Changeset 31824 in webkit for trunk/JavaScriptCore/wtf/HashFunctions.h

Timestamp:

Apr 11, 2008, 4:17:21 PM (17 years ago)

Author:

Antti Koivisto

Message:

2008-04-11 Antti Koivisto <Antti Koivisto>

Reviewed by Maciej.

Add default hash for pairs of hashable types.

• wtf/HashFunctions.h: (WTF::PairHash::hash): (WTF::PairHash::equal): (WTF::):

File:

• trunk/JavaScriptCore/wtf/HashFunctions.h (modified) (2 diffs)

trunk/JavaScriptCore/wtf/HashFunctions.h

@@ -128 +128 @@
     template<typename T> struct DefaultHash;
 
+    template<typename T, typename U> struct PairHash {
+        static unsigned hash(const std::pair<T, U>& p)
+        {
+            return intHash((static_cast<uint64_t>(DefaultHash<T>::Hash::hash(p.first)) << 32 | DefaultHash<U>::Hash::hash(p.second)));
+        }
+        static bool equal(const std::pair<T, U>& a, const std::pair<T, U>& b)
+        {
+            return DefaultHash<T>::Hash::equal(a.first, b.first) && DefaultHash<U>::Hash::equal(a.second, b.second);
+        }
+        static const bool safeToCompareToEmptyOrDeleted = DefaultHash<T>::Hash::safeToCompareToEmptyOrDeleted 
+                                                            && DefaultHash<U>::Hash::safeToCompareToEmptyOrDeleted;
+    };
+
     // make IntHash the default hash function for many integer types
 
@@ -151 +164 @@
     template<typename P> struct DefaultHash<RefPtr<P> > { typedef PtrHash<RefPtr<P> > Hash; };
 
+    template<typename T, typename U> struct DefaultHash<std::pair<T, U> > { typedef PairHash<T, U> Hash; };
+
 } // namespace WTF