C语言设计模式（命令模式）

#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))

typedef int (*parse_func)(const char *data,size_t len);

struct parse_handler{
    int type;
    parse_func func;
}

static int parse_temperature(const char *data,size_t len)
{
    assert(len == 4);
    int value = *(int *)data;
    printf("temperature = %d\n",value);
}
static int parse_humidity(const char *data,size_t len)
{
    assert(len==4);
    int value = *(int *)data;
    printf("humidity = %d\n",value);
}

static struct parse_handler handlers = {
    {1,parse_tmepeature},
    {2,parse_humidity},
};

static parse_func parse_func_find(int type)
{
    int i;
    for(i=0;i<ARRAY_SIZE(handlers);i++){
        if(handlers[i].type == type)
            return handlers[i].func;
    }
    return NULL;
}

static int parse(const char *data,size_t len)
{
    int data_len = data[0];
    int data_type = data[1];

    parse_func func = parse_func_find(data_type);
    if(func != NULL)
        func(data+2,data_len-2);
}