C语言实现状态机（二）

前言

对于之前的一篇博客《C语言实现状态机》（链接：https://blog.csdn.net/qq_36969264/article/details/105865099?spm=1001.2014.3001.5501），看网友的留言，似乎对pFsm->stNextState 和 EVENT_MAP_END的比较有一些误解。
这里需要解释一下，当时这么写是为了省事，但后面看这么写确实很容易让人误解，所以这篇文章的目的是为了修改掉这个容易让人误解的地方，同时对该状态机做了一些优化。

一、实现状态机的基本函数 1、定义相关结构体

typedef void (*STATE_ACTION)(void);	

typedef struct ACTION_MAP
{
	uint8_t 		stStateID;
	STATE_ACTION 	EnterAct;	
	STATE_ACTION 	RunningAct;	
	STATE_ACTION 	ExitAct;
}ACTION_MAP_t; 

typedef struct EVENT_MAP
{
	uint8_t	stEventID;
	uint8_t stCurState;
	uint8_t stNextState;
}EVENT_MAP_t; 

typedef struct FSM
{
	uint8_t u8Flag; 			
	uint8_t u8EventSum;			
	uint8_t u8ActSum;			
	uint8_t stCurState;
	uint8_t stNextState;
	ACTION_MAP_t *pActionMap;
	EVENT_MAP_t *pEventMap;
}FSM_t;

注：状态机控制结构FSM_t的元素u8Flag用于替代pFsm->stNextState 和 EVENT_MAP_END的比较，以实现相同的功能。

2、状态机初始化函数

初始化函数主要目的是为了将状态机与事件表、动作表关联起来。

void fsm_init(FSM_t* pFsm,EVENT_MAP_t* pEventMap,ACTION_MAP_t *pActionMap,
	uint8_t u8EventSum,uint8_t u8ActSum,uint8_t curState)
{
	pFsm->u8Flag = 0;
	pFsm->stNextState = 0;
	pFsm->u8EventSum = u8EventSum;
	pFsm->u8ActSum = u8ActSum;
	pFsm->stCurState = curState;
	pFsm->pEventMap = pEventMap;
	pFsm->pActionMap = pActionMap;
}

3、状态机转换函数

该函数的主要功能是通过查找事件表，以确定是否要进行状态切换，如果需要进行状态切换，则将标志位u8Flag 置1。

void fsm_state_transfer(FSM_t* pFsm, uint8_t stEventID)
{
	uint8_t i = 0;
	
	for(i=0; iu8EventSum; i++)
	{
		if((stEventID == pFsm->pEventMap[i].stEventID) 
			&& (pFsm->stCurState == pFsm->pEventMap[i].stCurState))
		{
			pFsm->stNextState = pFsm->pEventMap[i].stNextState;
			pFsm->u8Flag = 1;
			
			return;
		}
	}	
}

4、状态机动作执行函数

该函数为此状态机的精髓所在，一般的状态机在状态切换时只执行一次动作，或者周期执行同一动作。
而此状态机则在状态切换时执行当前动作的退出函数（一次），即ExitAct函数，实际应用当中可对该状态的一些变量进行清0，或者打印相关调试信息等；同时还会执行下一个状态的进入函数（一次），即EnterAct函数，实际应用当中可以对该状态的变量进行初始化等操作。在状态切换完成后，还会周期执行RunningAct函数。
这里的ExitAct函数和EnterAct函数类似于C++的构造函数和析构函数。

uint8_t get_action_sum(FSM_t* pFsm,uint8_t u8ID)
{
	int i = 0;
	
	for(i=0; iu8ActSum; i++)
	{
		if(u8ID == pFsm->pActionMap[i].stStateID)
			return i;
	}

	return -1;
}

void action_perfrom(FSM_t* pFsm)
{
	uint8_t u8CurID = -1, u8NextID = -1;
	
