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mpg123/system.c  view on Meta::CPAN

static int system_raw_read_head(int f,unsigned long *head)
{
	unsigned char buf[4];
	if(my_read(f,buf,4) != 4) {
		perror("read_head");
                return -1;
        }
	*head = (buf[0]<<24) + (buf[1]<<16) + (buf[2]<<8) + buf[3];

	if(verbose > 1)
		fprintf(stderr,"head: %08lx\n",*head);
	return 0;
}

static int system_raw_read_word(int f,int *word)
{
        unsigned char buf[2];
	int ret;

        if(my_read(f,buf,2) != 2) {
		perror("read_word");
                return -1;
        }
        *word = (buf[0]<<8) + buf[1];
        return 0;
}

static int system_raw_read(int f,int len,unsigned char *buf)
{
	
	if(my_read(f,buf,len) != len)
              return -1;
        return 0;
}

static int system_raw_skip(int f,int len)
{
	int ret;
	int cnt = 0;

	ret = lseek(f,len,SEEK_CUR);

	if(ret < 0 && errno == ESPIPE) {
		cnt = len;
		while(cnt) {
                        char buf[1024];
			if(cnt > 1024)
                           ret = read(f,buf,1024);
                        else
                           ret = read(f,buf,cnt);
                        if(ret < 0)
                           return -1;
                        cnt -= ret;
		}
                ret = len;
	}

        return ret;
}

static unsigned long system_raw_timer_value(unsigned char *buf)
{
	unsigned long val;

	if(!(buf[0] & 0x1) || !(buf[2] & 0x1) || !(buf[4] & 0x1)) {
		if(verbose)
			fprintf(stderr,"Warning: missing marker in time stamp!\n");
	}

	val  = (buf[0] & 0xe) << (29-1);
        val |= buf[1] << 21;
        val |= (buf[2] & 0xfe) << (14-1);
        val |= buf[3] << 7;
        val |= buf[4] >> 1;

	return val;
}

static int system_raw_read_packet_data(int fd,struct packet_info *pi)
{
    static unsigned char buf[16384];
    int len;
    int pos = 0;
    int i;

    if(system_raw_read_word(filept,&len) < 0)
        return -1;
    if(verbose > 1)
    	fprintf(stderr,"Stream video/audio len: %d\n",len);

    if(system_raw_read(fd,len,buf) < 0)
      return -1;

    for(i=0;i<16;i++,pos++) {
       if(buf[pos] != 0xff)
         break;
    }
    if(i == 16) {
       fprintf(stderr,"Ouch ... too much stuffing bytes!\n");
       return -1;
    }
    
    if( (buf[pos] & 0xc0) == 0x40 ) {
       pi->scale = (buf[pos] >> 5) & 0x1;
       pi->size  = (buf[pos] & 0x1f) << 8;
       pi->size |= buf[pos+1];
       pos += 2;
    }

    switch( buf[pos] & 0xf0) {
      case 0x00:
        if(buf[pos] != 0x0f) {
          fprintf(stderr,"Ouch ... illegal timer code!\n");
          return -1;
        }
        pos++;
        break;
      case 0x20:
        pi->pts = system_raw_timer_value(buf+pos);
        pos += 5;
        break;
      case 0x30:
        pi->pts = system_raw_timer_value(buf+pos);
        pos += 5;
        if( (buf[pos] & 0xf) != 0x10) {
          if(verbose)
          	fprintf(stderr,"DTS should start with 0x1x!\n");
	}
        pi->dts = system_raw_timer_value(buf+pos);
        pos += 5;
        break;
      default:
	if(verbose)
        	fprintf(stderr,"Ouch ... illegal timer code!\n");
        return -1;
 
    }


#if 1 
	write(1,buf+pos,len-pos);
#endif

	return 0;
}


static int system_raw_read_packet_info(int f,double *clock,unsigned long *rate)
{
	unsigned char buf[8];
	int i;

	if(my_read(f,buf,8) != 8) {
		perror("read_packet_info");
		return -1;
	}

	*clock = 0.0;
	for(i=0;i<5;i++) {
		*clock *= 256.0;
		*clock += (double) buf[4-i];
	}
	*rate = (buf[5]<<16) + (buf[6]<<8) + buf[7];
	return 0;
}

static int system_raw_read_system_header(int f,struct system_info *ssi) 
{
	int rlen,len;
	unsigned char buf[6+48*3];
	int i,cnt;

	if(system_raw_read_word(filept,&len) < 0)
		return -1;

	if(verbose > 1)
		fprintf(stderr,"system len: %d\n",len);

	rlen = len;
	if(len > 6 + 48 * 3) {
		if(verbose)
			fprintf(stderr,"Oops .. large System header!\n");
		rlen = 6+48*3;
	}
	if(my_read(f,buf,rlen) != rlen) {
		perror("raw_read_system_header");
		return -1;
	}

	if(len - rlen) {
		if(system_raw_skip(filept,len-rlen) < 0)
			return -1;
	}