c语言byte转16进制字符串

2022-11-08

利用sprintf来实现byte转换成16进制字符串,即在内存中00 01 0F 23 转换为"00010F23"。

unsigned char* src;	//源数据
int nLen;			//源数据长度
char* dst;			//转换后的数据
for (int i = 0; i < nLen; i++) 
{
	sprintf(dst + i * 2, "%02X", src[i] & 0xFF);
}

#include <stdio.h>

void print_hex(const void *data, size_t len) {
    char *buf = malloc(len * 2 + 1);
    char *p = buf;
    const unsigned char *byte_data = data;
    size_t i;

    for (i = 0; i < len; i++) {
        sprintf(p, "%02x", byte_data[i]);
        p += 2;
    }
    *p = '\0';

    printf("%s\n", buf);
    free(buf);
}

int main() {
    unsigned char data[3] = {0x12, 0x34, 0x56};
    print_hex(data, sizeof(data));
    // Prints: 123456
}

将上一转换后的字符串即"00010F23"还原成00 01 0F 23

@param pbDest: 转换后的数据
@param pbSrc:  源数据
@param nLen:   源数据长度
int StrToHex(unsigned char* pbDest, char* pbSrc, int nLen)
{

	BYTE high, low;
	int idx, ii = 0;

	for (idx = 0; idx < nLen; idx += 2)
	{

		high = pbSrc[idx];
		low  = pbSrc[idx + 1];

		if (high >= '0' && high <= '9')
			high = high - '0';
		else if (high >= 'A' && high <= 'F')
			high = high - 'A' + 10;
		else if (high >= 'a' && high <= 'f')
			high = high - 'a' + 10;
		else
			return ii;
		
		if (low >= '0' && low <= '9')
			low = low - '0';
		else if (low >= 'A' && low <= 'F')
			low = low - 'A' + 10;
		else if (low >= 'a' && low <= 'f')
			low = low - 'a' + 10;
		else
			return ii;

		pbDest[ii++] = high << 4 | low;
	}
	return ii;
}

C++

将unsigned char arr[] = { 0x48, 0x65, 0x6C, 0x6C, 0x6F }; 转换成std::string arr = "48656C6C6F";
std::string unsignedCharArrayToHexString(const unsigned char* arr, std::size_t size) {
    std::ostringstream oss;
    
    for (std::size_t i = 0; i < size; ++i) {
        oss << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(arr[i]);
    }
    
    return oss.str();
}

还原
std::vector<unsigned char> stringToUnsignedCharArray(const std::string& str) {
    std::vector<unsigned char> arr;
    
    for (std::size_t i = 0; i < str.length(); i += 2) {
        std::string byteString = str.substr(i,2);
        unsigned char byte = static_cast<unsigned char>(std::stoul(byteString, nullptr, 16));
        arr.push_back(byte);
    }
    
    return arr;
}

std::vector<unsigned char> vec = getBytes(strText);
unsigned char* pDest = vec.data();

将 std::string str="4561312465132"; str的长度13转换为00000013
std::string formatStringLength(const std::string& str) {
    std::ostringstream oss;
    oss << std::setw(8) << std::setfill('0') << str.length();
    return oss.str();
}

普通字符串转byte(unsigned char),std::string str = "22:55:0d:4b:7d:89ABCD123456789028e7aa99-b7d8-4da5-b4a2-8771b70c1349";
std::vector<unsigned char> getBytes(const std::string& str) {
        return std::vector<unsigned char>(str.begin(), str.end());
}