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1 | // ---------------------------------------------------------------------------- |
2 | // Copyright (C) 2009 Sebastian Redl | |
3 | // | |
4 | // Distributed under the Boost Software License, Version 1.0. | |
5 | // (See accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt) | |
7 | // | |
8 | // For more information, see www.boost.org | |
9 | // ---------------------------------------------------------------------------- | |
10 | ||
11 | #ifndef BOOST_PROPERTY_TREE_STREAM_TRANSLATOR_HPP_INCLUDED | |
12 | #define BOOST_PROPERTY_TREE_STREAM_TRANSLATOR_HPP_INCLUDED | |
13 | ||
14 | #include <boost/property_tree/ptree_fwd.hpp> | |
15 | ||
16 | #include <boost/optional.hpp> | |
17 | #include <boost/optional/optional_io.hpp> | |
18 | #include <boost/utility/enable_if.hpp> | |
19 | #include <boost/type_traits/decay.hpp> | |
20 | #include <boost/type_traits/integral_constant.hpp> | |
21 | #include <sstream> | |
22 | #include <string> | |
23 | #include <locale> | |
24 | #include <limits> | |
25 | ||
26 | namespace boost { namespace property_tree | |
27 | { | |
28 | ||
29 | template <typename Ch, typename Traits, typename E, typename Enabler = void> | |
30 | struct customize_stream | |
31 | { | |
32 | static void insert(std::basic_ostream<Ch, Traits>& s, const E& e) { | |
33 | s << e; | |
34 | } | |
35 | static void extract(std::basic_istream<Ch, Traits>& s, E& e) { | |
36 | s >> e; | |
37 | if(!s.eof()) { | |
38 | s >> std::ws; | |
39 | } | |
40 | } | |
41 | }; | |
42 | ||
43 | // No whitespace skipping for single characters. | |
44 | template <typename Ch, typename Traits> | |
45 | struct customize_stream<Ch, Traits, Ch, void> | |
46 | { | |
47 | static void insert(std::basic_ostream<Ch, Traits>& s, Ch e) { | |
48 | s << e; | |
49 | } | |
50 | static void extract(std::basic_istream<Ch, Traits>& s, Ch& e) { | |
51 | s.unsetf(std::ios_base::skipws); | |
52 | s >> e; | |
53 | } | |
54 | }; | |
55 | ||
56 | // Ugly workaround for numeric_traits that don't have members when not | |
57 | // specialized, e.g. MSVC. | |
58 | namespace detail | |
59 | { | |
60 | template <bool is_specialized> | |
61 | struct is_inexact_impl | |
62 | { | |
63 | template <typename T> | |
64 | struct test | |
65 | { | |
66 | typedef boost::false_type type; | |
67 | }; | |
68 | }; | |
69 | template <> | |
70 | struct is_inexact_impl<true> | |
71 | { | |
72 | template <typename T> | |
73 | struct test | |
74 | { | |
75 | typedef boost::integral_constant<bool, | |
76 | !std::numeric_limits<T>::is_exact> type; | |
77 | }; | |
78 | }; | |
79 | ||
80 | template <typename F> | |
81 | struct is_inexact | |
82 | { | |
83 | typedef typename boost::decay<F>::type decayed; | |
84 | typedef typename is_inexact_impl< | |
85 | std::numeric_limits<decayed>::is_specialized | |
86 | >::BOOST_NESTED_TEMPLATE test<decayed>::type type; | |
87 | static const bool value = type::value; | |
88 | }; | |
89 | } | |
90 | ||
91 | template <typename Ch, typename Traits, typename F> | |
92 | struct customize_stream<Ch, Traits, F, | |
93 | typename boost::enable_if< detail::is_inexact<F> >::type | |
94 | > | |
95 | { | |
96 | static void insert(std::basic_ostream<Ch, Traits>& s, const F& e) { | |
97 | #ifndef BOOST_NO_CXX11_NUMERIC_LIMITS | |
98 | s.precision(std::numeric_limits<F>::max_digits10); | |
99 | #else | |
100 | s.precision(std::numeric_limits<F>::digits10 + 2); | |
101 | #endif | |
102 | s << e; | |
103 | } | |
104 | static void extract(std::basic_istream<Ch, Traits>& s, F& e) { | |
105 | s >> e; | |
106 | if(!s.eof()) { | |
107 | s >> std::ws; | |
108 | } | |
109 | } | |
110 | }; | |
111 | ||
112 | template <typename Ch, typename Traits> | |
113 | struct customize_stream<Ch, Traits, bool, void> | |
