libstuff/rnd.c

   1 /*
   2  * Copyright (c) 2004, Apple Computer, Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1.  Redistributions of source code must retain the above copyright
   8  *     notice, this list of conditions and the following disclaimer.
   9  * 2.  Redistributions in binary form must reproduce the above copyright
  10  *     notice, this list of conditions and the following disclaimer in the
  11  *     documentation and/or other materials provided with the distribution.
  12  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  13  *     its contributors may be used to endorse or promote products derived
  14  *     from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
  20  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  24  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  25  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  * POSSIBILITY OF SUCH DAMAGE.
  27  */
  28 #include <stdint.h>
  29 #include "stuff/rnd.h"
  30 /*
  31  * rnd() rounds v to a multiple of r.
  32  */
  33 __private_extern__
  34 uint64_t
  35 rnd(
  36 uint64_t v,
  37 uint64_t r)
  38 {
  39         r--;
  40         v += r;
  41         v &= ~(int64_t)r;
  42         return(v);
  43 }