common/include/rounding.h

   1 /* nbdkit
   2  * Copyright Red Hat
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   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
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   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
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  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
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  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
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  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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  31  */
  32
  33 #ifndef NBDKIT_ROUNDING_H
  34 #define NBDKIT_ROUNDING_H
  35
  36 #include <assert.h>
  37
  38 #include "ispowerof2.h"
  39
  40 /* Round up i to next multiple of n (n must be a power of 2).
  41  */
  42 #define ROUND_UP(i, n) ({                          \
  43       assert (is_power_of_2 (n));                  \
  44       ((i) + (n) - 1) & -((typeof (i))(n));        \
  45 })
  46
  47 /* Round down i to next multiple of n (n must be a power of 2).
  48  */
  49 #define ROUND_DOWN(i, n) ({                         \
  50       assert (is_power_of_2 (n));                   \
  51       (i) & -((typeof (i))(n));                     \
  52 })
  53
  54 /* Return n / d, rounding the result up to the next integer. */
  55 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
  56
  57 #endif /* NBDKIT_ROUNDING_H */