github publish

VIDEO/LZW.C

@@ -0,0 +1,225 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <mem.h>
+#include <memman.h>
+
+
+#define LZW_MAX_CODES  4096
+
+typedef struct double_s
+  {
+  short group,chr,first,next;
+  }DOUBLE_S;
+
+typedef DOUBLE_S CODE_TABLE[LZW_MAX_CODES];
+
+DOUBLE_S *compress_dic;
+int clear_code;
+int end_code;
+int free_code;
+int nextgroup;
+int bitsize,init_bitsize;
+char old_value=0;
+
+void do_clear_code()
+  {
+  int i;
+
+  old_value=0;
+  nextgroup=free_code;
+  bitsize=init_bitsize;
+  for(i=0;i<clear_code;i++)
+     {
+     DOUBLE_S *p;
+     p=&compress_dic[i];
+     p->group=i;p->chr=-1;p->next=-1;p->first=-1;
+     }
+  }
+
+void reinit_lzw()
+  {
+  do_clear_code();
+  }
+
+void init_lzw_compressor(int dic_size)
+  {
+  compress_dic=(CODE_TABLE *)getmem(sizeof(CODE_TABLE));
+  clear_code=1<<dic_size;
+  end_code=clear_code+1;
+  free_code=end_code+1;
+  nextgroup=free_code;
+  init_bitsize=bitsize=dic_size+1;
+  do_clear_code();
+  }
+
+
+void done_lzw_compressor()
+  {
+  free(compress_dic);
+  }
+
+long output_code(void *target,long bitepos,int bitsize,int data);
+#pragma aux output_code parm [edi][edx][ebx][eax]=\
+     "mov     ecx,edx"\
+     "shr     ecx,3"\
+     "add     edi,ecx"\
+     "mov     ecx,edx"\
+     "and     cl,7h"\
+     "shl     eax,cl"\
+     "or      [edi],eax"\
+     "add     edx,ebx"\
+    value[edx] modify [ecx];
+
+
+int input_code(void *source,long *bitepos,int bitsize,int mask);
+#pragma aux input_code parm [esi][edi][ebx][edx]=\
+     "mov     ecx,[edi]"\
+     "mov     eax,ecx"\
+     "shr     eax,3"\
+     "mov     eax,[esi+eax]"\
+     "and     cl,7"\
+     "shr     eax,cl"\
+     "and     eax,edx"\
+     "add     [edi],ebx"\
+    value[eax] modify [ecx];
+
+
+int find_code(DOUBLE_S *p)
+  {
+  int ps;
+
+  ps=p->group;
+  ps=compress_dic[ps].first;
+  while (ps!=-1)
+     {
+     if (compress_dic[ps].chr==p->chr) return ps;
+     ps=compress_dic[ps].next;
+     }
+  return -1;
+  }
+
+
+void add_code(DOUBLE_S *p)
+  {
+  p->first=-1;p->next=compress_dic[p->group].first;
+  memcpy(&compress_dic[nextgroup],p,sizeof(DOUBLE_S));
+  compress_dic[p->group].first=nextgroup;
+  nextgroup++;
+  }
+
+
+long lzw_encode(char *source,void *target,int size)
+  {
+  long bitpos=0;
+  DOUBLE_S p;
+  int f;
+
+  clear:
+  old_value=p.group=*source++;size--;
+  while (size-->0)
+     {
+     p.chr=(int)((char)(*source++-old_value));old_value+=p.chr;
+     f=find_code(&p);
+     if (f<0)
+        {
+        bitpos=output_code(target,bitpos,bitsize,p.group);
+        add_code(&p);
+        if (nextgroup==(1<<bitsize)) bitsize++;
+        p.group=p.chr;
+        if (nextgroup>=LZW_MAX_CODES)
+           {
+           bitpos=output_code(target,bitpos,bitsize,p.group);
+           bitpos=output_code(target,bitpos,bitsize,clear_code);
+           do_clear_code();
+           goto clear;
+           }
+        }
+     else
+        p.group=f;
+     }
+  bitpos=output_code(target,bitpos,bitsize,p.group);
+  bitpos=output_code(target,bitpos,bitsize,end_code);
+  return (bitpos+8)>>3;
+  }
+
+
+void de_add_code(DOUBLE_S *p,int *mask)
+  {
+  DOUBLE_S *q;
+
+  q=&compress_dic[nextgroup];q->group=p->group;q->chr=p->chr;q->first=compress_dic[p->group].first+1;
+  nextgroup++;
+  if (nextgroup==*mask)
+     {
+     *mask=(*mask<<1)+1;
+     bitsize++;
+     }
+  }
+
+
+
+int expand_code(int code,char **target)
+  {
+  static int first;
+
+  if (code>end_code)
+     {
+     expand_code(compress_dic[code].group,target);
+     **target=old_value=compress_dic[code].chr+old_value;
+     (*target)++;
+     }
+  else
+     {
+     **target=old_value=code+old_value;
+     (*target)++;
+     first=code;
+     }
+  return first;
+  }
+
+char fast_expand_code(int code,char **target);
+#pragma aux fast_expand_code parm[eax][edi] modify [esi ecx] value [bl]
+
+void lzw_decode(void *source,char *target)
+  {
+  long bitpos=0;
+  int code,old,i;
+  DOUBLE_S p;
+  int old_first;
+  int mask=0xff;
+
+
+  for(i=0;i<LZW_MAX_CODES;i++) compress_dic[i].first=0;
+  clear:
+  old_value=0;
+  nextgroup=free_code;
+  bitsize=init_bitsize;
+  mask=(1<<bitsize)-1;
+  code=input_code(source,&bitpos,bitsize,mask);
+  old_first=fast_expand_code(code,&target);
+  old=code;
+  while ((code=input_code(source,&bitpos,bitsize,mask))!=end_code)
+     {
+     if (code==clear_code)
+        {
+        goto clear;
+        }
+     else if (code<nextgroup)
+        {
+        old_first=fast_expand_code(code,&target);
+        p.group=old;
+        p.chr=old_first;
+        de_add_code(&p,&mask);
+        old=code;
+        }
+     else
+        {
+        p.group=old;
+        p.chr=old_first;
+        de_add_code(&p,&mask);
+        old_first=fast_expand_code(code,&target);
+        old=code;
+        }
+     }
+    }
+