forked from boostorg/core
111 lines
3.2 KiB
C++
111 lines
3.2 KiB
C++
// Test for boost/core/bit.hpp (has_single_bit)
|
|
//
|
|
// Copyright 2020 Peter Dimov
|
|
// Distributed under the Boost Software License, Version 1.0.
|
|
// https://www.boost.org/LICENSE_1_0.txt
|
|
|
|
#include <boost/core/bit.hpp>
|
|
#include <boost/core/lightweight_test.hpp>
|
|
#include <boost/core/detail/splitmix64.hpp>
|
|
#include <boost/cstdint.hpp>
|
|
#include <limits>
|
|
|
|
template<class T> void test_single_bit( T x )
|
|
{
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), boost::core::popcount( x ) == 1 );
|
|
}
|
|
|
|
int main()
|
|
{
|
|
{
|
|
boost::uint8_t x = 0;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
|
|
|
|
x = 1;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
|
|
x = 2;
|
|
|
|
for( int i = 1; i < 8; ++i, x <<= 1 )
|
|
{
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint8_t>( x | ( x >> 1 ) ) ), false );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint8_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
|
|
}
|
|
}
|
|
|
|
{
|
|
boost::uint16_t x = 0;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
|
|
|
|
x = 1;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
|
|
x = 2;
|
|
|
|
for( int i = 1; i < 16; ++i, x <<= 1 )
|
|
{
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint16_t>( x | ( x >> 1 ) ) ), false );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint16_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
|
|
}
|
|
}
|
|
|
|
{
|
|
boost::uint32_t x = 0;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
|
|
|
|
x = 1;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
|
|
x = 2;
|
|
|
|
for( int i = 1; i < 32; ++i, x <<= 1 )
|
|
{
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint32_t>( x | ( x >> 1 ) ) ), false );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint32_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
|
|
}
|
|
}
|
|
|
|
{
|
|
boost::uint64_t x = 0;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
|
|
|
|
x = 1;
|
|
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
|
|
x = 2;
|
|
|
|
for( int i = 1; i < 64; ++i, x <<= 1 )
|
|
{
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint64_t>( x | ( x >> 1 ) ) ), false );
|
|
BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint64_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
|
|
}
|
|
}
|
|
|
|
boost::detail::splitmix64 rng;
|
|
|
|
for( int i = 0; i < 1000; ++i )
|
|
{
|
|
boost::uint64_t x = rng();
|
|
|
|
test_single_bit( static_cast<unsigned char>( x ) );
|
|
test_single_bit( static_cast<unsigned short>( x ) );
|
|
test_single_bit( static_cast<unsigned int>( x ) );
|
|
test_single_bit( static_cast<unsigned long>( x ) );
|
|
test_single_bit( static_cast<boost::ulong_long_type>( x ) );
|
|
}
|
|
|
|
return boost::report_errors();
|
|
}
|