Unverified Commit c952c748 authored by Herve Codina's avatar Herve Codina Committed by Mark Brown
Browse files

minmax: Introduce {min,max}_array() 



Introduce min_array() (resp max_array()) in order to get the
minimal (resp maximum) of values present in an array.

Signed-off-by: default avatarHerve Codina <herve.codina@bootlin.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20230623085830.749991-8-herve.codina@bootlin.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 524cfdf6

include/linux/minmax.h

+64 −0
Original line number Diff line number Diff line
@@ -133,6 +133,70 @@ 
 */

#define max_t(type, x, y)	__careful_cmp((type)(x), (type)(y), >)



/*

 * Remove a const qualifier from integer types

 * _Generic(foo, type-name: association, ..., default: association) performs a

 * comparison against the foo type (not the qualified type).

 * Do not use the const keyword in the type-name as it will not match the

 * unqualified type of foo.

 */

#define __unconst_integer_type_cases(type)	\

	unsigned type:  (unsigned type)0,	\

	signed type:    (signed type)0



#define __unconst_integer_typeof(x) typeof(			\

	_Generic((x),						\

		char: (char)0,					\

		__unconst_integer_type_cases(char),		\

		__unconst_integer_type_cases(short),		\

		__unconst_integer_type_cases(int),		\

		__unconst_integer_type_cases(long),		\

		__unconst_integer_type_cases(long long),	\

		default: (x)))



/*

 * Do not check the array parameter using __must_be_array().

 * In the following legit use-case where the "array" passed is a simple pointer,

 * __must_be_array() will return a failure.

 * --- 8< ---

 * int *buff

 * ...

 * min = min_array(buff, nb_items);

 * --- 8< ---

 *

 * The first typeof(&(array)[0]) is needed in order to support arrays of both

 * 'int *buff' and 'int buff[N]' types.

 *

 * The array can be an array of const items.

 * typeof() keeps the const qualifier. Use __unconst_integer_typeof() in order

 * to discard the const qualifier for the __element variable.

 */

#define __minmax_array(op, array, len) ({				\

	typeof(&(array)[0]) __array = (array);				\

	typeof(len) __len = (len);					\

	__unconst_integer_typeof(__array[0]) __element = __array[--__len]; \

	while (__len--)							\

		__element = op(__element, __array[__len]);		\

	__element; })



/**

 * min_array - return minimum of values present in an array

 * @array: array

 * @len: array length

 *

 * Note that @len must not be zero (empty array).

 */

#define min_array(array, len) __minmax_array(min, array, len)



/**

 * max_array - return maximum of values present in an array

 * @array: array

 * @len: array length

 *

 * Note that @len must not be zero (empty array).

 */

#define max_array(array, len) __minmax_array(max, array, len)



/**

 * clamp_t - return a value clamped to a given range using a given type

 * @type: the type of variable to use