initial import of NetBSD tree

1 files changed, 320 insertions, 0 deletions

diff --git a/usr.bin/telnet/ring.c b/usr.bin/telnet/ring.c
new file mode 100644
index 00000000000..694b045d831
--- /dev/null
+++ b/usr.bin/telnet/ring.c
@@ -0,0 +1,320 @@
+/*
+ * Copyright (c) 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+/* from: static char sccsid[] = "@(#)ring.c	8.1 (Berkeley) 6/6/93"; */
+static char *rcsid = "$Id: ring.c,v 1.1 1995/10/18 08:46:14 deraadt Exp $";
+#endif /* not lint */
+
+/*
+ * This defines a structure for a ring buffer.
+ *
+ * The circular buffer has two parts:
+ *(((
+ *	full:	[consume, supply)
+ *	empty:	[supply, consume)
+ *]]]
+ *
+ */
+
+#include	<stdio.h>
+#ifndef NO_STRING_H
+#include	<string.h>
+#endif
+#include	<strings.h>
+#include	<errno.h>
+
+#ifdef	size_t
+#undef	size_t
+#endif
+
+#include	<sys/types.h>
+#ifndef	FILIO_H
+#include	<sys/ioctl.h>
+#endif
+#include	<sys/socket.h>
+
+#include	"ring.h"
+#include	"general.h"
+
+/* Internal macros */
+
+#if	!defined(MIN)
+#define	MIN(a,b)	(((a)<(b))? (a):(b))
+#endif	/* !defined(MIN) */
+
+#define	ring_subtract(d,a,b)	(((a)-(b) >= 0)? \
+					(a)-(b): (((a)-(b))+(d)->size))
+
+#define	ring_increment(d,a,c)	(((a)+(c) < (d)->top)? \
+					(a)+(c) : (((a)+(c))-(d)->size))
+
+#define	ring_decrement(d,a,c)	(((a)-(c) >= (d)->bottom)? \
+					(a)-(c) : (((a)-(c))-(d)->size))
+
+
+/*
+ * The following is a clock, used to determine full, empty, etc.
+ *
+ * There is some trickiness here.  Since the ring buffers are initialized
+ * to ZERO on allocation, we need to make sure, when interpreting the
+ * clock, that when the times are EQUAL, then the buffer is FULL.
+ */
+static u_long ring_clock = 0;
+
+
+#define	ring_empty(d) (((d)->consume == (d)->supply) && \
+				((d)->consumetime >= (d)->supplytime))
+#define	ring_full(d) (((d)->supply == (d)->consume) && \
+				((d)->supplytime > (d)->consumetime))
+
+
+
+
+
+/* Buffer state transition routines */
+
+    ring_init(ring, buffer, count)
+Ring *ring;
+    unsigned char *buffer;
+    int count;
+{
+    memset((char *)ring, 0, sizeof *ring);
+
+    ring->size = count;
+
+    ring->supply = ring->consume = ring->bottom = buffer;
+
+    ring->top = ring->bottom+ring->size;
+
+
+    return 1;
+}
+
+/* Mark routines */
+
+/*
+ * Mark the most recently supplied byte.
+ */
+
+    void
+ring_mark(ring)
+    Ring *ring;
+{
+    ring->mark = ring_decrement(ring, ring->supply, 1);
+}
+
+/*
+ * Is the ring pointing to the mark?
+ */
+
+    int
+ring_at_mark(ring)
+    Ring *ring;
+{
+    if (ring->mark == ring->consume) {
+	return 1;
+    } else {
+	return 0;
+    }
+}
+
+/*
+ * Clear any mark set on the ring.
+ */
+
+    void
+ring_clear_mark(ring)
+    Ring *ring;
+{
+    ring->mark = 0;
+}
+
+/*
+ * Add characters from current segment to ring buffer.
+ */
+    void
+ring_supplied(ring, count)
+    Ring *ring;
+    int count;
+{
+    ring->supply = ring_increment(ring, ring->supply, count);
+    ring->supplytime = ++ring_clock;
+}
+
+/*
+ * We have just consumed "c" bytes.
