review request for 6798511/6860431: Include functionality of Surrogate in Character
Ulf.Zibis at gmx.de
Sat Mar 6 13:00:19 PST 2010
Very fast Sherman, much thanks.
Could you set the bug to accepted and evaluated, so my patch will have a
chance to get into the code base?
Am 03.03.2010 20:11, schrieb Xueming Shen:
> Martin Buchholz wrote:
>> Sherman, would you like to file bugs for Ulf's improvements?
>> On Wed, Mar 3, 2010 at 02:44, Ulf Zibis <Ulf.Zibis at gmx.de> wrote:
>>> Am 03.03.2010 09:00, schrieb Martin Buchholz:
>>>> Keep in mind that supplementary characters are extremely rare.
>>> Yes, but many API's in the JDK are used rarely.
>>> Why should they waste memory footprint / perform bad, particularly
>>> if it
>>> doesn't cost anything.
>> I admire your perfectionism.
>>>> Therefore the existing implementation
>>>> return codePoint>= MIN_SUPPLEMENTARY_CODE_POINT
>>>> && codePoint<= MAX_CODE_POINT;
>>>> will almost always perform just one comparison against a constant,
>>>> which is hard to beat.
>>> 1. Wondering: I think there are TWO comparisons.
>>> 2. Those comparisons need to load 32 bit values from machine code,
>>> only 8 bit values in my case.
>> It's a good point. In the machine code, shifts are likely to use
>> immediate values, and so will be a small win.
>> int x = codePoint >>> 16;
>> return x != 0 && x < 0x11;
>> (On modern hardware, these optimizations
>> are less valuable than they used to be;
>> ordinary integer arithmetic is almost free)
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