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detail/utf8_codecvt_facet.hpp
1
2 //******************************************************************************
3 // RCF - Remote Call Framework
4 //
5 // Copyright (c) 2005 - 2013, Delta V Software. All rights reserved.
6 // http://www.deltavsoft.com
7 //
8 // RCF is distributed under dual licenses - closed source or GPL.
9 // Consult your particular license for conditions of use.
10 //
11 // If you have not purchased a commercial license, you are using RCF
12 // under GPL terms.
13 //
14 // Version: 2.0
15 // Contact: support <at> deltavsoft.com
16 //
17 //******************************************************************************
18
19 #ifndef RCF_BOOST_UTF8_CODECVT_FACET_HPP
20 #define RCF_BOOST_UTF8_CODECVT_FACET_HPP
21
22 // MS compatible compilers support #pragma once
23 #if defined(_MSC_VER) && (_MSC_VER >= 1020)
24 # pragma once
25 #endif
26
28 // utf8_codecvt_facet.hpp
29
30 // This header defines class utf8_codecvt_facet, derived fro
31 // std::codecvt<wchar_t, char>, which can be used to convert utf8 data in
32 // files into wchar_t strings in the application.
33 //
34 // The header is NOT STANDALONE, and is not to be included by the USER.
35 // There are at least two libraries which want to use this functionality, and
36 // we want to avoid code duplication. It would be possible to create utf8
37 // library, but:
38 // - this requires review process first
39 // - in the case, when linking the a library which uses utf8
40 // (say 'program_options'), user should also link to the utf8 library.
41 // This seems inconvenient, and asking a user to link to an unrevieved
42 // library is strange.
43 // Until the above points are fixed, a library which wants to use utf8 must:
44 // - include this header from one of it's headers or sources
45 // - include the corresponding .cpp file from one of the sources
46 // - before including either file, the library must define
47 // - BOOST_UTF8_BEGIN_NAMESPACE to the namespace declaration that must be used
48 // - BOOST_UTF8_END_NAMESPACE to the code to close the previous namespace
49 // - declaration.
50 // - BOOST_UTF8_DECL -- to the code which must be used for all 'exportable'
51 // symbols.
52 //
53 // For example, program_options library might contain:
54 // #define BOOST_UTF8_BEGIN_NAMESPACE <backslash character>
55 // namespace boost { namespace program_options {
56 // #define BOOST_UTF8_END_NAMESPACE }}
57 // #define BOOST_UTF8_DECL BOOST_PROGRAM_OPTIONS_DECL
58 // #include "../../detail/utf8/utf8_codecvt.cpp"
59 //
60 // Essentially, each library will have its own copy of utf8 code, in
61 // different namespaces.
62
63 // Note:(Robert Ramey). I have made the following alterations in the original
64 // code.
65 // a) Rendered utf8_codecvt<wchar_t, char> with using templates
66 // b) Move longer functions outside class definition to prevent inlining
67 // and make code smaller
68 // c) added on a derived class to permit translation to/from current
69 // locale to utf8
70
71 // See http://www.boost.org for updates, documentation, and revision history.
72
73 // archives stored as text - note these ar templated on the basic
74 // stream templates to accommodate wide (and other?) kind of characters
75 //
76 // note the fact that on libraries without wide characters, ostream is
77 // is not a specialization of basic_ostream which in fact is not defined
78 // in such cases. So we can't use basic_ostream<OStream::char_type> but rather
79 // use two template parameters
80 //
81 // utf8_codecvt_facet
82 // This is an implementation of a std::codecvt facet for translating
83 // from UTF-8 externally to UCS-4. Note that this is not tied to
84 // any specific types in order to allow customization on platforms
85 // where wchar_t is not big enough.
86 //
87 // NOTES: The current implementation jumps through some unpleasant hoops in
88 // order to deal with signed character types. As a std::codecvt_base::result,
89 // it is necessary for the ExternType to be convertible to unsigned char.
90 // I chose not to tie the extern_type explicitly to char. But if any combination
91 // of types other than <wchar_t,char_t> is used, then std::codecvt must be
92 // specialized on those types for this to work.
