+++ /dev/null
-/*---------------------------------------------------------------------------
-
- 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 */
projects / wxWidgets.git / blobdiff