C++ const_iterator::toLower方法代码示例

// static
ChromaticKey KeyUtils::guessKeyFromText(const QString& text) {
    QString trimmed = text.trimmed();

    // Try using the user's custom notation.
    {
        QMutexLocker locker(&s_notationMutex);
        QMap<QString, ChromaticKey>::const_iterator it = s_reverseNotation.find(text);
        if (it != s_reverseNotation.end()) {
            return it.value();
        }
    }

    QRegExp openKeyMatcher(s_openKeyPattern, Qt::CaseInsensitive);
    if (openKeyMatcher.exactMatch(trimmed)) {
        bool ok = false;
        int openKeyNumber = openKeyMatcher.cap(1).toInt(&ok);

        // Regex should mean this never happens.
        if (!ok || openKeyNumber < 1 || openKeyNumber > 12) {
            return mixxx::track::io::key::INVALID;
        }

        bool major = openKeyMatcher.cap(2)
                .compare("d", Qt::CaseInsensitive) == 0;

        return openKeyNumberToKey(openKeyNumber, major);
    }

    QRegExp lancelotKeyMatcher(s_lancelotKeyPattern, Qt::CaseInsensitive);
    if (lancelotKeyMatcher.exactMatch(trimmed)) {
        bool ok = false;
        int lancelotNumber = lancelotKeyMatcher.cap(1).toInt(&ok);

        // Regex should mean this never happens.
        if (!ok || lancelotNumber < 1 || lancelotNumber > 12) {
            return mixxx::track::io::key::INVALID;
        }

        int openKeyNumber = lancelotNumberToOpenKeyNumber(lancelotNumber);

        bool major = lancelotKeyMatcher.cap(2)
                .compare("b", Qt::CaseInsensitive) == 0;

        return openKeyNumberToKey(openKeyNumber, major);
    }

    QRegExp keyMatcher(s_keyPattern, Qt::CaseInsensitive);
    if (keyMatcher.exactMatch(trimmed)) {
        // Take the first letter, lowercase it and subtract 'a' and we get a
        // number between 0-6. Look up the major key associated with that letter
        // from s_letterToMajorKey. Upper-case means major, lower-case means
        // minor. Then apply the sharps or flats to the key.
        QChar letter = keyMatcher.cap(1).at(0);
        int letterIndex = letter.toLower().toAscii() - 'a';
        bool major = letter.isUpper();

        // Now apply sharps and flats to the letter key.
        QString adjustments = keyMatcher.cap(2);
        int steps = 0;
        for (QString::const_iterator it = adjustments.begin();
             it != adjustments.end(); ++it) {
            // An m only comes at the end and
            if (it->toLower() == 'm') {
                major = false;
                break;
            }
            steps += (*it == '#' || *it == s_sharpSymbol[0]) ? 1 : -1;
        }

        ChromaticKey letterKey = static_cast<ChromaticKey>(
            s_letterToMajorKey[letterIndex] + (major ? 0 : 12));
        return scaleKeySteps(letterKey, steps);
    }

    // We didn't figure out the key. Womp womp.
    return mixxx::track::io::key::INVALID;
}