#358 replaceIllegalCharacters doesn't handle illegal filename

[devashish yadav]

StringHelper::replaceIllegalCharacters() currently replaces only the standard Windows filename characters:

wstring StringHelper::replaceIllegalCharacters(const wstring& filename)
{
    return replaceCharacters(filename, L"<>:\"/\\|?*", L"_");
}

However, it does not remove ASCII control characters (e.g. \r, \n, \t).

On my system, the Bluetooth audio endpoint property ({b3f8fa53-0004-438e-9003-51a46e139bfc},6) contains a trailing CRLF:

20 50 65 62 62 6C 65 20 56 33 0D 0A

which corresponds to:

" Pebble V3\r\n"

When DeviceSelector generates the backup filename:

L"backup_" +
StringHelper::replaceIllegalCharacters(deviceName) +
L"_" +
StringHelper::replaceIllegalCharacters(connectionName) +
L".reg"

the control characters are preserved, resulting in an invalid filename and the following error:

Error while opening file backup_ Pebble V3 _Headphones.reg for writing

A possible fix is to strip ASCII control characters before replacing the standard Windows filename characters:

wstring StringHelper::replaceIllegalCharacters(const wstring& filename)
{
    wstring sanitized;

    for (wchar_t c : filename)
    {
        if (c < 32)
            continue;

        sanitized += c;
    }

    return replaceCharacters(sanitized, L"<>:\"/\\|?*", L"_");
}