Changeset 19631 in webkit for trunk/JavaScriptCore/wtf/Vector.h

Timestamp:

Feb 14, 2007, 3:42:44 PM (18 years ago)

Author:

andersca

Message:

Reviewed by Darin.

Add new canCompareWithMemcmp vector trait and use it to determine whether
operator== can use memcmp.

• wtf/Vector.h: (WTF::): (WTF::VectorTypeOperations::compare): (WTF::operator==):
• wtf/VectorTraits.h: (WTF::):

File:

• trunk/JavaScriptCore/wtf/Vector.h (modified) (3 diffs)

trunk/JavaScriptCore/wtf/Vector.h

@@ -177 +177 @@
     };
     
+    template<bool canCompareWithMemcmp, typename T>
+    class VectorComparer;
+    
+    template<typename T>
+    struct VectorComparer<false, T>
+    {
+        static bool compare(const T* a, const T* b, size_t size)
+        {
+            for (size_t i = 0; i < size; ++i)
+                if (a[i] != b[i])
+                    return false;
+            return false;
+        }
+    };
+
+    template<typename T>
+    struct VectorComparer<true, T>
+    {
+        static bool compare(const T* a, const T* b, size_t size)
+        {
+            return memcmp(a, b, sizeof(T) * size) == 0;
+        }
+    };
+    
     template<typename T>
     struct VectorTypeOperations
@@ -208 +232 @@
         {
             VectorFiller<VectorTraits<T>::canFillWithMemset, T>::uninitializedFill(dst, dstEnd, val);
+        }
+        
+        static bool compare(const T* a, const T* b, size_t size)
+        {
+            return VectorComparer<VectorTraits<T>::canCompareWithMemcmp, T>::compare(a, b, size);
         }
     };
@@ -669 +698 @@
             return false;
 
-        for (size_t i = 0; i < a.size(); ++i)
-            if (a.at(i) != b.at(i))
-                return false;
-
-        return true;
+        return VectorTypeOperations<T>::compare(a.data(), b.data(), a.size());
     }