Hi Claes,
it looks good. And I have one minor improvement. Take look at the following
lines of the method FormatSpecifier#hexDouble(double, int):
3532 // Get exponent and append at the end.
3533 String exp = res.substring(idx + 1);
3534 int iexp = Integer.parseInt(exp) -54;
3535 return res.substring(0, idx) + "p"
3536 + Integer.toString(iexp);
The lines 3535-3536 are translated by the compiler to:
new StringBuilder().append(res.substring(0,
idx)).append("p").append(Integer.toString(iexp)).toString();
If we rewrite it to use StringBuilder, we can avoid creation of
intermediate String objects, e.g.:
3535 return new StringBuilder().append(res, 0,
idx).append('p')
3536 .append(iexp).toString();
But I'm not sure how common is the usage of #hexDouble-method. Maybe this
change is not worth it.
Best regards,
Andrej Golovnin
On Mon, Jul 14, 2014 at 2:23 PM, Claes Redestad <claes.redes...@oracle.com>
wrote:
> Hi again,
>
> updated webrev: http://cr.openjdk.java.net/~redestad/8050142/webrev.1
>
> changes:
> - specify capacity on line 2931 as suggested by Andrej Golovnin
> - exp.append("0") -> exp.append('0') on line 3781
> - merged append+justify into appendJustified as suggested by Peter Levart
> - replaced the reoccuring pattern of appending a number of zeros into a
> call to trailingZeros
>
> performance difference seemingly at noise levels in micros, but bonus to
> readability and Formatter*.class-files are now a total of 246 bytes smaller
>
> /Claes
>
>
> On 2014-07-14 13:29, Claes Redestad wrote:
>
>> Hi Peter,
>>
>> On 2014-07-14 13:25, Peter Levart wrote:
>>
>>> On 07/14/2014 12:07 PM, Claes Redestad wrote:
>>>
>>>> Hi,
>>>>
>>>> please review this patch which optimizes away some allocations from
>>>> java.util.Formatter and achieve 1.1-1.3x speedups of micros targetting
>>>> String.format. See bug for more details.
>>>>
>>>> webrev: http://cr.openjdk.java.net/~redestad/8050142/webrev.0
>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8050142
>>>>
>>>> Testing: JPRT, jtreg (java/lang/String, java/util/Formatter),
>>>> SPECjbb2013 and microbenchmarks
>>>>
>>>> Thanks!
>>>>
>>>> /Claes
>>>>
>>>
>>> Hi Claes,
>>>
>>> Since justify() result is always appended to the resulting Appendable,
>>> you could merge the functionality and eliminate constructing intermediary
>>> StringBuilder altogether:
>>>
>>> http://cr.openjdk.java.net/~plevart/jdk9-dev/Formatter/webrev.01/
>>>
>>> Looks good, especially eliminating the need for two different append
>> methods. I'll update based on this and other suggestions.
>>
>> /Claes
>>
>>> Regards, Peter
>>>
>>
>>
>
