include/linux/minmax.h

1 /* SPDX-License-Identifier: GPL-2.0 */
13  * - Avoid multiple evaluations of the arguments (so side-effects like
14  *   "x++" happen only once) when non-constant.
15  * - Perform signed v unsigned type-checking (to generate compile
17  * - Unsigned char/short are always promoted to signed int and can be
19  * - Unsigned arguments can be compared against non-negative signed constants.
20  * - Comparison of a signed argument against an unsigned constant fails
31  * In particular, statically non-negative signed integer expressions
39  * that contains the value.
42  * value (but without evaluating it for side effects!
53  * Check whether a signed value is always non-negative.
58  * On 64-bit any integer or pointer type can safely be cast to 'long long'.
59  * But on 32-bit we need to avoid warnings about casting pointers to integers
60  * of different sizes without truncating 64-bit values so 'long' or 'long long'
61  * must be used depending on the size of the value.
63  * This does not work for 128-bit signed integers since the cast would truncate
101  * min - return minimum of two values of the same or compatible types
102  * @x: first value
103  * @y: second value
108  * max - return maximum of two values of the same or compatible types
109  * @x: first value
110  * @y: second value
115  * umin - return minimum of two non-negative values
117  * @x: first value
118  * @y: second value
124  * umax - return maximum of two non-negative values
125  * @x: first value
126  * @y: second value
138  * min3 - return minimum of three values
139  * @x: first value
140  * @y: second value
141  * @z: third value
147  * max3 - return maximum of three values
148  * @x: first value
149  * @y: second value
150  * @z: third value
156  * min_t - return minimum of two values, using the specified type
158  * @x: first value
159  * @y: second value
164  * max_t - return maximum of two values, using the specified type
166  * @x: first value
167  * @y: second value
172  * min_not_zero - return the minimum that is _not_ zero, unless both are zero
198  * clamp - return a value clamped to a given range with typechecking
199  * @val: current value
200  * @lo: lowest allowable value
201  * @hi: highest allowable value
209  * clamp_t - return a value clamped to a given range using a given type
211  * @val: current value
212  * @lo: minimum allowable value
213  * @hi: maximum allowable value
221  * clamp_val - return a value clamped to a given range using val's type
222  * @val: current value
223  * @lo: minimum allowable value
224  * @hi: maximum allowable value
235  * In the following legit use-case where the "array" passed is a simple pointer,
237  * --- 8< ---
241  * --- 8< ---
253 	__unqual_scalar_typeof(__array[0]) __element = __array[--__len];\
254 	while (__len--)							\
259  * min_array - return minimum of values present in an array
268  * max_array - return maximum of values present in an array
276 static inline bool in_range64(u64 val, u64 start, u64 len)  in in_range64()  argument
278 	return (val - start) < len;  in in_range64()
281 static inline bool in_range32(u32 val, u32 start, u32 len)  in in_range32()  argument
283 	return (val - start) < len;  in in_range32()
287  * in_range - Determine if a value lies within a range.
288  * @val: Value to test.
289  * @start: First value in range.
292  * This is more efficient than "if (start <= val && val < (start + len))".
293  * It also gives a different answer if @start + @len overflows the size of
295  * which behaviour you want, or prove that start + len never overflow.
298 #define in_range(val, start, len)					\  argument
299 	((sizeof(start) | sizeof(len) | sizeof(val)) <= sizeof(u32) ?	\
300 		in_range32(val, start, len) : in_range64(val, start, len))
303  * swap - swap values of @a and @b
304  * @a: first value
305  * @b: second value