mirror of
https://github.com/ecency/ecency-mobile.git
synced 2024-12-22 12:51:42 +03:00
124 lines
2.8 KiB
C++
124 lines
2.8 KiB
C++
//////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// (C) Copyright Stephen Cleary 2000.
|
|
// (C) Copyright Ion Gaztanaga 2007-2013.
|
|
//
|
|
// Distributed under the Boost Software License, Version 1.0.
|
|
// (See accompanying file LICENSE_1_0.txt or copy at
|
|
// http://www.boost.org/LICENSE_1_0.txt)
|
|
//
|
|
// See http://www.boost.org/libs/container for documentation.
|
|
//
|
|
// This file is a slightly modified file from Boost.Pool
|
|
//
|
|
//////////////////////////////////////////////////////////////////////////////
|
|
|
|
#ifndef BOOST_CONTAINER_DETAIL_MATH_FUNCTIONS_HPP
|
|
#define BOOST_CONTAINER_DETAIL_MATH_FUNCTIONS_HPP
|
|
|
|
#ifndef BOOST_CONFIG_HPP
|
|
# include <boost/config.hpp>
|
|
#endif
|
|
|
|
#if defined(BOOST_HAS_PRAGMA_ONCE)
|
|
# pragma once
|
|
#endif
|
|
|
|
#include <boost/container/detail/config_begin.hpp>
|
|
#include <boost/container/detail/workaround.hpp>
|
|
|
|
#include <climits>
|
|
#include <boost/static_assert.hpp>
|
|
|
|
namespace boost {
|
|
namespace container {
|
|
namespace container_detail {
|
|
|
|
// Greatest common divisor and least common multiple
|
|
|
|
//
|
|
// gcd is an algorithm that calculates the greatest common divisor of two
|
|
// integers, using Euclid's algorithm.
|
|
//
|
|
// Pre: A > 0 && B > 0
|
|
// Recommended: A > B
|
|
template <typename Integer>
|
|
inline Integer gcd(Integer A, Integer B)
|
|
{
|
|
do
|
|
{
|
|
const Integer tmp(B);
|
|
B = A % B;
|
|
A = tmp;
|
|
} while (B != 0);
|
|
|
|
return A;
|
|
}
|
|
|
|
//
|
|
// lcm is an algorithm that calculates the least common multiple of two
|
|
// integers.
|
|
//
|
|
// Pre: A > 0 && B > 0
|
|
// Recommended: A > B
|
|
template <typename Integer>
|
|
inline Integer lcm(const Integer & A, const Integer & B)
|
|
{
|
|
Integer ret = A;
|
|
ret /= gcd(A, B);
|
|
ret *= B;
|
|
return ret;
|
|
}
|
|
|
|
template <typename Integer>
|
|
inline Integer log2_ceil(const Integer & A)
|
|
{
|
|
Integer i = 0;
|
|
Integer power_of_2 = 1;
|
|
|
|
while(power_of_2 < A){
|
|
power_of_2 <<= 1;
|
|
++i;
|
|
}
|
|
return i;
|
|
}
|
|
|
|
template <typename Integer>
|
|
inline Integer upper_power_of_2(const Integer & A)
|
|
{
|
|
Integer power_of_2 = 1;
|
|
|
|
while(power_of_2 < A){
|
|
power_of_2 <<= 1;
|
|
}
|
|
return power_of_2;
|
|
}
|
|
|
|
//This function uses binary search to discover the
|
|
//highest set bit of the integer
|
|
inline std::size_t floor_log2 (std::size_t x)
|
|
{
|
|
const std::size_t Bits = sizeof(std::size_t)*CHAR_BIT;
|
|
const bool Size_t_Bits_Power_2= !(Bits & (Bits-1));
|
|
BOOST_STATIC_ASSERT(((Size_t_Bits_Power_2)== true));
|
|
|
|
std::size_t n = x;
|
|
std::size_t log2 = 0;
|
|
|
|
for(std::size_t shift = Bits >> 1; shift; shift >>= 1){
|
|
std::size_t tmp = n >> shift;
|
|
if (tmp)
|
|
log2 += shift, n = tmp;
|
|
}
|
|
|
|
return log2;
|
|
}
|
|
|
|
} // namespace container_detail
|
|
} // namespace container
|
|
} // namespace boost
|
|
|
|
#include <boost/container/detail/config_end.hpp>
|
|
|
|
#endif
|