1 // Iostreams wrapper for stdio FILE* -*- C++ -*-
2
3 // Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 2, or (at your option)
9 // any later version.
10
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15
16 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19 // USA.
20
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
29
30 /** @file ext/stdio_sync_filebuf.h
31 * This file is a GNU extension to the Standard C++ Library.
32 */
33
34 #ifndef _STDIO_SYNC_FILEBUF_H
35 #define _STDIO_SYNC_FILEBUF_H 1
36
37 #pragma GCC system_header
38
39 #include <streambuf>
40 #include <unistd.h>
41 #include <cstdio>
42
43 #ifdef _GLIBCXX_USE_WCHAR_T
44 #include <cwchar>
45 #endif
46
_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)47 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
48
49 /// @brief class stdio_sync_filebuf.
50 template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
51 class stdio_sync_filebuf : public std::basic_streambuf<_CharT, _Traits>
52 {
53 public:
54 // Types:
55 typedef _CharT char_type;
56 typedef _Traits traits_type;
57 typedef typename traits_type::int_type int_type;
58 typedef typename traits_type::pos_type pos_type;
59 typedef typename traits_type::off_type off_type;
60
61 private:
62 // Underlying stdio FILE
63 std::__c_file* const _M_file;
64
65 // Last character gotten. This is used when pbackfail is
66 // called from basic_streambuf::sungetc()
67 int_type _M_unget_buf;
68
69 public:
70 explicit
71 stdio_sync_filebuf(std::__c_file* __f)
72 : _M_file(__f), _M_unget_buf(traits_type::eof())
73 { }
74
75 /**
76 * @return The underlying FILE*.
77 *
78 * This function can be used to access the underlying "C" file pointer.
79 * Note that there is no way for the library to track what you do
80 * with the file, so be careful.
81 */
82 std::__c_file* const
83 file() { return this->_M_file; }
84
85 protected:
86 int_type
87 syncgetc();
88
89 int_type
90 syncungetc(int_type __c);
91
92 int_type
93 syncputc(int_type __c);
94
95 virtual int_type
96 underflow()
97 {
98 int_type __c = this->syncgetc();
99 return this->syncungetc(__c);
100 }
101
102 virtual int_type
103 uflow()
104 {
105 // Store the gotten character in case we need to unget it.
106 _M_unget_buf = this->syncgetc();
107 return _M_unget_buf;
108 }
109
110 virtual int_type
111 pbackfail(int_type __c = traits_type::eof())
112 {
113 int_type __ret;
114 const int_type __eof = traits_type::eof();
115
116 // Check if the unget or putback was requested
117 if (traits_type::eq_int_type(__c, __eof)) // unget
118 {
119 if (!traits_type::eq_int_type(_M_unget_buf, __eof))
120 __ret = this->syncungetc(_M_unget_buf);
121 else // buffer invalid, fail.
122 __ret = __eof;
123 }
124 else // putback
125 __ret = this->syncungetc(__c);
126
127 // The buffered character is no longer valid, discard it.
128 _M_unget_buf = __eof;
129 return __ret;
130 }
131
132 virtual std::streamsize
133 xsgetn(char_type* __s, std::streamsize __n);
134
135 virtual int_type
136 overflow(int_type __c = traits_type::eof())
137 {
138 int_type __ret;
139 if (traits_type::eq_int_type(__c, traits_type::eof()))
140 {
141 if (std::fflush(_M_file))
142 __ret = traits_type::eof();
143 else
144 __ret = traits_type::not_eof(__c);
145 }
146 else
147 __ret = this->syncputc(__c);
148 return __ret;
149 }
150
151 virtual std::streamsize
152 xsputn(const char_type* __s, std::streamsize __n);
153
154 virtual int
155 sync()
156 { return std::fflush(_M_file); }
157
158 virtual std::streampos
159 seekoff(std::streamoff __off, std::ios_base::seekdir __dir,
160 std::ios_base::openmode = std::ios_base::in | std::ios_base::out)
161 {
