1 // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
2 // (C) Copyright 2003-2007 Jonathan Turkanis
3 // Distributed under the Boost Software License, Version 1.0. (See accompanying
4 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
5
6 // See http://www.boost.org/libs/iostreams for documentation.
7
8 #ifndef BOOST_IOSTREAMS_DETAIL_DIRECT_ADAPTER_HPP_INCLUDED
9 #define BOOST_IOSTREAMS_DETAIL_DIRECT_ADAPTER_HPP_INCLUDED
10
11 #if defined(_MSC_VER)
12 # pragma once
13 #endif
14
15 #include <boost/config.hpp> // SFINAE, MSVC, put ptrdiff_t in std.
16 #include <algorithm> // copy, min.
17 #include <cstddef> // ptrdiff_t.
18 #include <boost/detail/workaround.hpp>
19 #include <boost/iostreams/categories.hpp>
20 #include <boost/iostreams/detail/config/limits.hpp> // forwarding.
21 #include <boost/iostreams/detail/config/wide_streams.hpp> // locale.
22 #include <boost/iostreams/detail/double_object.hpp>
23 #include <boost/iostreams/detail/error.hpp>
24 #include <boost/iostreams/detail/ios.hpp> // openmode, seekdir, int types.
25 #include <boost/iostreams/traits.hpp> // mode_of, is_direct.
26 #include <boost/iostreams/operations.hpp>
27 #include <boost/mpl/bool.hpp>
28 #include <boost/mpl/or.hpp>
29 #include <boost/preprocessor/iteration/local.hpp>
30 #include <boost/preprocessor/repetition/enum_binary_params.hpp>
31 #include <boost/preprocessor/repetition/enum_params.hpp>
32 #include <boost/static_assert.hpp>
33 #include <boost/throw_exception.hpp>
34 #include <boost/type_traits/is_convertible.hpp>
35
36 // Must come last.
37 #include <boost/iostreams/detail/config/disable_warnings.hpp> // VC7.1
38
39 namespace boost { namespace iostreams { namespace detail {
40
41 //------------------Definition of direct_adapter_base-------------------------//
42
43 // Put all initialization in base class to faciliate forwarding.
44 template<typename Direct>
45 class direct_adapter_base {
46 public:
47 typedef typename char_type_of<Direct>::type char_type;
48 typedef typename mode_of<Direct>::type mode_type;
49 struct category
50 : mode_type,
51 device_tag,
52 closable_tag
53 #ifndef BOOST_IOSTREAMS_NO_LOCALE
54 , localizable_tag
55 #endif
56 { };
57 protected:
58 explicit direct_adapter_base(const Direct& d);
59 typedef is_convertible<category, two_sequence> is_double;
60 struct pointers {
pointersboost::iostreams::detail::direct_adapter_base::pointers61 pointers() : beg(0), ptr(0), end(0) { }
62 char_type *beg, *ptr, *end;
63 };
64 void init_input(mpl::true_);
init_input(mpl::false_)65 void init_input(mpl::false_) { }
66 void init_output(mpl::true_);
init_output(mpl::false_)67 void init_output(mpl::false_) { }
68 double_object<pointers, is_double> ptrs_;
69 Direct d_;
70 };
71
72 template<typename Direct>
73 class direct_adapter : private direct_adapter_base<Direct> {
74 private:
75 typedef direct_adapter_base<Direct> base_type;
76 typedef typename base_type::pointers pointers;
77 typedef typename base_type::is_double is_double;
78 using base_type::ptrs_;
79 using base_type::d_;
80 public:
81 typedef typename base_type::char_type char_type;
82 typedef typename base_type::category category;
83
84 // Constructors
85
86 #if !BOOST_WORKAROUND(BOOST_MSVC, <= 1310)
direct_adapter(const Direct & d)87 direct_adapter(const Direct& d) : base_type(d) { }
