Function mad_bit_read

modules/data/mp3/libmad/bit.c:141–179

* NAME: bit->read() * DESCRIPTION: read an arbitrary number of bits and return their UIMSBF value */

 * DESCRIPTION:	read an arbitrary number of bits and return their UIMSBF value
 */
unsigned long mad_bit_read(struct mad_bitptr *bitptr, unsigned int len)
{
  unsigned long value;

  if (bitptr->left == CHAR_BIT)
    bitptr->cache = *bitptr->byte;

  if (len < bitptr->left) {
    value = (bitptr->cache & ((1 << bitptr->left) - 1)) >>
      (bitptr->left - len);
    bitptr->left -= len;

    return value;
  }

  /* remaining bits in current byte */

  value = bitptr->cache & ((1 << bitptr->left) - 1);
  len  -= bitptr->left;

  bitptr->byte++;
  bitptr->left = CHAR_BIT;

  /* more bytes */

  while (len >= CHAR_BIT) {
    value = (value << CHAR_BIT) | *bitptr->byte++;
    len  -= CHAR_BIT;
  }

  if (len > 0) {
    bitptr->cache = *bitptr->byte;

    value = (value << len) | (bitptr->cache >> (CHAR_BIT - len));
    bitptr->left -= len;
  }

  return value;
}

# if 0
/*