diff options
Diffstat (limited to 'source/unzip/unshrink.c')
| -rw-r--r-- | source/unzip/unshrink.c | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/source/unzip/unshrink.c b/source/unzip/unshrink.c deleted file mode 100644 index 6deb4d4..0000000 --- a/source/unzip/unshrink.c +++ /dev/null @@ -1,177 +0,0 @@ -/*--------------------------------------------------------------------------- - - unshrink.c - - Shrinking is a Dynamic Lempel-Ziv-Welch compression algorithm with partial - clearing. - - ---------------------------------------------------------------------------*/ - - -#include "unz.h" -void flush_stack (int); - -/*************************************/ -/* UnShrink Defines, Globals, etc. */ -/*************************************/ - -/* MAX_BITS 13 (in unzip.h; defines size of global work area) */ -#define INIT_BITS 9 -#define FIRST_ENT 257 -#define CLEAR 256 -#define GetCode(dest) READBIT(codesize,dest) - -static void partial_clear (); - -int codesize, maxcode, maxcodemax, free_ent; - - - - -/*************************/ -/* Function unShrink() */ -/*************************/ - -void unShrink() -{ - register int code; - register int stackp; - int finchar; - int oldcode; - int incode; - - - /* decompress the file */ - codesize = INIT_BITS; - maxcode = (1 << codesize) - 1; - maxcodemax = HSIZE; /* (1 << MAX_BITS) */ - free_ent = FIRST_ENT; - - code = maxcodemax; - do { - prefix_of[code] = -1; - } while (--code > 255); -/* - OvdL: -Ox with SCO's 3.2.0 cc gives - a. warning: overflow in constant multiplication - b. segmentation fault (core dumped) when using the executable - for (code = maxcodemax; code > 255; code--) - prefix_of[code] = -1; - */ - - for (code = 255; code >= 0; code--) { - prefix_of[code] = 0; - suffix_of[code] = (byte) code; - } - - GetCode(oldcode); - if (zipeof) - return; - finchar = oldcode; - - stack[0] = finchar; - flush_stack (1); - - stackp = HSIZE; - - while (!zipeof) { - GetCode(code); - if (zipeof) - return; - - while (code == CLEAR) { - GetCode(code); - switch (code) { - case 1: - codesize++; - if (codesize == MAX_BITS) - maxcode = maxcodemax; - else - maxcode = (1 << codesize) - 1; - break; - - case 2: - partial_clear(); - break; - } - - GetCode(code); - if (zipeof) - return; - } - - - /* special case for KwKwK string */ - incode = code; - if (prefix_of[code] == -1) { - stack[--stackp] = (byte) finchar; - code = oldcode; - } - /* generate output characters in reverse order */ - while (code >= FIRST_ENT) { - if (prefix_of[code] == -1) { - stack[--stackp] = (byte) finchar; - code = oldcode; - } else { - stack[--stackp] = suffix_of[code]; - code = prefix_of[code]; - } - } - - finchar = suffix_of[code]; - stack[--stackp] = (byte) finchar; - - /* and put them out in forward order, block copy */ - flush_stack (HSIZE - stackp); - stackp = HSIZE; - - /* generate new entry */ - code = free_ent; - if (code < maxcodemax) { - prefix_of[code] = oldcode; - suffix_of[code] = (byte) finchar; - - do - code++; - while ((code < maxcodemax) && (prefix_of[code] != -1)); - - free_ent = code; - } - /* remember previous code */ - oldcode = incode; - } -} - - - -/******************************/ -/* Function partial_clear() */ -/******************************/ - -static void partial_clear() -{ - register int pr; - register int cd; - - /* mark all nodes as potentially unused */ - for (cd = FIRST_ENT; cd < free_ent; cd++) - prefix_of[cd] |= 0x8000; - - /* unmark those that are used by other nodes */ - for (cd = FIRST_ENT; cd < free_ent; cd++) { - pr = prefix_of[cd] & 0x7fff; /* reference to another node? */ - if (pr >= FIRST_ENT) /* flag node as referenced */ - prefix_of[pr] &= 0x7fff; - } - - /* clear the ones that are still marked */ - for (cd = FIRST_ENT; cd < free_ent; cd++) - if ((prefix_of[cd] & 0x8000) != 0) - prefix_of[cd] = -1; - - /* find first cleared node as next free_ent */ - cd = FIRST_ENT; - while ((cd < maxcodemax) && (prefix_of[cd] != -1)) - cd++; - free_ent = cd; -} |