feat!: make all functions have return values

ds.c

@@ -27,33 +27,45 @@ ds_dll_t
   return node;
 }
 
-void
+int
 ds_sll_insert(ds_sll_t *ll, void *data)
 {
+	if (!ll) {
+		return -1;
+	}
+
 	ds_ll_foreach(ds_sll_t, ll) {
 		if (!cur->data) {
 			cur->data = data;
-			return;
+			return 0;
 		} else if (!cur->next) {
 			cur->next = ds_sll_new_node(data);
-			return;
+			return 0;
 		}
 	}
+
+	return -1;
 }
 
-void
+int
 ds_dll_insert(ds_dll_t *ll, void *data)
 {
+	if (!ll) {
+		return -1;
+	}
+
 	ds_ll_foreach(ds_dll_t, ll) {
 		if (!cur->data) {
 			cur->data = data;
-			return;
+			return 0;
 		} else if (!cur->next) {
 			cur->next = ds_dll_new_node(data);
 			cur->next->prev = cur;
-			return;
+			return 0;
 		}
 	}
+
+	return -1;
 }
 
 void
@@ -152,7 +164,7 @@ ds_hmp_t
 	return hmp;
 }
 
-void
+int
 ds_hmp_free(ds_hmp_t **hmp, void kv_callback(_ds_hmp_kv_t *kv))
 {
 	int i;
@@ -160,7 +172,7 @@ ds_hmp_free(ds_hmp_t **hmp, void kv_callback(_ds_hmp_kv_t *kv))
 	ds_sll_t *ll;
 
 	if (!hmp || !*hmp) {
-		return;
+		return -1;
 	}
 
 	for (i = 0; i < (*hmp)->data_len; i++) {
@@ -179,6 +191,8 @@ ds_hmp_free(ds_hmp_t **hmp, void kv_callback(_ds_hmp_kv_t *kv))
 	}
 	free((*hmp)->data);
 	free(*hmp);
+
+	return 0;
 }
 
 int
@@ -194,13 +208,17 @@ _ds_hmp_gen_hash(char *str)
   return hash;
 }
 
-void
+int
 ds_hmp_insert(ds_hmp_t *hmp, char *key, void *data)
 {
 	_ds_hmp_kv_t *kv;
 	ds_sll_t *ll;
 	unsigned hash_pos;
 
+	if (!hmp || !key || !data) {
+		return -1;
+	}
+
 	kv = malloc(sizeof(_ds_hmp_kv_t));
 	kv->key = key;
 	kv->val = data;
@@ -213,6 +231,8 @@ ds_hmp_insert(ds_hmp_t *hmp, char *key, void *data)
 	/* get the ll and put the data into it */
 	ll = hmp->data[hash_pos];
 	ds_sll_insert(ll, kv);
+
+	return 0;
 }
 
 void