direct_adapter(const direct_adapter & d)88 direct_adapter(const direct_adapter& d) : base_type(d) { }
89 # define BOOST_PP_LOCAL_LIMITS (1, BOOST_IOSTREAMS_MAX_FORWARDING_ARITY)
90 #else
91 template<typename U>
92 struct is_direct
93 : mpl::or_<
94 is_same<U, direct_adapter<Direct> >,
95 is_same<U, Direct>
96 >
97 { };
98 template<typename U>
direct_adapter(const U & u)99 direct_adapter(const U& u)
100 : base_type(forward(u, is_direct<U>()))
101 { }
102 # define BOOST_PP_LOCAL_LIMITS (2, BOOST_IOSTREAMS_MAX_FORWARDING_ARITY)
103 #endif
104
105 #define BOOST_PP_LOCAL_MACRO(n) \
106 template<BOOST_PP_ENUM_PARAMS(n, typename P)> \
107 direct_adapter(BOOST_PP_ENUM_BINARY_PARAMS(n, const P, &p)) \
108 : base_type(Direct(BOOST_PP_ENUM_PARAMS(n, p))) \
109 { } \
110 /**/
111 #include BOOST_PP_LOCAL_ITERATE()
112 #undef BOOST_PP_LOCAL_MACRO
113
114 // Device interface.
115
116 std::streamsize read(char_type* s, std::streamsize n);
117 std::streamsize write(const char_type* s, std::streamsize n);
118 std::streampos seek( stream_offset, BOOST_IOS::seekdir,
119 BOOST_IOS::openmode = BOOST_IOS::in | BOOST_IOS::out );
120 void close();
121 void close(BOOST_IOS::openmode which);
122 #ifndef BOOST_IOSTREAMS_NO_LOCALE
123 void imbue(const std::locale&);
124 #endif
125
126 // Direct device access.
127
operator *()128 Direct& operator*() { return d_; }
operator ->()129 Direct* operator->() { return &d_; }
130 #if BOOST_WORKAROUND(BOOST_MSVC, <= 1310)
131 private:
132 template<typename U>
forward(const U & u,mpl::true_)133 static Direct forward(const U& u, mpl::true_) { return u; }
134 template<typename U>
forward(const U & u,mpl::false_)135 static Direct forward(const U& u, mpl::false_) { return Direct(u); }
136 #endif
137 };
138
139 //--------------Definition of wrap_direct and unwrap_direct-------------------//
140
141 template<typename Device>
142 struct wrap_direct_traits
143 : mpl::if_<
144 is_direct<Device>,
145 direct_adapter<Device>,
146 Device
147 >
148 { };
149
150 template<typename Device>
151 typename wrap_direct_traits<Device>::type
wrap_direct(Device dev)152 inline wrap_direct(Device dev)
153 {
154 typedef typename wrap_direct_traits<Device>::type type;
155 return type(dev);
156 }
157
158 template<typename Device>
unwrap_direct(Device & d)159 inline Device& unwrap_direct(Device& d) { return d; }
160
161 template<typename Device>
unwrap_direct(direct_adapter<Device> & d)162 inline Device& unwrap_direct(direct_adapter<Device>& d) { return *d; }
163
164 //--------------Implementation of direct_adapter_base-------------------------//
165
166 template<typename Direct>
direct_adapter_base(const Direct & d)167 direct_adapter_base<Direct>::direct_adapter_base(const Direct& d) : d_(d)
168 {
169 init_input(is_convertible<category, input>());
170 init_output(is_convertible<category, output>());
171 }
172
173 template<typename Direct>
init_input(mpl::true_)174 void direct_adapter_base<Direct>::init_input(mpl::true_)
175 {
176 std::pair<char_type*, char_type*> seq = iostreams::input_sequence(d_);
177 ptrs_.first().beg = seq.first;
178 ptrs_.first().ptr = seq.first;
179 ptrs_.first().end = seq.second;
180 }
181
182 template<typename Direct>
init_output(mpl::true_)183 void direct_adapter_base<Direct>::init_output(mpl::true_)
