path: root/src/corelib/text/qstringlist.cpp

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include <qstringlist.h>
#include <qset.h>
#if QT_CONFIG(regularexpression)
#  include <qregularexpression.h>
#endif
#include <private/qduplicatetracker_p.h>

#include <algorithm>
QT_BEGIN_NAMESPACE

/*! \typedef QStringListIterator
    \relates QStringList

    The QStringListIterator type definition provides a Java-style const
    iterator for QStringList.

    QStringList provides both \l{Java-style iterators} and
    \l{STL-style iterators}. The Java-style const iterator is simply
    a type definition for QListIterator<QString>.

    \sa QMutableStringListIterator, QStringList::const_iterator
*/

/*! \typedef QMutableStringListIterator
    \relates QStringList

    The QStringListIterator type definition provides a Java-style
    non-const iterator for QStringList.

    QStringList provides both \l{Java-style iterators} and
    \l{STL-style iterators}. The Java-style non-const iterator is
    simply a type definition for QMutableListIterator<QString>.

    \sa QStringListIterator, QStringList::iterator
*/

/*!
    \class QStringList
    \inmodule QtCore
    \brief The QStringList class provides a list of strings.

    \ingroup tools
    \ingroup shared
    \ingroup string-processing

    \reentrant

    QStringList inherits from QList<QString>. Like QList, QStringList is
    \l{implicitly shared}. It provides fast index-based access as well as fast
    insertions and removals. Passing string lists as value parameters is both
    fast and safe.

    All of QList's functionality also applies to QStringList. For example, you
    can use isEmpty() to test whether the list is empty, and you can call
    functions like append(), prepend(), insert(), replace(), removeAll(),
    removeAt(), removeFirst(), removeLast(), and removeOne() to modify a
    QStringList. In addition, QStringList provides a few convenience
    functions that make handling lists of strings easier:

    \tableofcontents

    \section1 Initializing

    The default constructor creates an empty list. You can use the
    initializer-list constructor to create a list with elements:

    \snippet qstringlist/main.cpp 0a

    \section1 Adding Strings

    Strings can be added to a list using the \l
    {QList::insert()}{insert()}, \l
    {QList::append()}{append()}, \l
    {QList::operator+=()}{operator+=()} and \l
    {operator<<()} functions.

    \l{operator<<()} can be used to
    conveniently add multiple elements to a list:

    \snippet qstringlist/main.cpp 0b

    \section1 Iterating Over the Strings

    See \l {Iterating over Containers}.

    \section1 Manipulating the Strings

    QStringList provides several functions allowing you to manipulate
    the contents of a list. You can concatenate all the strings in a
    string list into a single string (with an optional separator)
    using the join() function. For example:

    \snippet qstringlist/main.cpp 4

    The argument to join can be a single character or a string.

    To break up a string into a string list, use the QString::split()
    function:

    \snippet qstringlist/main.cpp 6

    The argument to split can be a single character, a string or a
    QRegularExpression.

    In addition, the \l {QStringList::operator+()}{operator+()}
    function allows you to concatenate two string lists into one. To
    sort a string list, use the sort() function.

    QString list also provides the filter() function which lets you
    to extract a new list which contains only those strings which
    contain a particular substring (or match a particular regular
    expression):

    \snippet qstringlist/main.cpp 7

    The contains() function tells you whether the list contains a
    given string, while the indexOf() function returns the index of
    the first occurrence of the given string. The lastIndexOf()
    function on the other hand, returns the index of the last
    occurrence of the string.

    Finally, the replaceInStrings() function calls QString::replace()
    on each string in the string list in turn. For example:

    \snippet qstringlist/main.cpp 8

    \sa QString
*/

/*!
    \fn QStringList::QStringList(const QString &str)

    Constructs a string list that contains the given string, \a
    str. Longer lists are easily created like this:

    \snippet qstringlist/main.cpp 9

    \sa append()
*/

/*!
    \fn QStringList::QStringList(const QList<QString> &other)

    Constructs a copy of \a other.

    This operation takes \l{constant time}, because QStringList is
    \l{implicitly shared}. This makes returning a QStringList from a
    function very fast. If a shared instance is modified, it will be
    copied (copy-on-write), and that takes \l{linear time}.

    \sa operator=()
*/

/*!
    \fn QStringList::QStringList(QList<QString> &&other)
    \overload
    \since 5.4

    Move-constructs from QList<QString>.

