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#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include "machine_type.h"
#include "config.h"
#include "buffers.h"
// retval: OK
//
tUInt32 openbuf(tBuffer* hBuf,tUInt8 bufnum,char* filename)
{
unsigned int filenamelen=0;
if (filename == NULL)
return RETNOK;
filenamelen=strlen(filename);
if (filenamelen>510)
filenamelen=510;
hBuf->changesnum=0;
hBuf->valid=0;
hBuf->fresh=1;
hBuf->file=fopen(filename,"rb");
memcpy(hBuf->filename,filename,filenamelen+1);
hBuf->filename[511]=0;
if (hBuf->file)
{
hBuf->valid=1;
hBuf->filesize=getfilesize(hBuf->file);
hBuf->bufsize=hBuf->filesize;
hBuf->bufferpos=-1;
return RETOK;
} else return RETNOK;
}
tUInt32 readbuf(tBuffer* hBuf,tInt64 pos)
{
tBool havetoread=0;
tInt32 bytesread;
if (hBuf->fresh || pos<hBuf->bufferpos || pos>(hBuf->bufferpos+BUFFERSIZE))
{
havetoread=1;
hBuf->bufferpos=pos&(~(BUFFERSIZE-1)); // floor
}
else if ((hBuf->bufferpos+BUFFERMARGIN)>pos && hBuf->bufferpos>=(BUFFERSIZE/2))
{
havetoread=1;
hBuf->bufferpos-=(BUFFERSIZE/2);
}
else if ((hBuf->bufferpos+BUFFERSIZE-BUFFERMARGIN)<pos && (hBuf->bufferpos+(BUFFERSIZE/2))<hBuf->bufsize && hBuf->bufsize>BUFFERSIZE)
{
havetoread=1;
hBuf->bufferpos+=(BUFFERSIZE/2);
}
if (havetoread)
{
hBuf->fresh=0;
if (hBuf->filesize>hBuf->bufferpos)
{
setfilepos(hBuf->file,hBuf->bufferpos);
bytesread=fread(hBuf->data,sizeof(tUInt8),BUFFERSIZE,hBuf->file);
if (bytesread!=BUFFERSIZE)
{
memset(&hBuf->data[bytesread],0,sizeof(tUInt8)*(BUFFERSIZE-bytesread)); // fill the rest with 0
}
} else {
memset(hBuf->data,0,sizeof(tUInt8)*BUFFERSIZE);
}
}
return RETOK;
}
tInt32 getbufferidx(tBuffer* hBuf,tInt64 pos)
{
tInt32 retval=OK;
if ((pos<(hBuf->bufferpos+BUFFERMARGIN)) || (pos>(hBuf->bufferpos+BUFFERSIZE-BUFFERMARGIN)))
{
retval=readbuf(hBuf,pos);
}
if (retval==OK)
{
retval=pos-(hBuf->bufferpos);
}
return retval;
}
tInt8 savechanges(tBuffer* hBuf)
{
int i;
fclose(hBuf->file);
if (hBuf->changesnum)
{
hBuf->file=fopen(hBuf->filename,"r+b");
if (hBuf->file==NULL) return RETNOK;
for (i=0;i<hBuf->changesnum;i++)
{
setfilepos(hBuf->file,hBuf->changes[i].pos);
fwrite(&(hBuf->changes[i].after),sizeof(tUInt8),1,hBuf->file);
}
fclose(hBuf->file);
}
return RETOK;
}
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