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