ceph/src/boost/boost/wave/util/functor_input.hpp

   1 /*=============================================================================
   2     Boost.Wave: A Standard compliant C++ preprocessor library
   3
   4     http://www.boost.org/
   5
   6     Copyright (c) 2001-2012 Hartmut Kaiser. Distributed under the Boost
   7     Software License, Version 1.0. (See accompanying file
   8     LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 =============================================================================*/
  10
  11 #if !defined(BOOST_FUNCTOR_INPUT_HPP_ED3A4C21_8F8A_453F_B438_08214FAC106A_INCLUDED)
  12 #define BOOST_FUNCTOR_INPUT_HPP_ED3A4C21_8F8A_453F_B438_08214FAC106A_INCLUDED
  13
  14 #include <boost/assert.hpp>
  15 #include <boost/spirit/include/classic_multi_pass.hpp>
  16 #include <boost/wave/wave_config.hpp>
  17
  18 // this must occur after all of the includes and before any code appears
  19 #ifdef BOOST_HAS_ABI_HEADERS
  20 #include BOOST_ABI_PREFIX
  21 #endif
  22
  23 ///////////////////////////////////////////////////////////////////////////////
  24 namespace boost {
  25 namespace wave {
  26 namespace util {
  27
  28 ///////////////////////////////////////////////////////////////////////////////
  29 //
  30 //  class functor_input
  31 //
  32 //      Implementation of the InputPolicy used by multi_pass
  33 //      functor_input gets tokens from a functor
  34 //      Note: the functor must have a typedef for result_type
  35 //            It also must have a static variable of type result_type defined
  36 //            to represent eof that is called eof.
  37 //
  38 //      This functor input policy template is essentially the same as the
  39 //      predefined multi_pass functor_input policy. The difference is,
  40 //      that the first token is not read at initialization time, but only
  41 //      just before returning the first token. Additionally it does not
  42 //      call operator new() twice but only once.
  43 //
  44 ///////////////////////////////////////////////////////////////////////////////
  45 struct functor_input {
  46
  47     template <typename FunctorT>
  48     class inner {
  49     private:
  50         typedef typename FunctorT::result_type result_type;
  51
  52     public:
  53         typedef result_type value_type;
  54
  55     private:
  56         struct Data {
  57             Data(FunctorT const &ftor_)
  58             :   ftor(ftor_), was_initialized(false)
  59             {}
  60
  61             FunctorT ftor;
  62             value_type curtok;
  63             bool was_initialized;
  64         };
  65
  66         // Needed by compilers not implementing the resolution to DR45. For
  67         // reference, see
  68         // http://www.open-std.org/JTC1/SC22/WG21/docs/cwg_defects.html#45.
  69
  70         friend struct Data;
  71
  72     public:
  73         typedef std::ptrdiff_t difference_type;
  74         typedef result_type *pointer;
  75         typedef result_type &reference;
  76
  77     protected:
  78         inner()
  79         :   data(0)
  80         {}
  81
  82         inner(FunctorT const &x)
  83         :   data(new Data(x))
  84         {}
  85
  86         inner(inner const &x)
  87         :   data(x.data)
  88         {}
  89
  90         void destroy()
  91         {
  92             delete data;
  93             data = 0;
  94         }
  95
  96         bool same_input(inner const &x) const
  97         {
  98             return data == x.data;
  99         }
 100
 101         void swap(inner &x)
 102         {
 103             boost::spirit::classic::impl::mp_swap(data, x.data);
 104         }
 105
 106         void ensure_initialized() const
 107         {
 108             if (data && !data->was_initialized) {
 109                 data->curtok = (data->ftor)();    // get the first token
 110                 data->was_initialized = true;
 111             }
 112         }
 113
 114     public:
 115         reference get_input() const
 116         {
 117             ensure_initialized();
 118             return data->curtok;
 119         }
 120
 121         void advance_input()
 122         {
 123             BOOST_ASSERT(0 != data);
 124             data->curtok = (data->ftor)();
 125             data->was_initialized = true;
 126         }
 127
 128         bool input_at_eof() const
 129         {
 130             ensure_initialized();
 131             return !data || data->curtok == data->ftor.eof;
 132         }
 133
 134         FunctorT& get_functor() const
 135         {
 136             BOOST_ASSERT(0 != data);
 137             return data->ftor;
 138         }
 139
 140     private:
 141         mutable Data *data;
 142     };
 143 };
 144
 145 ///////////////////////////////////////////////////////////////////////////////
 146 }   // namespace util
 147 }   // namespace wave
 148 }   // namespace boost
 149
 150 // the suffix header occurs after all of the code
 151 #ifdef BOOST_HAS_ABI_HEADERS
 152 #include BOOST_ABI_SUFFIX
 153 #endif
 154
 155 #endif // !defined(BOOST_FUNCTOR_INPUT_HPP_ED3A4C21_8F8A_453F_B438_08214FAC106A_INCLUDED)