ceph/src/boost/libs/core/test/has_single_bit_test.cpp

   1 // Test for boost/core/bit.hpp (has_single_bit)
   2 //
   3 // Copyright 2020 Peter Dimov
   4 // Distributed under the Boost Software License, Version 1.0.
   5 // https://www.boost.org/LICENSE_1_0.txt
   6
   7 #include <boost/core/bit.hpp>
   8 #include <boost/core/lightweight_test.hpp>
   9 #include <boost/core/detail/splitmix64.hpp>
  10 #include <boost/cstdint.hpp>
  11 #include <limits>
  12
  13 template<class T> void test_single_bit( T x )
  14 {
  15     BOOST_TEST_EQ( boost::core::has_single_bit( x ), boost::core::popcount( x ) == 1 );
  16 }
  17
  18 int main()
  19 {
  20     {
  21         boost::uint8_t x = 0;
  22
  23         BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
  24
  25         x = 1;
  26
  27         BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  28
  29         x = 2;
  30
  31         for( int i = 1; i < 8; ++i, x <<= 1 )
  32         {
  33             BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  34             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint8_t>( x | ( x >> 1 ) ) ), false );
  35             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint8_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
  36         }
  37     }
  38
  39     {
  40         boost::uint16_t x = 0;
  41
  42         BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
  43
  44         x = 1;
  45
  46         BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  47
  48         x = 2;
  49
  50         for( int i = 1; i < 16; ++i, x <<= 1 )
  51         {
  52             BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  53             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint16_t>( x | ( x >> 1 ) ) ), false );
  54             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint16_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
  55         }
  56     }
  57
  58     {
  59         boost::uint32_t x = 0;
  60
  61         BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
  62
  63         x = 1;
  64
  65         BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  66
  67         x = 2;
  68
  69         for( int i = 1; i < 32; ++i, x <<= 1 )
  70         {
  71             BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  72             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint32_t>( x | ( x >> 1 ) ) ), false );
  73             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint32_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
  74         }
  75     }
  76
  77     {
  78         boost::uint64_t x = 0;
  79
  80         BOOST_TEST_EQ( boost::core::has_single_bit( x ), false );
  81
  82         x = 1;
  83
  84         BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  85
  86         x = 2;
  87
  88         for( int i = 1; i < 64; ++i, x <<= 1 )
  89         {
  90             BOOST_TEST_EQ( boost::core::has_single_bit( x ), true );
  91             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint64_t>( x | ( x >> 1 ) ) ), false );
  92             BOOST_TEST_EQ( boost::core::has_single_bit( static_cast<boost::uint64_t>( x | ( x >> 1 ) | ( x >> 2 ) ) ), false );
  93         }
  94     }
  95
  96     boost::detail::splitmix64 rng;
  97
  98     for( int i = 0; i < 1000; ++i )
  99     {
 100         boost::uint64_t x = rng();
 101
 102         test_single_bit( static_cast<unsigned char>( x ) );
 103         test_single_bit( static_cast<unsigned short>( x ) );
 104         test_single_bit( static_cast<unsigned int>( x ) );
 105         test_single_bit( static_cast<unsigned long>( x ) );
 106         test_single_bit( static_cast<boost::ulong_long_type>( x ) );
 107     }
 108
 109     return boost::report_errors();
 110 }