184 {
185 std::pair<char_type*, char_type*> seq = iostreams::output_sequence(d_);
186 ptrs_.second().beg = seq.first;
187 ptrs_.second().ptr = seq.first;
188 ptrs_.second().end = seq.second;
189 }
190
191 //--------------Implementation of direct_adapter------------------------------//
192
193 template<typename Direct>
read(char_type * s,std::streamsize n)194 inline std::streamsize direct_adapter<Direct>::read
195 (char_type* s, std::streamsize n)
196 {
197 using namespace std;
198 pointers& get = ptrs_.first();
199 std::streamsize avail =
200 static_cast<std::streamsize>(get.end - get.ptr);
201 std::streamsize result = (std::min)(n, avail);
202 std::copy(get.ptr, get.ptr + result, s);
203 get.ptr += result;
204 return result != 0 ? result : -1;
205 }
206
207 template<typename Direct>
write(const char_type * s,std::streamsize n)208 inline std::streamsize direct_adapter<Direct>::write
209 (const char_type* s, std::streamsize n)
210 {
211 using namespace std;
212 pointers& put = ptrs_.second();
213 if (n > static_cast<std::streamsize>(put.end - put.ptr))
214 boost::throw_exception(write_area_exhausted());
215 std::copy(s, s + n, put.ptr);
216 put.ptr += n;
217 return n;
218 }
219
220 template<typename Direct>
seek(stream_offset off,BOOST_IOS::seekdir way,BOOST_IOS::openmode which)221 inline std::streampos direct_adapter<Direct>::seek
222 ( stream_offset off, BOOST_IOS::seekdir way,
223 BOOST_IOS::openmode which )
224 {
225 using namespace std;
226 pointers& get = ptrs_.first();
227 pointers& put = ptrs_.second();
228 if (way == BOOST_IOS::cur && get.ptr != put.ptr)
229 boost::throw_exception(bad_seek());
230 ptrdiff_t next = 0;
231 if ((which & BOOST_IOS::in) || !is_double::value) {
232 if (way == BOOST_IOS::beg)
233 next = off;
234 else if (way == BOOST_IOS::cur)
235 next = get.ptr - get.beg + off;
236 else
237 next = get.end - get.beg + off;
238 if (next >= 0 && next <= get.end - get.beg)
239 get.ptr = get.beg + next;
240 else
241 boost::throw_exception(bad_seek());
242 }
243 if ((which & BOOST_IOS::out) && is_double::value) {
244 if (way == BOOST_IOS::beg)
245 next = off;
246 else if (way == BOOST_IOS::cur)
247 next = put.ptr - put.beg + off;
248 else
249 next = put.end - put.beg + off;
250 if (next >= 0 && next <= put.end - put.beg)
251 put.ptr = put.beg + next;
252 else
253 boost::throw_exception(bad_seek());
254 }
255 return offset_to_position(next);
256 }
257
258 template<typename Direct>
close()259 void direct_adapter<Direct>::close()
260 {
261 BOOST_STATIC_ASSERT((!is_convertible<category, two_sequence>::value));
262 detail::close_all(d_);
263 }
264
265 template<typename Direct>
close(BOOST_IOS::openmode which)266 void direct_adapter<Direct>::close(BOOST_IOS::openmode which)
267 {
268 BOOST_STATIC_ASSERT((is_convertible<category, two_sequence>::value));
269 boost::iostreams::close(d_, which);
270 }
271
272 #ifndef BOOST_IOSTREAMS_NO_LOCALE
273 template<typename Direct>
imbue(const std::locale & loc)274 void direct_adapter<Direct>::imbue(const std::locale& loc)
275 { boost::iostreams::imbue(d_, loc); }
276 #endif
277
278 } } } // End namespaces detail, iostreams, boost.
279
280 #include <boost/iostreams/detail/config/enable_warnings.hpp>
281
282 #endif // #ifndef BOOST_IOSTREAMS_DETAIL_DIRECT_ADAPTER_HPP_INCLUDED
283