Line data    Source code

       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(FUNCTOR_INPUT_HPP_ED3A4C21_8F8A_453F_B438_08214FAC106A_INCLUDED)
      12             : #define 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           0 :             Data(FunctorT const &ftor_)
      58           0 :             :   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           0 :         inner()
      79           0 :         :   data(0)
      80             :         {}
      81             : 
      82           0 :         inner(FunctorT const &x)
      83           0 :         :   data(new Data(x))
      84           0 :         {}
      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           0 :         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           0 :         reference get_input() const
     116             :         {
     117           0 :             ensure_initialized();
     118           0 :             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           0 :         bool input_at_eof() const
     129             :         {
     130           0 :             ensure_initialized();
     131           0 :             return !data || data->curtok == data->ftor.eof;
     132             :         }
     133             : 
     134           0 :         FunctorT& get_functor() const
     135             :         {
     136           0 :             BOOST_ASSERT(0 != data);
     137           0 :             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(FUNCTOR_INPUT_HPP_ED3A4C21_8F8A_453F_B438_08214FAC106A_INCLUDED)