BSD 4_3_Reno release

[unix-history] / usr / src / usr.bin / telnet / ring.c

diff --git a/usr/src/usr.bin/telnet/ring.c b/usr/src/usr.bin/telnet/ring.c
index a738708..2d9f0b0 100644 (file)
--- a/usr/src/usr.bin/telnet/ring.c
+++ b/usr/src/usr.bin/telnet/ring.c
@@ -1,3 +1,26 @@
+/*
+ * Copyright (c) 1988 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted provided
+ * that: (1) source distributions retain this entire copyright notice and
+ * comment, and (2) distributions including binaries display the following
+ * acknowledgement:  ``This product includes software developed by the
+ * University of California, Berkeley and its contributors'' in the
+ * documentation or other materials provided with the distribution and in
+ * all advertising materials mentioning features or use of this software.
+ * 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 ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)ring.c     1.13 (Berkeley) 6/28/90";
+#endif /* not lint */
+

 /*
  * This defines a structure for a ring buffer.
  *
 /*
  * This defines a structure for a ring buffer.
  *


@@ -17,7 +40,9 @@
 #endif
 
 #include       <sys/types.h>
 #endif
 
 #include       <sys/types.h>

+#ifndef        FILIO_H

 #include       <sys/ioctl.h>
 #include       <sys/ioctl.h>

+#endif

 #include       <sys/socket.h>
 
 #include       "ring.h"
 #include       <sys/socket.h>
 
 #include       "ring.h"


@@ -29,12 +54,15 @@
 #define        MIN(a,b)        (((a)<(b))? (a):(b))
 #endif /* !defined(MIN) */
 
 #define        MIN(a,b)        (((a)<(b))? (a):(b))
 #endif /* !defined(MIN) */
 

-#define        ring_subtract(d,a,b)    ((((int)(a))-((int)(b)) >= 0)? \
+#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))
 
                                        (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.
 
 /*
  * The following is a clock, used to determine full, empty, etc.


@@ -73,6 +101,45 @@ int count;
     return 1;
 }
 
     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.
  */
 /*
  * Add characters from current segment to ring buffer.
  */


@@ -93,6 +160,13 @@ ring_consumed(ring, count)
 Ring *ring;
 int 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;
     /*
     ring->consume = ring_increment(ring, ring->consume, count);
     ring->consumetime = ++ring_clock;
     /*


@@ -139,27 +213,45 @@ Ring *ring;
     }
 }
 
     }
 }
 

-/* number of bytes that are available for consuming */
+/* 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;
 {
 int
 ring_full_count(ring)
 Ring *ring;
 {

-    if (ring_full(ring)) {
-       return ring->size;      /* nothing consumed, but full */
+    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 {
     } else {

-       return ring_subtract(ring, ring->supply, ring->consume);
+       return ring_subtract(ring, ring->mark, ring->consume);

     }
 }
 
     }
 }
 

-/* number of CONSECUTIVE bytes available for consuming */
+/*
+ * 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;
 {
 int
 ring_full_consecutive(ring)
 Ring *ring;
 {

-    if ((ring->supply < ring->consume) || ring_full(ring)) {
-       return ring_subtract(ring, ring->top, ring->consume);
+    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 {
     } else {

-       return ring_subtract(ring, ring->supply, ring->consume);
+       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);
+       }

     }
 }
 
     }
 }
 


@@ -183,6 +275,7 @@ int count;
     }
 }
 
     }
 }
 

+#ifdef notdef

 
 /*
  * Move data from the "consume" portion of the ring buffer
 
 /*
  * Move data from the "consume" portion of the ring buffer


@@ -203,25 +296,4 @@ int count;
        buffer += i;
     }
 }
        buffer += i;
     }
 }

-
-/* Mark routines */
-
-/* XXX do something here */
-void
-ring_mark(ring)
-Ring *ring;
-{
-}
-
-int
-ring_at_mark(ring)
-Ring *ring;
-{
-    return 0;
-}
-
-void
-ring_clear_mark(ring)
-Ring *ring;
-{
-}
+#endif