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// This is part of the iostream library, providing -*- C++ -*- input/output.
// Copyright (C) 1992 Per Bothner.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, 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
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free
// Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#ifdef __GNUG__
#pragma implementation
#endif
#include <stdiostream.h>
// A stdiobuf is "tied" to a FILE object (as used by the stdio package).
// Thus a stdiobuf is always synchronized with the corresponding FILE,
// though at the cost of some overhead. (If you use the implementation
// of stdio supplied with this library, you don't need stdiobufs.)
// This implementation inherits from filebuf, but implement the virtual
// functions sys_read/..., using the stdio functions fread/... instead
// of the low-level read/... system calls. This has the advantage that
// we get all of the nice filebuf semantics automatically, though
// with some overhead.
#ifndef SEEK_SET
#define SEEK_SET 0
#endif
#ifndef SEEK_CUR
#define SEEK_CUR 1
#endif
#ifndef SEEK_END
#define SEEK_END 2
#endif
stdiobuf::stdiobuf(FILE *f) : filebuf(fileno(f))
{
_file = f;
// Turn off buffer in stdiobuf. Instead, rely on buffering in (FILE).
// Thus the stdiobuf will be synchronized with the FILE.
setbuf(NULL, 0);
}
_G_ssize_t stdiobuf::sys_read(char* buf, size_t size)
{
return fread(buf, 1, size, _file);
}
_G_ssize_t stdiobuf::sys_write(const void *buf, long n)
{
_G_ssize_t count = fwrite(buf, 1, n, _file);
if (_fb._offset >= 0)
_fb._offset += n;
return count;
}
_G_fpos_t stdiobuf::sys_seek(_G_fpos_t offset, _seek_dir dir)
{
// Normally, equivalent to: fdir=dir
int fdir =
(dir == ios::beg) ? SEEK_SET :
(dir == ios::cur) ? SEEK_CUR :
(dir == ios::end) ? SEEK_END :
dir;
return fseek(_file, offset, fdir);
}
int stdiobuf::sys_close()
{
int status = fclose(_file);
_file = NULL;
return status;
}
int stdiobuf::sync()
{
if (filebuf::sync() == EOF)
return EOF;
if (!(xflags() & _S_NO_WRITES))
if (fflush(_file))
return EOF;
#if 0
// This loses when writing to a pipe.
if (fseek(_file, 0, SEEK_CUR) == EOF)
return EOF;
#endif
return 0;
}
int stdiobuf::overflow(int c /* = EOF*/)
{
if (filebuf::overflow(c) == EOF)
return EOF;
if (c != EOF)
return c;
return fflush(_file);
}
int stdiobuf::xsputn(const char* s, int n)
{
// The filebuf implementation of sputn loses.
return streambuf::xsputn(s, n);
}
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