Title: [184866] trunk/Source/_javascript_Core
- Revision
- 184866
- Author
- [email protected]
- Date
- 2015-05-26 11:56:42 -0700 (Tue, 26 May 2015)
Log Message
String.prototype.charCodeAt() should use StringView.
<https://webkit.org/b/145353>
Reviewed by Darin Adler.
Use JSString::view() in charCodeAt() to avoid reifying the JSString if it's
a substring. This avoids StringImpl allocation in some cases and ref churn
in all cases.
* runtime/StringPrototype.cpp:
(JSC::stringProtoFuncCharCodeAt):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (184865 => 184866)
--- trunk/Source/_javascript_Core/ChangeLog 2015-05-26 18:54:01 UTC (rev 184865)
+++ trunk/Source/_javascript_Core/ChangeLog 2015-05-26 18:56:42 UTC (rev 184866)
@@ -1,5 +1,19 @@
2015-05-26 Andreas Kling <[email protected]>
+ String.prototype.charCodeAt() should use StringView.
+ <https://webkit.org/b/145353>
+
+ Reviewed by Darin Adler.
+
+ Use JSString::view() in charCodeAt() to avoid reifying the JSString if it's
+ a substring. This avoids StringImpl allocation in some cases and ref churn
+ in all cases.
+
+ * runtime/StringPrototype.cpp:
+ (JSC::stringProtoFuncCharCodeAt):
+
+2015-05-26 Andreas Kling <[email protected]>
+
String.prototype.charAt() should use StringView.
<https://webkit.org/b/145352>
Modified: trunk/Source/_javascript_Core/runtime/StringPrototype.cpp (184865 => 184866)
--- trunk/Source/_javascript_Core/runtime/StringPrototype.cpp 2015-05-26 18:54:01 UTC (rev 184865)
+++ trunk/Source/_javascript_Core/runtime/StringPrototype.cpp 2015-05-26 18:56:42 UTC (rev 184866)
@@ -804,21 +804,17 @@
JSValue thisValue = exec->thisValue();
if (!checkObjectCoercible(thisValue))
return throwVMTypeError(exec);
- String s = thisValue.toString(exec)->value(exec);
- unsigned len = s.length();
+ StringView string = thisValue.toString(exec)->view(exec);
JSValue a0 = exec->argument(0);
if (a0.isUInt32()) {
uint32_t i = a0.asUInt32();
- if (i < len) {
- if (s.is8Bit())
- return JSValue::encode(jsNumber(s.characters8()[i]));
- return JSValue::encode(jsNumber(s.characters16()[i]));
- }
+ if (i < string.length())
+ return JSValue::encode(jsNumber(string[i]));
return JSValue::encode(jsNaN());
}
double dpos = a0.toInteger(exec);
- if (dpos >= 0 && dpos < len)
- return JSValue::encode(jsNumber(s[static_cast<int>(dpos)]));
+ if (dpos >= 0 && dpos < string.length())
+ return JSValue::encode(jsNumber(string[static_cast<int>(dpos)]));
return JSValue::encode(jsNaN());
}
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