Function mi_bitmap_bsr

system/lib/mimalloc/src/bitmap.c:1351–1368

bool mi_bitmap_bsr(mi_bitmap_t* bitmap, size_t* idx) {
  const size_t chunkmap_max = _mi_divide_up(mi_bitmap_chunk_count(bitmap), MI_BFIELD_BITS);
  for (size_t i = chunkmap_max; i > 0; ) {
    i--;
    mi_bfield_t cmap = mi_atomic_load_relaxed(&bitmap->chunkmap.bfields[i]);
    size_t cmap_idx;
    if (mi_bsr(cmap,&cmap_idx)) {
      // highest chunk
      const size_t chunk_idx = i*MI_BFIELD_BITS + cmap_idx;
      size_t cidx;
      if (mi_bchunk_bsr(&bitmap->chunks[chunk_idx], &cidx)) {
        *idx = (chunk_idx * MI_BCHUNK_BITS) + cidx;
        return true;
      }
    }
  }
  return false;
}

// Return count of all set bits in a bitmap.
size_t mi_bitmap_popcount(mi_bitmap_t* bitmap) {