	if(0 != pFsm->u8Flag)	
	{
		u8CurID = get_action_sum(pFsm,pFsm->stCurState);
		u8NextID = get_action_sum(pFsm,pFsm->stNextState);
		
		if((-1 != u8CurID) && (-1 != u8NextID))
		{
			pFsm->pActionMap[u8CurID].ExitAct();	
			pFsm->pActionMap[u8NextID].EnterAct(); 
		}
		else
		{
			pFsm->u8Flag = 0;								
			printf("State transition failed! curState = %d, nextState = %dn",pFsm->stCurState,pFsm->stNextState);
			return;
		}
	
		pFsm->stCurState = pFsm->stNextState;			
		pFsm->stNextState = -1;
		pFsm->u8Flag = 0;								
	}
	else
	{
		u8CurID = get_action_sum(pFsm,pFsm->stCurState);
		if(-1 != u8CurID)
			pFsm->pActionMap[u8CurID].RunningAct();
	}	
}

二、如何使用状态机

这里还是使用之前的博客里状态机流程图为例：

1、以流程图为标准定义事件表

数组eventMap就是对以上流程图的全部描述：

#define EVENT1 0
#define EVENT2 1
#define EVENT3 2
#define EVENT4 3
#define EVENT5 4

EVENT_MAP_t eventMap[] = 
{
	{EVENT1,	STATE1,	STATE2},
	{EVENT2,	STATE2,	STATE3},	
	{EVENT3,	STATE3,	STATE4},
	{EVENT4,	STATE4,	STATE1},
	{EVENT5,	STATE1,	STATE4},	
};

2、定义动作表

#define STATE1 0
#define STATE2 1
#define STATE3 2
#define STATE4 3

ACTION_MAP_t actionMap[] = 
{
	{STATE1,	state1_entry,	state1_do,	state1_exit},
	{STATE2,	state2_entry,	state2_do,	state2_exit},
	{STATE3,	state3_entry,	state3_do,	state3_exit},
	{STATE4,	state4_entry,	state4_do,	state4_exit},
};

3、实现动作函数

这里的每个函数的内容可以根据实际情况进行填充。

void state1_entry(void)
{
	printf("state1_entryn");
}
void state1_do(void)
{
	printf("state1_don");
}
void state1_exit(void)
{
	printf("state1_exitn");
}

void state2_entry(void)
{
	printf("state2_entryn");
}
void state2_do(void)
{
	printf("state2_don");
}
void state2_exit(void)
{
	printf("state2_exitn");
}

void state3_entry(void)
{
	printf("state3_entryn");
}
void state3_do(void)
{
	printf("state3_don");
}
void state3_exit(void)
{
	printf("state3_exitn");
}

void state4_entry(void)
{
	printf("state4_entryn");
}
void state4_do(void)
{
	printf("state4_don");
}
void state4_exit(void)
{
	printf("state4_exitn");
}

4、实现表获取函数

ACTION_MAP_t* get_action_map(uint8_t *total)
{
	*total = sizeof(actionMap)/sizeof(ACTION_MAP_t);
	return actionMap;
}


EVENT_MAP_t* get_event_map(uint8_t *total)
{
	*total = sizeof(eventMap)/sizeof(EVENT_MAP_t);
	return eventMap;
}

5、测试

int main(void)
{
	int i = 0;		
	uint8_t u8ActNum = 0, u8EventNum = 0;
	FSM_t stFsm;	
	ACTION_MAP_t* stActMap;
	EVENT_MAP_t* stEventMap;
	
	stActMap = get_action_map(&u8ActNum);
	stEventMap = get_event_map(&u8EventNum);
	
	fsm_init(&stFsm,stEventMap,stActMap,u8EventNum,u8ActNum,STATE1);
	while(1)
	{
		sleep(1);
		printf("i = %dn",i++);
		
		action_perfrom(&stFsm);
		
		
		if(1 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT1);
		}
		
		if(3 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT2);
		}
		
		if(5 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT3);
		}
		
		if(7 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT4);
		}	
		
		if(9 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT5);
		}
	}
	return 0;
}

