Base64 Encode

char* base64( const char* in, char* buffer, int bufferlen ){
    char* vals = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz01234567890+/=";
    int read = 0;
    int i = 0;
    int bufout = 0;
    while(in[i] != 0){
        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;
            12;
        }
        read = ( read + 6 ) % 8;
        if( read == 0 ) i ++;
        buffer[bufout++] = vals[reading];
    }
    while( read != 0 ){
        buffer[bufout++] = '=';
        read = ( read + 6 ) % 8;
    }
    buffer[bufout] = NULL;
    return buffer;
}