From d93eef112a5b5f004f2af168a7e34a19744a8456 Mon Sep 17 00:00:00 2001
From: Francesco <inbox@francescorocca.me>
Date: Tue, 2 Dec 2025 02:07:46 +0100
Subject: [PATCH] feat(hashmap): add hm_foreach and hm_clear

---
 hashmap/myhashmap.c | 257 +++++++++++++++++++++++++++++---------------
 1 file changed, 171 insertions(+), 86 deletions(-)

diff --git a/hashmap/myhashmap.c b/hashmap/myhashmap.c
index d407c9a..520bed1 100644
--- a/hashmap/myhashmap.c
+++ b/hashmap/myhashmap.c
@@ -13,7 +13,7 @@ static size_t get_mutex(hashmap_s *hashmap, size_t hash) {
 
 static size_t get_bucket_index(hashmap_s *hashmap, void *key) {
 	unsigned int hash = hashmap->hash(key);
-	return hash % MYCLIB_HASHMAP_SIZE;
+	return (size_t)(hash % MYCLIB_HASHMAP_SIZE);
 }
 
 static void free_bucket_content(hashmap_s *hashmap, bucket_s *bucket) {
@@ -21,29 +21,38 @@ static void free_bucket_content(hashmap_s *hashmap, bucket_s *bucket) {
 		return;
 	}
 
-	/* Free key if free function is provided */
-	if (hashmap->free_key != NULL && bucket->key != NULL) {
-		hashmap->free_key(bucket->key);
+	/* Free key if free function is provided, otherwise free raw pointer if allocated */
+	if (bucket->key != NULL) {
+		if (hashmap->free_key != NULL) {
+			hashmap->free_key(bucket->key);
+		} else {
+			free(bucket->key);
+		}
+		bucket->key = NULL;
 	}
 
-	/* Free value if free function is provided */
-	if (hashmap->free_value != NULL && bucket->value != NULL) {
-		hashmap->free_value(bucket->value);
+	/* Free value if free function is provided, otherwise free raw pointer if allocated */
+	if (bucket->value != NULL) {
+		if (hashmap->free_value != NULL) {
+			hashmap->free_value(bucket->value);
+		} else {
+			free(bucket->value);
+		}
+		bucket->value = NULL;
 	}
 }
 
 static bucket_s *find_bucket(hashmap_s *hashmap, void *key, bucket_s **prev) {
 	size_t index = get_bucket_index(hashmap, key);
 	bucket_s *bucket = &hashmap->map[index];
-
 	*prev = NULL;
 
-	/* Return NULL if first bucket is empty */
+	/* If primary bucket has no key, nothing stored here */
 	if (bucket->key == NULL) {
 		return NULL;
 	}
 
-	/* Search through the collision chain */
+	/* Search through chain */
 	while (bucket != NULL) {
 		if (hashmap->equal(bucket->key, key)) {
 			return bucket;
@@ -57,11 +66,17 @@ static bucket_s *find_bucket(hashmap_s *hashmap, void *key, bucket_s **prev) {
 
 hashmap_s *hm_new(hash_f *hash_fn, equal_f *equal_fn, free_key_f *free_key_fn,
 				  free_value_f *free_value_fn, size_t key_size, size_t value_size) {
+	if (hash_fn == NULL || equal_fn == NULL || key_size == 0 || value_size == 0) {
+		return NULL;
+	}
+
 	hashmap_s *hashmap = malloc(sizeof(hashmap_s));
 	if (hashmap == NULL) {
 		return NULL;
 	}
 
+	memset(hashmap, 0, sizeof *hashmap);
+
 	hashmap->hash = hash_fn;
 	hashmap->equal = equal_fn;
 	hashmap->free_key = free_key_fn;
@@ -75,7 +90,6 @@ hashmap_s *hm_new(hash_f *hash_fn, equal_f *equal_fn, free_key_f *free_key_fn,
 	hashmap->locks = malloc(sizeof(mtx_t) * hashmap->num_locks);
 	if (hashmap->locks == NULL) {
 		free(hashmap);
-
 		return NULL;
 	}
 
