boost/test/utils/lazy_ostream.hpp

   1 //  (C) Copyright Gennadiy Rozental 2008.
   2 //  Distributed under the Boost Software License, Version 1.0.
   3 //  (See accompanying file LICENSE_1_0.txt or copy at
   4 //  http://www.boost.org/LICENSE_1_0.txt)
   5
   6 //  See http://www.boost.org/libs/test for the library home page.
   7 //
   8 //  File        : $RCSfile$
   9 //
  10 //  Version     : $Revision$
  11 //
  12 //  Description : contains definition for all test tools in test toolbox
  13 // ***************************************************************************
  14
  15 #ifndef BOOST_TEST_LAZY_OSTREAM_HPP_070708GER
  16 #define BOOST_TEST_LAZY_OSTREAM_HPP_070708GER
  17
  18 // Boost.Test
  19 #include <boost/test/detail/config.hpp>
  20
  21 // STL
  22 #include <iosfwd>
  23
  24 #include <boost/test/detail/suppress_warnings.hpp>
  25
  26 //____________________________________________________________________________//
  27
  28 // ************************************************************************** //
  29 // **************                  lazy_ostream                ************** //
  30 // ************************************************************************** //
  31
  32 namespace boost {
  33
  34 namespace unit_test {
  35
  36 class lazy_ostream {
  37 public:
  38     static lazy_ostream&    instance()                                              { static lazy_ostream inst; return inst; }
  39
  40     friend std::ostream&    operator<<( std::ostream& ostr, lazy_ostream const& o ) { return o( ostr ); }
  41
  42     // access method
  43     bool                    empty() const                                           { return m_empty; }
  44
  45     // actual printing interface; to be accessed only by this class and children
  46     virtual std::ostream&   operator()( std::ostream& ostr ) const                  { return ostr; }
  47 protected:
  48     explicit                lazy_ostream( bool empty = true ) : m_empty( empty )    {}
  49
  50     // protected destructor to make sure right one is called
  51 #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x582))
  52 public:
  53 #endif
  54     BOOST_TEST_PROTECTED_VIRTUAL ~lazy_ostream()                                    {}
  55
  56 private:
  57     // Data members
  58     bool                    m_empty;
  59 };
  60
  61 //____________________________________________________________________________//
  62
  63 template<typename T>
  64 class lazy_ostream_impl : public lazy_ostream {
  65 public:
  66     lazy_ostream_impl( lazy_ostream const& prev, T value )
  67     : lazy_ostream( false )
  68     , m_prev( prev )
  69     , m_value( value )
  70     {}
  71 private:
  72     virtual std::ostream&   operator()( std::ostream& ostr ) const
  73     {
  74         return m_prev(ostr) << m_value;
  75     }
  76
  77     // Data members
  78     lazy_ostream const&     m_prev;
  79     T                       m_value;
  80 };
  81
  82 //____________________________________________________________________________//
  83
  84 template<typename T>
  85 inline lazy_ostream_impl<T const&>
  86 operator<<( lazy_ostream const& prev, T const& v )
  87 {
  88     return lazy_ostream_impl<T const&>( prev, v );
  89 }
  90
  91 //____________________________________________________________________________//
  92
  93 #if BOOST_TEST_USE_STD_LOCALE
  94
  95 template<typename R,typename S>
  96 inline lazy_ostream_impl<R& (BOOST_TEST_CALL_DECL *)(S&)>
  97 operator<<( lazy_ostream const& prev, R& (BOOST_TEST_CALL_DECL *man)(S&) )
  98 {
  99     return lazy_ostream_impl<R& (BOOST_TEST_CALL_DECL *)(S&)>( prev, man );
 100 }
 101
 102 //____________________________________________________________________________//
 103
 104 #endif
 105
 106 } // namespace unit_test
 107
 108 } // namespace boost
 109
 110 //____________________________________________________________________________//
 111
 112 #include <boost/test/detail/enable_warnings.hpp>
 113
 114 #endif // BOOST_TEST_LAZY_OSTREAM_HPP_070708GER