Implement key-value iterator

This patch implements an iterator that returns a pair containing both the
key and the value of an entry in QHash/QMap.

[ChangeLog][QtCore][Containers] Added an stl-like iterator to go through
QHash/QMap returning both the key and the value of the element pointed to.
That lets QHash/QMap interoperate better with stl's algorithms like
std::set_union.

Change-Id: Idbf8a8581510b3493648c34ab04c556de9fa4aa7
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index c59f789cb2..bcaaec0ec6 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -447,6 +447,9 @@ public:
         const_iterator base() const { return i; }
     };
 
+    typedef QKeyValueIterator<const Key&, const T&, const_iterator> const_key_value_iterator;
+    typedef QKeyValueIterator<const Key&, T&, iterator> key_value_iterator;
+
     // STL style
     inline iterator begin() { detach(); return iterator(d->firstNode()); }
     inline const_iterator begin() const { return const_iterator(d->firstNode()); }
@@ -458,6 +461,12 @@ public:
     inline const_iterator constEnd() const { return const_iterator(e); }
     inline key_iterator keyBegin() const { return key_iterator(begin()); }
     inline key_iterator keyEnd() const { return key_iterator(end()); }
+    inline key_value_iterator keyValueBegin() { return key_value_iterator(begin()); }
+    inline key_value_iterator keyValueEnd() { return key_value_iterator(end()); }
+    inline const_key_value_iterator keyValueBegin() const { return const_key_value_iterator(begin()); }
+    inline const_key_value_iterator constKeyValueBegin() const { return const_key_value_iterator(begin()); }
+    inline const_key_value_iterator keyValueEnd() const { return const_key_value_iterator(end()); }
+    inline const_key_value_iterator constKeyValueEnd() const { return const_key_value_iterator(end()); }
 
     QPair<iterator, iterator> equal_range(const Key &key);
     QPair<const_iterator, const_iterator> equal_range(const Key &key) const Q_DECL_NOTHROW;