shadow/lib/bit.h
Iker Pedrosa 3b3d3e5cd4 lib: bit_ceil_wrapul(): stop recursion
It should call bit_ceilul() instead of itself.

Fixes: 0712b236c3 ("Add bit manipulation functions")
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
2023-02-24 12:44:14 -06:00

54 lines
943 B
C

/*
* SPDX-FileCopyrightText: 2022 - 2023, Alejandro Colomar <alx@kernel.org>
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef SHADOW_INCLUDE_LIB_BIT_H_
#define SHADOW_INCLUDE_LIB_BIT_H_
#include <config.h>
#include <limits.h>
#ifndef ULONG_WIDTH
#define ULONG_WIDTH (sizeof(unsigned long) * CHAR_BIT)
#endif
inline unsigned long bit_ceilul(unsigned long x);
inline unsigned long bit_ceil_wrapul(unsigned long x);
inline int leading_zerosul(unsigned long x);
/* stdc_bit_ceilul(3) */
inline unsigned long
bit_ceilul(unsigned long x)
{
return 1 + (ULONG_MAX >> leading_zerosul(x));
}
/* stdc_bit_ceilul(3), but wrap instead of having Undefined Behavior */
inline unsigned long
bit_ceil_wrapul(unsigned long x)
{
if (x == 0)
return 0;
return bit_ceilul(x);
}
/* stdc_leading_zerosul(3) */
inline int
leading_zerosul(unsigned long x)
{
return (x == 0) ? ULONG_WIDTH : __builtin_clzl(x);
}
#endif // include guard