96 lines
3.0 KiB
C
96 lines
3.0 KiB
C
#include <c_LinkQueue.h>
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// 原地初始化：无哨兵模式，初始化 head 和 tail 全部指向 0
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c_err_t c_LinkQueue_Init(c_LinkQueue_t* self, c_size_t item_size, c_Allocator_t* allocator) {
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if (!self || item_size == 0) return C_ERR_PARAM;
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self->allocator = (allocator != NULL) ? *allocator : c_DefaultAllocator;
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self->item_size = item_size;
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self->size = 0;
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self->head = NULL;
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self->tail = NULL;
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return C_ERR_OK;
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}
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// 入队操作 (基于二级指针的完美 O(1) 极致分支优化)
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c_err_t c_LinkQueue_Enqueue(c_LinkQueue_t* self, const void* item) {
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if (!self || !item) return C_ERR_PARAM;
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// 1. 分配变长节点空间 (控制壳 + 业务数据一体化)
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c_size_t total_bytes = sizeof(c_LinkQueueNode_t) + self->item_size;
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c_LinkQueueNode_t* new_node = (c_LinkQueueNode_t*)c_Allocator_Alloc(&self->allocator, total_bytes);
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if (!new_node) return C_ERR_NOMEM;
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new_node->next = NULL;
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memcpy(QUEUE_NODE_DATA(new_node), item, self->item_size); // 泛型值深度复制
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// 2. 【二级指针艺术】：消灭空队列插入的分支
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// 如果队列为空，新节点应该挂在 head 上；如果不为空，新节点应该挂在 tail->next 上
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c_LinkQueueNode_t** pp = (self->head == NULL) ? &(self->head) : &(self->tail->next);
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// 一行代码，完美完成旧拓扑到新节点的挂接
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*pp = new_node;
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// 3. 将尾指针直接移到最新插入的节点上，自愈性推进
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self->tail = new_node;
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self->size++;
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return C_ERR_OK;
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}
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// 出队操作 (O(1) 性能，完美防御下溢)
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c_err_t c_LinkQueue_Dequeue(c_LinkQueue_t* self, void* out_item) {
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if (!self || self->size == 0 || !self->head) return C_ERR_OUTOFBOUND;
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// 锁定队头即将被剔除解体的物理节点
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c_LinkQueueNode_t* node_to_free = self->head;
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// 如果用户需要拷出快照副本，执行深度拷贝
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if (out_item) {
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memcpy(out_item, QUEUE_NODE_DATA(node_to_free), self->item_size);
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}
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// 队头指针向后大步滑进一格
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self->head = node_to_free->next;
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// 边界特殊维护：如果出队后队列彻底被掏空了，尾指针 tail 必须安全地缩回 NULL
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if (self->head == NULL) {
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self->tail = NULL;
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}
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// 闭环退还包装内存壳
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c_Allocator_Free(&self->allocator, node_to_free);
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self->size--;
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return C_ERR_OK;
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}
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// 查看队头元素 (只读原位窥探，零拷贝损耗)
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void* c_LinkQueue_Peek(const c_LinkQueue_t* self) {
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if (!self || self->size == 0 || !self->head) return NULL;
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return QUEUE_NODE_DATA(self->head);
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}
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// 高效清空队列
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void c_LinkQueue_Clear(c_LinkQueue_t* self) {
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if (!self) return;
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c_LinkQueueNode_t* curr = self->head;
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while (curr) {
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c_LinkQueueNode_t* next_to_free = curr->next;
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c_Allocator_Free(&self->allocator, curr);
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curr = next_to_free;
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}
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self->head = NULL;
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self->tail = NULL;
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self->size = 0;
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}
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// 彻底销毁
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void c_LinkQueue_Destroy(c_LinkQueue_t* self) {
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if (!self) return;
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c_LinkQueue_Clear(self);
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}
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