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/*
* Interface pour le programme de compression
* (c) 1995 Fabrice Bellard
*/
#include <stdlib.h>
//#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
/***************************************************************************
* Interface avec les routines de compression
*/
#define METHOD_NB 2 /* nombre total de méthodes de compression */
#define METHOD_STORE 0
#define METHOD_PPM 1
#define DEFAULT_SUFFIX ".st" /* extension par défault */
/* signature en début de fichier */
#define STAT_MAGIC_SIZE 4
char stat_magic[STAT_MAGIC_SIZE]={'P','P','M','S'};
#include "ppm_expander.h"
ppm_expander::~ppm_expander() {
if (needppmend) ppm.PPM_End();
ppm.arith.Arith_DecodeEnd();
if (buf_in!=NULL) delete [] buf_in;
if (buf_out!=NULL) delete [] buf_out;
if (my_read_buf != NULL) delete my_read_buf;
if (my_file_in != NULL) fclose(my_file_in);
}
int ppm_expander::OpenFile(const char* infile)
{
my_file_in=fopen(infile,"rb");
my_read_buf = new PPM_ReadBuf(my_file_in, this);
return home();
}
void ppm_expander::sizes(unsigned long& file, unsigned long& text)
{
struct stat _stat;
fstat(fileno(my_file_in),&_stat);
file = _stat.st_size;
text = numblocks*blocksize;
}
int ppm_expander::home()
{
fseek(my_file_in,0, SEEK_SET);
unsigned char header[STAT_MAGIC_SIZE];
size_t len=fread(header,1,STAT_MAGIC_SIZE,my_file_in);
if (strncmp((char*)header,stat_magic,STAT_MAGIC_SIZE)!=0) {
return 1;
}
if (len!=(STAT_MAGIC_SIZE)) {
return 1;
}
if (fread(&maxnode,sizeof(maxnode),1,my_file_in) != 1) return 1;
if (fread(&blocksize,sizeof(blocksize),1,my_file_in) != 1) return 1;
if (fread(&numblocks,sizeof(numblocks),1,my_file_in) != 1) return 1;
//fprintf(stderr,"<%u,%u,%u>\n",maxnode,blocksize,numblocks);
locate(0,0);
outbytes = 0;
return 0;
}
void ppm_expander::locate(unsigned int n) {
locate(n/blocksize, n%blocksize);
outbytes = n;
}
void ppm_expander::locate(unsigned short block, unsigned int n)
{
if (needppmend)
{
ppm.PPM_End();
needppmend = false;
}
size_t fpos;
fseek(my_file_in,STAT_MAGIC_SIZE+sizeof(maxnode)+sizeof(blocksize)+sizeof(numblocks)+block*sizeof(fpos),SEEK_SET);
fread(&fpos,sizeof(fpos),1,my_file_in);
fseek(my_file_in,fpos,SEEK_SET);
ppm.arith.Arith_DecodeInit(my_read_buf,buf_in,bufsize);
int err=ppm.PPM_Init(maxnode);
needppmend = true;
curblock = block;
for (int i = 0; i < n; i++) getch();
}
int ppm_expander::getch() {
if (curblock >= numblocks) return EOF;
int c=ppm.PPM_Decode();
if (c == SYM_EOF)
{
if (++curblock >= numblocks) return EOF;
locate(curblock,0);
c = ppm.PPM_Decode();
}
outbytes++;
return (c==SYM_EOF) ? EOF : c;
}
UINT PPM_ReadBuf::readbuf(UCHAR *buf,UINT len)
{
UINT len1;
parent->unsuspend();
len1=fread(buf,1,len,my_file_in);
return len1;
}
#ifndef __STATIC
extern "C"
{
CExpander* newcodec() { return new ppm_expander; }
}
#endif
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