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/* pow2, Copyright (c) 2016 Dave Odell <dmo2118@gmail.com>
*
* Permission to use, copy, modify, distribute, and sell this software and its
* documentation for any purpose is hereby granted without fee, provided that
* the above copyright notice appear in all copies and that both that
* copyright notice and this permission notice appear in supporting
* documentation. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*/
#ifndef POW2_H
#define POW2_H
#include <stdlib.h>
#include <limits.h>
/* Like i_log2, but no check for 0. */
#if defined __GNUC__ && __GNUC__ >= 4 || defined __clang__
# define i_log2_fast(x) (sizeof(long) * CHAR_BIT - __builtin_clzl(x) - 1)
#else
# define i_log2_fast(x) i_log2(x)
#endif
extern int i_log2(size_t x);
extern size_t to_pow2 (size_t x); /* return the next larger power of 2. */
#endif /* POW2_H */
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