RFR: 8327791: Optimization for new BigDecimal(String) [v12]

[Shaojin Wen]

On Wed, 13 Mar 2024 12:12:20 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> Shaojin Wen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   fix benchmark
>
> src/java.base/share/classes/java/math/BigDecimal.java line 596:
> 
>> 594:                 // First compact case, we need not to preserve the character
>> 595:                 // and we can just compute the value in place.
>> 596:                 for (; ; c = val.charAt(++offset)) {
> 
> This looks gnarly, and it's unclear if it's correct for invalid inputs like `""`, `"-"` and `"+"` since you're not testing for `len > 0` before going into the loop. Can you make sure there are tests covering such inputs and try to simplify this?

If the input is "+" or "-" an exception will be thrown on line 583

            boolean isneg = c == '-'; // leading minus means negative
            if (isneg || c == '+') {
                c = val.charAt(++offset); 
                len--;
            }

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PR Review Comment: https://git.openjdk.org/jdk/pull/18177#discussion_r1523235244