/*
   * A generic implementation of binary search for the Linux kernel
   *
   * Copyright (C) 2008-2009 Ksplice, Inc.
   * Author: Tim Abbott <tabbott@ksplice.com>
   *
   * 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 <linux/export.h>

  #include <linux/bsearch.h>
  
  /*
   * 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);