67 lines
2.3 KiB
C++
67 lines
2.3 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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stdio/fsetdefaultbuf.cpp
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Sets up default buffering semantics for a FILE.
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*******************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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extern "C" int fsetdefaultbuf(FILE* fp)
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{
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char* buf = (char*) malloc(sizeof(char) * BUFSIZ);
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if ( !buf )
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{
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// TODO: Determine whether this is truly what we would want and whether
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// a buffer should be pre-allocated when the FILE is created such that
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// this situation _cannot_ occur.
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// Alright, we're in a bit of a situation here. Normally, we'd go
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// buffered but we are out of memory. We could either fail, but that
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// would mean subsequent calls such as fgetc and fputc would also fail -
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// however that we are out of memory doesn't mean that IO would also
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// fail. Therefore we'll revert to unbuffered semantics and hope that's
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// good enough.
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return setvbuf(fp, NULL, _IONBF, 0);
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}
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// Determine the buffering semantics depending on whether the destination is
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// an interactive device or not.
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#if defined(__is_sortix_kernel)
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int mode = _IOLBF; // TODO: Detect this?
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#else
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int mode = fp->buffer_mode != -1 ? fp->buffer_mode
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: isatty(fileno(fp)) ? _IOLBF : _IOFBF;
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#endif
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int ret = setvbuf(fp, buf, mode, BUFSIZ);
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if ( ret )
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{
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free(buf);
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return -1;
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}
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// The buffer now belongs to the FILE.
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fp->flags |= _FILE_BUFFER_OWNED;
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return ret;
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}
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