RFR: 8343829: Unify decimal and hexadecimal parsing in FloatingDecimal [v9]

[Raffaello Giulietti]

On Fri, 9 May 2025 22:58:19 GMT, Chen Liang <liach at openjdk.org> wrote:

>> Raffaello Giulietti has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 14 additional commits since the last revision:
>> 
>>  - Removed useless comment.
>>  - Merge branch 'master' into 8343829
>>  - Added javadoc to refer to the grammar in j.l.Double.
>>  - Merge branch 'master' into 8343829
>>  - Make some static arrays @Stable.
>>  - Remove unused BIG_DECIMAL_EXPONENT
>>  - Merge branch 'master' into 8343829
>>  - Merge branch 'master' into 8343829
>>  - Redacted comments.
>>  - Merge branch 'master' into 8343829
>>  - ... and 4 more: https://git.openjdk.org/jdk/compare/8862cc91...88fe2c08
>
> src/java.base/share/classes/jdk/internal/math/FloatingDecimal.java line 1964:
> 
>> 1962: 
>> 1963:         /* Skip opt [FfDd]? suffix. */
>> 1964:         if (i < len && (((ch = in.charAt(i) | 0b10_0000)) == 'f' || ch == 'd')) {
> 
> Is it really right to ignore these suffix for all ix values?

Although this might seem surprising, yes, it is right.
This is what the `[Double|Float].valueOf(String)` specs say (these are the "main clients" of this class):
> Note that trailing format specifiers, [...] do not influence the results of this method.

> src/java.base/share/classes/jdk/internal/math/FloatingDecimal.java line 2006:
> 
>> 2004:          *
>> 2005:          *         |lz            |pt |tnz  |stop
>> 2006:          * 0000000012345600000023.4567000000000
> 
> Suggestion:
> 
>          *         |lz            |pt |tnz     |stop
>          * 0000000012345600000023.4567000000000

Addressed.

> src/java.base/share/classes/jdk/internal/math/FloatingDecimal.java line 2265:
> 
>> 2263: 
>> 2264:     /* Arithmetically "appends the digit" ch to v >= 0, clamping at 10^10. */
>> 2265:     private static long appendDigit(long v, int ch) {
> 
> Since this appends only decimal digit, should we name it `appendDecDegit`? In the use site we already note all exponents are decimals.

Addressed.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/22737#discussion_r2083096389
PR Review Comment: https://git.openjdk.org/jdk/pull/22737#discussion_r2083096060
PR Review Comment: https://git.openjdk.org/jdk/pull/22737#discussion_r2083096070