Changeset 36244 in webkit for trunk/JavaScriptCore/wtf/HashTraits.h

Timestamp:

Sep 6, 2008, 10:44:58 PM (17 years ago)

Author:

[email protected]

Message:

Merge squirrelfish-extreme to trunk.

File:

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

trunk/JavaScriptCore/wtf/HashTraits.h

@@ -82 +82 @@
     };
 
-    // default integer traits disallow both 0 and -1 as keys (max value instead of -1 for unsigned)
+    // Default integer traits disallow both 0 and -1 as keys (max value instead of -1 for unsigned).
     template<typename T> struct GenericHashTraitsBase<true, T> {
         static const bool emptyValueIsZero = true;
@@ -106 +106 @@
     template<> struct HashTraits<float> : FloatHashTraits<float> { };
     template<> struct HashTraits<double> : FloatHashTraits<double> { };
+
+    // Default unsigned traits disallow both 0 and max as keys -- use these traits to allow zero and disallow max - 1.
+    template<typename T> struct UnsignedWithZeroKeyHashTraits : GenericHashTraits<T> {
+        static const bool emptyValueIsZero = false;
+        static const bool needsDestruction = false;
+        static T emptyValue() { return std::numeric_limits<T>::max(); }
+        static void constructDeletedValue(T& slot) { slot = std::numeric_limits<T>::max() - 1; }
+        static bool isDeletedValue(T value) { return value == std::numeric_limits<T>::max() - 1; }
+    };
 
     template<typename P> struct HashTraits<P*> : GenericHashTraits<P*> {