C语言中16进制字符串转为字节流的实现

void HexStrToByte(const char* source, unsigned char* dest, int length)

{

    short i;

    unsigned char highByte, lowByte;

    for (i = 0; i < length; i += 2)

    {

        highByte = toupper(source[i]);

        lowByte  = toupper(source[i + 1]);

        if (highByte > 0x39)

            highByte -= 0x37;

        else

            highByte -= 0x30;

        if (lowByte > 0x39)

            lowByte -= 0x37;

        else

            lowByte -= 0x30;

        // dest[i / 2] = (highByte << 4) | lowByte;

        dest[(length-2-i)/2] = (highByte << 4) | lowByte;

    }

    return;

}