@@ -83,16 +97,18 @@ hashmap_s *hm_new(hash_f *hash_fn, equal_f *equal_fn, free_key_f *free_key_fn,
 	for (size_t i = 0; i < hashmap->num_locks; ++i) {
 		ret = mtx_init(&(hashmap->locks[i]), mtx_recursive);
 		if (ret != thrd_success) {
-			/* Mutex failed */
+			/* Mutex failed: cleanup previous inits and return NULL */
 			for (size_t j = 0; j < i; ++j) {
 				mtx_destroy(&(hashmap->locks[j]));
 			}
 
 			free(hashmap->locks);
 			free(hashmap);
+			return NULL;
 		}
 	}
 
+	/* Initialize buckets to zero */
 	memset(hashmap->map, 0, sizeof(hashmap->map));
 
 	return hashmap;
@@ -107,8 +123,7 @@ void hm_free(hashmap_s *hashmap) {
 	for (size_t i = 0; i < MYCLIB_HASHMAP_SIZE; ++i) {
 		bucket_s *bucket = &hashmap->map[i];
 
-		/* Free the first bucket if it contains data */
-		if (bucket->key != NULL) {
+		if (bucket->key != NULL || bucket->value != NULL) {
 			free_bucket_content(hashmap, bucket);
 		}
 
@@ -116,19 +131,31 @@ void hm_free(hashmap_s *hashmap) {
 		bucket = bucket->next;
 		while (bucket != NULL) {
 			bucket_s *next = bucket->next;
-			free_bucket_content(hashmap, bucket);
+			if (bucket->key != NULL || bucket->value != NULL) {
+				if (hashmap->free_key != NULL && bucket->key != NULL) {
+					hashmap->free_key(bucket->key);
+				} else if (bucket->key != NULL) {
+					free(bucket->key);
+				}
+
+				if (hashmap->free_value != NULL && bucket->value != NULL) {
+					hashmap->free_value(bucket->value);
+				} else if (bucket->value != NULL) {
+					free(bucket->value);
+				}
+			}
 			free(bucket);
 			bucket = next;
 		}
 	}
 
-	/* Free the mutex */
+	/* Free the mutexes */
 	for (size_t i = 0; i < hashmap->num_locks; ++i) {
 		mtx_destroy(&(hashmap->locks[i]));
 	}
 	free(hashmap->locks);
 
-	/* Free the hash map structure itself */
+	/* Free the hash map structure */
 	free(hashmap);
 }
 
@@ -147,35 +174,31 @@ bool hm_set(hashmap_s *hashmap, void *key, void *value) {
 		return false;
 	}
 
-	size_t mutex_id = get_mutex(hashmap, hashmap->hash(key));
+	size_t mutex_id = get_mutex(hashmap, (size_t)hashmap->hash(key));
 	mtx_t *mutex = &(hashmap->locks[mutex_id]);
 	if (mtx_lock(mutex) != thrd_success) {
 		return false;
 	}
 
-	bucket_s *prev;
+	bucket_s *prev = NULL;
 	bucket_s *existing = find_bucket(hashmap, key, &prev);
 
 	if (existing != NULL) {
-		/* Key exists, update value */
 		if (hashmap->free_value != NULL && existing->value != NULL) {
 			hashmap->free_value(existing->value);
+		} else if (existing->value != NULL) {
+			free(existing->value);
 		}
 
 		existing->value = malloc(hashmap->value_size);
 		if (existing->value == NULL) {
 			mtx_unlock(mutex);
-
 			return false;
 		}
 
 		memcpy(existing->value, value, hashmap->value_size);
 
-		/* Increase size */
-		hashmap->size++;
-
 		mtx_unlock(mutex);
-
 		return true;
 	}
 
@@ -188,7 +211,6 @@ bool hm_set(hashmap_s *hashmap, void *key, void *value) {
 		bucket->key = malloc(hashmap->key_size);
 		if (bucket->key == NULL) {
 			mtx_unlock(mutex);
-
 			return false;
 		}
 
@@ -197,32 +219,32 @@ bool hm_set(hashmap_s *hashmap, void *key, void *value) {
 			free(bucket->key);
 			bucket->key = NULL;
 			mtx_unlock(mutex);
-
 			return false;
 		}
 
-		hashmap->size++;
 		memcpy(bucket->key, key, hashmap->key_size);
 		memcpy(bucket->value, value, hashmap->value_size);
 		bucket->next = NULL;
-		mtx_unlock(mutex);
 
+		hashmap->size++;
+		mtx_unlock(mutex);
 		return true;
 	}
 
-	/* Create new bucket and insert at head of collision chain */
+	/* Collision: create new bucket and insert at head (after primary) */
 	bucket_s *new_bucket = malloc(sizeof(bucket_s));
 	if (new_bucket == NULL) {
 		mtx_unlock(mutex);
-
 		return false;
 	}
+	new_bucket->key = NULL;
+	new_bucket->value = NULL;
+	new_bucket->next = NULL;
 
 	new_bucket->key = malloc(hashmap->key_size);
 	if (new_bucket->key == NULL) {
 		free(new_bucket);
 		mtx_unlock(mutex);
-
 		return false;
 	}
 
