RFR: 8316150: Refactor get chars and string size

[Jim Laskey]

On Fri, 22 Sep 2023 13:50:37 GMT, Shaojin Wen <duke at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/util/DecimalDigits.java line 115:
>> 
>>> 113:         }
>>> 114:         return 10 + d;
>>> 115:     }
>> 
>> @wenshao How about of using [this](https://github.com/plokhotnyuk/jsoniter-scala/blob/6b72cf75ad7f53e8a285d512009d164c3eabbb3a/jsoniter-scala-core/jvm/src/main/scala/com/github/plokhotnyuk/jsoniter_scala/core/JsonWriter.scala#L2367-L2369) trick to avoid multiplications in a loop?
>
> This implementation is copied from Integer.stringSize. In 2015, @Shipilev modified the table lookup to the current implementation. In actual testing, this algorithm is faster.

No doubt, but that algorithm could have been easily integrated into the Digits implementation without disruption.

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PR Review Comment: https://git.openjdk.org/jdk/pull/15699#discussion_r1334490412