D:/WorkAround/prequengine/trunk/src/filereader.c

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#include "filereader.h"

void frfeed(filereader* fr)
{
        fread(fr->buffer, BUFFER_SIZE, 1, fr->fd);
        fr->bufferPos = 0;
}

void frread(filereader* fr, void* destPtr, unsigned long int size)
{
        if(BUFFER_SIZE-fr->bufferPos >= size)
        {
                memcpy(destPtr,&fr->buffer[fr->bufferPos],size);
                fr->bufferPos += size;
        }
        else
        {
                // feed what we can
                char* tempPtr = (char*)destPtr;
                memcpy( tempPtr, &fr->buffer[fr->bufferPos], BUFFER_SIZE-fr->bufferPos );
                tempPtr+=BUFFER_SIZE-fr->bufferPos;
                size-=BUFFER_SIZE-fr->bufferPos;

                // feed the rest
                do
                {
                        fr->currSector++;
                        frfeed(fr);
                        if(size>=BUFFER_SIZE)
                        {
                                memcpy(tempPtr, fr->buffer, BUFFER_SIZE);
                                tempPtr+=BUFFER_SIZE;
                                size-=BUFFER_SIZE;
                        }
                        else
                        {
                                memcpy(tempPtr, fr->buffer, size);
                                fr->bufferPos += size;
                                size=0;
                        }
                }while(size>0);
        }
}

void frseek(filereader* fr, unsigned long int seekPosition)
{
        unsigned long int sectorToSeek;

        sectorToSeek = seekPosition / 2048;

        fseek(fr->fd, sectorToSeek * 2048, SEEK_SET);

        fr->currSector = sectorToSeek;
        frfeed(fr);
        fr->bufferPos = (seekPosition - (sectorToSeek*2048));
}

int fropen(filereader* fr, const char* filename)
{
        fr->fd = fopen((const char*)filename,"rb");

        if(fr->fd)
        {
                fr->currSector = 0;
                frfeed(fr);
                return 1;
        }

        return 0;
}

void frclose(filereader* fr)
{
        fclose(fr->fd);
}

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