<i18n dev> RFR: 8358880: Performance of parsing with DecimalFormat can be improved [v3]

[Johannes Graham]

On Thu, 12 Jun 2025 22:52:21 GMT, Justin Lu <jlu at openjdk.org> wrote:

>> Unfortunately some check is required (a test fails), but I now realize what I had was wrong. The issue is that on line 1084 (https://github.com/openjdk/jdk/pull/25644/files#diff-79e6fd549b5ec5e7f49658581beddcb07fcbb0c09ae8e1117c385b66514da6d2R1084)) exp can overflow and become positive again. I've updated the check to avoid the overflow.
>
> Ah got it, I see your point. We would have goten underflow in `ASCIIToBinaryConverter.doubleValue()` for some extreme cases without a check. 
> 
> Is there a specific example you have that requires the switch to the newer check? Adding a comment along those lines might be helpful. Actually, I thought DigitList caps `decimalAt` to Integer.MIN/MAX, so then the first check you had would have been fine. (Maybe I am missing something?)

I don't have a specific example, so I've reverted to my original check. I'm a bit unsettled by the check for an extreme value later in `doubleValue()` comparing against `MIN_DECIMAL_EXPONENT - 1`

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PR Review Comment: https://git.openjdk.org/jdk/pull/25644#discussion_r2145942325