On Tue, 7 Feb 2023 12:53:25 GMT, Tagir F. Valeev <tval...@openjdk.org> wrote:
>> clamp() methods added to Math and StrictMath >> >> `int clamp(long, int, int)` is somewhat different, as it accepts a `long` >> value and safely clamps it to an `int` range. Other overloads work with a >> particular type (long, float and double). Using similar approach in other >> cases (e.g. `float clamp(double, float, float)`) may cause accidental >> precision loss even if the value is within range, so I decided to avoid this. >> >> In all cases, `max >= min` precondition should met. For double and float we >> additionally order `-0.0 < 0.0`, similarly to what Math.max or >> Double.compare do. In double and float overloads I try to keep at most one >> arg-check comparison on common path, so the order of checks might look >> unusual. >> >> For tests, I noticed that tests in java/lang/Math don't use any testing >> framework (even newer tests), so I somehow mimic the approach of neighbour >> tests. > > Tagir F. Valeev has updated the pull request incrementally with one > additional commit since the last revision: > > Comments in tests Regarding the asymmetric `int clamp( long value, int min, int max )` method: I understand the idea behind using `long`, but IMHO there is a good reason to use `int`instead. When using the `var` keyword, it could easy result in unwanted type change from `long` to `int`. E.g. following simple code unexpectedly changes the type from `long` to `int`: ~~~java var longValue = 1234L; var intValue = Math.clamp( longValue, 0, 100 ); ~~~ When doing the same with `Math.min()` and `max()`, it does **not change type**: ~~~java var longValue2 = Math.min( 100, Math.max( longValue, 0 ) ); ~~~ If you don't want that type change, it is required to pass a long min or max value: ~~~java var longValue = 1234L; var longValue2 = Math.clamp( longValue, 0L, 100 ); ~~~ This is confusing, isn't it? The idea behind using `long` as first parameter is "This allows to use method to safely cast long value to int" (from javadoc). But if changing to `int clamp( int value, int min, int max )`, safely casting long to int is still possible by passing int values to min and max an casting the result to int. E.g.: ~~~java int a = (int) Math.clamp( longValue, 0, 100 ); ~~~ Also not sure whether the idea behind clamp is to provide a mechanism for safe casting... IMHO the benefit of "safe casting long to int" is very low compared to the risk of unwanted type change when using `var` keyword. ------------- PR: https://git.openjdk.org/jdk/pull/12428
