测试用例

Foundation/c_ArrayList.c

@@ -4,7 +4,8 @@
 /* ------------------------------------------------------------------------------------------------------------------ */
 /*  */
 
-#define DEFAULT_INITIAL_CAPACITY 4
+#define DEFAULT_INITIAL_CAPACITY    4
+#define MIN_SHRINK_CAPACITY         4
 
 /* ------------------------------------------------------------------------------------------------------------------ */
 /*  */
@@ -13,14 +14,17 @@ c_err_t c_ArrayList_Init(c_ArrayList_t* self, c_size_t obj_size, c_size_t capaci
     if (!self || obj_size == 0) return C_ERR_PARAM;
 
     self->obj_size = (int)obj_size;
-    self->capacity = (capacity > 0) ? capacity : DEFAULT_INITIAL_CAPACITY;
     self->size = 0;
+    self->capacity = capacity;
 
-    // 分配連續記憶體空間：容量 * 單個物件大小
-    self->array = C_ALLOC(self->capacity * self->obj_size);
-    if (!self->array) {
-        self->capacity = 0;
-        return C_ERR_NOMEM;
+    if (capacity==0) {
+        self->array = NULL;
+    }else {
+        self->array = C_ALLOC(self->capacity * self->obj_size);
+        if (!self->array) {
+            self->capacity = 0;
+            return C_ERR_NOMEM;
+        }
     }
 
     return C_ERR_OK;
@@ -35,11 +39,11 @@ void c_ArrayList_Destroy(c_ArrayList_t* self) {
 }
 
 c_err_t c_ArrayList_Add(c_ArrayList_t* self, void* obj) {
-    if (!self || !self->array || !obj) return C_ERR_PARAM;
+    if (!self || !obj) return C_ERR_PARAM;
 
     // 動態擴容邏輯
     if (self->size >= self->capacity) {
-        const c_size_t new_capacity = self->capacity<<1;
+        const c_size_t new_capacity = (self->capacity==0)?DEFAULT_INITIAL_CAPACITY:(self->capacity<<1);
         void* new_array = C_REALLOC(self->array, new_capacity * self->obj_size);
         if (!new_array) {
             return C_ERR_NOMEM;
@@ -79,6 +83,19 @@ c_err_t c_ArrayList_Remove(c_ArrayList_t* self, c_size_t index) {
     }
 
     self->size--;
+
+    // 策略：当实际大小少于等于容量的 1/4，且缩容后的容量不低于设定的最小阈值时触发
+    if (self->size > 0 && self->size <= (self->capacity >> 2)) {
+        c_size_t new_capacity = self->capacity >> 1; // 容量减半
+        void* new_array = C_REALLOC(self->array, new_capacity * self->obj_size);
+        if (new_array) { // 如果 realloc 失败不影响原有数据安全，这里采用安全赋值
+            self->array = new_array;
+            self->capacity = new_capacity;
+        }
+    }
+
+
     return C_ERR_OK;
 }
 
+