[857] | 1 | /*=============================================================================
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| 2 | Boost.Wave: A Standard compliant C++ preprocessor library
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| 3 |
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| 4 | http://www.boost.org/
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| 5 |
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| 6 | Copyright (c) 2001-2005 Hartmut Kaiser. Distributed under the Boost
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| 7 | Software License, Version 1.0. (See accompanying file
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| 8 | LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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| 9 | =============================================================================*/
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| 10 |
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| 11 | #if !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)
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| 12 | #define TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED
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| 13 |
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| 14 | #include <boost/iterator_adaptors.hpp>
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| 15 | #if BOOST_ITERATOR_ADAPTORS_VERSION >= 0x0200
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| 16 | #include <boost/iterator/transform_iterator.hpp>
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| 17 | #endif // BOOST_ITERATOR_ADAPTORS_VERSION >= 0x0200
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| 18 |
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| 19 | #include <boost/assert.hpp>
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| 20 |
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| 21 | ///////////////////////////////////////////////////////////////////////////////
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| 22 | namespace boost {
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| 23 | namespace wave {
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| 24 | namespace impl {
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| 25 |
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| 26 | #if BOOST_ITERATOR_ADAPTORS_VERSION < 0x0200
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| 27 |
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| 28 | ///////////////////////////////////////////////////////////////////////////////
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| 29 | //
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| 30 | // Transform Iterator Adaptor
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| 31 | //
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| 32 | // Upon deference, apply some unary function object and return the
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| 33 | // result by reference.
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| 34 | //
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| 35 | // This class is adapted from the Boost.Iterator library, where a similar
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| 36 | // class exists, which returns the next item by value
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| 37 | //
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| 38 | ///////////////////////////////////////////////////////////////////////////////
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| 39 | template <class AdaptableUnaryFunctionT>
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| 40 | struct ref_transform_iterator_policies
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| 41 | : public boost::default_iterator_policies
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| 42 | {
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| 43 | ref_transform_iterator_policies()
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| 44 | {}
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| 45 | ref_transform_iterator_policies(const AdaptableUnaryFunctionT &f)
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| 46 | : m_f(f) {}
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| 47 |
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| 48 | template <class IteratorAdaptorT>
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| 49 | typename IteratorAdaptorT::reference
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| 50 | dereference(const IteratorAdaptorT &iter) const
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| 51 | { return m_f(*iter.base()); }
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| 52 |
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| 53 | AdaptableUnaryFunctionT m_f;
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| 54 | };
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| 55 |
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| 56 | template <class AdaptableUnaryFunctionT, class IteratorT>
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| 57 | class ref_transform_iterator_generator
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| 58 | {
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| 59 | typedef typename AdaptableUnaryFunctionT::result_type value_type;
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| 60 |
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| 61 | public:
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| 62 | typedef boost::iterator_adaptor<
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| 63 | IteratorT,
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| 64 | ref_transform_iterator_policies<AdaptableUnaryFunctionT>,
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| 65 | value_type, value_type const &, value_type const *,
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| 66 | std::input_iterator_tag>
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| 67 | type;
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| 68 | };
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| 69 |
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| 70 | template <class AdaptableUnaryFunctionT, class IteratorT>
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| 71 | inline
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| 72 | typename ref_transform_iterator_generator<
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| 73 | AdaptableUnaryFunctionT, IteratorT>::type
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| 74 | make_ref_transform_iterator(
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| 75 | IteratorT base,
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| 76 | const AdaptableUnaryFunctionT &f = AdaptableUnaryFunctionT())
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| 77 | {
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| 78 | typedef typename ref_transform_iterator_generator<
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| 79 | AdaptableUnaryFunctionT, IteratorT>::type
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| 80 | result_t;
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| 81 | return result_t(base, f);
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| 82 | }
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| 83 |
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| 84 | // Retrieve the token value given a parse node
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| 85 | // This is used in conjunction with the ref_transform_iterator above, to
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| 86 | // get the token values while iterating directly over the parse tree.
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| 87 | template <typename TokenT, typename ParseTreeNodeT>
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| 88 | struct get_token_value {
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| 89 |
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| 90 | typedef TokenT result_type;
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| 91 |
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| 92 | TokenT const &operator()(ParseTreeNodeT const &node) const
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| 93 | {
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| 94 | BOOST_ASSERT(1 == std::distance(node.value.begin(),
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| 95 | node.value.end()));
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| 96 | return *node.value.begin();
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| 97 | }
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| 98 | };
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| 99 |
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| 100 | #else // BOOST_ITERATOR_ADAPTORS_VERSION < 0x0200
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| 101 |
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| 102 | ///////////////////////////////////////////////////////////////////////////////
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| 103 | //
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| 104 | // The new Boost.Iterator library already conatins a transform_iterator usable
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| 105 | // for our needs. The code below wraps this up.
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| 106 | //
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| 107 | ///////////////////////////////////////////////////////////////////////////////
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| 108 | template <class AdaptableUnaryFunctionT, class IteratorT>
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| 109 | class ref_transform_iterator_generator
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| 110 | {
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| 111 | typedef typename AdaptableUnaryFunctionT::result_type return_type;
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| 112 | typedef typename AdaptableUnaryFunctionT::argument_type argument_type;
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| 113 |
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| 114 | public:
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| 115 | typedef boost::transform_iterator<
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| 116 | return_type (*)(argument_type), IteratorT, return_type>
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| 117 | type;
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| 118 | };
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| 119 |
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| 120 | template <class AdaptableUnaryFunctionT, class IteratorT>
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| 121 | inline
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| 122 | typename ref_transform_iterator_generator<
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| 123 | AdaptableUnaryFunctionT, IteratorT>::type
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| 124 | make_ref_transform_iterator(
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| 125 | IteratorT base, AdaptableUnaryFunctionT const &f)
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| 126 | {
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| 127 | typedef typename ref_transform_iterator_generator<
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| 128 | AdaptableUnaryFunctionT, IteratorT>::type
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| 129 | iterator_type;
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| 130 | return iterator_type(base, f.transform);
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| 131 | }
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| 132 |
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| 133 | // Retrieve the token value given a parse node
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| 134 | // This is used in conjunction with the ref_transform_iterator above, to
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| 135 | // get the token values while iterating directly over the parse tree.
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| 136 | template <typename TokenT, typename ParseTreeNodeT>
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| 137 | struct get_token_value {
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| 138 |
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| 139 | typedef TokenT const &result_type;
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| 140 | typedef ParseTreeNodeT const &argument_type;
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| 141 |
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| 142 | static result_type
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| 143 | transform (argument_type node)
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| 144 | {
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| 145 | BOOST_ASSERT(1 == std::distance(node.value.begin(),
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| 146 | node.value.end()));
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| 147 | return *node.value.begin();
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| 148 | }
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| 149 | };
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| 150 |
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| 151 | #endif // BOOST_ITERATOR_ADAPTORS_VERSION < 0x0200
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| 152 |
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| 153 | ///////////////////////////////////////////////////////////////////////////////
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| 154 | } // namespace impl
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| 155 | } // namespace wave
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| 156 | } // namespace boost
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| 157 |
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| 158 | #endif // !defined(TRANSFORM_ITERATOR_HPP_D492C659_88C7_4258_8C42_192F9AE80EC0_INCLUDED)
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