/* * A generic implementation of binary search for the Linux kernel * * Copyright (C) 2008-2009 Ksplice, Inc. * Author: Tim Abbott * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; version 2. */ #include #include /* * bsearch - binary search an array of elements * @key: pointer to item being searched for * @base: pointer to first element to search * @num: number of elements * @size: size of each element * @cmp: pointer to comparison function * * This function does a binary search on the given array. The * contents of the array should already be in ascending sorted order * under the provided comparison function. * * Note that the key need not have the same type as the elements in * the array, e.g. key could be a string and the comparison function * could compare the string with the struct's name field. However, if * the key and elements in the array are of the same type, you can use * the same comparison function for both sort() and bsearch(). */ void *bsearch(const void *key, const void *base, size_t num, size_t size, int (*cmp)(const void *key, const void *elt)) { size_t start = 0, end = num; int result; while (start < end) { size_t mid = start + (end - start) / 2; result = cmp(key, base + mid * size); if (result < 0) end = mid; else if (result > 0) start = mid + 1; else return (void *)base + mid * size; } return NULL; } EXPORT_SYMBOL(bsearch); 2883aaea363f7a897ff06d2e6c73ae7aae285bcb'>refslogtreecommitdiff
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