嵌入式中常用的巧妙方法

嵌入式中常用的巧妙方法 - （汇总）

概述

做项目，掌握以下方法，可提高开发效率，把时间全部放在需求上。

1、快速获取结构体成员大小

#include <stdio.h>   // 获取结构体成员大小
#define  GET_MEMBER_SIZE(type, member)   sizeof(((type*)0)->member)// 获取结构体成员偏移量
#define  GET_MEMBER_OFFSET(type, member)  ((size_t)(&(((type*)0)->member)))typedef struct _test_struct0
{char x;char y;char z;
}test_struct0;typedef struct _test_struct1
{char a;char c;short b;int d;test_struct0 e;
}test_struct1;int main(int arc, char* argv[])
{printf("GET_MEMBER_SIZE(test_struct1, a) = %ld\n", GET_MEMBER_SIZE(test_struct1, a));printf("GET_MEMBER_SIZE(test_struct1, c) = %ld\n", GET_MEMBER_SIZE(test_struct1, c));printf("GET_MEMBER_SIZE(test_struct1, b) = %ld\n", GET_MEMBER_SIZE(test_struct1, b));printf("GET_MEMBER_SIZE(test_struct1, d) = %ld\n", GET_MEMBER_SIZE(test_struct1, d));printf("GET_MEMBER_SIZE(test_struct1, e) = %ld\n", GET_MEMBER_SIZE(test_struct1, e));printf("test_struct1 size = %ld\n", sizeof(test_struct1));printf("GET_MEMBER_OFFSET(a): %ld\n", GET_MEMBER_OFFSET(test_struct1, a));printf("GET_MEMBER_OFFSET(c): %ld\n", GET_MEMBER_OFFSET(test_struct1, c));printf("GET_MEMBER_OFFSET(b): %ld\n", GET_MEMBER_OFFSET(test_struct1, b));printf("GET_MEMBER_OFFSET(d): %ld\n", GET_MEMBER_OFFSET(test_struct1, d));printf("GET_MEMBER_OFFSET(e): %ld\n", GET_MEMBER_OFFSET(test_struct1, e));return 0;
}

运行结果：

2、文件操作

文件操作平时用得很多，为了方便使用，可以自己根据实际需要再封装一层：

#include <stdio.h>   static int file_opt_write(const char* filename, void* ptr, int size)
{FILE* fp;size_t num;fp = fopen(filename, "wb");if (NULL == fp){printf("open %s file error!\n", filename);return -1;}num = fwrite(ptr, 1, size, fp);if (num != size){fclose(fp);printf("write %s file error!\n", filename);return -1;}fclose(fp);return num;
}static int file_opt_read(const char* filename, void* ptr, int size)
{FILE* fp;size_t num;fp = fopen(filename, "rb");if (NULL == fp){printf("open %s file error!\n", filename);return -1;}num = fread(ptr, 1, size, fp);if (num != size){fclose(fp);printf("write %s file error!\n", filename);return -1;}fclose(fp);return num;
}typedef struct _test_data_info
{char a;char c;short b;int d;
}test_data_info;int main(int arc, char* argv[])
{
#define FILE_NAME  "./test_file"test_data_info write_data = { 0 };write_data.a = 1;write_data.b = 2;write_data.c = 3;write_data.d = 4;printf("write_data.a = %d\n", write_data.a);printf("write_data.b = %d\n", write_data.b);printf("write_data.c = %d\n", write_data.c);printf("write_data.d = %d\n", write_data.d);file_opt_write(FILE_NAME, (test_data_info*)&write_data, sizeof(test_data_info));test_data_info read_data = { 0 };file_opt_read(FILE_NAME, (test_data_info*)&read_data, sizeof(test_data_info));printf("read_data.a = %d\n", read_data.a);printf("read_data.b = %d\n", read_data.b);printf("read_data.c = %d\n", read_data.c);printf("read_data.d = %d\n", read_data.d);return 0;
}

运行结果：

3、进度条

有时候，加上进度条可以比较方便知道当前的下载进度、写入文件的进度等。

#include <stdio.h>    
#include <string.h>    
#include <windows.h>typedef struct _progress_t
{int cur_size;int sum_size;
}progress_t;void progress_bar(progress_t* progress_data)
{int percentage = 0;int cnt = 0;char proBuf[102];memset(proBuf, '\0', sizeof(proBuf));percentage = (int)(progress_data->cur_size * 100 / progress_data->sum_size);printf("percentage = %d %%\n", percentage);if (percentage <= 100){while (cnt <= percentage){printf("[%-100s] [%d%%]\r", proBuf, cnt);fflush(stdout);proBuf[cnt] = '#';Sleep(1);cnt++;}}printf("\n");
}int main(int arc, char* argv[])
{progress_t progress_test = { 0 };progress_test.cur_size = 82;progress_test.sum_size = 100;progress_bar(&progress_test);return 0;
}

运行结果：

4、日志输出

日志输出常常需要带一些格式。最简单的方式如：

// 定义日志等级
typedef enum {LOG_DEBUG,LOG_INFO,LOG_WARNING,LOG_ERROR,
} log_level_t;// 封装的日志函数
void log_message(log_level_t level, const char* message, const char* file, int line) {switch (level) {case LOG_DEBUG:printf("DEBUG: %s (%s:%d)\n", message, file, line);break;case LOG_INFO:printf("INFO: %s (%s:%d)\n", message, file, line);break;case LOG_WARNING:printf("WARNING: %s (%s:%d)\n", message, file, line);break;case LOG_ERROR:printf("ERROR: %s (%s:%d)\n", message, file, line);break;default:break;}
}// 在代码中使用封装的日志函数
int main() {log_message(LOG_INFO, "This is an info message", __FILE__, __LINE__);log_message(LOG_DEBUG, "This is a debug message", __FILE__, __LINE__);log_message(LOG_WARNING, "This is a warning message", __FILE__, __LINE__);log_message(LOG_ERROR, "This is an error message", __FILE__, __LINE__);return 0;
}

运行结果：