fix(roaring64): art_find_at would return the wrong leaf

If a leaf shared all but the last byte, art_find_at could return the incorrrect
leaf, rather than returning NULL

Fixes #552

src/art/art.c

@@ -1093,7 +1093,7 @@ static art_val_t *art_find_at(const art_node_t *node,
  depth += inner_node->prefix_size + 1;
  }
  art_leaf_t *leaf = CAST_LEAF(node);
- if (depth >= ART_KEY_BYTES - 1) {
+ if (depth >= ART_KEY_BYTES) {
  return (art_val_t *)leaf;
  }
  uint8_t common_prefix =

tests/roaring64_unit.cpp

@@ -191,6 +191,7 @@ DEFINE_TEST(test_add_range_closed) {
  // Range spans more than two containers.
  roaring64_bitmap_t* r = roaring64_bitmap_create();
  roaring64_bitmap_add_range_closed(r, 100, 300000);
+ assert_int_equal(roaring64_bitmap_get_cardinality(r), 300000 - 100 + 1);
  roaring64_bulk_context_t context{};
  assert_false(roaring64_bitmap_contains_bulk(r, &context, 99));
  for (uint64_t i = 100; i <= 300000; ++i) {
@@ -199,6 +200,15 @@ DEFINE_TEST(test_add_range_closed) {
  assert_false(roaring64_bitmap_contains_bulk(r, &context, 300001));
  roaring64_bitmap_free(r);
  }
+ {
+ // Add a range that spans multiple ART levels (end >> 16 == 0x0101)
+ roaring64_bitmap_t* r = roaring64_bitmap_create();
+ uint64_t end = 0x101ffff;
+ uint64_t start = 0;
+ roaring64_bitmap_add_range_closed(r, start, end);
+ assert_int_equal(roaring64_bitmap_get_cardinality(r), end - start + 1);
+ roaring64_bitmap_free(r);
+ }
 }
 
 DEFINE_TEST(test_contains_bulk) {