67577 - basic_nsAReadableString<CharT>::Equals should short circuit

Status: RESOLVED FIXED

(Core :: XPCOM, defect)

Description

[John Bandhauer]

I think the template method...

PRBool
basic_nsAReadableString<CharT>::Equals( const basic_nsAReadableString<CharT>& 
rhs ) const

...should short-circuit when Length() != rhs.Length(). This might often avoid 
lots of unnecessary groveling through the chars in Compare. In cases where the 
lengths are equal the cost of this check is a duplicated pair of Length() calls 
- since ::Compare will itself still need to do this.

I have no numbers to show this as a win, only my guess. Do with it what you will 
:)

Comment 1

[Scott Collins]

Here's a patch ---

Index: mozilla/string/public/nsAReadableString.h
===================================================================
RCS file: /cvsroot/mozilla/string/public/nsAReadableString.h,v
retrieving revision 1.93
diff -u -2 -r1.93 nsAReadableString.h
--- nsAReadableString.h	2001/02/07 03:04:46	1.93
+++ nsAReadableString.h	2001/02/23 00:50:01
@@ -516,5 +516,5 @@
 basic_nsAReadableString<CharT>::Equals( const basic_nsAReadableString<CharT>&
rhs ) const
   {
-    return Compare(rhs) == 0;
+    return Length() == rhs.Length() && Compare(rhs) == 0;
   }

Comment 2

[Peter "jag" Annema]

r=jag

Comment 3

[Ben Goodger (use ben at mozilla dot org for email)]

a=[e-mail]

Comment 4

[David Hyatt]

sr=hyatt

Comment 5

[Scott Collins]

fix checked in, thanks guys.  Hope this makes you happy, jband.