sfset.c revision 34f9b3eef6fdadbda0a846aa4d68691ac40eace5
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2009 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#include "sfhdr.h"
/* Set some control flags or file descript for the stream
**
** Written by Kiem-Phong Vo.
*/
#if __STD_C
int sfset(Sfio_t* f, int flags, int set)
#else
int sfset(f,flags,set)
Sfio_t* f;
int flags;
int set;
#endif
{
reg int oflags;
SFMTXDECL(f);
SFMTXENTER(f,0);
if(flags == 0 && set == 0)
SFMTXRETURN(f, (f->flags&SF_FLAGS));
if((oflags = (f->mode&SF_RDWR)) != (int)f->mode && _sfmode(f,oflags,0) < 0)
SFMTXRETURN(f, 0);
if(flags == 0)
SFMTXRETURN(f, (f->flags&SF_FLAGS));
SFLOCK(f,0);
/* preserve at least one rd/wr flag */
oflags = f->flags;
if(!(f->bits&SF_BOTH) || (flags&SF_RDWR) == SF_RDWR )
flags &= ~SF_RDWR;
/* set the flag */
if(set)
f->flags |= (flags&SF_SETS);
else f->flags &= ~(flags&SF_SETS);
/* must have at least one of read/write */
if(!(f->flags&SF_RDWR))
f->flags |= (oflags&SF_RDWR);
if(f->extent < 0)
f->flags &= ~SF_APPENDWR;
/* turn to appropriate mode as necessary */
if((flags &= SF_RDWR) )
{ if(!set)
{ if(flags == SF_READ)
flags = SF_WRITE;
else flags = SF_READ;
}
if((flags == SF_WRITE && !(f->mode&SF_WRITE)) ||
(flags == SF_READ && !(f->mode&(SF_READ|SF_SYNCED))) )
(void)_sfmode(f,flags,1);
}
/* if not shared or unseekable, public means nothing */
if(!(f->flags&SF_SHARE) || f->extent < 0)
f->flags &= ~SF_PUBLIC;
SFOPEN(f,0);
SFMTXRETURN(f, (oflags&SF_FLAGS));
}