    After a successful construction, \a other will be empty.
*/

/*!
    \fn QStringList &QStringList::operator=(const QList<QString> &other)
    \since 5.4

    Copy assignment operator from QList<QString>. Assigns the \a other
    list of strings to this string list.

    After the operation, \a other and \c *this will be equal.
*/

/*!
    \fn QStringList &QStringList::operator=(QList<QString> &&other)
    \overload
    \since 5.4

    Move assignment operator from QList<QString>. Moves the \a other
    list of strings to this string list.

    After the operation, \a other will be empty.
*/

/*!
    \fn void QStringList::sort(Qt::CaseSensitivity cs)

    Sorts the list of strings in ascending order.

//! [comparison-case-sensitivity]
    If \a cs is \l Qt::CaseSensitive (the default), the string comparison
    is case sensitive; otherwise the comparison is case insensitive.
//! [comparison-case-sensitivity]

    Sorting is performed using the STL's std::sort() algorithm,
    which averages \l{linear-logarithmic time}, i.e. O(\e{n} log \e{n}).

    If you want to sort your strings in an arbitrary order, consider
    using the QMap class. For example, you could use a QMap<QString,
    QString> to create a case-insensitive ordering (e.g. with the keys
    being lower-case versions of the strings, and the values being the
    strings), or a QMap<int, QString> to sort the strings by some
    integer index.
*/

void QtPrivate::QStringList_sort(QStringList *that, Qt::CaseSensitivity cs)
{
    if (cs == Qt::CaseSensitive) {
        std::sort(that->begin(), that->end());
    } else {
        auto CISCompare = [](const auto &s1, const auto &s2) {
            return s1.compare(s2, Qt::CaseInsensitive) < 0;
        };
        std::sort(that->begin(), that->end(), CISCompare);
    }
}


/*!
    \fn QStringList QStringList::filter(const QString &str, Qt::CaseSensitivity cs) const

    Returns a list of all the strings containing the substring \a str.

    \include qstringlist.cpp comparison-case-sensitivity

    \snippet qstringlist/main.cpp 5
    \snippet qstringlist/main.cpp 10

    This is equivalent to

    \snippet qstringlist/main.cpp 11
    \snippet qstringlist/main.cpp 12

    \sa contains()
*/

template <typename String>
static QStringList filter_helper(const QStringList &that, const String &needle, Qt::CaseSensitivity cs)
{
    QStringList res;
    for (const auto &s : that) {
        if (s.contains(needle, cs))
            res.append(s);
    }
    return res;
}

/*!
    \fn QStringList QStringList::filter(QStringView str, Qt::CaseSensitivity cs) const
    \overload
    \since 5.14
*/
QStringList QtPrivate::QStringList_filter(const QStringList *that, QStringView str,
                                          Qt::CaseSensitivity cs)
{
    return filter_helper(*that, str, cs);
}

/*!
    \fn QStringList QStringList::filter(const QStringMatcher &matcher) const
    \since 6.7
    \overload

    Returns a list of all the strings matched by \a matcher (i.e. for which
    \c matcher.indexIn() returns an index >= 0).

    Using a QStringMatcher may be faster when searching in large lists and/or
    in lists with long strings (the best way to find out is benchmarking).

    For example:
    \snippet qstringlist/main.cpp 18

    \sa contains()
*/

QStringList QtPrivate::QStringList_filter(const QStringList &that, const QStringMatcher &matcher)
{
    QStringList res;
    for (const auto &s : that) {
        if (matcher.indexIn(s) != -1)
            res.append(s);
    }
    return res;
}

/*!
    \fn QStringList QStringList::filter(QLatin1StringView str, Qt::CaseSensitivity cs) const
    \since 6.7
    \overload
*/

QStringList QtPrivate::QStringList_filter(const QStringList &that, QLatin1StringView needle,
                                          Qt::CaseSensitivity cs)
{
    return filter_helper(that, needle, cs);
}

template<typename T>
static bool stringList_contains(const QStringList &stringList, const T &str, Qt::CaseSensitivity cs)
{
    for (const auto &string : stringList) {
        if (string.size() == str.size() && string.compare(str, cs) == 0)
            return true;
    }
    return false;
}


/*!
    \fn bool QStringList::contains(const QString &str, Qt::CaseSensitivity cs) const

    Returns \c true if the list contains the string \a str; otherwise
    returns \c false.

