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mpg123/readers.c  view on Meta::CPAN

    return TRUE;
}

static int mapped_head_shift(struct reader *rds,unsigned long *head)
{
    if(mappnt + 1 > mapend)
	return FALSE;
    *head <<= 8;
    *head |= *mappnt++;
    *head &= 0xffffffff;
    return TRUE;
}

static int mapped_skip_bytes(struct reader *rds,int len)
{
    if(mappnt + len > mapend)
	return FALSE;
    mappnt += len;
    if (param.usebuffer)
	buffer_resync();
    return TRUE;
}

static int mapped_read_frame_body(struct reader *rds,unsigned char *buf,
				  int size)
{
    if(size <= 0) {
	fprintf(stderr,"Ouch. Read_frame called with size <= 0\n");
	return FALSE;
    }
    if(mappnt + size > mapend)
	return FALSE;
    memcpy(buf,mappnt,size);
    mappnt += size;

    return TRUE;
}

static int mapped_back_bytes(struct reader *rds,int bytes)
{
    if( (mappnt - bytes) < mapbuf || (mappnt - bytes + 4) > mapend)
        return -1;
    mappnt -= bytes;
    if(param.usebuffer)
	buffer_resync();
    return 0;
}

static int mapped_back_frame(struct reader *rds,struct frame *fr,int num)
{
    long bytes;
    unsigned long newhead;


    if(!firsthead)
        return 0;

    bytes = (fr->framesize+8)*(num+2);

    /* Buffered mode is a bit trickier. From the size of the buffered
     * output audio stream we have to make a guess at the number of frames
     * this corresponds to.
     */
    if(param.usebuffer) 
	bytes += (long)(xfermem_get_usedspace(buffermem) /
			(buffermem->buf[0] * buffermem->buf[1] 
			 * (buffermem->buf[2] & AUDIO_FORMAT_MASK ?
			    16.0 : 8.0 )) 
			* (tabsel_123[fr->lsf][fr->lay-1][fr->bitrate_index] << 10));
    /*
      bytes += (long)(compute_buffer_offset(fr)*compute_bpf(fr));  
    */

    if( (mappnt - bytes) < mapbuf || (mappnt - bytes + 4) > mapend)
        return -1;
    mappnt -= bytes;

    newhead = (mappnt[0]<<24) + (mappnt[1]<<16) + (mappnt[2]<<8) + mappnt[3];
    mappnt += 4;

    while( (newhead & HDRCMPMASK) != (firsthead & HDRCMPMASK) ) {
        if(mappnt + 1 > mapend)
            return -1;
        newhead <<= 8;
        newhead |= *mappnt++;
        newhead &= 0xffffffff;
    }
    mappnt -= 4;

    read_frame(fr);
    read_frame(fr);

    if(fr->lay == 3)
        set_pointer(fr->sideInfoSize,512);

    if(param.usebuffer)
	buffer_resync();
    
    return 0;
}

static long mapped_tell(struct reader *rds)
{
    return mappnt - mapbuf;
}

#endif

/*****************************************************************
 * read frame helper
 */

struct reader *rd;
struct reader readers[] = {
#ifdef READ_SYSTEM
    { system_init,
      NULL,	/* filled in by system_init() */
      NULL,
      NULL,
      NULL,
      NULL,