1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_HELPER_MACROS_H_
3 #define _LINUX_HELPER_MACROS_H_
4
5 #define __find_closest(x, a, as, op) \
6 ({ \
7 typeof(as) __fc_i, __fc_as = (as) - 1; \
8 typeof(x) __fc_x = (x); \
9 typeof(*a) const *__fc_a = (a); \
10 for (__fc_i = 0; __fc_i < __fc_as; __fc_i++) { \
11 if (__fc_x op DIV_ROUND_CLOSEST(__fc_a[__fc_i] + \
12 __fc_a[__fc_i + 1], 2)) \
13 break; \
14 } \
15 (__fc_i); \
16 })
17
18 /**
19 * find_closest - locate the closest element in a sorted array
20 * @x: The reference value.
21 * @a: The array in which to look for the closest element. Must be sorted
22 * in ascending order.
23 * @as: Size of 'a'.
24 *
25 * Returns the index of the element closest to 'x'.
26 */
27 #define find_closest(x, a, as) __find_closest(x, a, as, <=)
28
29 /**
30 * find_closest_descending - locate the closest element in a sorted array
31 * @x: The reference value.
32 * @a: The array in which to look for the closest element. Must be sorted
33 * in descending order.
34 * @as: Size of 'a'.
35 *
36 * Similar to find_closest() but 'a' is expected to be sorted in descending
37 * order.
38 */
39 #define find_closest_descending(x, a, as) __find_closest(x, a, as, >=)
40
41 #endif