95 lines
2.7 KiB
C++
95 lines
2.7 KiB
C++
// Test for boost/core/bit.hpp (bit_width)
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//
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// Copyright 2020 Peter Dimov
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// Distributed under the Boost Software License, Version 1.0.
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// https://www.boost.org/LICENSE_1_0.txt
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#include <boost/core/bit.hpp>
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#include <boost/core/lightweight_test.hpp>
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#include <boost/core/detail/splitmix64.hpp>
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#include <boost/cstdint.hpp>
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#include <limits>
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template<class T> void test_width( T x )
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{
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BOOST_TEST_EQ( boost::core::bit_width( x ), std::numeric_limits<T>::digits - boost::core::countl_zero( x ) );
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}
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int main()
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{
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{
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boost::uint8_t x = 0;
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BOOST_TEST_EQ( boost::core::bit_width( x ), 0 );
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x = 1;
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for( int i = 0; i < 8; ++i, x <<= 1 )
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{
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BOOST_TEST_EQ( boost::core::bit_width( x ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint8_t>( x | ( x >> 1 ) ) ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint8_t>( x | ( x >> 2 ) ) ), i+1 );
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}
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}
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{
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boost::uint16_t x = 0;
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BOOST_TEST_EQ( boost::core::bit_width( x ), 0 );
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x = 1;
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for( int i = 0; i < 16; ++i, x <<= 1 )
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{
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BOOST_TEST_EQ( boost::core::bit_width( x ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint16_t>( x | ( x >> 1 ) ) ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint16_t>( x | ( x >> 2 ) ) ), i+1 );
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}
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}
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{
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boost::uint32_t x = 0;
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BOOST_TEST_EQ( boost::core::bit_width( x ), 0 );
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x = 1;
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for( int i = 0; i < 32; ++i, x <<= 1 )
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{
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BOOST_TEST_EQ( boost::core::bit_width( x ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint32_t>( x | ( x >> 1 ) ) ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint32_t>( x | ( x >> 2 ) ) ), i+1 );
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}
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}
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{
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boost::uint64_t x = 0;
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BOOST_TEST_EQ( boost::core::bit_width( x ), 0 );
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x = 1;
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for( int i = 0; i < 64; ++i, x <<= 1 )
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{
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BOOST_TEST_EQ( boost::core::bit_width( x ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint64_t>( x | ( x >> 1 ) ) ), i+1 );
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BOOST_TEST_EQ( boost::core::bit_width( static_cast<boost::uint64_t>( x | ( x >> 2 ) ) ), i+1 );
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}
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}
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boost::detail::splitmix64 rng;
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for( int i = 0; i < 1000; ++i )
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{
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boost::uint64_t x = rng();
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test_width( static_cast<unsigned char>( x ) );
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test_width( static_cast<unsigned short>( x ) );
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test_width( static_cast<unsigned int>( x ) );
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test_width( static_cast<unsigned long>( x ) );
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test_width( static_cast<unsigned long long>( x ) );
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}
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return boost::report_errors();
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}
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