regex.c:717
static int
is_in_list_mbc(c, b)
    unsigned long c;
    const unsigned char *b;
{
  unsigned short size;
  unsigned short i, j;

  size = *b++;
  b += size + 2;
  size = EXTRACT_UNSIGNED(&b[-2]);
  if (size == 0) return 0;

  for (i = 0, j = size; i < j; ) {
    unsigned short k = (unsigned short)(i + j) >> 1;

    if (c > EXTRACT_MBC(&b[k*8+4]))
      i = k + 1;
    else
      j = k;
  }
  if (i < size && EXTRACT_MBC(&b[i*8]) <= c)
    return 1;

  return 0;
}
