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
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