调试信息如下：

三、附上代码 fsm.c

#include 
#include "fsm.h"

void fsm_init(FSM_t* pFsm,EVENT_MAP_t* pEventMap,ACTION_MAP_t *pActionMap,
	uint8_t u8EventSum,uint8_t u8ActSum,uint8_t curState)
{
	pFsm->u8Flag = 0;
	pFsm->stNextState = 0;
	pFsm->u8EventSum = u8EventSum;
	pFsm->u8ActSum = u8ActSum;
	pFsm->stCurState = curState;
	pFsm->pEventMap = pEventMap;
	pFsm->pActionMap = pActionMap;
}

void fsm_state_transfer(FSM_t* pFsm, uint8_t stEventID)
{
	uint8_t i = 0;
	
	for(i=0; iu8EventSum; i++)
	{
		if((stEventID == pFsm->pEventMap[i].stEventID) 
			&& (pFsm->stCurState == pFsm->pEventMap[i].stCurState))
		{
			pFsm->stNextState = pFsm->pEventMap[i].stNextState;
			pFsm->u8Flag = 1;
			
			return;
		}
	}	
}

uint8_t get_action_sum(FSM_t* pFsm,uint8_t u8ID)
{
	int i = 0;
	
	for(i=0; iu8ActSum; i++)
	{
		if(u8ID == pFsm->pActionMap[i].stStateID)
			return i;
	}

	return -1;
}

void action_perfrom(FSM_t* pFsm)
{
	uint8_t u8CurID = -1, u8NextID = -1;
	
	if(0 != pFsm->u8Flag)	
	{
		u8CurID = get_action_sum(pFsm,pFsm->stCurState);
		u8NextID = get_action_sum(pFsm,pFsm->stNextState);
		
		if((-1 != u8CurID) && (-1 != u8NextID))
		{
			pFsm->pActionMap[u8CurID].ExitAct();	
			pFsm->pActionMap[u8NextID].EnterAct(); 
		}
		else
		{
			pFsm->u8Flag = 0;								
			printf("State transition failed! curState = %d, nextState = %dn",pFsm->stCurState,pFsm->stNextState);
			return;
		}
	
		pFsm->stCurState = pFsm->stNextState;			
		pFsm->stNextState = -1;
		pFsm->u8Flag = 0;								
	}
	else
	{
		u8CurID = get_action_sum(pFsm,pFsm->stCurState);
		if(-1 != u8CurID)
			pFsm->pActionMap[u8CurID].RunningAct();
	}	
}

fsm.h

#ifndef FSM_H
#define FSM_H

#include "common.h"

typedef void (*STATE_ACTION)(void);	

typedef struct ACTION_MAP
{
	uint8_t 		stStateID;
	STATE_ACTION 	EnterAct;	
	STATE_ACTION 	RunningAct;	
	STATE_ACTION 	ExitAct;
}ACTION_MAP_t; 

typedef struct EVENT_MAP
{
	uint8_t	stEventID;
	uint8_t stCurState;
	uint8_t stNextState;
}EVENT_MAP_t; 

typedef struct FSM
{
	uint8_t u8Flag; 			
	uint8_t u8EventSum;			
	uint8_t u8ActSum;			
	uint8_t stCurState;
	uint8_t stNextState;
	ACTION_MAP_t *pActionMap;
	EVENT_MAP_t *pEventMap;
}FSM_t; 


void fsm_init(FSM_t* pFsm,EVENT_MAP_t* pEventMap,ACTION_MAP_t *pActionMap,
	uint8_t u8EventSum,uint8_t u8ActSum,uint8_t curState);
void fsm_state_transfer(FSM_t* pFsm, uint8_t stEventID);
void action_perfrom(FSM_t* pFsm);

