macros/utils: add LIMIT() and ABS() macros

[Enoch247]

Contribution description

This patch adds a macro that can be used to limit a value to a given range. It also adds the classic ABS() macro to go along with the existing MAX() and MIN() macros.

Testing procedure

It's fairly trivial. I have used it and it works in my application code.

Issues/PRs references

• none known

[riot-ci]

Murdock results

✔️ PASSED

fa7a577 tests/unittests: add test for ABS() macro

Success	Failures	Total	Runtime
10016	0	10016	09m:34s

Artifacts

• Documentation preview

[Enoch247]

Looks like there is a name collision with a macro defined in a esp32 package. I am open to other names for the new macro. LIMIT_TO_RANGE() perhaps? Something shorter?

[benpicco]

If you use the same definition as ESP32, would it still be a redefinition? 🤔

[Enoch247]

If you use the same definition as ESP32, would it still be a redefinition? 🤔

I tested the following and did not get an error or warning:

#define FOO 1
#define FOO 1

I don't know if that is promised by the language or just allowed by gcc. Do you know off the top of your head before I go looking? It does feel a bit precarious thought to rely on matching a macro defined outside the source tree.

I though about moving it to macros/math.h and calling it MATH_LIMIT(). That would require including utils.h in math.h. In my opinion MAX() and MIN()should be moved to math.h, but I think that change would affect a lot of people.

[benpicco]

If it works on CI you can be sure that all supported compilers are covered.

[Enoch247]

Ok, I made the change.

Also I added the classic ABS macro to go with MAX/MIN.

[benpicco]

Please squash!

[Enoch247]

squashed

[Enoch247]

Please wait to merge. I will added unit tests for these macros.

[Enoch247]

Ok, unit tests are added now for new and some existing macros.