libio/stdstreams.cc

   1 /* This is part of libio/iostream, providing -*- C++ -*- input/output.
   2 Copyright (C) 1993 Free Software Foundation
   3
   4 This file is part of the GNU IO Library.  This library is free
   5 software; you can redistribute it and/or modify it under the
   6 terms of the GNU General Public License as published by the
   7 Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 This library is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this library; see the file COPYING.  If not, write to the Free
  17 Software Foundation, 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  18
  19 As a special exception, if you link this library with files
  20 compiled with a GNU compiler to produce an executable, this does not cause
  21 the resulting executable to be covered by the GNU General Public License.
  22 This exception does not however invalidate any other reasons why
  23 the executable file might be covered by the GNU General Public License. */
  24
  25 /* Written by Per Bothner (bothner@cygnus.com). */
  26
  27 #include "libioP.h"
  28 #include "streambuf.h"
  29 #include <stdio.h>
  30
  31 // The ANSI draft requires that operations on cin/cout/cerr can be
  32 // mixed with operations on stdin/stdout/stderr on a character by
  33 // character basis.  This normally requires that the streambuf's
  34 // used by cin/cout/cerr be stdiostreams.  However, if the stdio
  35 // implementation is the one that is built using this library,
  36 // then we don't need to, since in that case stdin/stdout/stderr
  37 // are identical to _IO_stdin/_IO_stdout/_IO_stderr.
  38
  39 #include "libio.h"
  40
  41 #ifdef _STDIO_USES_IOSTREAM
  42 #define CIN_SBUF _IO_stdin_
  43 #define COUT_SBUF _IO_stdout_
  44 #define CERR_SBUF _IO_stderr_
  45 static int use_stdiobuf = 0;
  46 #else
  47 #define CIN_SBUF _IO_stdin_buf
  48 #define COUT_SBUF _IO_stdout_buf
  49 #define CERR_SBUF _IO_stderr_buf
  50 static int use_stdiobuf = 1;
  51 #endif
  52
  53 #define cin CIN
  54 #define cout COUT
  55 #define cerr CERR
  56 #define clog CLOG
  57 #include "iostream.h"
  58 #undef cin
  59 #undef cout
  60 #undef cerr
  61 #undef clog
  62
  63 #ifdef __GNUG__
  64 #define PAD 0 /* g++ allows 0-length arrays. */
  65 #else
  66 #define PAD 1
  67 #endif
  68 struct _fake_istream {
  69     struct myfields {
  70 #ifdef __GNUC__
  71         _ios_fields *vb; /* pointer to virtual base class ios */
  72         _IO_ssize_t _gcount;
  73 #else
  74         /* This is supposedly correct for cfront. */
  75         _IO_ssize_t _gcount;
  76         void *vptr;
  77         _ios_fields *vb; /* pointer to virtual base class ios */
  78 #endif
  79     } mine;
  80     _ios_fields base;
  81     char filler[sizeof(struct istream)-sizeof(struct _ios_fields)+PAD];
  82 };
  83 struct _fake_ostream {
  84     struct myfields {
  85 #ifndef __GNUC__
  86         void *vptr;
  87 #endif
  88         _ios_fields *vb; /* pointer to virtual base class ios */
  89     } mine;
  90     _ios_fields base;
  91     char filler[sizeof(struct ostream)-sizeof(struct _ios_fields)+PAD];
  92 };
  93
  94
  95 #ifdef _IO_NEW_STREAMS
  96 #define STD_STR(SBUF, TIE, EXTRA_FLAGS) \
  97  (streambuf*)&SBUF, TIE, 0, ios::skipws|ios::dec|EXTRA_FLAGS, ' ',0,0,6
  98 #else
  99 #define STD_STR(SBUF, TIE, EXTRA_FLAGS) \
 100  (streambuf*)&SBUF, TIE, 0, ios::dont_close|ios::dec|ios::skipws|EXTRA_FLAGS, ' ',0,0,6
 101 #endif
 102
 103 #ifdef __GNUC__
 104 #define OSTREAM_DEF(NAME, SBUF, TIE, EXTRA_FLAGS, ASM) \
 105   _fake_ostream NAME ASM = { {&NAME.base}, {STD_STR(SBUF, TIE, EXTRA_FLAGS) }};
 106 #define ISTREAM_DEF(NAME, SBUF, TIE, EXTRA_FLAGS) \
 107   _fake_istream NAME = { {&NAME.base}, {STD_STR(SBUF, TIE, EXTRA_FLAGS) }};
 108 #else
 109 #define OSTREAM_DEF(NAME, SBUF, TIE, EXTRA_FLAGS) \
 110   _fake_ostream NAME = { {0, &NAME.base}, {STD_STR(SBUF, TIE, EXTRA_FLAGS) }};
 111 #define ISTREAM_DEF(NAME, SBUF, TIE, EXTRA_FLAGS) \
 112   _fake_istream NAME = {{0, 0, &NAME.base}, {STD_STR(SBUF, TIE, EXTRA_FLAGS)}};
 113 #endif
 114
 115 OSTREAM_DEF(cout, COUT_SBUF, NULL, 0, )
 116 OSTREAM_DEF(cerr, CERR_SBUF,(ostream*)&cout, ios::unitbuf, )
 117 ISTREAM_DEF(cin, CIN_SBUF,  (ostream*)&cout, 0)
 118
 119 /* Only for (partial) compatibility with AT&T's library. */
 120 #if _G_CLOG_CONFLICT
 121 OSTREAM_DEF(clog, CERR_SBUF, (ostream*)&cout, 0, __asm__ ("__IO_clog"))
 122 #else
 123 OSTREAM_DEF(clog, CERR_SBUF, (ostream*)&cout, 0, )
 124 #endif
 125
 126 // Switches between using _IO_std{in,out,err} and __std{in,out,err}_buf
 127 // for standard streams.  This does not normally need to be called
 128 // explicitly, but is provided for AT&T compatibility.
 129
 130 int ios::sync_with_stdio(int new_state)
 131 {
 132 #ifdef _STDIO_USES_IOSTREAM
 133     // It is always synced.
 134     return 0;
 135 #else
 136     if (new_state == use_stdiobuf) // The usual case now.
 137         return use_stdiobuf;
 138     if (new_state) {
 139         cin.base._strbuf = (streambuf*)&_IO_stdin_buf;
 140         cout.base._strbuf = (streambuf*)&_IO_stdout_buf;
 141         cerr.base._strbuf = (streambuf*)&_IO_stderr_buf;
 142         clog.base._strbuf = (streambuf*)&_IO_stderr_buf;
 143     } else {
 144         cin.base._strbuf = (streambuf*)_IO_stdin;
 145         cout.base._strbuf = (streambuf*)_IO_stdout;
 146         cerr.base._strbuf = (streambuf*)_IO_stderr;
 147         clog.base._strbuf = (streambuf*)_IO_stderr;
 148     }
 149     int old_state = use_stdiobuf;
 150     use_stdiobuf = new_state;
 151     return old_state;
 152 #endif
 153 }