{

// If the data starts with a Unicode BOM, we can use detection provided by QTextCodec.

if(startsWithBom(data)) {

QTextCodec *codec = encoding.isEmpty()? QTextCodec::codecForName("UTF-8") : QTextCodec::codecForName(encoding.toUtf8());

QTextCodec *detectedCodec = QTextCodec::codecForUtfText(data, nullptr);

return detectedCodec == codec;

}

// Truncate to the first few bytes for quick testing

QByteArray::size_type testSize = quickTest? std::min(QByteArray::size_type(512), data.size()) : data.size();

// If the quick test has been requested and we have to truncate the string, we have to use

// an approach where truncated multibyte characters are not interpreted as invalid characters.

if(quickTest && data.size() > testSize) {

// We can assume that the default encoding (UTF-8) and all the ISO-8859

// cannot contain character zero.

// This has to be checked explicitly because toUnicode() is using zero as

// a terminator for these encodings.

if((encoding.isEmpty() || encoding.startsWith("ISO-8859")) && data.contains('\0'))

return false;

QTextCodec::ConverterState state;

QTextCodec *codec = encoding.isEmpty()? QTextCodec::codecForName("UTF-8") : QTextCodec::codecForName(encoding.toUtf8());

codec->toUnicode(data.constData(), testSize, &state);

return state.invalidChars == 0;

} else {

// Convert to Unicode if necessary

data = decodeString(data, encoding);

QString text (data);

bool isPrintable = true;

for(QChar character : text) {

if(character.isNonCharacter() || (character.category() == QChar::Other_Control && !character.isSpace())) {

isPrintable = false;

break;

}

}

// Perform check

return isPrintable && text.toUtf8() == data;

}

{

QFile file(fileName);

if (file.open(QFile::ReadOnly)) {

QByteArray data = file.read(512);

return !data.isEmpty() && isTextOnly(data);

} else {

return false;

}

for(QChar ch : text) {

switch(ch.direction()) {

case QChar::DirR:

case QChar::DirAL:

case QChar::DirRLE:

case QChar::DirRLO:

case QChar::DirRLI:

return true;

default:

break;

}

}

return false;

{

if(data.startsWith(bom3) ||

data.startsWith(bom2a) || data.startsWith(bom2b) ||

data.startsWith(bom4a) || data.startsWith(bom4b))

return true;

else

return false;

{

if(data.startsWith(bom3))

{

QByteArray bom = data.left(3);

data.remove(0, 3);

return bom;

} else if(data.startsWith(bom2a) || data.startsWith(bom2b)) {

QByteArray bom = data.left(2);

data.remove(0, 2);

return bom;

} else if(data.startsWith(bom4a) || data.startsWith(bom4b)) {

QByteArray bom = data.left(4);

data.remove(0, 4);

return bom;

} else {

return QByteArray();

}

{

// Check if it's an image. First do a quick test by calling canRead() which only checks the first couple of bytes or so. Only if

// that returned true, do a more sophisticated test of the data. This way we get both, good performance and proper data checking.

QBuffer imageBuffer(const_cast<QByteArray*>(&data));

QImageReader readerBuffer(&imageBuffer);

QString imageFormat = readerBuffer.format();

if(readerBuffer.canRead() && !readerBuffer.read().isNull())

return imageFormat;

else

return QString();

QStringList strings;

for (const QByteArray &item : list) {

strings.append(QString::fromUtf8(item));

}

return strings;

{

if(encoding.isEmpty())

return str;

else

return QTextCodec::codecForName(encoding.toUtf8())->fromUnicode(str);

{

if(encoding.isEmpty())

return str;

else

return QTextCodec::codecForName(encoding.toUtf8())->toUnicode(str).toUtf8();

{

static const std::vector<QString> units = {"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB"};

double size = static_cast<double>(byteCount);

for(const QString& unit : units)

{

if(size < 1024.0)

return QString::number(size, 'f', 2) + " " + unit;

size /= 1024.0;

}

return QString::number(size, 'f', 2) + " YiB";

{

// Store the current size so we can easily check later if the string has been changed

int oldSize = query.size();

// This implements a simple state machine to strip the query from comments

QChar quote;

for(int i=0;i<query.size();i++)

{

// Are we in quote state?

if(quote.isNull())

{

// We are currently not in quote state

// So are we starting a quote?

if((query.at(i) == '\'' || query.at(i) == '\"' || query.at(i) == '[') && (i == 0 || query.at(i-1) != '\\'))

{

// Quoted text is beginning. Switch to the quote state

quote = query.at(i);

} else if(query.at(i) == '-' && i+1 < query.size() && query.at(i+1) == '-') {

// This is an end of line comment. Remove anything till the end of the line or the end of the string if this is the last line

int pos_next_line_break = query.indexOf('\n', i);

if(pos_next_line_break == -1)

query = query.left(i);

else

query.remove(i, pos_next_line_break - i); // The \n is left in intentionally

} else if(query.at(i) == '/' && i+1 < query.size() && query.at(i+1) == '*') {

// This is a block comment. Remove anything till the end of the block or the end of the string if the block is not closed

int pos_end_comment = query.indexOf("*/", i);

if(pos_end_comment == -1)

query = query.left(i);

else

query.remove(i, pos_end_comment - i + 2); // Add 2 to include the */

}

} else {

// We are currently in quote state

// If this is the closing quote character, switch back to normal state

if((query.at(i) == quote) && (i == 0 || query.at(i-1) != '\\'))

quote = QChar(0);

}

}

query = query.trimmed();

if (oldSize != query.size()) {

// Remove multiple line breaks that might have been created by deleting comments till the end of the line but not including the line break

query.replace(QRegularExpression("\\n+"), "\n");

// Also remove any remaining whitespace at the end of each line

query.replace(QRegularExpression("[ \t]+\n"), "\n");

}