Bug 16207 – JavaScript regular expressions should match UTF-16 code units rather than characters

• Component: JavaScriptCore
• Status: RESOLVED FIXED

[Darin Adler]

Testing with other browsers indicates that the JavaScript regular expression code needs to treat surrogate pairs as two "characters" rather than a single character to match them.

This is good news in a way, because it's an easy way to make the regular expression engine faster, by removing the UTF-16 smarts from most of the engine.

[Darin Adler]

Created attachment 17606 [details]
patch, speeds up SunSpider

[Adam Roben (:aroben)]

Comment on attachment 17606 [details]
patch, speeds up SunSpider

 2425                                 d = *++ptr;

The precedence here seems correct, but potentially confusing. Maybe *(++ptr) would be better?

 757                 int c = *stack.currentFrame->args.subjectPtr++;

Again, parentheses might make it clearer what precedence you're expecting here (and in the other instances of this expression).

 1640                                 if (stack.currentFrame->args.subjectPtr >= md.end_subject || isNewline(*stack.currentFrame->args.subjectPtr))

Why did you leave the comparison with md.end_subject here but now elsewhere?

r=me

[Darin Adler]

Committed revision 28243.