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1 | // Copyright (c) 2001 Daniel C. Nuffer |
2 | // Copyright (c) 2001-2011 Hartmut Kaiser | |
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 | #if !defined(BOOST_SPIRIT_ITERATOR_LEX_INPUT_POLICY_MAR_16_2007_1205PM) | |
8 | #define BOOST_SPIRIT_ITERATOR_LEX_INPUT_POLICY_MAR_16_2007_1205PM | |
9 | ||
10 | #include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp> | |
11 | #include <boost/spirit/home/support/iterators/detail/multi_pass.hpp> | |
12 | ||
13 | namespace boost { namespace spirit { namespace iterator_policies | |
14 | { | |
15 | /////////////////////////////////////////////////////////////////////////////// | |
16 | // class lex_input | |
17 | // Implementation of the InputPolicy used by multi_pass | |
18 | // | |
19 | // The lex_input class gets tokens (integers) from yylex() | |
20 | /////////////////////////////////////////////////////////////////////////// | |
21 | struct lex_input | |
22 | { | |
23 | typedef int value_type; | |
24 | ||
25 | /////////////////////////////////////////////////////////////////////// | |
26 | template <typename T> | |
27 | class unique : public detail::default_input_policy | |
28 | { | |
29 | public: | |
30 | typedef std::ptrdiff_t difference_type; | |
31 | typedef std::ptrdiff_t distance_type; | |
32 | typedef int* pointer; | |
33 | typedef int& reference; | |
34 | ||
35 | protected: | |
36 | unique() {} | |
37 | explicit unique(T) {} | |
38 | ||
39 | public: | |
40 | template <typename MultiPass> | |
41 | static typename MultiPass::reference get_input(MultiPass& mp) | |
42 | { | |
43 | value_type& curtok = mp.shared()->curtok; | |
44 | if (-1 == curtok) | |
45 | { | |
46 | extern int yylex(); | |
47 | curtok = yylex(); | |
48 | } | |
49 | return curtok; | |
50 | } | |
51 | ||
52 | template <typename MultiPass> | |
53 | static void advance_input(MultiPass& mp) | |
54 | { | |
55 | extern int yylex(); | |
56 | mp.shared()->curtok = yylex(); | |
57 | } | |
58 | ||
59 | // test, whether we reached the end of the underlying stream | |
60 | template <typename MultiPass> | |
61 | static bool input_at_eof(MultiPass const& mp) | |
62 | { | |
63 | return mp.shared()->curtok == 0; | |
64 | } | |
65 | ||
66 | template <typename MultiPass> | |
67 | static bool input_is_valid(MultiPass const&, value_type const& t) | |
68 | { | |
69 | return -1 != t; | |
70 | } | |
71 | }; | |
72 | ||
73 | /////////////////////////////////////////////////////////////////////// | |
74 | template <typename T> | |
75 | struct shared | |
76 | { | |
77 | explicit shared(T) : curtok(-1) {} | |
78 | ||
79 | value_type curtok; | |
80 | }; | |
81 | }; | |
82 | ||
83 | }}} | |
84 | ||
85 | #endif | |
86 |