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/optional.hpp> |
17 | #include <boost/optional/optional_io.hpp> |
18 | #include <boost/core/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 (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 (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 (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 (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 (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 (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 |
230 | |