162 std::streampos __ret(std::streamoff(-1));
163 int __whence;
164 if (__dir == std::ios_base::beg)
165 __whence = SEEK_SET;
166 else if (__dir == std::ios_base::cur)
167 __whence = SEEK_CUR;
168 else
169 __whence = SEEK_END;
170 #ifdef _GLIBCXX_USE_LFS
171 if (!fseeko64(_M_file, __off, __whence))
172 __ret = std::streampos(ftello64(_M_file));
173 #else
174 if (!fseek(_M_file, __off, __whence))
175 __ret = std::streampos(std::ftell(_M_file));
176 #endif
177 return __ret;
178 }
179
180 virtual std::streampos
181 seekpos(std::streampos __pos,
182 std::ios_base::openmode __mode =
183 std::ios_base::in | std::ios_base::out)
184 { return seekoff(std::streamoff(__pos), std::ios_base::beg, __mode); }
185 };
186
187 template<>
188 inline stdio_sync_filebuf<char>::int_type
syncgetc()189 stdio_sync_filebuf<char>::syncgetc()
190 { return std::getc(_M_file); }
191
192 template<>
193 inline stdio_sync_filebuf<char>::int_type
syncungetc(int_type __c)194 stdio_sync_filebuf<char>::syncungetc(int_type __c)
195 { return std::ungetc(__c, _M_file); }
196
197 template<>
198 inline stdio_sync_filebuf<char>::int_type
syncputc(int_type __c)199 stdio_sync_filebuf<char>::syncputc(int_type __c)
200 { return std::putc(__c, _M_file); }
201
202 template<>
203 inline std::streamsize
xsgetn(char * __s,std::streamsize __n)204 stdio_sync_filebuf<char>::xsgetn(char* __s, std::streamsize __n)
205 {
206 std::streamsize __ret = std::fread(__s, 1, __n, _M_file);
207 if (__ret > 0)
208 _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
209 else
210 _M_unget_buf = traits_type::eof();
211 return __ret;
212 }
213
214 template<>
215 inline std::streamsize
xsputn(const char * __s,std::streamsize __n)216 stdio_sync_filebuf<char>::xsputn(const char* __s, std::streamsize __n)
217 { return std::fwrite(__s, 1, __n, _M_file); }
218
219 #ifdef _GLIBCXX_USE_WCHAR_T
220 template<>
221 inline stdio_sync_filebuf<wchar_t>::int_type
syncgetc()222 stdio_sync_filebuf<wchar_t>::syncgetc()
223 { return std::getwc(_M_file); }
224
225 template<>
226 inline stdio_sync_filebuf<wchar_t>::int_type
syncungetc(int_type __c)227 stdio_sync_filebuf<wchar_t>::syncungetc(int_type __c)
228 { return std::ungetwc(__c, _M_file); }
229
230 template<>
231 inline stdio_sync_filebuf<wchar_t>::int_type
syncputc(int_type __c)232 stdio_sync_filebuf<wchar_t>::syncputc(int_type __c)
233 { return std::putwc(__c, _M_file); }
234
235 template<>
236 inline std::streamsize
xsgetn(wchar_t * __s,std::streamsize __n)237 stdio_sync_filebuf<wchar_t>::xsgetn(wchar_t* __s, std::streamsize __n)
238 {
239 std::streamsize __ret = 0;
240 const int_type __eof = traits_type::eof();
241 while (__n--)
242 {
243 int_type __c = this->syncgetc();
244 if (traits_type::eq_int_type(__c, __eof))
245 break;
246 __s[__ret] = traits_type::to_char_type(__c);
247 ++__ret;
248 }
249
250 if (__ret > 0)
251 _M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
252 else
253 _M_unget_buf = traits_type::eof();
254 return __ret;
255 }
256
257 template<>
258 inline std::streamsize
xsputn(const wchar_t * __s,std::streamsize __n)259 stdio_sync_filebuf<wchar_t>::xsputn(const wchar_t* __s,
260 std::streamsize __n)
261 {
262 std::streamsize __ret = 0;
263 const int_type __eof = traits_type::eof();
264 while (__n--)
265 {
266 if (traits_type::eq_int_type(this->syncputc(*__s++), __eof))
267 break;
268 ++__ret;
269 }
270 return __ret;
271 }
272 #endif
273
274 #if _GLIBCXX_EXTERN_TEMPLATE
275 extern template class stdio_sync_filebuf<char>;
276 #ifdef _GLIBCXX_USE_WCHAR_T
277 extern template class stdio_sync_filebuf<wchar_t>;
278 #endif
279 #endif
280
281 _GLIBCXX_END_NAMESPACE
282
283 #endif
284