Imported Upstream version 93u+upstream

1 files changed, 119 insertions, 0 deletions

diff --git a/src/lib/libast/sfio/sfswap.c b/src/lib/libast/sfio/sfswap.c
new file mode 100644
index 0000000..4ffc614
--- /dev/null
+++ b/src/lib/libast/sfio/sfswap.c
@@ -0,0 +1,119 @@
+/***********************************************************************
+*                                                                      *
+*               This software is part of the ast package               *
+*          Copyright (c) 1985-2011 AT&T Intellectual Property          *
+*                      and is licensed under the                       *
+*                 Eclipse Public License, Version 1.0                  *
+*                    by AT&T Intellectual Property                     *
+*                                                                      *
+*                A copy of the License is available at                 *
+*          http://www.eclipse.org/org/documents/epl-v10.html           *
+*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
+*                                                                      *
+*              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;
+}