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嵌入式开发中状态模式实现

news 2025/8/27 14:42:41

文章目录

- 状态模式
- 代码实现
- 代码解释
- 小结

状态模式

状态模式（State Pattern）是一种行为设计模式，它允许对象在内部状态改变时改变它的行为。在嵌入式系统中，状态模式尤其适用于那些根据外部事件或内部条件频繁改变状态并且每种状态下行为不同的场景，例如设备的不同工作模式切换、任务调度、传感器状态管理、通信协议状态机等。

代码实现

#include <stdio.h>// 定义ACTION_PREPARE, ACTION_RUN, ACTION_END为合适的宏或整数值
#define ACTION_PREPARE 1
#define ACTION_RUN     2
#define ACTION_END     3// 首先声明 WashingMachine 结构体
typedef struct WashingMachineTag WashingMachine;// 定义状态枚举
typedef enum {STATE_STANDBY,STATE_PREPARING,STATE_RUNNING,STATE_FINISHED
} WashingMachineState;// 定义指向处理函数的指针类型
typedef void (*StateMachineAction)(WashingMachine *);// 洗衣机结构体
struct WashingMachineTag  {WashingMachineState state;StateMachineAction on_prepare;StateMachineAction on_run;StateMachineAction on_end;
} ;// 待机状态下准备
static void standby_prepare(WashingMachine *machine) {printf("Machine is preparing for washing.\n");machine->state = STATE_PREPARING;
}// 准备状态下运行
static void preparing_run(WashingMachine *machine) {printf("Machine has started running.\n");machine->state = STATE_RUNNING;
}// 运行状态下结束
static void running_end(WashingMachine *machine) {printf("Washing cycle completed.\n");machine->state = STATE_FINISHED;
}// 初始化洗衣机状态及其对应的处理函数
void init_washing_machine(WashingMachine *machine) {machine->state = STATE_STANDBY;machine->on_prepare = standby_prepare;machine->on_run = preparing_run;machine->on_end = running_end;
}// 根据当前状态执行相应操作
void operate_washing_machine(WashingMachine *machine, int action) {switch (machine->state) {case STATE_STANDBY:if (action == ACTION_PREPARE) {machine->on_prepare(machine);} else {printf("Invalid action in STANDBY state.\n");}break;case STATE_PREPARING:if (action == ACTION_RUN) {machine->on_run(machine);} else {printf("Invalid action in PREPARING state.\n");}break;case STATE_RUNNING:if (action == ACTION_END) {machine->on_end(machine);} else {printf("Invalid action in RUNNING state.\n");}break;case STATE_FINISHED:printf("Machine is already in FINISHED state.\n");break;default:printf("Unknown machine state.\n");break;}
}int main() {WashingMachine machine;init_washing_machine(&machine);// 根据实际需求调用操作函数operate_washing_machine(&machine, ACTION_PREPARE);operate_washing_machine(&machine, ACTION_RUN);operate_washing_machine(&machine, ACTION_END);return 0;
}