数据转换：C51数字转字符最快速的方法 ASCII转换

//字节流转换为十六进制字符串
 
void ByteToHexStr(const unsigned char* source, char* dest, int sourceLen)
{
    short i;
    unsigned char highByte, lowByte;
    for (i = 0; i < sourceLen; i++)
    {
        highByte = source[i] >> 4;
        lowByte = source[i] & 0x0f ;
        highByte += 0x30;
        if (highByte > 0x39)
                dest[i * 2] = highByte + 0x07;
        else
                dest[i * 2] = highByte;
        lowByte += 0x30;
        if (lowByte > 0x39)
            dest[i * 2 + 1] = lowByte + 0x07;
        else
            dest[i * 2 + 1] = lowByte;
    }
    return ;
}
 
 
//字节流转换为十六进制字符串的另一种实现方式
 
void Hex2Str( const char *sSrc,  char *sDest, int nSrcLen )
{
    int  i;
    char szTmp[3];
    for( i = 0; i < nSrcLen; i++ )
    {
        sprintf( szTmp, "%02X", (unsigned char) sSrc[i] );
        memcpy( &sDest[i * 2], szTmp, 2 );
    }
    return ;
}
 
 
 
//十六进制字符串转换为字节流
void HexStrToByte(const char* source, unsigned char* dest, int sourceLen)
{
    short i;
    unsigned char highByte, lowByte;
    for (i = 0; i < sourceLen; 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;
    }
    return ;
}