summaryrefslogtreecommitdiff
path: root/libstdc++-v3/include/ext/stdio_sync_filebuf.h
blob: 4b6014954181c98856c35f26559e1af40648a1c6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
// Iostreams wrapper for stdio FILE* -*- C++ -*-

// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2009, 2010
// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file ext/stdio_sync_filebuf.h
 *  This file is a GNU extension to the Standard C++ Library.
 */

#ifndef _STDIO_SYNC_FILEBUF_H
#define _STDIO_SYNC_FILEBUF_H 1

#pragma GCC system_header

#include <streambuf>
#include <unistd.h>
#include <cstdio>
#include <bits/c++io.h>  // For __c_file

#ifdef _GLIBCXX_USE_WCHAR_T
#include <cwchar>
#endif

namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  /**
   *  @brief Provides a layer of compatibility for C.
   *  @ingroup io
   *
   *  This GNU extension provides extensions for working with standard
   *  C FILE*'s.  It must be instantiated by the user with the type of
   *  character used in the file stream, e.g., stdio_filebuf<char>.
  */
  template<typename _CharT, typename _Traits = std::char_traits<_CharT> >
    class stdio_sync_filebuf : public std::basic_streambuf<_CharT, _Traits>
    {
    public:
      // Types:
      typedef _CharT					char_type;
      typedef _Traits					traits_type;
      typedef typename traits_type::int_type		int_type;
      typedef typename traits_type::pos_type		pos_type;
      typedef typename traits_type::off_type		off_type;

    private:
      // Underlying stdio FILE
      std::__c_file* const _M_file;

      // Last character gotten. This is used when pbackfail is
      // called from basic_streambuf::sungetc()
      int_type _M_unget_buf;

    public:
      explicit
      stdio_sync_filebuf(std::__c_file* __f)
      : _M_file(__f), _M_unget_buf(traits_type::eof())
      { }

      /**
       *  @return  The underlying FILE*.
       *
       *  This function can be used to access the underlying C file pointer.
       *  Note that there is no way for the library to track what you do
       *  with the file, so be careful.
       */
      std::__c_file* const
      file() { return this->_M_file; }

    protected:
      int_type
      syncgetc();

      int_type
      syncungetc(int_type __c);

      int_type
      syncputc(int_type __c);

      virtual int_type
      underflow()
      {
	int_type __c = this->syncgetc();
	return this->syncungetc(__c);
      }

      virtual int_type
      uflow()
      {
	// Store the gotten character in case we need to unget it.
	_M_unget_buf = this->syncgetc();
	return _M_unget_buf;
      }

      virtual int_type
      pbackfail(int_type __c = traits_type::eof())
      {
	int_type __ret;
	const int_type __eof = traits_type::eof();

	// Check if the unget or putback was requested
	if (traits_type::eq_int_type(__c, __eof)) // unget
	  {
	    if (!traits_type::eq_int_type(_M_unget_buf, __eof))
	      __ret = this->syncungetc(_M_unget_buf);
	    else // buffer invalid, fail.
	      __ret = __eof;
	  }
	else // putback
	  __ret = this->syncungetc(__c);

	// The buffered character is no longer valid, discard it.
	_M_unget_buf = __eof;
	return __ret;
      }

      virtual std::streamsize
      xsgetn(char_type* __s, std::streamsize __n);

      virtual int_type
      overflow(int_type __c = traits_type::eof())
      {
	int_type __ret;
	if (traits_type::eq_int_type(__c, traits_type::eof()))
	  {
	    if (std::fflush(_M_file))
	      __ret = traits_type::eof();
	    else
	      __ret = traits_type::not_eof(__c);
	  }
	else
	  __ret = this->syncputc(__c);
	return __ret;
      }

      virtual std::streamsize
      xsputn(const char_type* __s, std::streamsize __n);

