RFR: 8316704: Regex-free parsing of Formatter and FormatProcessor specifiers [v17]

[Claes Redestad]

On Mon, 9 Oct 2023 20:40:43 GMT, 温绍锦 <duke at openjdk.org> wrote:

>> @cl4es made performance optimizations for the simple specifiers of String.format in PR https://github.com/openjdk/jdk/pull/2830. Based on the same idea, I continued to make improvements. I made patterns like %2d %02d also be optimized.
>> 
>> The following are the test results based on MacBookPro M1 Pro: 
>> 
>> 
>> -Benchmark                          Mode  Cnt     Score     Error  Units
>> -StringFormat.complexFormat         avgt   15  1862.233 ? 217.479  ns/op
>> -StringFormat.int02Format           avgt   15   312.491 ?  26.021  ns/op
>> -StringFormat.intFormat             avgt   15    84.432 ?   4.145  ns/op
>> -StringFormat.longFormat            avgt   15    87.330 ?   6.111  ns/op
>> -StringFormat.stringFormat          avgt   15    63.985 ?  11.366  ns/op
>> -StringFormat.stringIntFormat       avgt   15    87.422 ?   0.147  ns/op
>> -StringFormat.widthStringFormat     avgt   15   250.740 ?  32.639  ns/op
>> -StringFormat.widthStringIntFormat  avgt   15   312.474 ?  16.309  ns/op
>> 
>> +Benchmark                          Mode  Cnt    Score    Error  Units
>> +StringFormat.complexFormat         avgt   15  740.626 ? 66.671  ns/op (+151.45)
>> +StringFormat.int02Format           avgt   15  131.049 ?  0.432  ns/op (+138.46)
>> +StringFormat.intFormat             avgt   15   67.229 ?  4.155  ns/op (+25.59)
>> +StringFormat.longFormat            avgt   15   66.444 ?  0.614  ns/op (+31.44)
>> +StringFormat.stringFormat          avgt   15   62.619 ?  4.652  ns/op (+2.19)
>> +StringFormat.stringIntFormat       avgt   15   89.606 ? 13.966  ns/op (-2.44)
>> +StringFormat.widthStringFormat     avgt   15   52.462 ? 15.649  ns/op (+377.95)
>> +StringFormat.widthStringIntFormat  avgt   15  101.814 ?  3.147  ns/op (+206.91)
>
> 温绍锦 has updated the pull request incrementally with one additional commit since the last revision:
> 
>   move testcase from BasicInt to Basic-X

test/jdk/java/util/Formatter/Basic-X.java.template line 1748:

> 1746:         // perhaps an IllegalFormatArgumentIndexException should be defined?
> 1747:         tryCatch("%<%", IllegalFormatFlagsException.class);
> 1748: 

After adding test-cases to this template you need to run `genBasic.sh` (in the same folder) to regenerate all the `Basic*` tests. These changes then need to be added to the PR.

FWIW these new and existing tests that provoke `IllegalFormatPrecisionException` and `UnknownFormatConversionException` are common to all types, meaning there seems to be little point in generating them out into each and every `BasicByte`, `BasicInt` et.c.. Perhaps it would make more sense to add such tests directly to Basic.java to avoid some redundancy here - or a new `BasicCommon` test to put common tests into?

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PR Review Comment: https://git.openjdk.org/jdk/pull/15776#discussion_r1350933399