Changeset 43104 in webkit for trunk/JavaScriptCore/runtime

Timestamp:

Apr 30, 2009, 4:36:38 PM (16 years ago)

Author:

[email protected]

Message:

2009-04-30 Maciej Stachowiak <​[email protected]>

Reviewed by Gavin Barraclough.

• Concatenate final three strings in simple replace case at one go

~0.2% SunSpider speedup

• runtime/StringPrototype.cpp: (JSC::stringProtoFuncReplace): Use new replaceRange helper instead of taking substrings and concatenating three strings.
• runtime/UString.cpp: (JSC::UString::replaceRange): New helper function.
• runtime/UString.h:

Location:

trunk/JavaScriptCore/runtime

Files:

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

trunk/JavaScriptCore/runtime/StringPrototype.cpp

@@ -352 +352 @@
 
     int ovector[2] = { matchPos, matchPos + matchLen };
-    return jsString(exec, source.substr(0, matchPos)
-        + substituteBackreferences(replacementString, source, ovector, 0)
-        + source.substr(matchPos + matchLen));
+    return jsString(exec, source.replaceRange(matchPos, matchLen, substituteBackreferences(replacementString, source, ovector, 0)));
 }
 

trunk/JavaScriptCore/runtime/UString.cpp

@@ -982 +982 @@
 }
 
+UString UString::replaceRange(int rangeStart, int rangeLength, const UString& replacement) const
+{
+    m_rep->checkConsistency();
+
+    int replacementLength = replacement.size();
+    int totalLength = size() - rangeLength + replacementLength;
+    if (totalLength == 0)
+        return "";
+
+    UChar* buffer = allocChars(totalLength);
+    if (!buffer)
+        return null();
+
+    copyChars(buffer, data(), rangeStart);
+    copyChars(buffer + rangeStart, replacement.data(), replacementLength);
+    int rangeEnd = rangeStart + rangeLength;
+    copyChars(buffer + rangeStart + replacementLength, data() + rangeEnd, size() - rangeEnd);
+
+    return UString::Rep::create(buffer, totalLength);
+}
+
+
 UString& UString::append(const UString &t)
 {

trunk/JavaScriptCore/runtime/UString.h

@@ -245 +245 @@
         UString spliceSubstringsWithSeparators(const Range* substringRanges, int rangeCount, const UString* separators, int separatorCount) const;
 
+        UString replaceRange(int rangeStart, int RangeEnd, const UString& replacement) const;
+
         UString& append(const UString&);
         UString& append(const char*);