Changeset 4639 in webkit for trunk/JavaScriptCore/kjs/array_object.cpp

Timestamp:

Jul 13, 2003, 2:40:45 PM (22 years ago)

Author:

darin

Message:

Reviewed by Maciej.

• do some improvements Maciej suggested while reviewing the array index change

• kjs/array_object.cpp: (getArrayIndex): Return a flag to say whether the index was value separately, to avoid in-band signalling. (ArrayInstanceImp::get): Update for new getArrayIndex parameters. (ArrayInstanceImp::put): Ditto. (ArrayInstanceImp::hasProperty): Ditto. (ArrayInstanceImp::setLength): Ditto.

• kjs/ustring.cpp: (UString::toStrictUInt32): Check for overflow in a way that avoids doing a divide every time through the loop. But note that it adds an extra branch to the loop. I wonder which is worse.

File:

• trunk/JavaScriptCore/kjs/array_object.cpp (modified) (5 diffs)

trunk/JavaScriptCore/kjs/array_object.cpp

@@ -73 +73 @@
 // Rule from ECMA 15.2 about what an array index is.
 // Must exactly match string form of an unsigned integer, and be less than 2^32 - 1.
-
-const unsigned maxUInt32 = 0xFFFFFFFFU;
-const unsigned notArrayIndex = maxUInt32;
-
-unsigned getArrayIndex(const Identifier &propertyName)
+bool getArrayIndex(const Identifier &propertyName, unsigned &index)
 {
   bool ok;
-  unsigned index = propertyName.toStrictUInt32(&ok);
-  if (!ok || index >= maxUInt32)
-    return notArrayIndex;
-  return index;
+  unsigned i = propertyName.toStrictUInt32(&ok);
+  if (!ok || i >= 0xFFFFFFFFU)
+    return false;
+  index = i;
+  return true;
 }
 
@@ -91 +88 @@
     return Number(length);
 
-  unsigned index = getArrayIndex(propertyName);
-  if (index != notArrayIndex) {
+  unsigned index;
+  if (getArrayIndex(propertyName, index)) {
     if (index >= length)
       return Undefined();
@@ -124 +121 @@
   }
   
-  unsigned index = getArrayIndex(propertyName);
-  if (index != notArrayIndex) {
+  unsigned index;
+  if (getArrayIndex(propertyName, index)) {
     put(exec, index, value, attr);
     return;
@@ -157 +154 @@
     return true;
   
-  unsigned index = getArrayIndex(propertyName);
-  if (index != notArrayIndex) {
+  unsigned index;
+  if (getArrayIndex(propertyName, index)) {
     if (index >= length)
       return false;
@@ -265 +262 @@
     while (it != sparseProperties.end()) {
       Reference ref = it++;
-      unsigned index = getArrayIndex(ref.getPropertyName(exec));
-      if (index != notArrayIndex && index > newLength) {
+      unsigned index;
+      if (getArrayIndex(ref.getPropertyName(exec), index) && index > newLength) {
         ref.deleteValue(exec);
       }