114 lines
3.7 KiB
C
114 lines
3.7 KiB
C
// This is part of the iostream library, providing input/output for C++.
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// Copyright (C) 1992 Per Bothner.
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Library General Public License for more details.
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//
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// You should have received a copy of the GNU Library General Public
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// License along with this library; if not, write to the Free
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// Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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#include "ioprivate.h"
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#include <stdio.h>
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// This file defines the standard streambufs, corresponding to cin, cout, cerr.
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// We define two sets:
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//
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// __std_filebuf_0, __std_filebuf_1, __std_filebuf_2 are filebufs using
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// file descriptor 0/1/2.
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//
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// __stdin_stdiobuf, __stdout_stdiobuf, __stderr_stdiobuf are stdiostreams
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// pointing to stdin, stdout, stderr.
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// To avoid problems depending on constructor order (and for
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// efficiency) the standard streambufs (and streams) are
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// constructed statically using C-style '{ ... }' initializers.
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// Since you're not allowed to do this for structs that
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// have virtuals, we define fake streambuf and stream classes
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// that don't have any C++-isms, and initialize those.
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// To initialize the vtable field of the standard filebufs,
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// we use the expression 'vt_filebuf' which must evaluate to
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// (the address of) the virtual function table for the
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// filebuf class.
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#if _G_NAMES_HAVE_UNDERSCORE
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#define UNDERSCORE "_"
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#else
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#define UNDERSCORE ""
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#endif
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// First define the filebuf-based objects.
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#if !defined(vt_filebuf)
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#ifndef __GNUG__
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// This works for cfront.
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#define vt_filebuf __vtbl__7filebuf
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extern char vt_filebuf[1];
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#elif _G_DOLLAR_IN_LABEL
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extern char vt_filebuf[1] asm(UNDERSCORE "_vt$filebuf");
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#else
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extern char vt_filebuf[1] asm(UNDERSCORE "_vt.filebuf");
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#endif
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#endif /* !defined(vt_filebuf) */
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struct _fake_filebuf {
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struct __streambuf s;
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char* vtable;
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struct __file_fields f;
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};
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#define FILEBUF_LITERAL(CHAIN, FLAGS) \
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{ _IO_MAGIC+_S_LINKED+_S_IS_FILEBUF+_S_IS_BACKUPBUF+FLAGS, \
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0, 0, 0, 0, 0, 0, 0, 0, CHAIN, 0, 0, 0, 0, 0}
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#define DEF_FILEBUF(NAME, FD, CHAIN, FLAGS) \
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_fake_filebuf NAME = {FILEBUF_LITERAL(CHAIN, FLAGS), vt_filebuf, {FD}};
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DEF_FILEBUF(__std_filebuf_0, 0, 0, _S_NO_WRITES);
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DEF_FILEBUF(__std_filebuf_1, 1, (streambuf*)&__std_filebuf_0, _S_NO_READS);
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DEF_FILEBUF(__std_filebuf_2, 2, (streambuf*)&__std_filebuf_1,
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_S_NO_READS+_S_UNBUFFERED);
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// Nest define the stdiobuf-bases objects.
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#if !defined(vt_stdiobuf)
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#ifndef __GNUG__
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// This works for cfront.
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#define vt_stdiobuf __vtbl__8stdiobuf
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extern char vt_stdiobuf[1];
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#elif _G_DOLLAR_IN_LABEL
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extern char vt_stdiobuf[1] asm(UNDERSCORE "_vt$stdiobuf");
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#else
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extern char vt_stdiobuf[1] asm(UNDERSCORE "_vt.stdiobuf");
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#endif
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#endif /* !defined(vt_stdiobuf) */
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struct _fake_stdiobuf {
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struct __streambuf s;
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char* vtable;
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struct __file_fields f;
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FILE *_f;
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};
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#define DEF_STDIOBUF(NAME, FILE, FD, CHAIN, FLAGS) \
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_fake_stdiobuf NAME[1] = {{ \
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FILEBUF_LITERAL(CHAIN, (FLAGS)|_S_UNBUFFERED),\
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vt_stdiobuf, {FD}, FILE}};
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DEF_STDIOBUF(__stdin_stdiobuf, stdin, 0, (streambuf*)&__std_filebuf_2,
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_S_NO_WRITES);
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DEF_STDIOBUF(__stdout_stdiobuf, stdout, 1, (streambuf*)__stdin_stdiobuf,
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_S_NO_READS);
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DEF_STDIOBUF(__stderr_stdiobuf, stderr, 2, (streambuf*)__stdout_stdiobuf,
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_S_NO_READS);
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streambuf* streambuf::_list_all = (streambuf*)__stderr_stdiobuf;
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