嵌入式编程-C语言使用小技巧

编译时条件不成立，则发生Assert

#define COMPILE_TIME_ASSERT(x) \
	do { \
		switch (0) { case 0: case ((x) ? 1: 0): default : break; } \
	} while (0)

#endif

剖析: 实现原理，其实就是当x为false是，switch case中写了两遍case 0，此时编译会报错.
使用示例:

COMPILE_TIME_ASSERT(XLAT_TABLES_SIZE == sizeof(xlat_tables));

C语言中 LOG函数重定义–加TAG

#define EMSG(fmt, args...) TEE_LogPrintf("aes_demo "fmt"\n", ##args)

C语言中字符串的形式打印16进制数据

#define PRINT_BUF_MAX			(32)
#define TAG_STRING_MAX			(32)
static void print_step_hex_data(const char *tag, void *pbuf, size_t len)
{
	int i;
	char buf[PRINT_BUF_MAX * 4] = {0};
	char temp_buf[4] = {0};

	sprintf(buf,"%s",tag);

	for (i=0;i<len;i++) {
		if(i % 16 ==0)
			strcat(buf,"\n");
		sprintf(temp_buf," %02x",*((char *)pbuf + i)&0xff);
		strcat(buf, temp_buf);
	}
	strcat(buf,"\n");

	LOGI("%s", buf);
}

void print_hex_data(const char *tag, void *pbuf, size_t len)
{
	int i;
	uint32_t block;
	uint32_t remainder;
	void *p;
	char tag_buf[TAG_STRING_MAX + 6] = {0};
	char tail_buf[6+1] = {0};

	p = pbuf;
	if (len<=PRINT_BUF_MAX)
		return print_step_hex_data(tag, p, len);
	else {
		block = len / PRINT_BUF_MAX;
		remainder = len % PRINT_BUF_MAX;
		for (i=0;i<block;i++) {
			memcpy(tag_buf,tag,TAG_STRING_MAX);
			sprintf(tail_buf,"[%i]",i);
			strcat(tag_buf, tail_buf);
			print_step_hex_data(tag_buf, p, PRINT_BUF_MAX);
			p = (char *)p + PRINT_BUF_MAX;
		}
		if (remainder) {
			memcpy(tag_buf,tag,TAG_STRING_MAX);
			sprintf(tail_buf,"[%i]",i);
			strcat(tag_buf, tail_buf);
			print_step_hex_data(tag_buf, p, remainder);
		}
	}
}