RFR: 8351443: Improve robustness of StringBuilder [v7]

[Raffaello Giulietti]

On Fri, 9 May 2025 13:28:44 GMT, Raffaello Giulietti <rgiulietti at openjdk.org> wrote:

>> Roger Riggs has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add an assert to inflateToUTF16 method
>>   Add doc of preconditions to appendChars... methods
>>   Correct misc javadoc
>
> src/java.base/share/classes/java/lang/AbstractStringBuilder.java line 1901:
> 
>> 1899:         }
>> 1900:         return value;
>> 1901:     }
> 
> I think the logic can be simplified, without a need for the loop.
> 
>     private static byte[] putCharsAt(byte[] value, byte coder, int count, int index, char[] s, int off, int end) {
>         if (isLatin1(coder)) {
>             int latin1Len = StringUTF16.compress(s, off, value, index, end - off);
>             if (latin1Len < end - off) {
>                 value = inflateToUTF16(value, count);
>                 StringUTF16.putCharsSB(value, index + latin1Len, s, off + latin1Len, end);
>             }
>         } else {
>             StringUTF16.putCharsSB(value, index, s, off, end);
>         }
>         return value;
>     }

Unfortunately, my simplification isn't sound when `s` is concurrently modified.
Please disregard.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24967#discussion_r2081978097