1 files changed, 25 insertions, 9 deletions

diff --git a/core/oa_hash_map.h b/core/oa_hash_map.h
index 83621bec14..5ea6d8b0d4 100644
--- a/core/oa_hash_map.h
+++ b/core/oa_hash_map.h
@@ -78,8 +78,7 @@ private:
 		p_hash = p_hash & ~DELETED_HASH_BIT; // we don't care if it was deleted or not
 
 		uint32_t original_pos = p_hash % capacity;
-
-		return p_pos - original_pos;
+		return (p_pos - original_pos) % capacity;
 	}
 
 	_FORCE_INLINE_ void _construct(uint32_t p_pos, uint32_t p_hash, const TKey &p_key, const TValue &p_value) {
@@ -152,17 +151,16 @@ private:
 		}
 	}
 
-	void _resize_and_rehash() {
+	void _resize_and_rehash(uint32_t p_new_capacity) {
+
+		uint32_t old_capacity = capacity;
+		capacity = p_new_capacity;
 
 		TKey *old_keys = keys;
 		TValue *old_values = values;
 		uint32_t *old_hashes = hashes;
 
-		uint32_t old_capacity = capacity;
-
-		capacity = old_capacity * 2;
 		num_elements = 0;
-
 		keys = memnew_arr(TKey, capacity);
 		values = memnew_arr(TValue, capacity);
 		hashes = memnew_arr(uint32_t, capacity);
@@ -187,6 +185,10 @@ private:
 		memdelete_arr(old_hashes);
 	}
 
+	void _resize_and_rehash() {
+		_resize_and_rehash(capacity * 2);
+	}
+
 public:
 	_FORCE_INLINE_ uint32_t get_capacity() const { return capacity; }
 	_FORCE_INLINE_ uint32_t get_num_elements() const { return num_elements; }
@@ -199,11 +201,15 @@ public:
 
 		for (uint32_t i = 0; i < capacity; i++) {
 
+			if (hashes[i] == EMPTY_HASH) {
+				continue;
+			}
+
 			if (hashes[i] & DELETED_HASH_BIT) {
 				continue;
 			}
 
-			hashes[i] |= DELETED_HASH_BIT;
+			hashes[i] = EMPTY_HASH;
 			values[i].~TValue();
 			keys[i].~TKey();
 		}
@@ -272,6 +278,16 @@ public:
 		num_elements--;
 	}
 
+	/**
+	 * reserves space for a number of elements, useful to avoid many resizes and rehashes
+	 *  if adding a known (possibly large) number of elements at once, must be larger than old
+	 *  capacity.
+	 **/
+	void reserve(uint32_t p_new_capacity) {
+		ERR_FAIL_COND(p_new_capacity < capacity);
+		_resize_and_rehash(p_new_capacity);
+	}
+
 	struct Iterator {
 		bool valid;
 
@@ -336,7 +352,7 @@ public:
 		hashes = memnew_arr(uint32_t, p_initial_capacity);
 
 		for (uint32_t i = 0; i < p_initial_capacity; i++) {
-			hashes[i] = 0;
+			hashes[i] = EMPTY_HASH;
 		}
 	}