[PATCH v9 13/14] include/array_length.h: add array_foreach[_const] macros

[Adhemerval Zanella Netto]

On 16/06/25 14:56, Florian Weimer wrote:
> * Adhemerval Zanella Netto:
> 
>> On 11/06/25 22:35, H. Peter Anvin wrote:
>>> Add simple-to-use iterator macros for arrays.  They are used instead
>>> of explicit for statements, like:
>>>
>>>       /* Test all common speeds */
>>>       array_foreach_const (ts, test_speeds)
>>> 	test (fd, *ts);
>>>
>>> In this case, ts will be a const pointer to each of the elements of
>>> test_speeds in turn.
>>>
>>> Named array_foreach*() to allow for other kinds of equivalent iterator
>>> macros in the future.
>>>
>>> Signed-off-by: "H. Peter Anvin" (Intel) <hpa@zytor.com>
>>
>> LGTM, thanks.
>>
>> Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
>>
>>> ---
>>>  include/array_length.h | 14 ++++++++++++++
>>>  1 file changed, 14 insertions(+)
>>>
>>> diff --git a/include/array_length.h b/include/array_length.h
>>> index 2305e211b210..53e436b53387 100644
>>> --- a/include/array_length.h
>>> +++ b/include/array_length.h
>>> @@ -33,4 +33,18 @@
>>>     VAR must evaluate to an array, not a pointer.  */
>>>  #define array_end(var) (&(var)[array_length (var)])
>>>  
>>> +/* array_foreach (PTR, ARRAY) iterates over all the elements in an
>>> +   array, assigning the locally defined pointer variable PTR to each
>>> +   element in turn.
>>> +
>>> +   array_foreach_const (PTR, ARRAY) does the same, but PTR is declared
>>> +   const even if the array is not. */
> 
> Note that PTR is not a variable, but an identifier.  The comment does
> not make this quite clear.  And PTR is not declared const, it's declared
> as a pointer *to* const.
> 
> I wasn't sure if I like these macros, but I think they are not too bad,
> given that the way they work, the loop body is not covered by the macro,
> and break, continue, return all keep working as expected.
> 
>>> +#define array_foreach(ptr, array)                                      \
>>> +  for (__typeof ((array)[0]) *ptr = (array) ;			       \
>>> +       ptr < array_end(array) ; ptr++)
>>> +
>>> +#define array_foreach_const(ptr, array)                                \
>>> +  for (const __typeof ((array)[0]) *ptr = (array) ;		       \
>>> +       ptr < array_end(array) ; ptr++)
>>> +
>>>  #endif /* _ARRAY_LENGTH_H */
> 
> Please fix the style nits (missing spaces before '(') before committing.

Ack, I have updated my branch with these fixes.

> 
> Thanks,
> Florian
>