C函数指针状态机实现
有限状态机（finite state machine）简称FSM，表示有限个状态及在这些状态之间的转移和动作等行为的数学模型，在计算机领域有着广泛的应用。FSM是一种逻辑单元内部的一种高效编程方法，在服务器编程中，服务器可以根据不同状态或者消息类型进行相应的处理逻辑，使得程序逻辑清晰易懂。
#include <stdio.h>//函数指针实现FSMenum year_state{ SPRING = , SUMMER, AUTUMN, WINTER};enum year_event{ EVENT1 = , EVENT2, EVENT3, EVENT4};typedef struct FsmTable_s{ int event; // 事件 int CurState; // 当前状态 void (*eventActFun)(); //函数指针 int nextState; // 下一个状态} FsmTable_t;void spring_thing(){ printf("this is spring\n");}void summer_thing(){ printf("this is summer\n");}void autumn_thing(){ printf("this is autumn\n");}void winter_thing(){ printf("this is winter\n");}FsmTable_t year_table[] ={ //{到来的事件，当前的状态，将要要执行的函数，下一个状态} { EVENT1, SPRING, summer_thing, SUMMER }, { EVENT2, SUMMER, autumn_thing, AUTUMN }, { EVENT3, AUTUMN, winter_thing, WINTER }, { EVENT4, WINTER, spring_thing, SPRING }, //add your codes here};typedef struct FSM_s{ int curState;//当前状态 FsmTable_t * pFsmTable;//状态表 int size;//表的项数} FSM_t;/*状态机注册,给它一个状态表*/void FSM_Regist(FSM_t *pFSM, FsmTable_t *pFsmTable){ pFSM->pFsmTable = pFsmTable;}/*状态迁移*/void FSM_StateTransfer(FSM_t* pFsm, int state){ pFsm->curState = state;}/*事件处理*/void FSM_EventHandle(FSM_t* pFsm, int event){ FsmTable_t* pActTable = pFsm->pFsmTable; void (*eventActFun)() = NULL; //函数指针初始化为空 int NextState; int CurState = pFsm->curState; int g_max_num = pFsm->size; ; //标识是否满足条件 int i; ; i < g_max_num; i++) { if (event == pActTable[i].event && CurState == pActTable[i].CurState) { flag = ; eventActFun = pActTable[i].eventActFun; NextState = pActTable[i].nextState; break; } } if (flag) { if (eventActFun) { eventActFun(); } FSM_StateTransfer(pFsm, NextState); } else { printf("There is no match\n"); }}int main(){ FSM_t year_fsm; FSM_Regist(&year_fsm, year_table); year_fsm.curState = SPRING; year_fsm.size = sizeof(year_table)/sizeof(FsmTable_t); printf("\n-------1--init spring------\n"); printf("state:%d\n",year_fsm.curState); printf("\n-------2--spring->summer------\n"); FSM_EventHandle(&year_fsm,EVENT1); printf("state:%d\n",year_fsm.curState); printf("\n-------3--summer->autumn------\n"); FSM_EventHandle(&year_fsm,EVENT2); printf("state:%d\n",year_fsm.curState); printf("\n-------4--autumn->winter------\n"); FSM_EventHandle(&year_fsm,EVENT3); printf("state:%d\n",year_fsm.curState); printf("\n-------5--winter->spring------\n"); FSM_EventHandle(&year_fsm,EVENT4); printf("state:%d\n",year_fsm.curState); printf("\n-------6--receive EVENT2 not EVENT1------\n"); FSM_EventHandle(&year_fsm,EVENT2); printf("state:%d\n",year_fsm.curState);}
