Changeset 4639 in webkit for trunk/JavaScriptCore/kjs/ustring.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/ustring.cpp (modified) (1 diff)

trunk/JavaScriptCore/kjs/ustring.cpp

@@ -686 +686 @@
     const unsigned d = c - '0';
     
-    // Check for overflow.
-    const unsigned maxProduct = 0xFFFFFFFFU - d;
-    if (i > maxProduct / 10)
+    // Multiply by 10, checking for overflow out of 32 bits.
+    if (i > 0xFFFFFFFFU / 10)
       return 0;
+    i *= 10;
     
-    // Add in another digit.
-    i *= 10;
+    // Add in the digit, checking for overflow out of 32 bits.
+    const unsigned max = 0xFFFFFFFFU - d;
+    if (i > max)
+        return 0;
     i += d;