1 files changed, 98 insertions, 0 deletions
diff --git a/src/lib/libast/sfio/sfpurge.c b/src/lib/libast/sfio/sfpurge.c
new file mode 100644
index 0000000..c3b4106
--- /dev/null
+++ b/src/lib/libast/sfio/sfpurge.c
@@ -0,0 +1,98 @@
+/***********************************************************************
+*                                                                      *
+*               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"
+
+/*	Delete all pending data in the buffer
+**
+**	Written by Kiem-Phong Vo.
+*/
+
+#if __STD_C
+int sfpurge(Sfio_t* f)
+#else
+int sfpurge(f)
+Sfio_t*	f;
+#endif
+{
+	reg int	mode;
+	SFMTXDECL(f);
+
+	SFMTXENTER(f,-1);
+
+	if((mode = f->mode&SF_RDWR) != (int)f->mode && _sfmode(f,mode|SF_SYNCED,0) < 0)
+		SFMTXRETURN(f, -1);
+
+	if((f->flags&SF_IOCHECK) && f->disc && f->disc->exceptf)
+		(void)(*f->disc->exceptf)(f,SF_PURGE,(Void_t*)((int)1),f->disc);
+
+	if(f->disc == _Sfudisc)
+		(void)sfclose((*_Sfstack)(f,NIL(Sfio_t*)));
+
+	/* cannot purge read string streams */
+	if((f->flags&SF_STRING) && (f->mode&SF_READ) )
+		goto done;
+
+	SFLOCK(f,0);
+
+	/* if memory map must be a read stream, pretend data is gone */
+#ifdef MAP_TYPE
+	if(f->bits&SF_MMAP)
+	{	f->here -= f->endb - f->next;
+		if(f->data)
+		{	SFMUNMAP(f,f->data,f->endb-f->data);
+			(void)SFSK(f,f->here,SEEK_SET,f->disc);
+		}
+		SFOPEN(f,0);
+		SFMTXRETURN(f, 0);
+	}
+#endif
+
+	switch(f->mode&~SF_LOCK)
+	{
+	default :
+		SFOPEN(f,0);
+		SFMTXRETURN(f, -1);
+	case SF_WRITE :
+		f->next = f->data;
+		if(!f->proc || !(f->flags&SF_READ) || !(f->mode&SF_WRITE) )
+			break;
+
+		/* 2-way pipe, must clear read buffer */
+		(void)_sfmode(f,SF_READ,1);
+		/* fall through */
+	case SF_READ:
+		if(f->extent >= 0 && f->endb > f->next)
+		{	f->here -= f->endb-f->next;
+			(void)SFSK(f,f->here,SEEK_SET,f->disc);
+		}
+		f->endb = f->next = f->data;
+		break;
+	}
+
+	SFOPEN(f,0);
+
+done:
+	if((f->flags&SF_IOCHECK) && f->disc && f->disc->exceptf)
+		(void)(*f->disc->exceptf)(f,SF_PURGE,(Void_t*)((int)0),f->disc);
+
+	SFMTXRETURN(f, 0);
+}