1 ///////////////////////////////////////////////////////////////////////////////
2 // sequence.hpp
3 //
4 // Copyright 2008 Eric Niebler. Distributed under the Boost
5 // Software License, Version 1.0. (See accompanying file
6 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7
8 #ifndef BOOST_XPRESSIVE_DETAIL_DYNAMIC_SEQUENCE_HPP_EAN_04_10_2006
9 #define BOOST_XPRESSIVE_DETAIL_DYNAMIC_SEQUENCE_HPP_EAN_04_10_2006
10
11 // MS compatible compilers support #pragma once
12 #if defined(_MSC_VER)
13 # pragma once
14 #endif
15
16 #include <boost/assert.hpp>
17 #include <boost/intrusive_ptr.hpp>
18 #include <boost/xpressive/detail/utility/width.hpp>
19 #include <boost/xpressive/detail/detail_fwd.hpp>
20
21 namespace boost { namespace xpressive { namespace detail
22 {
23
24 ///////////////////////////////////////////////////////////////////////////////
25 // sequence
26 template<typename BidiIter>
27 struct sequence
28 {
sequenceboost::xpressive::detail::sequence29 sequence()
30 : pure_(true)
31 , width_(0)
32 , quant_(quant_none)
33 , head_()
34 , tail_(0)
35 , alt_end_xpr_()
36 , alternates_(0)
37 {
38 }
39
40 template<typename Matcher>
sequenceboost::xpressive::detail::sequence41 sequence(intrusive_ptr<dynamic_xpression<Matcher, BidiIter> > const &xpr)
42 : pure_(Matcher::pure)
43 , width_(xpr->Matcher::get_width())
44 , quant_(static_cast<quant_enum>(Matcher::quant))
45 , head_(xpr)
46 , tail_(&xpr->next_)
47 , alt_end_xpr_()
48 , alternates_(0)
49 {
50 }
51
52 template<typename Traits>
sequenceboost::xpressive::detail::sequence53 sequence(intrusive_ptr<dynamic_xpression<alternate_matcher<alternates_vector<BidiIter>, Traits>, BidiIter> > const &xpr)
54 : pure_(true)
55 , width_(0)
56 , quant_(quant_none)
57 , head_(xpr)
58 , tail_(&xpr->next_)
59 , alt_end_xpr_()
60 , alternates_(&xpr->alternates_)
61 {
62 }
63
emptyboost::xpressive::detail::sequence64 bool empty() const
65 {
66 return !this->head_;
67 }
68
operator +=boost::xpressive::detail::sequence69 sequence<BidiIter> &operator +=(sequence<BidiIter> const &that)
70 {
71 if(this->empty())
72 {
73 *this = that;
74 }
75 else if(!that.empty())
76 {
77 *this->tail_ = that.head_;
78 this->tail_ = that.tail_;
79 // keep track of sequence width and purity
80 this->width_ += that.width_;
81 this->pure_ = this->pure_ && that.pure_;
82 this->set_quant_();
83 }
84 return *this;
85 }
86
operator |=boost::xpressive::detail::sequence87 sequence<BidiIter> &operator |=(sequence<BidiIter> that)
88 {
89 BOOST_ASSERT(!this->empty());
90 BOOST_ASSERT(0 != this->alternates_);
91
92 // Keep track of width and purity
93 if(this->alternates_->empty())
94 {
95 this->width_ = that.width_;
96 this->pure_ = that.pure_;
97 }
98 else
99 {
100 this->width_ |= that.width_;
101 this->pure_ = this->pure_ && that.pure_;
102 }
103
104 // through the wonders of reference counting, all alternates_ can share an end_alternate
105 if(!this->alt_end_xpr_)
106 {
107 this->alt_end_xpr_ = new alt_end_xpr_type;
108 }
109
110 // terminate each alternate with an alternate_end_matcher
111 that += sequence(this->alt_end_xpr_);
112 this->alternates_->push_back(that.head_);
113 this->set_quant_();
114 return *this;
115 }
116
repeatboost::xpressive::detail::sequence117 void repeat(quant_spec const &spec)
118 {
119 this->xpr().matchable()->repeat(spec, *this);
120 }
121
xprboost::xpressive::detail::sequence122 shared_matchable<BidiIter> const &xpr() const
123 {
124 return this->head_;
125 }
126
widthboost::xpressive::detail::sequence127 detail::width width() const
128 {
129 return this->width_;
130 }
131
pureboost::xpressive::detail::sequence132 bool pure() const
133 {
134 return this->pure_;
135 }
136
quantboost::xpressive::detail::sequence137 quant_enum quant() const
138 {
139 return this->quant_;
140 }
141
142 private:
143 typedef dynamic_xpression<alternate_end_matcher, BidiIter> alt_end_xpr_type;
144
set_quant_boost::xpressive::detail::sequence145 void set_quant_()
146 {
147 this->quant_ = (!is_unknown(this->width_) && this->pure_)
148 ? (!this->width_ ? quant_none : quant_fixed_width)
149 : quant_variable_width;
150 }
151
152 bool pure_;
153 detail::width width_;
154 quant_enum quant_;
155 shared_matchable<BidiIter> head_;
156 shared_matchable<BidiIter> *tail_;
157 intrusive_ptr<alt_end_xpr_type> alt_end_xpr_;
158 alternates_vector<BidiIter> *alternates_;
159 };
160
161 template<typename BidiIter>
operator +(sequence<BidiIter> left,sequence<BidiIter> const & right)162 inline sequence<BidiIter> operator +(sequence<BidiIter> left, sequence<BidiIter> const &right)
163 {
164 return left += right;
165 }
166
167 template<typename BidiIter>
operator |(sequence<BidiIter> left,sequence<BidiIter> const & right)168 inline sequence<BidiIter> operator |(sequence<BidiIter> left, sequence<BidiIter> const &right)
169 {
170 return left |= right;
171 }
172
173 }}} // namespace boost::xpressive::detail
174
175 #endif
176