Imported Upstream version 93u+upstream

1 files changed, 89 insertions, 0 deletions

diff --git a/src/lib/libast/sfio/sfpeek.c b/src/lib/libast/sfio/sfpeek.c
new file mode 100644
index 0000000..22cf807
--- /dev/null
+++ b/src/lib/libast/sfio/sfpeek.c
@@ -0,0 +1,89 @@
+/***********************************************************************
+*                                                                      *
+*               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"
+
+/*	Safe access to the internal stream buffer.
+**	This function is obsolete. sfreserve() should be used.
+**
+**	Written by Kiem-Phong Vo (06/27/90).
+*/
+
+#if _BLD_sfio && defined(__EXPORT__)
+#define extern	__EXPORT__
+#endif
+
+#if __STD_C
+extern ssize_t sfpeek(reg Sfio_t* f, Void_t** bp, reg size_t size)
+#else
+extern ssize_t sfpeek(f,bp,size)
+reg Sfio_t*	f;	/* file to peek */
+Void_t**	bp;	/* start of data area */
+reg size_t	size;	/* size of peek */
+#endif
+{	reg ssize_t	n, sz;
+	reg int		mode;
+
+	/* query for the extent of the remainder of the buffer */
+	if((sz = size) == 0 || !bp)
+	{	if(f->mode&SF_INIT)
+			(void)_sfmode(f,0,0);
+
+		if((f->flags&SF_RDWRSTR) == SF_RDWRSTR)
+		{	SFSTRSIZE(f);
+			n = (f->data+f->here) - f->next;
+		}
+		else	n = f->endb - f->next;
+
+		if(!bp)
+			return n;
+		else if(n > 0)	/* size == 0 */
+		{	*bp = (Void_t*)f->next;
+			return 0;
+		}
+		/* else fall down and fill buffer */
+	}
+
+	if(!(mode = f->flags&SF_READ) )
+		mode = SF_WRITE;
+	if((int)f->mode != mode && _sfmode(f,mode,0) < 0)
+		return -1;
+
+	*bp = sfreserve(f, sz <= 0 ? 0 : sz > f->size ? f->size : sz, 0);
+
+	if(*bp && sz >= 0)
+		return sz;
+
+	if((n = sfvalue(f)) > 0)
+	{	*bp = (Void_t*)f->next;
+		if(sz < 0)
+		{	f->mode |= SF_PEEK;
+			f->endr = f->endw = f->data;
+		}
+		else
+		{	if(sz > n)
+				sz = n;
+			f->next += sz;
+		}
+	}
+
+	return (sz >= 0 && n >= sz) ? sz : n;
+}