Changeset 43856 in webkit for trunk/JavaScriptCore/runtime

Timestamp:

May 19, 2009, 1:01:22 AM (16 years ago)

Author:

[email protected]

Message:

2009-05-19 Maciej Stachowiak <​[email protected]>

Reviewed by Gavin Barraclough.

• speed up string comparison, especially for short strings

~1% on SunSpider

• JavaScriptCore.exp:
• runtime/UString.cpp:
• runtime/UString.h: (JSC::operator==): Inline UString's operator==, since it is called from hot places in the runtime. Also, specialize 2-char strings in a similar way to 1-char, since we're taking the hit of a switch anyway.

Location:

trunk/JavaScriptCore/runtime

Files:

• UString.cpp (modified) (1 diff)
• UString.h (modified) (1 diff)

trunk/JavaScriptCore/runtime/UString.cpp

@@ -1567 +1567 @@
 }
 
-bool operator==(const UString& s1, const UString& s2)
-{
-    int size = s1.size();
-    switch (size) {
-        case 0:
-            return !s2.size();
-        case 1:
-            return s2.size() == 1 && s1.data()[0] == s2.data()[0];
-        default:
-            return s2.size() == size && memcmp(s1.data(), s2.data(), size * sizeof(UChar)) == 0;
-    }
-}
-
 bool operator==(const UString& s1, const char *s2)
 {

trunk/JavaScriptCore/runtime/UString.h

@@ -356 +356 @@
     PassRefPtr<UString::Rep> concatenate(UString::Rep*, double);
 
-    bool operator==(const UString&, const UString&);
+    inline bool operator==(const UString& s1, const UString& s2)
+    {
+        int size = s1.size();
+        switch (size) {
+        case 0:
+            return !s2.size();
+        case 1:
+            return s2.size() == 1 && s1.data()[0] == s2.data()[0];
+        case 2: {
+            if (s2.size() != 2)
+                return false;
+            const UChar* d1 = s1.data();
+            const UChar* d2 = s2.data();
+            return (d1[0] == d2[0]) & (d1[1] == d2[1]);
+        }
+        default:
+            return s2.size() == size && memcmp(s1.data(), s2.data(), size * sizeof(UChar)) == 0;
+        }
+    }
+
 
     inline bool operator!=(const UString& s1, const UString& s2)