    \include qstringlist.cpp comparison-case-sensitivity

    \sa indexOf(), lastIndexOf(), QString::contains()
 */

/*!
    \fn bool QStringList::contains(QStringView str, Qt::CaseSensitivity cs) const
    \overload
    \since 5.12

    Returns \c true if the list contains the string \a str; otherwise
    returns \c false.

    \include qstringlist.cpp comparison-case-sensitivity
 */
bool QtPrivate::QStringList_contains(const QStringList *that, QStringView str,
                                     Qt::CaseSensitivity cs)
{
    return stringList_contains(*that, str, cs);
}

/*!
    \fn bool QStringList::contains(QLatin1StringView str, Qt::CaseSensitivity cs) const
    \overload
    \since 5.10

    Returns \c true if the list contains the Latin-1 string viewed by \a str; otherwise
    returns \c false.

    \include qstringlist.cpp comparison-case-sensitivity

    \sa indexOf(), lastIndexOf(), QString::contains()
 */
bool QtPrivate::QStringList_contains(const QStringList *that, QLatin1StringView str,
                                     Qt::CaseSensitivity cs)
{
    return stringList_contains(*that, str, cs);
}


#if QT_CONFIG(regularexpression)
/*!
    \fn QStringList QStringList::filter(const QRegularExpression &re) const
    \overload
    \since 5.0

    Returns a list of all the strings that match the regular
    expression \a re.
*/
QStringList QtPrivate::QStringList_filter(const QStringList *that, const QRegularExpression &re)
{
    QStringList res;
    for (const auto &str : *that) {
        if (str.contains(re))
            res.append(str);
    }
    return res;
}
#endif // QT_CONFIG(regularexpression)

/*!
    \fn QStringList &QStringList::replaceInStrings(const QString &before, const QString &after, Qt::CaseSensitivity cs)

    Returns a string list where every string has had the \a before
    text replaced with the \a after text wherever the \a before text
    is found.

    \include qstringlist.cpp comparison-case-sensitivity

    For example:

    \snippet qstringlist/main.cpp 5
    \snippet qstringlist/main.cpp 13

    \sa QString::replace()
*/

/*!
    \fn QStringList &QStringList::replaceInStrings(QStringView before, const QString &after, Qt::CaseSensitivity cs)
    \overload
    \since 5.14
*/

/*!
    \fn QStringList &QStringList::replaceInStrings(const QString &before, QStringView after, Qt::CaseSensitivity cs)
    \overload
    \since 5.14
*/

/*!
    \fn QStringList &QStringList::replaceInStrings(QStringView before, QStringView after, Qt::CaseSensitivity cs)
    \overload
    \since 5.14
*/
void QtPrivate::QStringList_replaceInStrings(QStringList *that, QStringView before,
                                             QStringView after, Qt::CaseSensitivity cs)
{
    // Before potentially detaching "that" list, check if any string contains "before"
    qsizetype i = -1;
    for (qsizetype j = 0; j < that->size(); ++j) {
        if (that->at(j).contains(before, cs)) {
            i = j;
            break;
        }
    }
    if (i == -1)
        return;

    for (; i < that->size(); ++i)
        (*that)[i].replace(before.data(), before.size(), after.data(), after.size(), cs);
}

#if QT_CONFIG(regularexpression)
/*!
    \fn QStringList &QStringList::replaceInStrings(const QRegularExpression &re, const QString &after)
    \overload
    \since 5.0

    Replaces every occurrence of the regular expression \a re, in each of the
    string lists's strings, with \a after. Returns a reference to the string
    list.

    For example:

    \snippet qstringlist/main.cpp 5
    \snippet qstringlist/main.cpp 16

    For regular expressions that contain capturing groups,
    occurrences of \b{\\1}, \b{\\2}, ..., in \a after are
    replaced with the string captured by the corresponding capturing group.

