ceph/src/boost/libs/wave/samples/real_positions/correct_token_positions.hpp

   1 /*=============================================================================
   2     Boost.Wave: A Standard compliant C++ preprocessor library
   3
   4     http://www.boost.org/
   5
   6     Copyright (c) 2001-2010 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_CORRECT_TOKEN_POSITIONS_HK_061106_INCLUDED)
  12 #define BOOST_CORRECT_TOKEN_POSITIONS_HK_061106_INCLUDED
  13
  14 #include <boost/iterator/transform_iterator.hpp>
  15
  16 ///////////////////////////////////////////////////////////////////////////////
  17 namespace detail
  18 {
  19     // count the newlines in a C style comment
  20     template <typename String>
  21     unsigned count_newlines(String const& str)
  22     {
  23         unsigned newlines = 0;
  24         typename String::size_type p = str.find_first_of('\n');
  25         while (p != String::npos)
  26         {
  27             ++newlines;
  28             p = str.find_first_of('\n', p+1);
  29         }
  30         return newlines;
  31     }
  32
  33     // return the length of the last line in a C style comment
  34     template <typename String>
  35     unsigned last_line_length(String const& str)
  36     {
  37         unsigned len = str.size();
  38         typename String::size_type p = str.find_last_of('\n');
  39         if (p != String::npos)
  40             len -= p;
  41         return len;
  42     }
  43 }
  44
  45 ///////////////////////////////////////////////////////////////////////////////
  46 //  This is the position correcting functor
  47 template <typename Token>
  48 struct correct_token_position
  49 :   public boost::wave::context_policies::eat_whitespace<Token>
  50 {
  51     correct_token_position(typename Token::string_type filename)
  52     :   pos(filename) {}
  53
  54     ///////////////////////////////////////////////////////////////////////////
  55     //
  56     //  The function 'generated_token' will be called by the library whenever a
  57     //  token is about to be returned from the library.
  58     //
  59     //  The parameter 'ctx' is a reference to the context object used for
  60     //  instantiating the preprocessing iterators by the user.
  61     //
  62     //  The parameter 't' is the token about to be returned from the library.
  63     //  This function may alter the token, but in this case it must be
  64     //  implemented with a corresponding signature:
  65     //
  66     //      TokenT const&
  67     //      generated_token(ContextT const& ctx, TokenT& t);
  68     //
  69     //  which makes it possible to modify the token in place.
  70     //
  71     //  The default behavior is to return the token passed as the parameter
  72     //  without modification.
  73     //
  74     ///////////////////////////////////////////////////////////////////////////
  75     template <typename Context>
  76     Token const&
  77     generated_token(Context const& ctx, Token& token)
  78     {
  79         typedef typename Token::string_type string_type;
  80         typedef typename Token::position_type position_type;
  81
  82         using namespace boost::wave;
  83
  84         // adjust the current position
  85         position_type current_pos(pos);
  86
  87         token_id id = token_id(token);
  88         string_type const& v (token.get_value());
  89
  90         switch (id) {
  91         case T_NEWLINE:
  92         case T_CPPCOMMENT:
  93             pos.set_line(current_pos.get_line()+1);
  94             pos.set_column(1);
  95             break;
  96
  97         case T_CCOMMENT:
  98             {
  99                 unsigned lines = detail::count_newlines(v);
 100                 if (lines > 0) {
 101                     pos.set_line(current_pos.get_line() + lines);
 102                     pos.set_column(detail::last_line_length(v));
 103                 }
 104                 else {
 105                     pos.set_column(current_pos.get_column() +
 106                         detail::last_line_length(v));
 107                 }
 108             }
 109             break;
 110
 111         default:
 112             pos.set_column(current_pos.get_column() + v.size());
 113             break;
 114         }
 115
 116         // set the new position in the token to be returned
 117         token.set_corrected_position(current_pos);
 118         return token;
 119     }
 120
 121     typename Token::position_type pos;
 122 };
 123
 124 ///////////////////////////////////////////////////////////////////////////////
 125
 126 #endif