#endif

action.c

#include 
#include "action.h"

void state1_entry(void);
void state1_do(void);
void state1_exit(void);
void state2_entry(void);
void state2_do(void);
void state2_exit(void);
void state3_entry(void);
void state3_do(void);
void state3_exit(void);
void state4_entry(void);
void state4_do(void);
void state4_exit(void);


ACTION_MAP_t actionMap[] = 
{
	{STATE1,	state1_entry,	state1_do,	state1_exit},
	{STATE2,	state2_entry,	state2_do,	state2_exit},
	{STATE3,	state3_entry,	state3_do,	state3_exit},
	{STATE4,	state4_entry,	state4_do,	state4_exit},
};
void state1_entry(void)
{
	printf("state1_entryn");
}
void state1_do(void)
{
	printf("state1_don");
}
void state1_exit(void)
{
	printf("state1_exitn");
}

void state2_entry(void)
{
	printf("state2_entryn");
}
void state2_do(void)
{
	printf("state2_don");
}
void state2_exit(void)
{
	printf("state2_exitn");
}

void state3_entry(void)
{
	printf("state3_entryn");
}
void state3_do(void)
{
	printf("state3_don");
}
void state3_exit(void)
{
	printf("state3_exitn");
}

void state4_entry(void)
{
	printf("state4_entryn");
}
void state4_do(void)
{
	printf("state4_don");
}
void state4_exit(void)
{
	printf("state4_exitn");
}

ACTION_MAP_t* get_action_map(uint8_t *total)
{
	*total = sizeof(actionMap)/sizeof(ACTION_MAP_t);
	return actionMap;
}

action.h

#ifndef ACTION_H
#define ACTION_H

#include "common.h"
#include "fsm.h"

#define STATE1 0
#define STATE2 1
#define STATE3 2
#define STATE4 3

ACTION_MAP_t* get_action_map(uint8_t *total);

#endif

event.c

#include "event.h"

EVENT_MAP_t eventMap[] = 
{
	{EVENT1,	STATE1,	STATE2},
	{EVENT2,	STATE2,	STATE3},	
	{EVENT3,	STATE3,	STATE4},
	{EVENT4,	STATE4,	STATE1},
	{EVENT5,	STATE1,	STATE4},	
};

EVENT_MAP_t* get_event_map(uint8_t *total)
{
	*total = sizeof(eventMap)/sizeof(EVENT_MAP_t);
	return eventMap;
}

event.h

#ifndef EVENT_H
#define EVENT_H

#include "fsm.h"
#include "common.h"
#include "action.h"

#define EVENT1 0
#define EVENT2 1
#define EVENT3 2
#define EVENT4 3
#define EVENT5 4

EVENT_MAP_t* get_event_map(uint8_t* total);

#endif

common.h

#ifndef COMMON_H
#define COMMON_H

typedef  unsigned char uint8_t;


#endif

main.c

int main(void)
{
	int i = 0;		
	uint8_t u8ActNum = 0, u8EventNum = 0;
	FSM_t stFsm;	
	ACTION_MAP_t* stActMap;
	EVENT_MAP_t* stEventMap;
	
	stActMap = get_action_map(&u8ActNum);
	stEventMap = get_event_map(&u8EventNum);
	
	fsm_init(&stFsm,stEventMap,stActMap,u8EventNum,u8ActNum,STATE1);
	while(1)
	{
		sleep(1);
		printf("i = %dn",i++);
		
		action_perfrom(&stFsm);
		
		
		if(1 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT1);
		}
		
		if(3 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT2);
		}
		
		if(5 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT3);
		}
		
		if(7 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT4);
		}	
		
		if(9 == (i%10))
		{
			fsm_state_transfer(&stFsm,EVENT5);
		}
	}
	return 0;
}

Makefile

objects = fsm.o action.o event.o

main:*.o
	cc -o $@ $^

*.o:*.c 
	cc -c $^

clean:
	rm *.o -rf
	rm main -rf

C语言实现状态机（二）

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