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>

1 files changed, 30 insertions, 0 deletions

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>