93
94 #include <locale>
95 #include <cwchar> // for mbstate_t
96 #include <cstddef> // for std::size_t
97
98 #include <boost/config.hpp>
99 #include <boost/detail/workaround.hpp>
100
101 #ifdef _MSC_VER
102 #pragma warning( push )
103 #pragma warning( disable: 4263 ) // warning C4263: 'int RcfBoost::boost::program_options::detail::utf8_codecvt_facet::do_length(const mbstate_t &,const char *,const char *,size_t) const' : member function does not override any base class virtual member function
104 #endif
105
106 #if defined(BOOST_NO_STDC_NAMESPACE)
107 namespace std {
108 using ::mbstate_t;
109 using ::size_t;
110 }
111 #endif
112
113 #if !defined(__MSL_CPP__) && !defined(__LIBCOMO__)
114 #define BOOST_CODECVT_DO_LENGTH_CONST const
115 #else
116 #define BOOST_CODECVT_DO_LENGTH_CONST
117 #endif
118
119 // maximum lenght of a multibyte string
120 #define MB_LENGTH_MAX 8
121
122 BOOST_UTF8_BEGIN_NAMESPACE
123
124 struct BOOST_UTF8_DECL utf8_codecvt_facet :
125 public std::codecvt<wchar_t, char, std::mbstate_t>
126 {
127 public:
128 explicit utf8_codecvt_facet(std::size_t no_locale_manage=0)
129 : std::codecvt<wchar_t, char, std::mbstate_t>(no_locale_manage)
130 {}
131 protected:
132 virtual std::codecvt_base::result do_in(
133 std::mbstate_t& state,
134 const char * from,
135 const char * from_end,
136 const char * & from_next,
137 wchar_t * to,
138 wchar_t * to_end,
139 wchar_t*& to_next
140 ) const;
141
142 virtual std::codecvt_base::result do_out(
143 std::mbstate_t & state, const wchar_t * from,
144 const wchar_t * from_end, const wchar_t* & from_next,
145 char * to, char * to_end, char * & to_next
146 ) const;
147
148 bool invalid_continuing_octet(unsigned char octet_1) const {
149 return (octet_1 < 0x80|| 0xbf< octet_1);
150 }
151
152 bool invalid_leading_octet(unsigned char octet_1) const {
153 return (0x7f < octet_1 && octet_1 < 0xc0) ||
154 (octet_1 > 0xfd);
155 }
156
157 // continuing octets = octets except for the leading octet
158 static unsigned int get_cont_octet_count(unsigned char lead_octet) {
159 return get_octet_count(lead_octet) - 1;
160 }
161
162 static unsigned int get_octet_count(unsigned char lead_octet);
163
164 // How many "continuing octets" will be needed for this word
165 // == total octets - 1.
166 int get_cont_octet_out_count(wchar_t word) const ;
167
168 virtual bool do_always_noconv() const throw() { return false; }
169
170 // UTF-8 isn't really stateful since we rewind on partial conversions
171 virtual std::codecvt_base::result do_unshift(
172 std::mbstate_t&,
173 char * from,
174 char * /*to*/,
175 char * & next
176 ) const
177 {
178 next = from;
179 return ok;
180 }
181
182 virtual int do_encoding() const throw() {
183 const int variable_byte_external_encoding=0;
184 return variable_byte_external_encoding;
185 }
186
187 // How many char objects can I process to get <= max_limit
188 // wchar_t objects?
189 virtual int do_length(
190 BOOST_CODECVT_DO_LENGTH_CONST std::mbstate_t &,
191 const char * from,
192 const char * from_end,
193 std::size_t max_limit
194 #if BOOST_WORKAROUND(__IBMCPP__, BOOST_TESTED_AT(600))
195 ) const throw();
196 #else
197 ) const;
198 #endif
199
200 // Largest possible value do_length(state,from,from_end,1) could return.
201 virtual int do_max_length() const throw () {
202 return 6; // largest UTF-8 encoding of a UCS-4 character
203 }
204 };
205
206 BOOST_UTF8_END_NAMESPACE
207
208 #ifdef _MSC_VER
209 #pragma warning( pop )
210 #endif
211
212 #endif // RCF_BOOST_UTF8_CODECVT_FACET_HPP