113 lines
3.0 KiB
C
113 lines
3.0 KiB
C
// This is part of the iostream library, providing -*- C++ -*- input/output.
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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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#ifdef __GNUG__
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#pragma implementation
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#endif
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#include <stdiostream.h>
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// A stdiobuf is "tied" to a FILE object (as used by the stdio package).
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// Thus a stdiobuf is always synchronized with the corresponding FILE,
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// though at the cost of some overhead. (If you use the implementation
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// of stdio supplied with this library, you don't need stdiobufs.)
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// This implementation inherits from filebuf, but implement the virtual
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// functions sys_read/..., using the stdio functions fread/... instead
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// of the low-level read/... system calls. This has the advantage that
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// we get all of the nice filebuf semantics automatically, though
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// with some overhead.
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#ifndef SEEK_SET
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#define SEEK_SET 0
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#endif
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#ifndef SEEK_CUR
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#define SEEK_CUR 1
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#endif
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#ifndef SEEK_END
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#define SEEK_END 2
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#endif
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stdiobuf::stdiobuf(FILE *f) : filebuf(fileno(f))
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{
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_file = f;
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// Turn off buffer in stdiobuf. Instead, rely on buffering in (FILE).
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// Thus the stdiobuf will be synchronized with the FILE.
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setbuf(NULL, 0);
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}
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_G_ssize_t stdiobuf::sys_read(char* buf, size_t size)
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{
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return fread(buf, 1, size, _file);
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}
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_G_ssize_t stdiobuf::sys_write(const void *buf, long n)
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{
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_G_ssize_t count = fwrite(buf, 1, n, _file);
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if (_fb._offset >= 0)
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_fb._offset += n;
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return count;
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}
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_G_fpos_t stdiobuf::sys_seek(_G_fpos_t offset, _seek_dir dir)
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{
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// Normally, equivalent to: fdir=dir
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int fdir =
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(dir == ios::beg) ? SEEK_SET :
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(dir == ios::cur) ? SEEK_CUR :
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(dir == ios::end) ? SEEK_END :
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dir;
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return fseek(_file, offset, fdir);
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}
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int stdiobuf::sys_close()
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{
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int status = fclose(_file);
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_file = NULL;
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return status;
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}
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int stdiobuf::sync()
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{
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if (filebuf::sync() == EOF)
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return EOF;
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if (!(xflags() & _S_NO_WRITES))
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if (fflush(_file))
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return EOF;
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#if 0
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// This loses when writing to a pipe.
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if (fseek(_file, 0, SEEK_CUR) == EOF)
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return EOF;
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#endif
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return 0;
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}
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int stdiobuf::overflow(int c /* = EOF*/)
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{
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if (filebuf::overflow(c) == EOF)
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return EOF;
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if (c != EOF)
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return c;
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return fflush(_file);
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}
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int stdiobuf::xsputn(const char* s, int n)
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{
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// The filebuf implementation of sputn loses.
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return streambuf::xsputn(s, n);
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}
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