[vte] [ring] Keep ring->next instead of ring->length

[Behdad Esfahbod <behdad src gnome org>]

commit de3f63efab64408c2eb3b0e02e358063769c9396
Author: Behdad Esfahbod <behdad behdad org>
Date:   Mon Sep 7 01:30:44 2009 -0400

    [ring] Keep ring->next instead of ring->length

 src/ring.c |   45 ++++++++++++++++++++-------------------------
 src/ring.h |    8 ++++----
 2 files changed, 24 insertions(+), 29 deletions(-)
---
diff --git a/src/ring.c b/src/ring.c
index f44e442..6c46198 100644
--- a/src/ring.c
+++ b/src/ring.c
@@ -295,14 +295,13 @@ void _vte_row_data_shrink (VteRowData *row, guint max_len)
 static void
 _vte_ring_validate (VteRing * ring)
 {
-	guint i, max;
+	guint i;
 	g_assert(ring != NULL);
 	_vte_debug_print(VTE_DEBUG_RING,
 			" Delta = %u, Length = %u, Max = %u, Mask = %x.\n",
-			ring->delta, ring->length, ring->max, ring->mask);
-	g_assert(ring->length <= ring->max);
-	max = ring->delta + ring->length;
-	for (i = ring->delta; i < max; i++)
+			ring->delta, ring->next - ring->delta, ring->max, ring->mask);
+	g_assert(ring->next - ring->delta <= ring->max);
+	for (i = ring->delta; i < ring->next; i++)
 		g_assert(_vte_ring_contains(ring, i));
 }
 #else
@@ -362,7 +361,7 @@ _vte_ring_free (VteRing *ring)
 void
 _vte_ring_resize (VteRing *ring, guint max_rows)
 {
-	guint position, end, old_max, old_mask;
+	guint position, old_max, old_mask;
 	VteRowData *old_array;
 
 	max_rows = MAX(max_rows, 2);
@@ -373,8 +372,6 @@ _vte_ring_resize (VteRing *ring, guint max_rows)
 	_vte_debug_print(VTE_DEBUG_RING, "Resizing ring.\n");
 	_vte_ring_validate(ring);
 
-	end = ring->delta + ring->length;
-
 	old_max = ring->max;
 	old_mask = ring->mask;
 	old_array = ring->array;
@@ -384,7 +381,7 @@ _vte_ring_resize (VteRing *ring, guint max_rows)
 	if (ring->mask != old_mask) {
 		ring->array = g_malloc0 (sizeof (ring->array[0]) * (ring->mask + 1));
 
-		for (position = ring->delta; position < end; position++) {
+		for (position = ring->delta; position < ring->next; position++) {
 			_vte_row_data_fini (_vte_ring_index(ring, position));
 			*_vte_ring_index(ring, position) = old_array[position & old_mask];
 			old_array[position & old_mask].cells = NULL;
@@ -396,9 +393,8 @@ _vte_ring_resize (VteRing *ring, guint max_rows)
 		g_free (old_array);
 	}
 
-	if (ring->length > ring->max) {
-	  ring->length = ring->max;
-	  ring->delta = end - ring->max;
+	if (ring->next - ring->delta > ring->max) {
+	  ring->delta = ring->next - ring->max;
 	}
 
 	_vte_ring_validate(ring);
@@ -407,8 +403,8 @@ _vte_ring_resize (VteRing *ring, guint max_rows)
 void
 _vte_ring_shrink (VteRing *ring, guint max_len)
 {
-	if (ring->length > max_len)
-		ring->length = max_len;
+	if (ring->next - ring->delta > max_len)
+		ring->next = ring->delta + max_len;
 }
 
 /**
@@ -428,20 +424,19 @@ _vte_ring_insert_internal (VteRing * ring, guint position)
 	VteRowData *row, tmp;
 
 	g_return_val_if_fail(position >= ring->delta, NULL);
-	g_return_val_if_fail(position <= ring->delta + ring->length, NULL);
+	g_return_val_if_fail(position <= ring->next, NULL);
 
 	_vte_debug_print(VTE_DEBUG_RING, "Inserting at position %u.\n", position);
 	_vte_ring_validate(ring);
 
-	tmp = *_vte_ring_index (ring, ring->delta + ring->length);
-	for (i = ring->delta + ring->length; i > position; i--)
+	tmp = *_vte_ring_index (ring, ring->next);
+	for (i = ring->next; i > position; i--)
 		*_vte_ring_index (ring, i) = *_vte_ring_index (ring, i - 1);
 	*_vte_ring_index (ring, position) = tmp;
 
 	row = _vte_row_data_init(_vte_ring_index(ring, position));
-	if (ring->length < ring->max)
-		ring->length++;
-	else
+	ring->next++;
+	if (ring->next - ring->delta > ring->max)
 		ring->delta++;
 
 	_vte_ring_validate(ring);
@@ -479,7 +474,7 @@ _vte_ring_insert (VteRing *ring, guint position)
 VteRowData *
 _vte_ring_append (VteRing * ring)
 {
-	return _vte_ring_insert_internal (ring, ring->delta + ring->length);
+	return _vte_ring_insert_internal (ring, ring->next);
 }
 
 /**
@@ -502,12 +497,12 @@ _vte_ring_remove (VteRing * ring, guint position)
 	_vte_ring_validate(ring);
 
 	tmp = *_vte_ring_index (ring, position);
-	for (i = position; i < ring->delta + ring->length - 1; i++)
+	for (i = position; i < ring->next - 1; i++)
 		*_vte_ring_index (ring, i) = *_vte_ring_index (ring, i + 1);
-	*_vte_ring_index (ring, ring->delta + ring->length - 1) = tmp;
+	*_vte_ring_index (ring, ring->next - 1) = tmp;
 
-	if (ring->length > 0)
-		ring->length--;
+	if (ring->next > ring->delta)
+		ring->next--;
 
 	_vte_ring_validate(ring);
 }
diff --git a/src/ring.h b/src/ring.h
index 5eb41ba..1437a12 100644
--- a/src/ring.h
+++ b/src/ring.h
@@ -140,16 +140,16 @@ void _vte_row_data_shrink (VteRowData *row, guint max_len);
 typedef struct _VteRing VteRing;
 
 struct _VteRing {
-	guint delta, length, max, mask;
+	guint delta, next, max, mask;
 	VteRowData *array;
 };
 
 #define _vte_ring_contains(__ring, __position) \
 	(((__position) >= (__ring)->delta) && \
-	 ((__position) < (__ring)->delta + (__ring)->length))
+	 ((__position) < (__ring)->next))
 #define _vte_ring_delta(__ring) ((__ring)->delta + 0)
-#define _vte_ring_length(__ring) ((__ring)->length + 0)
-#define _vte_ring_next(__ring) ((__ring)->delta + (__ring)->length)
+#define _vte_ring_length(__ring) ((__ring)->next - (__ring)->delta)
+#define _vte_ring_next(__ring) ((__ring)->next + 0)
 #define _vte_ring_index(__ring, __position) (&(__ring)->array[(__position) & (__ring)->mask])
 
 VteRing *_vte_ring_new (guint max_rows);