITS(t->b) + e -= 16; + NEEDBITS(e) + } while ((e = (t = t->v.t + ((~(unsigned)b) & mask_bits[e]))->e) > 16); + DUMPBITS(t->b) + n = t->v.n; + if (e) /* get length extra bits */ + { + NEEDBITS(8) + n += (unsigned)b & 0xff; + DUMPBITS(8) + } + + /* do the copy */ + s -= n; + do { + n -= (e = (e = WSIZE - ((d &= WSIZE-1) > w ? d : w)) > n ? n : e); + if (u && w <= d) + { + memset(slide + w, 0, e); + w += e; + d += e; + } + else +#ifndef NOMEMCPY + if (w - d >= e) /* (this test assumes unsigned comparison) */ + { + memcpy(slide + w, slide + d, e); + w += e; + d += e; + } + else /* do it slow to avoid memcpy() overlap */ +#endif /* !NOMEMCPY */ + do { + slide[w++] = slide[d++]; + } while (--e); + if (w == WSIZE) + { + flush(w); + w = u = 0; + } + } while (n); + } + } + + /* flush out slide */ + flush(w); + return pfile_in_zip_read_info->rest_read_compressed ? 5 : 0; /* should have read csize bytes */ +} + + + +int explode () +/* Explode an imploded compressed stream. Based on the general purpose + bit flag, decide on coded or uncoded literals, and an 8K or 4K sliding + window. Construct the literal (if any), length, and distance codes and + the tables needed to decode them (using huft_build() from inflate.c), + and call the appropriate routine for the type of data in the remainder + of the stream. The four routines are nearly identical, differing only + in whether the literal is decoded or simply read in, and in how many + bits are read in, uncoded, for the low distance bits. */ +{ + unsigned r; /* return codes */ + struct huft *tb; /* literal code table */ + struct huft *tl; /* length code table */ + struct huft *td; /* distance code table */ + int bb; /* bits for tb */ + int bl; /* bits for tl */ + int bd; /* bits for td */ + unsigned l[256]; /* bit lengths for codes */ + + + /* Tune base table sizes. Note: I thought that to truly optimize speed, + I would have to select different bl, bd, and bb values for different + compressed file sizes. I was suprised to find out the the values of + 7, 7, and 9 worked best over a very wide range of sizes, except that + bd = 8 worked marginally better for large compressed sizes. */ + bl = 7; + bd = pUnzip->pfile_in_zip_read->rest_read_compressed > 200000L ? 8 : 7; + + + /* With literal tree--minimum match length is 3 */ + hufts = 0; /* initialze huft's malloc'ed */ + if (pUnzip->cur_file_info.flag & 4) + { + bb = 9; /* base table size for literals */ + if ((r = get_tree(l, 256)) != 0) + return r; + if ((r = huft_build(l, 256, 256, NULL, NULL, &tb, &bb)) != 0) + { + if (r == 1) + huft_free(tb); + return r; + } + if ((r = get_tree(l, 64)) != 0) + return r; + if ((r = huft_build(l, 64, 0, cplen3, extra, &tl, &bl)) != 0) + { + if (r == 1) + huft_free(tl); + huft_free(tb); + return r; + } + if ((r = get_tree(l, 64)) != 0) + return r; + if (pUnzip->cur_file_info.flag & 2) /* true if 8K */ + { + if ((r = huft_build(l, 64, 0, cpdist8, extra, &td, &bd)) != 0) + { + if (r == 1) + huft_free(td); + huft_free(tl); + huft_free(tb); + return r; + } + r = explode_lit8(tb, tl, td, bb, bl, bd); + } + else /* else 4K */ + { + if ((r = huft_build(l, 64, 0, cpdist4, extra, &td, &bd)) != 0) + { + if (r == 1) + huft_free(td); + huft_free(tl); + huft_free(tb); + return r; + } + r = explode_lit4(tb, tl, td, bb, bl, bd); + } + huft_free(td); + huft_free(tl); + huft_free(tb); + } + else + + + /* No literal tree--minimum match length is 2 */ + { + if ((r = get_tree(l, 64)) != 0) + return r; + if ((r = huft_build(l, 64, 0, cplen2, extra, &tl, &bl)) != 0) + { + if (r == 1) + huft_free(tl); + return r; + } + if ((r = get_tree(l, 64)) != 0) + return r; + if (pUnzip->cur_file_info.flag & 2) /* true if 8K */ + { + if ((r = huft_build(l, 64, 0, cpdist8, extra, &td, &bd)) != 0) + { + if (r == 1) + huft_free(td); + huft_free(tl); + return r; + } + r = explode_nolit8(tl, td, bl, bd); + } + else /* else 4K */ + { + if ((r = huft_build(l, 64, 0, cpdist4, extra, &td, &bd)) != 0) + { + if (r == 1) + huft_free(td); + huft_free(tl); + return r; + } + r = explode_nolit4(tl, td, bl, bd); + } + huft_free(td); + huft_free(tl); + } +#ifdef DEBUG + fprintf(stderr, "<%u > ", hufts); +#endif /* DEBUG */ + return r; +} + + +int ReadByte(x) + UWORD *x; +{ + /* + * read a byte; return 8 if byte available, 0 if not + */ + + if (pfile_in_zip_read_info->stream.avail_in == 0) + { + unsigned int uReadThis = UNZ_BUFSIZE; + + if (pfile_in_zip_read_info->rest_read_compressed <= 0) + return (0); + + if (pfile_in_zip_read_info->rest_read_compressed < uReadThis) + uReadThis = (uInt) pfile_in_zip_read_info->rest_read_compressed; + if (uReadThis == 0) + return UNZ_EOF; + if (fseek (pfile_in_zip_read_info->file, + pfile_in_zip_read_info->pos_in_zipfile + + pfile_in_zip_read_info->byte_before_the_zipfile, SEEK_SET) != 0) + return UNZ_ERRNO; + if (fread (pfile_in_zip_read_info->read_buffer, uReadThis, 1, + pfile_in_zip_read_info->file) != 1) + return UNZ_ERRNO; + pfile_in_zip_read_info->pos_in_zipfile += uReadThis; + + pfile_in_zip_read_info->rest_read_compressed -= uReadThis; + + pfile_in_zip_read_info->stream.next_in = + (Bytef *) pfile_in_zip_read_info->read_buffer; + pfile_in_zip_read_info->stream.avail_in = (uInt) uReadThis; + } + + *x = *pfile_in_zip_read_info->stream.next_in++; + pfile_in_zip_read_info->stream.avail_in--; + + return 8; +} + +/* 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 */ + +unsigned hufts; /* track memory usage */ + + +int huft_build(b, n, s, d, e, t, m) +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) */ +ush *d; /* list of base values for non-simple codes */ +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. */ +{ + unsigned a; /* counter for codes of length k */ + unsigned c[BMAX+1]; /* bit length count table */ + 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 l; /* bits per table (returned in m) */ + 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 */ + memset(c, 0, sizeof(c)); + p = b; i = n; + do { + c[*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 */ + l = *m; + for (j = 1; j <= BMAX; j++) + if (c[j]) + break; + k = j; /* minimum code length */ + if ((unsigned)l < j) + l = j; + for (i = BMAX; i; i--) + if (c[i]) + break; + g = i; /* maximum code length */ + if ((unsigned)l > i) + l = i; + *m = l; + + + /* 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 */ + p = b; i = 0; + do { + if ((j = *p++) != 0) + v[x[j]++] = i; + } while (++i < n); + + + /* 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; /* bits decoded == (l * h) */ + 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; /* previous table always l bits */ + + /* compute minimum size table less than or equal to l bits */ + z = (z = g - w) > (unsigned)l ? l : z; /* upper limit on table size */ + 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 */ + } + } + z = 1 << j; /* table entries for j-bit table */ + + /* 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 */ + } + hufts += z + 1; /* track memory usage */ + *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; /* 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 >> (w - l); /* (get around Turbo C bug) */ + 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 = *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]) + { + h--; /* don't need to update q */ + w -= l; + } + } + } + + + /* Return true (1) if we were given an incomplete table */ + return y != 0 && g != 1; +} + + +int huft_free(t) +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(p); + p = q; + } + return 0; +} + +void flush(w) +unsigned w; /* number of bytes to flush */ +/* Do the equivalent of OUTB for the bytes slide[0..w-1]. */ +{ + memmove (pfile_in_zip_read_info->stream.next_out, slide, w); + pfile_in_zip_read_info->crc32 = crc32 (pfile_in_zip_read_info->crc32, + pfile_in_zip_read_info->stream.next_out, + w); + pfile_in_zip_read_info->stream.next_out += w; + pfile_in_zip_read_info->stream.avail_out -= w; + pfile_in_zip_read_info->stream.total_out += w; +} + +void flush_stack(w) +unsigned w; /* number of bytes to flush */ +/* Do the equivalent of OUTB for the bytes slide[0..w-1]. */ +{ + memmove (pfile_in_zip_read_info->stream.next_out, stack, w); + pfile_in_zip_read_info->crc32 = crc32 (pfile_in_zip_read_info->crc32, + pfile_in_zip_read_info->stream.next_out, + w); + pfile_in_zip_read_info->stream.next_out += w; + pfile_in_zip_read_info->stream.avail_out -= w; + pfile_in_zip_read_info->stream.total_out += w; +} + +/****************************/ +/* Function FillBitBuffer() */ +/****************************/ + +int FillBitBuffer() +{ + /* + * Fill bitbuf, which is 32 bits. This function is only used by the + * READBIT and PEEKBIT macros (which are used by all of the uncompression + * routines). + */ + UWORD temp; + + zipeof = 1; + while (bits_left < 25 && ReadByte(&temp) == 8) + { + bitbuf |= (ULONG)temp << bits_left; + bits_left += 8; + zipeof = 0; + } + return 0; +} + |