On Wed, 5 Feb 2025 12:58:49 GMT, Shaojin Wen <s...@openjdk.org> wrote:
>> This is an optimization for decimal Integer.parseInt and Long.parseLong,
>> which improves performance by about 10%. The optimization includes:
>> 1. Improve performance by parsing 2 numbers at a time, which has performance
>> improvements for numbers with length >= 3.
>> 2. It uses charAt(0) for the first number. Assuming that the optimization
>> can eliminate boundary checks, this will be more friendly to parsing numbers
>> with length 1.
>> 3. It removes the reliance on the Character.digit method and eliminates the
>> reliance on the CharacterDataLatin1#DIGITS cache array, which avoids
>> performance degradation caused by cache misses.
>
> Shaojin Wen has updated the pull request incrementally with one additional
> commit since the last revision:
>
> copyright
src/java.base/share/classes/jdk/internal/util/DecimalDigits.java line 138:
> 136:
> 137: /**
> 138: * Determine whether the two strings in bytes are both numbers. If
> they are, return d0 * 10 + d1, otherwise return -1
This is confusing: two strings?
Also, "digits" would be better than "numbers".
Finally, d0 and d1 are not defined here.
src/java.base/share/classes/jdk/internal/util/DecimalDigits.java line 144:
> 142: */
> 143: @ForceInline
> 144: public static int digit2(byte[] str, int offset) {
Suggestion:
public static int digit2(byte[] str, int offset) {
// Used by trusted callers. Assumes all necessary bounds checks have
been done by the caller.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/22919#discussion_r1943003191
PR Review Comment: https://git.openjdk.org/jdk/pull/22919#discussion_r1943003383
