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Diffstat (limited to 'Build/source/libs/unzip/unreduce.c')
-rw-r--r-- | Build/source/libs/unzip/unreduce.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/Build/source/libs/unzip/unreduce.c b/Build/source/libs/unzip/unreduce.c new file mode 100644 index 00000000000..4cfb3fec6f5 --- /dev/null +++ b/Build/source/libs/unzip/unreduce.c @@ -0,0 +1,230 @@ +/*--------------------------------------------------------------------------- + + unreduce.c + + The Reducing algorithm is actually a combination of two distinct algorithms. + The first algorithm compresses repeated byte sequences, and the second al- + gorithm takes the compressed stream from the first algorithm and applies a + probabilistic compression method. + + * Copyright 1989 Samuel H. Smith; All rights reserved + * + * Do not distribute modified versions without my permission. + * Do not remove or alter this notice or any other copyright notice. + * If you use this in your own program you must distribute source code. + * Do not use any of this in a commercial product. + + See the accompanying file "COPYING" in UnZip source and binary distributions + for further information. This code is NOT used unless USE_SMITH_CODE is + explicitly defined (==> COPYRIGHT_CLEAN is not defined). + + ---------------------------------------------------------------------------*/ + + +#define UNZIP_INTERNAL +#include "unzip.h" /* defines COPYRIGHT_CLEAN by default */ + + +#ifndef COPYRIGHT_CLEAN + +/**************************************/ +/* UnReduce Defines, Typedefs, etc. */ +/**************************************/ + +#define DLE 144 + +typedef uch f_array[64]; /* for followers[256][64] */ + + + +/******************************/ +/* UnReduce Local Functions */ +/******************************/ + +static void LoadFollowers OF((__GPRO__ f_array *followers, uch *Slen)); + + + +/*******************************/ +/* UnReduce Global Constants */ +/*******************************/ + +static ZCONST shrint L_table[] = +{0, 0x7f, 0x3f, 0x1f, 0x0f}; + +static ZCONST shrint D_shift[] = +{0, 0x07, 0x06, 0x05, 0x04}; +static ZCONST shrint D_mask[] = +{0, 0x01, 0x03, 0x07, 0x0f}; + +static ZCONST shrint B_table[] = +{8, 1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, + 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, + 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, + 8, 8, 8, 8}; + + + + + +/*************************/ +/* Function unreduce() */ +/*************************/ + +void unreduce(__G) /* expand probabilistically reduced data */ + __GDEF +{ + register int lchar = 0; + shrint nchar; + shrint ExState = 0; + shrint V = 0; + shrint Len = 0; + long s = G.ucsize; /* number of bytes left to decompress */ + unsigned w = 0; /* position in output window slide[] */ + unsigned u = 1; /* true if slide[] unflushed */ + uch Slen[256]; + + f_array *followers = (f_array *)(slide + 0x4000); + int factor = G.lrec.compression_method - 1; + + LoadFollowers(__G__ followers, Slen); + + while (s > 0 /* && (!zipeof) */) { + if (Slen[lchar] == 0) + READBITS(8, nchar) /* ; */ + else { + READBITS(1, nchar) /* ; */ + if (nchar != 0) + READBITS(8, nchar) /* ; */ + else { + shrint follower; + int bitsneeded = B_table[Slen[lchar]]; + + READBITS(bitsneeded, follower) /* ; */ + nchar = followers[lchar][follower]; + } + } + /* expand the resulting byte */ + switch (ExState) { + + case 0: + if (nchar != DLE) { + s--; + slide[w++] = (uch)nchar; + if (w == 0x4000) { + flush(__G__ slide, (ulg)w, 0); + w = u = 0; + } + } + else + ExState = 1; + break; + + case 1: + if (nchar != 0) { + V = nchar; + Len = V & L_table[factor]; + if (Len == L_table[factor]) + ExState = 2; + else + ExState = 3; + } else { + s--; + slide[w++] = DLE; + if (w == 0x4000) + { + flush(__G__ slide, (ulg)w, 0); + w = u = 0; + } + ExState = 0; + } + break; + + case 2:{ + Len += nchar; + ExState = 3; + } + break; + + case 3:{ + register unsigned e; + register unsigned n = Len + 3; + register unsigned d = w - ((((V >> D_shift[factor]) & + D_mask[factor]) << 8) + nchar + 1); + + s -= n; + do { + n -= (e = (e = 0x4000 - ((d &= 0x3fff) > w ? d : w)) > n ? + n : e); + if (u && w <= d) + { + memzero(slide + w, e); + w += e; + d += e; + } + else + if (w - d < e) /* (assume unsigned comparison) */ + do { /* slow to avoid memcpy() overlap */ + slide[w++] = slide[d++]; + } while (--e); + else + { + memcpy(slide + w, slide + d, e); + w += e; + d += e; + } + if (w == 0x4000) + { + flush(__G__ slide, (ulg)w, 0); + w = u = 0; + } + } while (n); + + ExState = 0; + } + break; + } + + /* store character for next iteration */ + lchar = nchar; + } + + /* flush out slide */ + flush(__G__ slide, (ulg)w, 0); +} + + + + + +/******************************/ +/* Function LoadFollowers() */ +/******************************/ + +static void LoadFollowers(__G__ followers, Slen) + __GDEF + f_array *followers; + uch *Slen; +{ + register int x; + register int i; + + for (x = 255; x >= 0; x--) { + READBITS(6, Slen[x]) /* ; */ + for (i = 0; (uch)i < Slen[x]; i++) + READBITS(8, followers[x][i]) /* ; */ + } +} + +#endif /* !COPYRIGHT_CLEAN */ |