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

[Florian Weimer]

* 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.

Thanks,
Florian