      virtual int
      sync()
      { return std::fflush(_M_file); }

      virtual std::streampos
      seekoff(std::streamoff __off, std::ios_base::seekdir __dir,
	      std::ios_base::openmode = std::ios_base::in | std::ios_base::out)
      {
	std::streampos __ret(std::streamoff(-1));
	int __whence;
	if (__dir == std::ios_base::beg)
	  __whence = SEEK_SET;
	else if (__dir == std::ios_base::cur)
	  __whence = SEEK_CUR;
	else
	  __whence = SEEK_END;
#ifdef _GLIBCXX_USE_LFS
	if (!fseeko64(_M_file, __off, __whence))
	  __ret = std::streampos(ftello64(_M_file));
#else
	if (!fseek(_M_file, __off, __whence))
	  __ret = std::streampos(std::ftell(_M_file));
#endif
	return __ret;
      }

      virtual std::streampos
      seekpos(std::streampos __pos,
	      std::ios_base::openmode __mode =
	      std::ios_base::in | std::ios_base::out)
      { return seekoff(std::streamoff(__pos), std::ios_base::beg, __mode); }
    };

  template<>
    inline stdio_sync_filebuf<char>::int_type
    stdio_sync_filebuf<char>::syncgetc()
    { return std::getc(_M_file); }

  template<>
    inline stdio_sync_filebuf<char>::int_type
    stdio_sync_filebuf<char>::syncungetc(int_type __c)
    { return std::ungetc(__c, _M_file); }

  template<>
    inline stdio_sync_filebuf<char>::int_type
    stdio_sync_filebuf<char>::syncputc(int_type __c)
    { return std::putc(__c, _M_file); }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<char>::xsgetn(char* __s, std::streamsize __n)
    {
      std::streamsize __ret = std::fread(__s, 1, __n, _M_file);
      if (__ret > 0)
	_M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
      else
	_M_unget_buf = traits_type::eof();
      return __ret;
    }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<char>::xsputn(const char* __s, std::streamsize __n)
    { return std::fwrite(__s, 1, __n, _M_file); }

#ifdef _GLIBCXX_USE_WCHAR_T
  template<>
    inline stdio_sync_filebuf<wchar_t>::int_type
    stdio_sync_filebuf<wchar_t>::syncgetc()
    { return std::getwc(_M_file); }

  template<>
    inline stdio_sync_filebuf<wchar_t>::int_type
    stdio_sync_filebuf<wchar_t>::syncungetc(int_type __c)
    { return std::ungetwc(__c, _M_file); }

  template<>
    inline stdio_sync_filebuf<wchar_t>::int_type
    stdio_sync_filebuf<wchar_t>::syncputc(int_type __c)
    { return std::putwc(__c, _M_file); }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<wchar_t>::xsgetn(wchar_t* __s, std::streamsize __n)
    {
      std::streamsize __ret = 0;
      const int_type __eof = traits_type::eof();
      while (__n--)
	{
	  int_type __c = this->syncgetc();
	  if (traits_type::eq_int_type(__c, __eof))
	    break;
	  __s[__ret] = traits_type::to_char_type(__c);
	  ++__ret;
	}

      if (__ret > 0)
	_M_unget_buf = traits_type::to_int_type(__s[__ret - 1]);
      else
	_M_unget_buf = traits_type::eof();
      return __ret;
    }

  template<>
    inline std::streamsize
    stdio_sync_filebuf<wchar_t>::xsputn(const wchar_t* __s,
					std::streamsize __n)
    {
      std::streamsize __ret = 0;
      const int_type __eof = traits_type::eof();
      while (__n--)
	{
	  if (traits_type::eq_int_type(this->syncputc(*__s++), __eof))
	    break;
	  ++__ret;
	}
      return __ret;
    }
#endif

#if _GLIBCXX_EXTERN_TEMPLATE
  extern template class stdio_sync_filebuf<char>;
#ifdef _GLIBCXX_USE_WCHAR_T
  extern template class stdio_sync_filebuf<wchar_t>;
#endif
#endif

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#endif