Function mi_segment_map_index_of

3rd/mimalloc-2.0.9/src/segment-cache.c:287–300

static _Atomic(uintptr_t) mi_segment_map[MI_SEGMENT_MAP_WSIZE + 1];  // 2KiB per TB with 64MiB segments

static size_t mi_segment_map_index_of(const mi_segment_t* segment, size_t* bitidx) {
  mi_assert_internal(_mi_ptr_segment(segment + 1) == segment); // is it aligned on MI_SEGMENT_SIZE?
  if ((uintptr_t)segment >= MI_MAX_ADDRESS) {
    *bitidx = 0;
    return MI_SEGMENT_MAP_WSIZE;
  }
  else {
    const uintptr_t segindex = ((uintptr_t)segment) / MI_SEGMENT_SIZE;
    *bitidx = segindex % MI_INTPTR_BITS;
    const size_t mapindex = segindex / MI_INTPTR_BITS;
    mi_assert_internal(mapindex < MI_SEGMENT_MAP_WSIZE);
    return mapindex;
  }
}

void _mi_segment_map_allocated_at(const mi_segment_t* segment) {
  size_t bitidx;