设计模式的C语言应用---编码实践(状态机模式2)

#include "stdafx.h"

/*
https://bbs.huaweicloud.com/blogs/111099
基于state_mode_simple1
网址上的 示例2:
	有一个灯，按下开按钮，就会开灯，按下关按钮就会关灯。
	和一般等不同的是，两次开之间的灯的明暗不一样。
	也就是说，第一次开的时候，是高亮，关灯后，再开是低亮，下次再开是高亮，循环往复。
    这就是一个很典型的简单的有限状态机。
    简单的描述有3个状态，关灯[STATE_OFF]，
    高亮[STATE_HIGH_LIGHT]，低亮[STATE_LOW_LIGHT]。
大型一点的项目，比如复杂协议的实现，
一个状态转移到下一个状态的情况是比较复杂的，
无法用当前状态和事件简单确定，所以一般需要函数。
*/

#define STATE_DEPEND 4
#define STATE_OFF        0
#define STATE_HIGH_LIGHT 1
#define STATE_LOW_LIGHT  2
#define STATE_MAX        3
#define EVENT_BTN_OFF    0
#define EVENT_BTN_ON     1
#define EVENT_MAX        2

int last_state = STATE_LOW_LIGHT;
int last_light_state = STATE_LOW_LIGHT;
int lfsm_ignore(int cur_stat, int event);
int lfsm_btn_on(int cur_stat, int event);
int lfsm_btn_off(int cur_stat, int event);

struct {

	int(*func) (int cur_stat, int event);

	int next_state;

} light_fsm[STATE_MAX][EVENT_MAX] = 
{
	//STATE_OFF
	{
		{ lfsm_ignore, STATE_MAX }, /*EVETN_BTN_OFF*/
		{ lfsm_btn_on, STATE_DEPEND }, /*EVETN_BTN_ON*/
	},

	//STATE_HIGH_LIGHT
	{
		{ lfsm_btn_off, STATE_OFF }, /*EVETN_BTN_OFF*/
		{ lfsm_ignore, STATE_MAX }, /*EVETN_BTN_ON*/
	},

	//STATE_LOW_LIGHT
	{
		{ lfsm_btn_off, STATE_OFF }, /*EVETN_BTN_OFF*/
		{ lfsm_ignore, STATE_MAX }, /*EVETN_BTN_ON*/
	},

};

int lfsm_ignore(int cur_stat, int event)
{
	printf("invalid state or event\n");
	return 0;
}

int lfsm_btn_on(int cur_stat, int event)
{
	if (last_light_state == STATE_HIGH_LIGHT)
	{
		return STATE_LOW_LIGHT;
	}
	else if (last_light_state == STATE_LOW_LIGHT)
	{
		return STATE_HIGH_LIGHT;
	}
	else
	{
		printf("invalid state.\n");
		return STATE_MAX;
	}
}


int lfsm_btn_off(int cur_stat, int event)
{
	//last_light_state = cur_stat;
	return 0;
}

int light_change_state(int cur_stat, int next_state, int event)
{
		//if light on has special handling
	if (next_state == STATE_HIGH_LIGHT)
	{
		last_light_state = next_state;
		printf("rejoice,now bright light-high\n");
	}
	else if (next_state == STATE_LOW_LIGHT)
	{
		last_light_state = next_state;
		printf("rejoice,now bright light-low\n");
	}

	//other state change related handlings, maybe use curent state and next 
	//next state,or event type
	last_state = cur_stat;
	cur_stat = next_state;
	return 0;
}

int light_event_happen(int event)
{
	//if light on has special handling
	if (event == EVENT_BTN_OFF)
	{
		printf("someone turn off light\n");
	}
	//other event type related handlings
	return 0;
}

int simple2_light_fsm_event(int cur_stat, int event)
{
	int next_state, next_state_tmp;
	next_state_tmp = light_fsm[cur_stat][event].func(cur_stat, event);
	if (next_state_tmp == STATE_MAX)
	{
		printf("fsm error\n");
		return -1;
	}

	if (light_fsm[cur_stat][event].next_state == STATE_DEPEND)
	{
		next_state = next_state_tmp;
	}
	else
	{
		next_state = light_fsm[cur_stat][event].next_state;
	}

	light_change_state(cur_stat, next_state, event);
	light_event_happen(event);
	return 0;
}

int main()
{
	int light_state = STATE_OFF;

	printf("light_state=STATE_OFF, event=EVENT_BTN_OFF.\n");
	simple2_light_fsm_event(light_state, EVENT_BTN_OFF);
	printf("\n");

	printf("light_state=STATE_OFF, event=EVENT_BTN_ON.\n");
	simple2_light_fsm_event(light_state, EVENT_BTN_ON);
	printf("\n");

	printf("light_state=STATE_OFF, event=EVENT_BTN_OFF.\n");
	simple2_light_fsm_event(light_state, EVENT_BTN_OFF);
	printf("\n");

	printf("light_state=STATE_OFF, event=EVENT_BTN_ON.\n");
	simple2_light_fsm_event(light_state, EVENT_BTN_ON);
	printf("\n");

	printf("light_state=STATE_OFF, event=EVENT_BTN_ON.\n");
	simple2_light_fsm_event(light_state, EVENT_BTN_ON);
	printf("\n");

	getchar();
	return 1;
}