Function mi_arena_memid_create

3rd/mimalloc-2.0.9/src/arena.c:114–118

#define MI_MEMID_OS   0

static size_t mi_arena_memid_create(mi_arena_id_t id, bool exclusive, mi_bitmap_index_t bitmap_index) {
  mi_assert_internal(((bitmap_index << 8) >> 8) == bitmap_index); // no overflow?
  mi_assert_internal(id >= 0 && id <= 0x7F);
  return ((bitmap_index << 8) | ((uint8_t)id & 0x7F) | (exclusive ? 0x80 : 0));
}

static bool mi_arena_memid_indices(size_t arena_memid, size_t* arena_index, mi_bitmap_index_t* bitmap_index) {
  *bitmap_index = (arena_memid >> 8);