roundcubemail/program/lib/Roundcube/rcube_mime.php
public static function decode($input, $encoding = '7bit')
    {
        switch (strtolower($encoding)) {
        case 'quoted-printable':
            return quoted_printable_decode($input);
        case 'base64':
            return base64_decode($input);
        case 'x-uuencode':
        case 'x-uue':
        case 'uue':
        case 'uuencode':
            return convert_uudecode($input);
        case '7bit':
        default:
            return $input;
        }
    }
public static function decode($input, $encoding = '7bit')
    {
        switch (strtolower($encoding)) {
        case 'quoted-printable':
            return quoted_printable_decode($input);
        case 'base64':
            return base64_decode($input);
        case 'x-uuencode':
        case 'x-uue':
        case 'uue':
        case 'uuencode':
            return convert_uudecode($input);
        case '7bit':
        default:
            return $input;
        }
    }
public static function decode ( $ input , $ encoding = '7bit' ) { switch ( strtolower ( $ encoding ) ) { case 'quoted-printable' : return quoted_printable_decode ( $ input ) ; case 'base64' : return base64_decode ( $ input ) ; case 'x-uuencode' : case 'x-uue' : case 'uue' : case 'uuencode' : return convert_uudecode ( $ input ) ; case '7bit' : default : return $ input ; } }
Decode a mime part

@param string $input    Input string
@param string $encoding Part encoding

@return string Decoded string
Decode a mime part