1// Copyright Vladimir Prus 2004.
2// Distributed under the Boost Software License, Version 1.0.
3// (See accompanying file LICENSE_1_0.txt
4// or copy at http://www.boost.org/LICENSE_1_0.txt)
5
6#include <fstream>
7#include <locale.h>
8#include <locale>
9#include <iostream>
10#include <string>
11#include <locale>
12#include <stdexcept>
13
14#include <boost/config.hpp>
15
16#define BOOST_PROGRAM_OPTIONS_SOURCE
17#include <boost/program_options/config.hpp>
18#include <boost/program_options/detail/convert.hpp>
19#include <boost/program_options/detail/utf8_codecvt_facet.hpp>
20#include <boost/throw_exception.hpp>
21
22#include <boost/bind.hpp>
23
24using namespace std;
25
26namespace boost { namespace detail {
27
28 /* Internal function to actually perform conversion.
29 The logic in from_8_bit and to_8_bit function is exactly
30 the same, except that one calls 'in' method of codecvt and another
31 calls the 'out' method, and that syntax difference makes straightforward
32 template implementation impossible.
33
34 This functions takes a 'fun' argument, which should have the same
35 parameters and return type and the in/out methods. The actual converting
36 function will pass functional objects created with boost::bind.
37 Experiments show that the performance loss is less than 10%.
38 */
39 template<class ToChar, class FromChar, class Fun>
40 std::basic_string<ToChar>
41 convert(const std::basic_string<FromChar>& s, Fun fun)
42
43 {
44 std::basic_string<ToChar> result;
45
46 std::mbstate_t state = std::mbstate_t();
47
48 const FromChar* from = s.data();
49 const FromChar* from_end = s.data() + s.size();
50 // The interface of cvt is not really iterator-like, and it's
51 // not possible the tell the required output size without the conversion.
52 // All we can is convert data by pieces.
53 while(from != from_end) {
54
55 // std::basic_string does not provide non-const pointers to the data,
56 // so converting directly into string is not possible.
57 ToChar buffer[32];
58
59 ToChar* to_next = buffer;
60 // Need variable because boost::bind doesn't work with rvalues.
61 ToChar* to_end = buffer + 32;
62 std::codecvt_base::result r =
63 fun(state, from, from_end, from, buffer, to_end, to_next);
64
65 if (r == std::codecvt_base::error)
66 boost::throw_exception(
67 std::logic_error("character conversion failed"));
68 // 'partial' is not an error, it just means not all source
69 // characters were converted. However, we need to check that at
70 // least one new target character was produced. If not, it means
71 // the source data is incomplete, and since we don't have extra
72 // data to add to source, it's error.
73 if (to_next == buffer)
74 boost::throw_exception(
75 std::logic_error("character conversion failed"));
76
77 // Add converted characters
78 result.append(buffer, to_next);
79 }
80
81 return result;
82 }
83}}
84
85namespace boost {
86
87#ifndef BOOST_NO_STD_WSTRING
88 BOOST_PROGRAM_OPTIONS_DECL std::wstring
89 from_8_bit(const std::string& s,
90 const std::codecvt<wchar_t, char, std::mbstate_t>& cvt)
91 {
92 return detail::convert<wchar_t>(
93 s,
94 boost::bind(&std::codecvt<wchar_t, char, mbstate_t>::in,
95 &cvt,
96 _1, _2, _3, _4, _5, _6, _7));
97 }
98
99 BOOST_PROGRAM_OPTIONS_DECL std::string
100 to_8_bit(const std::wstring& s,
101 const std::codecvt<wchar_t, char, std::mbstate_t>& cvt)
102 {
103 return detail::convert<char>(
104 s,
105 boost::bind(&codecvt<wchar_t, char, mbstate_t>::out,
106 &cvt,
107 _1, _2, _3, _4, _5, _6, _7));
108 }
109
110
111 namespace {
112 boost::program_options::detail::utf8_codecvt_facet
113 utf8_facet;
114 }
115
116 BOOST_PROGRAM_OPTIONS_DECL std::wstring
117 from_utf8(const std::string& s)
118 {
119 return from_8_bit(s, utf8_facet);
120 }
121
122 BOOST_PROGRAM_OPTIONS_DECL std::string
123 to_utf8(const std::wstring& s)
124 {
125 return to_8_bit(s, utf8_facet);
126 }
127
128 BOOST_PROGRAM_OPTIONS_DECL std::wstring
129 from_local_8_bit(const std::string& s)
130 {
131 typedef codecvt<wchar_t, char, mbstate_t> facet_type;
132 return from_8_bit(s,
133 BOOST_USE_FACET(facet_type, locale()));
134 }
135
136 BOOST_PROGRAM_OPTIONS_DECL std::string
137 to_local_8_bit(const std::wstring& s)
138 {
139 typedef codecvt<wchar_t, char, mbstate_t> facet_type;
140 return to_8_bit(s,
141 BOOST_USE_FACET(facet_type, locale()));
142 }
143#endif
144
145 namespace program_options
146 {
147 BOOST_PROGRAM_OPTIONS_DECL std::string to_internal(const std::string& s)
148 {
149 return s;
150 }
151
152#ifndef BOOST_NO_STD_WSTRING
153 BOOST_PROGRAM_OPTIONS_DECL std::string to_internal(const std::wstring& s)
154 {
155 return to_utf8(s);
156 }
157#endif
158 }
159
160
161}
162