@@ -231,44 +253,54 @@ bool hm_set(hashmap_s *hashmap, void *key, void *value) {
 		free(new_bucket->key);
 		free(new_bucket);
 		mtx_unlock(mutex);
-
 		return false;
 	}
 
-	hashmap->size++;
 	memcpy(new_bucket->key, key, hashmap->key_size);
 	memcpy(new_bucket->value, value, hashmap->value_size);
+
+	/* Insert new_bucket at head of chain */
 	new_bucket->next = bucket->next;
 	bucket->next = new_bucket;
 
+	hashmap->size++;
 	mtx_unlock(mutex);
-
 	return true;
 }
 
 static bucket_s *get_bucket_copy(bucket_s *from, size_t key_size, size_t value_size) {
+	if (from == NULL) {
+		return NULL;
+	}
+
 	bucket_s *copy = malloc(sizeof(bucket_s));
 	if (copy == NULL) {
 		return NULL;
 	}
-	memcpy(copy, from, sizeof(bucket_s));
+	copy->key = NULL;
+	copy->value = NULL;
+	copy->next = NULL;
 
-	copy->key = malloc(key_size);
-	if (copy->key == NULL) {
-		free(copy);
-
-		return NULL;
+	if (from->key != NULL) {
+		copy->key = malloc(key_size);
+		if (copy->key == NULL) {
+			free(copy);
+			return NULL;
+		}
+		memcpy(copy->key, from->key, key_size);
 	}
-	memcpy(copy->key, from->key, key_size);
 
-	copy->value = malloc(value_size);
-	if (copy->value == NULL) {
-		free(copy->key);
-		free(copy);
-
-		return NULL;
+	if (from->value != NULL) {
+		copy->value = malloc(value_size);
+		if (copy->value == NULL) {
+			free(copy->key);
+			free(copy);
+			return NULL;
+		}
+		memcpy(copy->value, from->value, value_size);
 	}
-	memcpy(copy->value, from->value, value_size);
+
+	copy->next = NULL;
 
 	return copy;
 }
@@ -278,25 +310,22 @@ bucket_s *hm_get(hashmap_s *hashmap, void *key) {
 		return NULL;
 	}
 
-	size_t mutex_id = get_mutex(hashmap, hashmap->hash(key));
+	size_t mutex_id = get_mutex(hashmap, (size_t)hashmap->hash(key));
 	mtx_t *mutex = &(hashmap->locks[mutex_id]);
 	if (mtx_lock(mutex) != thrd_success) {
 		return NULL;
 	}
 
-	bucket_s *prev;
+	bucket_s *prev = NULL;
 	bucket_s *found = find_bucket(hashmap, key, &prev);
 
 	if (found) {
 		bucket_s *copy = get_bucket_copy(found, hashmap->key_size, hashmap->value_size);
-
 		mtx_unlock(mutex);
-
 		return copy;
 	}
 
 	mtx_unlock(mutex);
-
 	return NULL;
 }
 
@@ -305,50 +334,47 @@ bool hm_remove(hashmap_s *hashmap, void *key) {
 		return false;
 	}
 
-	size_t mutex_id = get_mutex(hashmap, hashmap->hash(key));
+	size_t mutex_id = get_mutex(hashmap, (size_t)hashmap->hash(key));
 	mtx_t *mutex = &(hashmap->locks[mutex_id]);
 	if (mtx_lock(mutex) != thrd_success) {
 		return false;
 	}
 
-	bucket_s *prev;
+	bucket_s *prev = NULL;
 	bucket_s *to_remove = find_bucket(hashmap, key, &prev);
 
 	if (to_remove == NULL) {
 		mtx_unlock(mutex);
-
 		return false;
 	}
 
-	/* Free the content of the bucket */
-	free_bucket_content(hashmap, to_remove);
-
-	/* Handle removal based on position in chain */
 	if (prev == NULL) {
-		/* Removing first bucket in chain */
 		if (to_remove->next != NULL) {
-			/* Move next bucket's content to first bucket and free the next bucket */
 			bucket_s *next_bucket = to_remove->next;
+
+			free_bucket_content(hashmap, to_remove);
+
 			to_remove->key = next_bucket->key;
 			to_remove->value = next_bucket->value;
 			to_remove->next = next_bucket->next;
+
 			free(next_bucket);
 		} else {
-			/* No next bucket, mark first bucket as empty */
-			to_remove->key = NULL;
-			to_remove->value = NULL;
+			free_bucket_content(hashmap, to_remove);
 			to_remove->next = NULL;
 		}
 	} else {
-		/* Removing bucket from middle/end of chain */
+		free_bucket_content(hashmap, to_remove);
+
 		prev->next = to_remove->next;
 		free(to_remove);
 	}
 