    For example:

    \snippet qstringlist/main.cpp 5
    \snippet qstringlist/main.cpp 17
*/
void QtPrivate::QStringList_replaceInStrings(QStringList *that, const QRegularExpression &re,
                                             const QString &after)
{
    // Before potentially detaching "that" list, check if any string contains "before"
    qsizetype i = -1;
    for (qsizetype j = 0; j < that->size(); ++j) {
        if (that->at(j).contains(re)) {
            i = j;
            break;
        }
    }
    if (i == -1)
        return;

    for (; i < that->size(); ++i)
        (*that)[i].replace(re, after);
}
#endif // QT_CONFIG(regularexpression)

static qsizetype accumulatedSize(const QStringList &list, qsizetype seplen)
{
    qsizetype result = 0;
    if (!list.isEmpty()) {
        for (const auto &e : list)
            result += e.size() + seplen;
        result -= seplen;
    }
    return result;
}

/*!
    \fn QString QStringList::join(const QString &separator) const

    Joins all the string list's strings into a single string with each
    element separated by the given \a separator (which can be an
    empty string).

    \sa QString::split()
*/

/*!
    \fn QString QStringList::join(QChar separator) const
    \since 5.0
    \overload join()
*/
QString QtPrivate::QStringList_join(const QStringList *that, const QChar *sep, qsizetype seplen)
{
    const qsizetype totalLength = accumulatedSize(*that, seplen);
    const qsizetype size = that->size();

    QString res;
    if (totalLength == 0)
        return res;
    res.reserve(totalLength);
    for (qsizetype i = 0; i < size; ++i) {
        if (i)
            res.append(sep, seplen);
        res += that->at(i);
    }
    return res;
}

/*!
    \fn QString QStringList::join(QLatin1StringView separator) const
    \since 5.8
    \overload join()
*/
QString QtPrivate::QStringList_join(const QStringList &list, QLatin1StringView sep)
{
    QString result;
    if (!list.isEmpty()) {
        result.reserve(accumulatedSize(list, sep.size()));
        const auto end = list.end();
        auto it = list.begin();
        result += *it;
        while (++it != end) {
            result += sep;
            result += *it;
        }
    }
    return result;
}

/*!
    \fn QString QStringList::join(QStringView separator) const
    \overload
    \since 5.14
*/
QString QtPrivate::QStringList_join(const QStringList *that, QStringView sep)
{
    return QStringList_join(that, sep.data(), sep.size());
}

/*!
    \fn QStringList QStringList::operator+(const QStringList &other) const

    Returns a string list that is the concatenation of this string
    list with the \a other string list.

    \sa append()
*/

/*!
    \fn QStringList &QStringList::operator<<(const QString &str)

    Appends the given string, \a str, to this string list and returns
    a reference to the string list.

    \sa append()
*/

/*!
    \fn QStringList &QStringList::operator<<(const QStringList &other)

    \overload

    Appends the \a other string list to the string list and returns a reference to
    the latter string list.
*/

/*!
    \fn QStringList &QStringList::operator<<(const QList<QString> &other)
    \since 5.4

    \overload

    Appends the \a other string list to the string list and returns a reference to
    the latter string list.
*/

/*!
    \fn qsizetype QStringList::indexOf(const QString &str, qsizetype from, Qt::CaseSensitivity cs) const
    \fn qsizetype QStringList::indexOf(QStringView str, qsizetype from, Qt::CaseSensitivity cs) const
    \fn qsizetype QStringList::indexOf(QLatin1StringView str, qsizetype from, Qt::CaseSensitivity cs) const

    Returns the index position of the first match of \a str in the list,
    searching forward from index position \a from. Returns -1 if no item
    matched.

    \include qstringlist.cpp comparison-case-sensitivity

//! [overloading-base-class-methods]
    \note The \a cs parameter was added in Qt 6.7, i.e. these methods now overload
    the methods inherited from the base class. Prior to that these methods only
    had two parameters. This change is source compatible and existing code should
    continue to work.
//! [overloading-base-class-methods]

    \sa lastIndexOf()
*/

template <typename String>
qsizetype indexOf_helper(const QStringList &that, String needle, qsizetype from,
                         Qt::CaseSensitivity cs)
{
    if (from < 0) // Historical behavior
        from = qMax(from + that.size(), 0);

    if (from >= that.size())
        return -1;

    for (qsizetype i = from; i < that.size(); ++i) {
        if (needle.compare(that.at(i), cs) == 0)
            return i;
    }
    return -1;
}

qsizetype QtPrivate::QStringList_indexOf(const QStringList &that, QStringView needle,
                                         qsizetype from, Qt::CaseSensitivity cs)
{
    return indexOf_helper(that, needle, from, cs);
}

qsizetype QtPrivate::QStringList_indexOf(const QStringList &that, QLatin1StringView needle,
                                         qsizetype from, Qt::CaseSensitivity cs)
{
    return indexOf_helper(that, needle, from, cs);
}

