add vec_clear

include/lfvector.h

@@ -14,6 +14,8 @@ int vec_init(Vector *vec, void (*destroy)(void *data));
 
 int vec_init_with_capacity(Vector *vec, void (*destroy)(void *data), size_t cap);
 
+void vec_clear(Vector *vec);
+
 void vec_destroy(Vector *vec);
 
 int vec_insert(Vector *vec, void *data, size_t index);

src/vector.c

@@ -34,7 +34,11 @@ int vec_init_with_capacity(Vector *vec, void (*destroy)(void *data), size_t capa
 }
 
 static int vec_grow(Vector *const vec) {
-    vec->capacity *= 2;
+    if (vec->capacity == 0) {
+        vec->capacity = 1;
+    } else {
+        vec->capacity *= 2;
+    }
 
     vec->elements = reallocarray(vec->elements, vec->capacity, sizeof(void *));
 
@@ -44,12 +48,18 @@ static int vec_grow(Vector *const vec) {
     return 0;
 }
 
+void vec_clear(Vector *vec) {
+    vec_destroy(vec);
+    vec_init(vec, vec->destroy);
+}
+
 void vec_destroy(Vector *vec) {
     if (vec->destroy) {
         for (size_t i = 0; i < vec_len(vec); ++i) {
             vec->destroy(vec->elements[i]);
         }
     }
+    free(vec->elements);
 }
 
 int vec_insert(Vector *vec, void *data, size_t index) {

tests/tests.c

@@ -268,6 +268,11 @@ void test_vector() {
     assert(vec_len(v) == vec_cap(v));
     printf("cap after shrink: %zu\n", vec_cap(v));
 
+    vec_clear(v);
+    assert(vec_len(v) == 0);
+    printf("\ncap after clear: %zu\n", vec_cap(v));
+    printf("len after clear: %zu\n", vec_len(v));
+
     vec_destroy(v);
     free(v);
 }