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minmax: Introduce {min,max}_array()

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

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/20230623085830.749991-8-herve.codina@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>
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Herve Codina 2023-06-23 10:58:24 +02:00 committed by Mark Brown
parent 524cfdf6b8
commit c952c748c7
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1 changed files with 64 additions and 0 deletions
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64
include/linux/minmax.h
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@ -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