On Fri, 6 Oct 2023 03:16:50 GMT, Quan Anh Mai <[email protected]> wrote:
>> Raffaello Giulietti has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> Avoid localized integers in radix-out-of-range exception messages.
>
> Could we parse the signed int by parsing the unsigned suffix then prepend the
> sign? It will unify the code path of `parseInt` and `parseUnsignedInt`.
>
> Thanks.
@merykitty For a `String` input that would mean copying the suffix, which could
be quite long, or make use of the method that accepts a `CharSequence`, which
has different (although more complete) exception messages. Perhaps in a
followup PR.
What would be _really_ nice is to be able to write, for example (leaving apart
the exception messages issue above)
public static int parseInt(String s, int radix)
throws NumberFormatException {
return parseInt(s, 0, s.length(), radix); // delegate to the CharSequence
method
}
and leave it to the runtime compiler to perform something similar to
* make a copy of the `parseInt(CharSequence,int,int,int)` code into
`parseInt(String,int)`
* adapt the copy to the `String` case by replacing `invokeinterface` for
`charAt()` with `invokevirtual`, which can be further optimized to direct
invocation because `String` is final, and eventually inlined perfectly.
Currently, that does not seem to happen, but I might be wrong.
This would spare us 4 code duplications here, and perhaps in many other places
where we have almost identical methods for `String` and `CharSequence`.
> src/java.base/share/classes/java/lang/Integer.java line 767:
>
>> 765: /* Use MIN_VALUE + x < MIN_VALUE + y as unsigned x < y
>> comparison */
>> 766: while (i < len && (digit = digit(s.charAt(i++), radix)) >= 0
>> 767: && (inRange = MIN_VALUE + result < MIN_VALUE +
>> multmax
>
> `compareUnsigned(result, multmax) < 0` would be better here.
Oops @merykitty, I see right now that `compareUnsigned` is an intrinsic, so
I'll give it a try.
-------------
PR Comment: https://git.openjdk.org/jdk/pull/16050#issuecomment-1750314751
PR Review Comment: https://git.openjdk.org/jdk/pull/16050#discussion_r1348509327
