Changeset 101186 in webkit

Timestamp:

Nov 25, 2011, 10:01:06 PM (15 years ago)

Author:

msaboff@apple.com

Message:

Array.toString always uses StringImpl::characters()
​https://bugs.webkit.org/show_bug.cgi?id=72969

If all component strings are 8 bit, create an 8 bit result string for toString().

This appears to be performance neutral to sunspider and v8.

Reviewed by Filip Pizlo.

• runtime/ArrayPrototype.cpp:

(JSC::arrayProtoFuncToString):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• runtime/ArrayPrototype.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2011-11-25  Michael Saboff  <msaboff@apple.com>
+
+        Array.toString always uses StringImpl::characters()
+        https://bugs.webkit.org/show_bug.cgi?id=72969
+
+        If all component strings are 8 bit, create an 8 bit result string for toString().
+
+        This appears to be performance neutral to sunspider and v8.
+
+        Reviewed by Filip Pizlo.
+
+        * runtime/ArrayPrototype.cpp:
+        (JSC::arrayProtoFuncToString):
+
 2011-11-24  Michael Saboff  <msaboff@apple.com>
 

trunk/Source/JavaScriptCore/runtime/ArrayPrototype.cpp

@@ -186 +186 @@
     unsigned totalSize = length ? length - 1 : 0;
     Vector<RefPtr<StringImpl>, 256> strBuffer(length);
+    bool allStrings8Bit = true;
 
     for (unsigned k = 0; k < length; k++) {
@@ -200 +201 @@
         strBuffer[k] = str.impl();
         totalSize += str.length();
+        allStrings8Bit = allStrings8Bit && str.is8Bit();
         
         if (!strBuffer.data()) {
@@ -210 +212 @@
     if (!totalSize)
         return JSValue::encode(jsEmptyString(exec));
+
+    if (allStrings8Bit) {
+        Vector<LChar> buffer;
+        buffer.reserveCapacity(totalSize);
+        if (!buffer.data())
+            return JSValue::encode(throwOutOfMemoryError(exec));
+        
+        for (unsigned i = 0; i < length; i++) {
+            if (i)
+                buffer.append(',');
+            if (RefPtr<StringImpl> rep = strBuffer[i])
+                buffer.append(rep->characters8(), rep->length());
+        }
+        ASSERT(buffer.size() == totalSize);
+        return JSValue::encode(jsString(exec, UString::adopt(buffer)));        
+    }
+
     Vector<UChar> buffer;
     buffer.reserveCapacity(totalSize);