mirror of
https://github.com/matrix-construct/construct
synced 2024-11-14 14:01:08 +01:00
57 lines
1.2 KiB
C++
57 lines
1.2 KiB
C++
// Matrix Construct
|
|
//
|
|
// Copyright (C) Matrix Construct Developers, Authors & Contributors
|
|
// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
|
|
//
|
|
// Permission to use, copy, modify, and/or distribute this software for any
|
|
// purpose with or without fee is hereby granted, provided that the above
|
|
// copyright notice and this permission notice is present in all copies. The
|
|
// full license for this software is available in the LICENSE file.
|
|
|
|
#pragma once
|
|
#define HAVE_IRCD_MATH_LOG2_H
|
|
|
|
namespace ircd::math
|
|
{
|
|
template<class Z> constexpr bool is_pow2(const Z);
|
|
template<class Z> constexpr Z next_pow2(const Z);
|
|
template<class Z> constexpr Z log2(const Z);
|
|
template<class Z> constexpr Z sqr(const Z);
|
|
}
|
|
|
|
template<class Z>
|
|
inline constexpr Z
|
|
ircd::math::sqr(const Z n)
|
|
{
|
|
return pow(n, 2);
|
|
}
|
|
|
|
template<class Z>
|
|
inline constexpr Z
|
|
ircd::math::log2(const Z n)
|
|
{
|
|
return n > Z{1}?
|
|
Z{1} + log2(n >> 1):
|
|
0;
|
|
}
|
|
|
|
template<class Z>
|
|
inline constexpr Z
|
|
ircd::math::next_pow2(Z v)
|
|
{
|
|
--v;
|
|
v |= v >> 1;
|
|
v |= v >> 2;
|
|
v |= v >> 4;
|
|
v |= v >> 8;
|
|
v |= v >> 16;
|
|
v |= v >> 32;
|
|
return ++v;
|
|
}
|
|
|
|
template<class Z>
|
|
inline constexpr bool
|
|
ircd::math::is_pow2(const Z v)
|
|
{
|
|
return v && !(v & (v - Z{1}));
|
|
}
|