1 /*
2  * Copyright (c) 1999
3  * Silicon Graphics Computer Systems, Inc.
4  *
5  * Copyright (c) 1999
6  * Boris Fomitchev
7  *
8  * This material is provided "as is", with absolutely no warranty expressed
9  * or implied. Any use is at your own risk.
10  *
11  * Permission to use or copy this software for any purpose is hereby granted
12  * without fee, provided the above notices are retained on all copies.
13  * Permission to modify the code and to distribute modified code is granted,
14  * provided the above notices are retained, and a notice that the code was
15  * modified is included with the above copyright notice.
16  *
17  */
18 
19 // This header defines two streambufs:
20 // stdio_istreambuf, a read-only streambuf synchronized with a C stdio
21 // FILE object
22 // stdio_ostreambuf, a write-only streambuf synchronized with a C stdio
23 // FILE object.
24 // Note that neither stdio_istreambuf nor stdio_ostreambuf is a template;
25 // both classes are derived from basic_streambuf<char, char_traits<char> >.
26 
27 // Note: the imbue() member function is a no-op.  In particular, these
28 // classes assume that codecvt<char, char, mbstate_t> is always an identity
29 // transformation.  This is true of the default locale, and of all locales
30 // defined for the C I/O library.  If you need to use a locale where
31 // the codecvt<char, char, mbstate_t> facet performs a nontrivial
32 // conversion, then you should use basic_filebuf<> instead of stdio_istreambuf
33 // or stdio_ostreambuf.  (If you don't understand what any of this means,
34 // then it's not a feature you need to worry about.  Locales where
35 // codecvt<char, char, mbstate_t> does something nontrivial are a rare
36 // corner case.)
37 
38 
39 #ifndef _STLP_STDIO_STREAMBUF
40 #define _STLP_STDIO_STREAMBUF
41 
42 #include <streambuf>
43 #include <cstdio>              // For FILE.
44 
45 _STLP_BEGIN_NAMESPACE
46 _STLP_MOVE_TO_PRIV_NAMESPACE
47 
48 // Base class for features common to stdio_istreambuf and stdio_ostreambuf
49 class stdio_streambuf_base :
50   public basic_streambuf<char, char_traits<char> > /* FILE_basic_streambuf */ {
51 public:                         // Constructor, destructor.
52   // The argument may not be null.  It must be an open file pointer.
53   stdio_streambuf_base(FILE*);
54 
55   // The destructor flushes the stream, but does not close it.
56   ~stdio_streambuf_base();
57 
58 protected:                      // Virtual functions from basic_streambuf.
59   streambuf* setbuf(char*, streamsize);
60 
61   pos_type seekoff(off_type, ios_base::seekdir,
62                    ios_base::openmode
63                           = ios_base::in | ios_base::out);
64   pos_type seekpos(pos_type,
65                    ios_base::openmode
66                           = ios_base::in | ios_base::out);
67   int sync();
68 
69 protected:
70   FILE* _M_file;
71 };
72 
73 class stdio_istreambuf : public stdio_streambuf_base {
74 public:                         // Constructor, destructor.
stdio_istreambuf(FILE * __f)75   stdio_istreambuf(FILE* __f) : stdio_streambuf_base(__f) {}
76   ~stdio_istreambuf();
77 
78 protected:                      // Virtual functions from basic_streambuf.
79   streamsize showmanyc();
80   int_type underflow();
81   int_type uflow();
82   virtual int_type pbackfail(int_type c = traits_type::eof());
83 };
84 
85 class stdio_ostreambuf : public stdio_streambuf_base {
86 public:                         // Constructor, destructor.
stdio_ostreambuf(FILE * __f)87   stdio_ostreambuf(FILE* __f) : stdio_streambuf_base(__f) {}
88   ~stdio_ostreambuf();
89 
90 protected:                      // Virtual functions from basic_streambuf.
91   streamsize showmanyc();
92   int_type overflow(int_type c = traits_type::eof());
93 };
94 
95 _STLP_MOVE_TO_STD_NAMESPACE
96 _STLP_END_NAMESPACE
97 
98 #endif /* _STLP_STDIO_STREAMBUF */
99 
100 // Local Variables:
101 // mode:C++
102 // End:
103