/*!
    \fn qsizetype QStringList::lastIndexOf(const QString &str, qsizetype from, Qt::CaseSensitivity cs) const
    \fn qsizetype QStringList::lastIndexOf(QStringView str, qsizetype from, Qt::CaseSensitivity cs) const
    \fn qsizetype QStringList::lastIndexOf(QLatin1StringView str, qsizetype from, Qt::CaseSensitivity cs) const

    Returns the index position of the last match of \a str in the list,
    searching backward from index position \a from. If \a from is -1 (the
    default), the search starts at the last item. Returns -1 if no item
    matched.

    \include qstringlist.cpp comparison-case-sensitivity

    \include qstringlist.cpp overloading-base-class-methods

    \sa indexOf()
*/

template <typename String>
qsizetype lastIndexof_helper(const QStringList &that, String needle, qsizetype from,
                             Qt::CaseSensitivity cs)
{
    if (from < 0)
        from += that.size();
    else if (from >= that.size())
        from = that.size() - 1;

     for (qsizetype i = from; i >= 0; --i) {
        if (needle.compare(that.at(i), cs) == 0)
            return i;
    }

    return -1;
}

qsizetype QtPrivate::QStringList_lastIndexOf(const QStringList &that, QLatin1StringView needle,
                                            qsizetype from, Qt::CaseSensitivity cs)
{
    return lastIndexof_helper(that, needle, from, cs);
}

qsizetype QtPrivate::QStringList_lastIndexOf(const QStringList &that, QStringView needle,
                                             qsizetype from, Qt::CaseSensitivity cs)
{
    return lastIndexof_helper(that, needle, from, cs);
}

#if QT_CONFIG(regularexpression)
/*!
    \fn qsizetype QStringList::indexOf(const QRegularExpression &re, qsizetype from) const
    \overload
    \since 5.0

    Returns the index position of the first exact match of \a re in
    the list, searching forward from index position \a from. Returns
    -1 if no item matched.

    \sa lastIndexOf()
*/
qsizetype QtPrivate::QStringList_indexOf(const QStringList *that, const QRegularExpression &re, qsizetype from)
{
    if (from < 0)
        from = qMax(from + that->size(), qsizetype(0));

    QString exactPattern = QRegularExpression::anchoredPattern(re.pattern());
    QRegularExpression exactRe(exactPattern, re.patternOptions());

    for (qsizetype i = from; i < that->size(); ++i) {
        QRegularExpressionMatch m = exactRe.match(that->at(i));
        if (m.hasMatch())
            return i;
    }
    return -1;
}

/*!
    \fn qsizetype QStringList::lastIndexOf(const QRegularExpression &re, qsizetype from) const
    \overload
    \since 5.0

    Returns the index position of the last exact match of \a re in
    the list, searching backward from index position \a from. If \a
    from is -1 (the default), the search starts at the last item.
    Returns -1 if no item matched.

    \sa indexOf()
*/
qsizetype QtPrivate::QStringList_lastIndexOf(const QStringList *that, const QRegularExpression &re, qsizetype from)
{
    if (from < 0)
        from += that->size();
    else if (from >= that->size())
        from = that->size() - 1;

    QString exactPattern = QRegularExpression::anchoredPattern(re.pattern());
    QRegularExpression exactRe(exactPattern, re.patternOptions());

    for (qsizetype i = from; i >= 0; --i) {
        QRegularExpressionMatch m = exactRe.match(that->at(i));
        if (m.hasMatch())
            return i;
    }
    return -1;
}
#endif // QT_CONFIG(regularexpression)

/*!
    \fn qsizetype QStringList::removeDuplicates()

    \since 4.5

    This function removes duplicate entries from a list.
    The entries do not have to be sorted. They will retain their
    original order.

    Returns the number of removed entries.
*/
qsizetype QtPrivate::QStringList_removeDuplicates(QStringList *that)
{
    QDuplicateTracker<QString> seen(that->size());
    return that->removeIf([&](const QString &s) { return seen.hasSeen(s); });
}

QT_END_NAMESPACE