Function mi_bitmap_mask_across

3rd/mimalloc-2.0.9/src/bitmap.c:302–311

Helper for masks across fields; returns the mid count, post_mask may be 0

// Helper for masks across fields; returns the mid count, post_mask may be 0
static size_t mi_bitmap_mask_across(mi_bitmap_index_t bitmap_idx, size_t bitmap_fields, size_t count, size_t* pre_mask, size_t* mid_mask, size_t* post_mask) {
  MI_UNUSED_RELEASE(bitmap_fields);
  const size_t bitidx = mi_bitmap_index_bit_in_field(bitmap_idx);
  if mi_likely(bitidx + count <= MI_BITMAP_FIELD_BITS) {
    *pre_mask = mi_bitmap_mask_(count, bitidx);
    *mid_mask = 0;
    *post_mask = 0;
    mi_assert_internal(mi_bitmap_index_field(bitmap_idx) < bitmap_fields);
    return 0;
  }
  else {
    const size_t pre_bits = MI_BITMAP_FIELD_BITS - bitidx;
    mi_assert_internal(pre_bits < count);