BITMAP_BYTES
for (j = 0; j < BITMAP_BYTES; j++) {
b->top = offset = ((l + (BITMAP_BYTES - 1)) / BITMAP_BYTES) - 1;
shift = ((l + (BITMAP_BYTES - 1)) % BITMAP_BYTES) * 8;
if ((ret->d = calloc(1, BITMAP_BYTES)) == NULL) {
memset(b->d, 0, b->len * BITMAP_BYTES);
nlen, BITMAP_BYTES)) == NULL)