On Fri, 19 Sep 2025 01:15:14 GMT, Guanqiang Han <g...@openjdk.org> wrote:
>> test/jdk/jdk/internal/util/TestUtfLen.java line 50:
>>
>>> 48: for (int i = 0; i < iterations; i++) {
>>> 49: total += ModifiedUtf.utfLen(chunk, 0);
>>> 50: }
>>
>> Suggestion:
>>
>> long total = ModifiedUtf.utfLen(chunk.repeat(iterations), 0);
>
> String.repeat() cannot generate a string whose total length exceeds
> Integer.MAX_VALUE due to internal limits. That’s why I used a small chunk and
> accumulated UTF-8 length in a loop.It seems that the String type cannot hold
> a string whose length exceeds Integer.MAX_VALUE.
> https://github.com/openjdk/jdk/blob/e3a4c28409ac62feee9efe069e3a3482e7e2cdd2/src/java.base/share/classes/java/lang/String.java#L4875
jshell --add-exports java.base/jdk.internal.util=ALL-UNNAMED
| Welcome to JShell -- Version 24
| For an introduction type: /help intro
jshell> import jdk.internal.util.ModifiedUtf;
jshell> var s = "\u0100\u0100\u2600".repeat(Integer.MAX_VALUE / 6 - 1);
s ==> "???????????????????????????????????????????????? ...
?????????????????????????"
jshell> ModifiedUtf.utfLen(s)
| Error:
| method utfLen in class jdk.internal.util.ModifiedUtf cannot be applied to
given types;
| required: java.lang.String,int
| found: java.lang.String
| reason: actual and formal argument lists differ in length
| ModifiedUtf.utfLen(s)
| ^----------------^
jshell> ModifiedUtf.utfLen(s, 0)
$3 ==> -1789569716
You can construct such a string if the number of bytes in the Modified UTF 8
form is more than the number of bytes in UTF16 form, such as if you use all
3-byte characters.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/27285#discussion_r2361493886
