ceph/src/boost/libs/beast/test/beast/core/detail/empty_base_optimization.cpp

   1 //
   2 // Copyright (c) 2016-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/beast
   8 //
   9
  10 // Test that header file is self-contained.
  11 #include <boost/beast/core/detail/empty_base_optimization.hpp>
  12
  13 #include <boost/beast/unit_test/suite.hpp>
  14
  15 namespace boost {
  16 namespace beast {
  17 namespace detail {
  18
  19 class empty_base_optimization_test
  20     : public beast::unit_test::suite
  21 {
  22 public:
  23     template<class T>
  24     class test1
  25         : private empty_base_optimization<T>
  26     {
  27         using Base = empty_base_optimization<T>;
  28         void* m_p;
  29     public:
  30         explicit test1 (T const& t)
  31             : Base (t)
  32         {}
  33
  34         T&       member()       {return Base::member();}
  35         T const& member() const {return Base::member();}
  36     };
  37
  38     template<class T>
  39     class test2
  40     {
  41         void* m_p;
  42         T m_t;
  43     public:
  44         explicit test2 (T const& t)
  45             : m_t (t)
  46         {}
  47
  48         T&       member()       {return m_t;}
  49         T const& member() const {return m_t;}
  50     };
  51
  52     struct Empty
  53     {
  54         operator bool() {return true;}
  55     };
  56
  57     static
  58     bool
  59     test_one()
  60     {
  61         test1<int> t1(1);
  62         test2<int> t2(2);
  63         static_assert(sizeof(t1) == sizeof(t2), "don't optimize for int");
  64         if(t1.member() != 1)
  65             return false;
  66         if(t2.member() != 2)
  67             return false;
  68         return true;
  69     }
  70
  71     static
  72     bool
  73     test_two()
  74     {
  75         test1<Empty> t1((Empty()));
  76         test2<Empty> t2((Empty()));
  77         static_assert(sizeof(t1) < sizeof(t2), "do optimize for Empty");
  78         if(t1.member() != true)
  79             return false;
  80         if(t2.member() != true)
  81             return false;
  82         return true;
  83     }
  84
  85     void
  86     run()
  87     {
  88         BEAST_EXPECT(test_one());
  89         BEAST_EXPECT(test_two());
  90         pass();
  91     }
  92 };
  93
  94 BEAST_DEFINE_TESTSUITE(beast,core,empty_base_optimization);
  95
  96 } // detail
  97 } // beast
  98 } // boost