Base 64

String base64( String data ){
    String vals = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890+/=";
    System.Text.StringBuilder buffer = new System.Text.StringBuilder();
    char[] in = data.ToCharArray(0, data.Length);

    int read = 0;
    int i = 0;
    while( i < data.Length ){
        if( bufout >= bufferlen - read / 2 )
            break;
        int reading;
        if( read <= 2 ){
            reading = ( in[i] >> (2-read) ) & 0x3F;
        }
        else{
            reading = ( ( in[i++] << read ) & 0xFF ) >> 2;
            reading += ( in[i] >> (8-read+2) ) & 0x3F;
        }
        read = ( read + 6 ) % 8;
        if( read == 0 ) i ++;
        buffer.Append( vals.Substring(reading, 1) );
    }
    while( read != 0 ){
        buffer.Append( "=" );
        read = ( read + 6 ) % 8;
    }
    return buffer.ToString();
}