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 |
42 | |