在一读一写限制下，无锁环形队列如何实现？

环形一读一写队列中，不需要担心unsigned long溢出问题，因为溢出后自动回归，相减值还会保留。

示例一(注：Max_Count 必须为 2 的指数，即：2, 4, 8, 16...)：

// 队列尺寸#define Max_Count 4096#define Max_Mask 4095 // = Max_Count - 1// 变量void* List[Max_Count];unsigned long Push_Count;unsigned long Pop_Count;// 初始化队列void InitQueue(){ Push_Count = 0; Pop_Count = 0; memset(List, 0, sizeof(List));}// 加入bool Push(void* AData){ if (Push_Count - Pop_Count < Max_Count) { List[Push_Count & Max_Mask] = AData; Push_Count++; return true; } else return false;}// 取出void* Pop(){ // 初始化 void* result = NULL; // 判断是否为空 if (Push_Count != Pop_Count) { result = List[Pop_Count & Max_Mask]; Pop_Count++; } // 返回结果 return result;}

 

示例二(注：Max_Count >= 2)：

// 队列尺寸#define Max_Count 4096#define High_Index 4095 // = Max_Count - 1// 变量void* List[Max_Count];unsigned long Push_Count;unsigned long Push_Index;unsigned long Pop_Count;unsigned long Pop_Index;// 初始化队列void InitQueue(){ Push_Count = 0; Push_Index = 0; Pop_Count = 0; Pop_Index = 0; memset(List, 0, sizeof(List));}// 加入bool Push(void* AData){ if (Push_Count - Pop_Count < Max_Count) { List[Push_Index] = AData; Push_Count++; if (Push_Index == High_Index) Push_Index = 0; else Push_Index++; return true; } else return false;}// 取出void* Pop(){ // 初始化 void* result = NULL; // 判断是否为空 if (Push_Count != Pop_Count) { result = List[Pop_Index]; Pop_Count++; if (Pop_Index == High_Index) Pop_Index = 0; else Pop_Index++; } // 返回结果 return result;}