/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2011 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"
/* Swap two streams. If the second argument is NULL,
** a new stream will be created. Always return the second argument
** or the new stream. Note that this function will always work
** unless streams are locked by SF_PUSH.
**
** Written by Kiem-Phong Vo.
*/
#if __STD_C
Sfio_t* sfswap(reg Sfio_t* f1, reg Sfio_t* f2)
#else
Sfio_t* sfswap(f1,f2)
reg Sfio_t* f1;
reg Sfio_t* f2;
#endif
{
Sfio_t tmp;
int f1pool, f2pool, f1mode, f2mode, f1flags, f2flags;
if(!f1 || (f1->mode&SF_AVAIL) || (SFFROZEN(f1) && (f1->mode&SF_PUSH)) )
return NIL(Sfio_t*);
if(f2 && SFFROZEN(f2) && (f2->mode&SF_PUSH) )
return NIL(Sfio_t*);
if(f1 == f2)
return f2;
f1mode = f1->mode;
SFLOCK(f1,0);
f1->mode |= SF_PUSH; /* make sure there is no recursion on f1 */
if(f2)
{ f2mode = f2->mode;
SFLOCK(f2,0);
f2->mode |= SF_PUSH; /* make sure there is no recursion on f2 */
}
else
{ f2 = f1->file == 0 ? sfstdin :
f1->file == 1 ? sfstdout :
f1->file == 2 ? sfstderr : NIL(Sfio_t*);
if((!f2 || !(f2->mode&SF_AVAIL)) )
{ if(!(f2 = (Sfio_t*)malloc(sizeof(Sfio_t))) )
{ f1->mode = f1mode;
SFOPEN(f1,0);
return NIL(Sfio_t*);
}
SFCLEAR(f2,NIL(Vtmutex_t*));
}
f2->mode = SF_AVAIL|SF_LOCK;
f2mode = SF_AVAIL;
}
if(!f1->pool)
f1pool = -1;
else for(f1pool = f1->pool->n_sf-1; f1pool >= 0; --f1pool)
if(f1->pool->sf[f1pool] == f1)
break;
if(!f2->pool)
f2pool = -1;
else for(f2pool = f2->pool->n_sf-1; f2pool >= 0; --f2pool)
if(f2->pool->sf[f2pool] == f2)
break;
f1flags = f1->flags;
f2flags = f2->flags;
/* swap image and pool entries */
memcpy((Void_t*)(&tmp),(Void_t*)f1,sizeof(Sfio_t));
memcpy((Void_t*)f1,(Void_t*)f2,sizeof(Sfio_t));
memcpy((Void_t*)f2,(Void_t*)(&tmp),sizeof(Sfio_t));
if(f2pool >= 0)
f1->pool->sf[f2pool] = f1;
if(f1pool >= 0)
f2->pool->sf[f1pool] = f2;
if(f2flags&SF_STATIC)
f2->flags |= SF_STATIC;
else f2->flags &= ~SF_STATIC;
if(f1flags&SF_STATIC)
f1->flags |= SF_STATIC;
else f1->flags &= ~SF_STATIC;
if(f2mode&SF_AVAIL) /* swapping to a closed stream */
{ if(!(f1->flags&SF_STATIC) )
free(f1);
}
else
{ f1->mode = f2mode;
SFOPEN(f1,0);
}
f2->mode = f1mode;
SFOPEN(f2,0);
return f2;
}