1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | #ifndef _LINUX_HELPER_MACROS_H_ |
3 | #define _LINUX_HELPER_MACROS_H_ |
4 | |
5 | #include <linux/math.h> |
6 | |
7 | #define __find_closest(x, a, as, op) \ |
8 | ({ \ |
9 | typeof(as) __fc_i, __fc_as = (as) - 1; \ |
10 | typeof(x) __fc_x = (x); \ |
11 | typeof(*a) const *__fc_a = (a); \ |
12 | for (__fc_i = 0; __fc_i < __fc_as; __fc_i++) { \ |
13 | if (__fc_x op DIV_ROUND_CLOSEST(__fc_a[__fc_i] + \ |
14 | __fc_a[__fc_i + 1], 2)) \ |
15 | break; \ |
16 | } \ |
17 | (__fc_i); \ |
18 | }) |
19 | |
20 | /** |
21 | * find_closest - locate the closest element in a sorted array |
22 | * @x: The reference value. |
23 | * @a: The array in which to look for the closest element. Must be sorted |
24 | * in ascending order. |
25 | * @as: Size of 'a'. |
26 | * |
27 | * Returns the index of the element closest to 'x'. |
28 | */ |
29 | #define find_closest(x, a, as) __find_closest(x, a, as, <=) |
30 | |
31 | /** |
32 | * find_closest_descending - locate the closest element in a sorted array |
33 | * @x: The reference value. |
34 | * @a: The array in which to look for the closest element. Must be sorted |
35 | * in descending order. |
36 | * @as: Size of 'a'. |
37 | * |
38 | * Similar to find_closest() but 'a' is expected to be sorted in descending |
39 | * order. |
40 | */ |
41 | #define find_closest_descending(x, a, as) __find_closest(x, a, as, >=) |
42 | |
43 | /** |
44 | * is_insidevar - check if the @ptr points inside the @var memory range. |
45 | * @ptr: the pointer to a memory address. |
46 | * @var: the variable which address and size identify the memory range. |
47 | * |
48 | * Evaluates to true if the address in @ptr lies within the memory |
49 | * range allocated to @var. |
50 | */ |
51 | #define is_insidevar(ptr, var) \ |
52 | ((uintptr_t)(ptr) >= (uintptr_t)(var) && \ |
53 | (uintptr_t)(ptr) < (uintptr_t)(var) + sizeof(var)) |
54 | |
55 | #endif |
56 | |