From dfb00bd479ded5bc4e86424c9678412c5ff72282 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@kdab.com>
Date: Fri, 27 Mar 2015 20:56:44 +0100
Subject: QList: add relational operators <,<=,>,>=

std::vector has them, too.

[ChangeLog][QtCore][QList] Added relational operators <, <=, >, >= if the element
type supports operator<.

Change-Id: Id2bd905e92c0365ad9f439d49908045c8df309c3
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/tools/qlist.cpp | 48 +++++++++++++++++++++++++++++++++++++++++++++
 src/corelib/tools/qlist.h   | 30 ++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)

(limited to 'src/corelib/tools')

diff --git a/src/corelib/tools/qlist.cpp b/src/corelib/tools/qlist.cpp
index db00dcb458..ef47ec1c05 100644
--- a/src/corelib/tools/qlist.cpp
+++ b/src/corelib/tools/qlist.cpp
@@ -584,6 +584,54 @@ void **QListData::erase(void **xi)
     \sa operator==()
 */
 
+/*! \fn bool operator<(const QList<T> &lhs, const QList<T> &rhs)
+    \since 5.6
+    \relates QList
+
+    Returns \c true if list \a lhs is
+    \l{http://en.cppreference.com/w/cpp/algorithm/lexicographical_compare}
+    {lexicographically less than} \a rhs; otherwise returns \c false.
+
+    This function requires the value type to have an implementation
+    of \c operator<().
+*/
+
+/*! \fn bool operator<=(const QList<T> &lhs, const QList<T> &rhs)
+    \since 5.6
+    \relates QList
+
+    Returns \c true if list \a lhs is
+    \l{http://en.cppreference.com/w/cpp/algorithm/lexicographical_compare}
+    {lexicographically less than or equal to} \a rhs; otherwise returns \c false.
+
+    This function requires the value type to have an implementation
+    of \c operator<().
+*/
+
+/*! \fn bool operator>(const QList<T> &lhs, const QList<T> &rhs)
+    \since 5.6
+    \relates QList
+
+    Returns \c true if list \a lhs is
+    \l{http://en.cppreference.com/w/cpp/algorithm/lexicographical_compare}
+    {lexicographically greater than} \a rhs; otherwise returns \c false.
+
+    This function requires the value type to have an implementation
+    of \c operator<().
+*/
+
+/*! \fn bool operator>=(const QList<T> &lhs, const QList<T> &rhs)
+    \since 5.6
+    \relates QList
+
+    Returns \c true if list \a lhs is
+    \l{http://en.cppreference.com/w/cpp/algorithm/lexicographical_compare}
+    {lexicographically greater than or equal to} \a rhs; otherwise returns \c false.
+
+    This function requires the value type to have an implementation
+    of \c operator<().
+*/
+
 /*!
     \fn int QList::size() const
 
diff --git a/src/corelib/tools/qlist.h b/src/corelib/tools/qlist.h
index 57e67d52d7..7d90f72876 100644
--- a/src/corelib/tools/qlist.h
+++ b/src/corelib/tools/qlist.h
@@ -1015,6 +1015,36 @@ inline int QList<T>::count_impl(const T &t, QListData::ArrayCompatibleLayout) co
 Q_DECLARE_SEQUENTIAL_ITERATOR(List)
 Q_DECLARE_MUTABLE_SEQUENTIAL_ITERATOR(List)
 
+template <typename T>
+bool operator<(const QList<T> &lhs, const QList<T> &rhs)
+    Q_DECL_NOEXCEPT_EXPR(noexcept(std::lexicographical_compare(lhs.begin(), lhs.end(),
+                                                               rhs.begin(), rhs.end())))
+{
+    return std::lexicographical_compare(lhs.begin(), lhs.end(),
+                                        rhs.begin(), rhs.end());
+}
+
+template <typename T>
+inline bool operator>(const QList<T> &lhs, const QList<T> &rhs)
+    Q_DECL_NOEXCEPT_EXPR(noexcept(lhs < rhs))
+{
+    return rhs < lhs;
+}
+
+template <typename T>
+inline bool operator<=(const QList<T> &lhs, const QList<T> &rhs)
+    Q_DECL_NOEXCEPT_EXPR(noexcept(lhs < rhs))
+{
+    return !(lhs > rhs);
+}
+
+template <typename T>
+inline bool operator>=(const QList<T> &lhs, const QList<T> &rhs)
+    Q_DECL_NOEXCEPT_EXPR(noexcept(lhs < rhs))
+{
+    return !(lhs < rhs);
+}
+
 QT_END_NAMESPACE
 
 #include <QtCore/qbytearraylist.h>
-- 
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