From 184e7d8514d38aa8a63fd9624809b1ff1a9e1b8b Mon Sep 17 00:00:00 2001
From: Vftdan <vftdan@gmail.com>
Date: Mon, 19 Aug 2024 21:19:04 +0200
Subject: [PATCH] Hashtable entry deletion method

---
 hash_table.c | 33 +++++++++++++++++++++++++++++++++
 hash_table.h |  9 +++++++++
 2 files changed, 42 insertions(+)

diff --git a/hash_table.c b/hash_table.c
index 471f2fc..849fca5 100644
--- a/hash_table.c
+++ b/hash_table.c
@@ -325,3 +325,36 @@ hash_table_find_impl(const HashTableDynamicData * ht, const HashTableKey key)
 
 	return -1;
 }
+
+bool
+hash_table_delete_at_index_impl(HashTableDynamicData * ht, const HashTableIndex index)
+{
+	if (!ht) {
+		return false;
+	}
+
+	if (index < 0 || (size_t) index > ht->capacity) {
+		return false;
+	}
+
+	HashTableKeyEntry *key_entry_ptr = ht->key_array + index;
+	void *value_ptr = ht->value_array + (ht->value_size * index);
+
+	if (!key_entry_ptr->key.bytes) {
+		// No entry at index
+		return false;
+	}
+
+	// TODO find base_index and reduce its max_collision_offset when provably justified
+
+	hash_table_key_deinit_copied(&key_entry_ptr->key);
+	ht->length -= 1;
+
+	void (*value_deinit)(void*) = ht->value_deinit;
+	if (value_deinit) {
+		value_deinit(value_ptr);
+	}
+	memset(value_ptr, 0, ht->value_size);
+
+	return true;
+}
diff --git a/hash_table.h b/hash_table.h
index dc29193..69a8af4 100644
--- a/hash_table.h
+++ b/hash_table.h
@@ -53,10 +53,19 @@ void hash_table_init_impl(HashTableDynamicData * dyndata, size_t value_size, voi
 void hash_table_deinit_impl(HashTableDynamicData * dyndata);
 HashTableIndex hash_table_insert_impl(HashTableDynamicData * dyndata, const HashTableKey key, const void * value_ptr);
 HashTableIndex hash_table_find_impl(const HashTableDynamicData * dyndata, const HashTableKey key);
+bool hash_table_delete_at_index_impl(HashTableDynamicData * dyndata, const HashTableIndex index);
+
+__attribute__((unused)) inline static bool
+hash_table_delete_by_key_impl(HashTableDynamicData * dyndata, const HashTableKey key)
+{
+	return hash_table_delete_at_index_impl(dyndata, hash_table_find_impl(dyndata, key));
+}
 
 #define hash_table_init(ht, value_deinit) hash_table_init_impl(&(ht)->as_HashTableDynamicData, sizeof(*(ht)->value_array), IMPLICIT_CAST(void(void*), void(typeof((ht)->value_array)), value_deinit))
 #define hash_table_deinit(ht) hash_table_deinit_impl(&(ht)->as_HashTableDynamicData)
 #define hash_table_insert(ht, key, value_ptr) hash_table_insert_impl(&(ht)->as_HashTableDynamicData, key, IMPLICIT_CAST(const void, const typeof(*(ht)->value_array), value_ptr))
 #define hash_table_find(ht, key) hash_table_find_impl(&(ht)->as_HashTableDynamicData, key)
+#define hash_table_delete_at_index(ht, index) hash_table_delete_at_index_impl(&(ht)->as_HashTableDynamicData, index)
+#define hash_table_delete_by_key(ht, key) hash_table_delete_by_key_impl(&(ht)->as_HashTableDynamicData, key)
 
 #endif /* end of include guard: HASH_TABLE_H_ */