1 /* SPDX-License-Identifier: GPL-2.0 */
9  * min()/max()/clamp() macros must accomplish three things:
11  * - avoid multiple evaluations of the arguments (so side-effects like
12  *   "x++" happen only once) when non-constant.
13  * - perform strict type-checking (to generate warnings instead of
16  * - retain result as a constant expressions when called with only
64  * min - return minimum of two values of the same or compatible types
68 #define min(x, y)	__careful_cmp(x, y, <)  macro
71  * max - return maximum of two values of the same or compatible types
78  * min3 - return minimum of three values
83 #define min3(x, y, z) min((typeof(x))min(x, y), z)
86  * max3 - return maximum of three values
94  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
101 	__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
104  * clamp - return a value clamped to a given range with strict typechecking
118  * Or not use min/max/clamp at all, of course.
122  * min_t - return minimum of two values, using the specified type
130  * max_t - return maximum of two values, using the specified type
139  * _Generic(foo, type-name: association, ..., default: association) performs a
141  * Do not use the const keyword in the type-name as it will not match the
160  * In the following legit use-case where the "array" passed is a simple pointer,
162  * --- 8< ---
165  * min = min_array(buff, nb_items);
166  * --- 8< ---
175 #define __minmax_array(op, array, len) ({				\  argument
177 	typeof(len) __len = (len);					\
178 	__unconst_integer_typeof(__array[0]) __element = __array[--__len]; \
179 	while (__len--)							\
184  * min_array - return minimum of values present in an array
186  * @len: array length
188  * Note that @len must not be zero (empty array).
190 #define min_array(array, len) __minmax_array(min, array, len)  argument
193  * max_array - return maximum of values present in an array
195  * @len: array length
197  * Note that @len must not be zero (empty array).
199 #define max_array(array, len) __minmax_array(max, array, len)  argument
202  * clamp_t - return a value clamped to a given range using a given type
214  * clamp_val - return a value clamped to a given range using val's type
226 static inline bool in_range64(u64 val, u64 start, u64 len)  in in_range64()  argument
228 	return (val - start) < len;  in in_range64()
231 static inline bool in_range32(u32 val, u32 start, u32 len)  in in_range32()  argument
233 	return (val - start) < len;  in in_range32()
237  * in_range - Determine if a value lies within a range.
240  * @len: Number of values in range.
242  * This is more efficient than "if (start <= val && val < (start + len))".
243  * It also gives a different answer if @start + @len overflows the size of
245  * which behaviour you want, or prove that start + len never overflow.
248 #define in_range(val, start, len)					\  argument
249 	((sizeof(start) | sizeof(len) | sizeof(val)) <= sizeof(u32) ?	\
250 		in_range32(val, start, len) : in_range64(val, start, len))
253  * swap - swap values of @a and @b