-	hashmap->size--;
+	if (hashmap->size > 0) {
+		hashmap->size--;
+	}
 
 	mtx_unlock(mutex);
-
 	return true;
 }
 
@@ -357,7 +383,7 @@ size_t hm_size(hashmap_s *hashmap) {
 		return 0;
 	}
 
-	/* Use the first mutex */
+	/* Use the first mutex to protect read of size */
 	mtx_t *mutex = &hashmap->locks[0];
 	if (mtx_lock(mutex) != thrd_success) {
 		return 0;
@@ -375,23 +401,14 @@ bool hm_contains(hashmap_s *hashmap, void *key) {
 		return false;
 	}
 
-	bool res = true;
+	bool res = false;
 
-	size_t mutex_id = get_mutex(hashmap, hashmap->hash(key));
-	mtx_t *mutex = &hashmap->locks[mutex_id];
-	if (mtx_lock(mutex) != thrd_success) {
-		return false;
+	bucket_s *b = hm_get(hashmap, key);
+	if (b != NULL) {
+		res = true;
+		hm_free_bucket(b);
 	}
 
-	bucket_s *bucket = hm_get(hashmap, key);
-	if (bucket == NULL) {
-		res = false;
-	} else {
-		hm_free_bucket(bucket);
-	}
-
-	mtx_unlock(mutex);
-
 	return res;
 }
 
@@ -400,7 +417,34 @@ void hm_foreach(hashmap_s *hashmap, void (*callback)(bucket_s *bucket)) {
 		return;
 	}
 
-	// TODO
+	for (size_t i = 0; i < MYCLIB_HASHMAP_SIZE; ++i) {
+		size_t mutex_id = get_mutex(hashmap, i);
+		mtx_t *mutex = &hashmap->locks[mutex_id];
+		if (mtx_lock(mutex) != thrd_success) {
+			continue;
+		}
+
+		bucket_s *bucket = &hashmap->map[i];
+		if (bucket->key != NULL) {
+			bucket_s *copy = get_bucket_copy(bucket, hashmap->key_size, hashmap->value_size);
+			if (copy != NULL) {
+				callback(copy);
+				hm_free_bucket(copy);
+			}
+		}
+
+		bucket = bucket->next;
+		while (bucket != NULL) {
+			bucket_s *copy = get_bucket_copy(bucket, hashmap->key_size, hashmap->value_size);
+			if (copy != NULL) {
+				callback(copy);
+				hm_free_bucket(copy);
+			}
+			bucket = bucket->next;
+		}
+
+		mtx_unlock(mutex);
+	}
 }
 
 void hm_clear(hashmap_s *hashmap) {
@@ -408,5 +452,46 @@ void hm_clear(hashmap_s *hashmap) {
 		return;
 	}
 
-	// TODO
+	for (size_t i = 0; i < MYCLIB_HASHMAP_SIZE; ++i) {
+		size_t mutex_id = get_mutex(hashmap, i);
+		mtx_t *mutex = &hashmap->locks[mutex_id];
+		if (mtx_lock(mutex) != thrd_success) {
+			continue;
+		}
+
+		bucket_s *bucket = &hashmap->map[i];
+
+		if (bucket->key != NULL || bucket->value != NULL) {
+			free_bucket_content(hashmap, bucket);
+		}
+
+		bucket = bucket->next;
+		while (bucket != NULL) {
+			bucket_s *next = bucket->next;
+			if (bucket->key != NULL) {
+				if (hashmap->free_key != NULL) {
+					hashmap->free_key(bucket->key);
+				} else {
+					free(bucket->key);
+				}
+			}
+			if (bucket->value != NULL) {
+				if (hashmap->free_value != NULL) {
+					hashmap->free_value(bucket->value);
+				} else {
+					free(bucket->value);
+				}
+			}
+			free(bucket);
+			bucket = next;
+		}
+
+		hashmap->map[i].key = NULL;
+		hashmap->map[i].value = NULL;
+		hashmap->map[i].next = NULL;
+
+		mtx_unlock(mutex);
+	}
+
+	hashmap->size = 0;
 }