114 | { | |
115 | static void insert(std::basic_ostream<Ch, Traits>& s, bool e) { | |
116 | s.setf(std::ios_base::boolalpha); | |
117 | s << e; | |
118 | } | |
119 | static void extract(std::basic_istream<Ch, Traits>& s, bool& e) { | |
120 | s >> e; | |
121 | if(s.fail()) { | |
122 | // Try again in word form. | |
123 | s.clear(); | |
124 | s.setf(std::ios_base::boolalpha); | |
125 | s >> e; | |
126 | } | |
127 | if(!s.eof()) { | |
128 | s >> std::ws; | |
129 | } | |
130 | } | |
131 | }; | |
132 | ||
133 | template <typename Ch, typename Traits> | |
134 | struct customize_stream<Ch, Traits, signed char, void> | |
135 | { | |
136 | static void insert(std::basic_ostream<Ch, Traits>& s, signed char e) { | |
137 | s << (int)e; | |
138 | } | |
139 | static void extract(std::basic_istream<Ch, Traits>& s, signed char& e) { | |
140 | int i; | |
141 | s >> i; | |
142 | // out of range? | |
143 | if(i > (std::numeric_limits<signed char>::max)() || | |
144 | i < (std::numeric_limits<signed char>::min)()) | |
145 | { | |
146 | s.clear(); // guarantees eof to be unset | |
147 | e = 0; | |
148 | s.setstate(std::ios_base::badbit); | |
149 | return; | |
150 | } | |
151 | e = (signed char)i; | |
152 | if(!s.eof()) { | |
153 | s >> std::ws; | |
154 | } | |
155 | } | |
156 | }; | |
157 | ||
158 | template <typename Ch, typename Traits> | |
159 | struct customize_stream<Ch, Traits, unsigned char, void> | |
160 | { | |
161 | static void insert(std::basic_ostream<Ch, Traits>& s, unsigned char e) { | |
162 | s << (unsigned)e; | |
163 | } | |
164 | static void extract(std::basic_istream<Ch,Traits>& s, unsigned char& e){ | |
165 | unsigned i; | |
166 | s >> i; | |
167 | // out of range? | |
168 | if(i > (std::numeric_limits<unsigned char>::max)()) { | |
169 | s.clear(); // guarantees eof to be unset | |
170 | e = 0; | |
171 | s.setstate(std::ios_base::badbit); | |
172 | return; | |
173 | } | |
174 | e = (unsigned char)i; | |
175 | if(!s.eof()) { | |
176 | s >> std::ws; | |
177 | } | |
178 | } | |
179 | }; | |
180 | ||
181 | /// Implementation of Translator that uses the stream overloads. | |
182 | template <typename Ch, typename Traits, typename Alloc, typename E> | |
183 | class stream_translator | |
184 | { | |
185 | typedef customize_stream<Ch, Traits, E> customized; | |
186 | public: | |
187 | typedef std::basic_string<Ch, Traits, Alloc> internal_type; | |
188 | typedef E external_type; | |
189 | ||
190 | explicit stream_translator(std::locale loc = std::locale()) | |
191 | : m_loc(loc) | |
192 | {} | |
193 | ||
194 | boost::optional<E> get_value(const internal_type &v) { | |
195 | std::basic_istringstream<Ch, Traits, Alloc> iss(v); | |
196 | iss.imbue(m_loc); | |
197 | E e; | |
198 | customized::extract(iss, e); | |
199 | if(iss.fail() || iss.bad() || iss.get() != Traits::eof()) { | |
200 | return boost::optional<E>(); | |
201 | } | |
202 | return e; | |
203 | } | |
204 | boost::optional<internal_type> put_value(const E &v) { | |
205 | std::basic_ostringstream<Ch, Traits, Alloc> oss; | |
206 | oss.imbue(m_loc); | |
207 | customized::insert(oss, v); | |
208 | if(oss) { | |
209 | return oss.str(); | |
210 | } | |
211 | return boost::optional<internal_type>(); | |
212 | } | |
213 | ||
214 | private: | |
215 | std::locale m_loc; | |
216 | }; | |
217 | ||
218 | // This is the default translator when basic_string is the internal type. | |
219 | // Unless the external type is also basic_string, in which case | |
220 | // id_translator takes over. | |
221 | template <typename Ch, typename Traits, typename Alloc, typename E> | |
222 | struct translator_between<std::basic_string<Ch, Traits, Alloc>, E> | |
223 | { | |
224 | typedef stream_translator<Ch, Traits, Alloc, E> type; | |
225 | }; | |
226 | ||
227 | }} | |
228 | ||
229 | #endif |