Function _mi_bitmap_unclaim

3rd/mimalloc-2.0.9/src/bitmap.c:140–148

Set `count` bits at `bitmap_idx` to 0 atomically Returns `true` if all `count` bits were 1 previously.

// Set `count` bits at `bitmap_idx` to 0 atomically
// Returns `true` if all `count` bits were 1 previously.
bool _mi_bitmap_unclaim(mi_bitmap_t bitmap, size_t bitmap_fields, size_t count, mi_bitmap_index_t bitmap_idx) {
  const size_t idx = mi_bitmap_index_field(bitmap_idx);
  const size_t bitidx = mi_bitmap_index_bit_in_field(bitmap_idx);
  const size_t mask = mi_bitmap_mask_(count, bitidx);
  mi_assert_internal(bitmap_fields > idx); MI_UNUSED(bitmap_fields);
  // mi_assert_internal((bitmap[idx] & mask) == mask);
  size_t prev = mi_atomic_and_acq_rel(&bitmap[idx], ~mask);
  return ((prev & mask) == mask);
}


// Set `count` bits at `bitmap_idx` to 1 atomically