From ff45715ce50b80ab16ee0d0dc7fff0c47a51959a Mon Sep 17 00:00:00 2001
From: Nicolas Pitre <nico@cam.org>
Date: Mon, 15 May 2006 13:47:16 -0400
Subject: pack-object: slightly more efficient

Avoid creating a delta index for objects with maximum depth since they
are not going to be used as delta base anyway.  This also reduce peak
memory usage slightly as the current object's delta index is not useful
until the next object in the loop is considered for deltification. This
saves a bit more than 1% on CPU usage.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/delta.h b/delta.h
index 727ae30..7b3f86d 100644
--- a/delta.h
+++ b/delta.h
@@ -18,6 +18,8 @@ create_delta_index(const void *buf, unsigned long bufsize);
 
 /*
  * free_delta_index: free the index created by create_delta_index()
+ *
+ * Given pointer must be what create_delta_index() returned, or NULL.
  */
 extern void free_delta_index(struct delta_index *index);
 
diff --git a/pack-objects.c b/pack-objects.c
index 526c090..b430b02 100644
--- a/pack-objects.c
+++ b/pack-objects.c
@@ -1105,17 +1105,14 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 
 		if (entry->size < 50)
 			continue;
-		if (n->index)
-			free_delta_index(n->index);
+		free_delta_index(n->index);
+		n->index = NULL;
 		free(n->data);
 		n->entry = entry;
 		n->data = read_sha1_file(entry->sha1, type, &size);
 		if (size != entry->size)
 			die("object %s inconsistent object length (%lu vs %lu)",
 			    sha1_to_hex(entry->sha1), size, entry->size);
-		n->index = create_delta_index(n->data, size);
-		if (!n->index)
-			die("out of memory");
 
 		j = window;
 		while (--j > 0) {
@@ -1135,6 +1132,11 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 		 */
 		if (entry->delta && depth <= entry->depth)
 			continue;
+
+		n->index = create_delta_index(n->data, size);
+		if (!n->index)
+			die("out of memory");
+
 		idx++;
 		if (idx >= window)
 			idx = 0;
@@ -1144,8 +1146,7 @@ static void find_deltas(struct object_entry **list, int window, int depth)
 		fputc('\n', stderr);
 
 	for (i = 0; i < window; ++i) {
-		if (array[i].index)
-			free_delta_index(array[i].index);
+		free_delta_index(array[i].index);
 		free(array[i].data);
 	}
 	free(array);
-- 
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