+ */
+    void
+ring_consumed(ring, count)
+    Ring *ring;
+    int count;
+{
+    if (count == 0)	/* don't update anything */
+	return;
+
+    if (ring->mark &&
+		(ring_subtract(ring, ring->mark, ring->consume) < count)) {
+	ring->mark = 0;
+    }
+    ring->consume = ring_increment(ring, ring->consume, count);
+    ring->consumetime = ++ring_clock;
+    /*
+     * Try to encourage "ring_empty_consecutive()" to be large.
+     */
+    if (ring_empty(ring)) {
+	ring->consume = ring->supply = ring->bottom;
+    }
+}
+
+
+
+/* Buffer state query routines */
+
+
+/* Number of bytes that may be supplied */
+    int
+ring_empty_count(ring)
+    Ring *ring;
+{
+    if (ring_empty(ring)) {	/* if empty */
+	    return ring->size;
+    } else {
+	return ring_subtract(ring, ring->consume, ring->supply);
+    }
+}
+
+/* number of CONSECUTIVE bytes that may be supplied */
+    int
+ring_empty_consecutive(ring)
+    Ring *ring;
+{
+    if ((ring->consume < ring->supply) || ring_empty(ring)) {
+			    /*
+			     * if consume is "below" supply, or empty, then
+			     * return distance to the top
+			     */
+	return ring_subtract(ring, ring->top, ring->supply);
+    } else {
+				    /*
+				     * else, return what we may.
+				     */
+	return ring_subtract(ring, ring->consume, ring->supply);
+    }
+}
+
+/* Return the number of bytes that are available for consuming
+ * (but don't give more than enough to get to cross over set mark)
+ */
+
+    int
+ring_full_count(ring)
+    Ring *ring;
+{
+    if ((ring->mark == 0) || (ring->mark == ring->consume)) {
+	if (ring_full(ring)) {
+	    return ring->size;	/* nothing consumed, but full */
+	} else {
+	    return ring_subtract(ring, ring->supply, ring->consume);
+	}
+    } else {
+	return ring_subtract(ring, ring->mark, ring->consume);
+    }
+}
+
+/*
+ * Return the number of CONSECUTIVE bytes available for consuming.
+ * However, don't return more than enough to cross over set mark.
+ */
+    int
+ring_full_consecutive(ring)
+    Ring *ring;
+{
+    if ((ring->mark == 0) || (ring->mark == ring->consume)) {
+	if ((ring->supply < ring->consume) || ring_full(ring)) {
+	    return ring_subtract(ring, ring->top, ring->consume);
+	} else {
+	    return ring_subtract(ring, ring->supply, ring->consume);
+	}
+    } else {
+	if (ring->mark < ring->consume) {
+	    return ring_subtract(ring, ring->top, ring->consume);
+	} else {	/* Else, distance to mark */
+	    return ring_subtract(ring, ring->mark, ring->consume);
+	}
+    }
+}
+
+/*
+ * Move data into the "supply" portion of of the ring buffer.
+ */
+    void
+ring_supply_data(ring, buffer, count)
+    Ring *ring;
+    unsigned char *buffer;
+    int count;
+{
+    int i;
+
+    while (count) {
+	i = MIN(count, ring_empty_consecutive(ring));
+	memcpy(ring->supply, buffer, i);
+	ring_supplied(ring, i);
+	count -= i;
+	buffer += i;
+    }
+}
+
+#ifdef notdef
+
+/*
+ * Move data from the "consume" portion of the ring buffer
+ */
+    void
+ring_consume_data(ring, buffer, count)
+    Ring *ring;
+    unsigned char *buffer;
+    int count;
+{
+    int i;
+
+    while (count) {
+	i = MIN(count, ring_full_consecutive(ring));
+	memcpy(buffer, ring->consume, i);
+	ring_consumed(ring, i);
+	count -= i;
+	buffer += i;
+    }
+}
+#endif
+