[Bf-blender-cvs] [793b73e] master: Fix T37712: Point cache index lookup crashed with 0 points stored.

[Lukas Tönne]

Commit: 793b73edc269e7e801c2e72f4ae6d11951608f74
Author: Lukas Tönne
Date:   Mon Dec 9 11:02:41 2013 +0100
http://developer.blender.org/rB793b73edc269e7e801c2e72f4ae6d11951608f74

Fix T37712: Point cache index lookup crashed with 0 points stored.

The BKE_ptcache_mem_index_find is using unsigned ints for binary search
"high" values - but this leads to integer overflow if the totpoint
number is 0 and causes invalid array access.

===================================================================

M	source/blender/blenkernel/intern/pointcache.c

===================================================================

diff --git a/source/blender/blenkernel/intern/pointcache.c b/source/blender/blenkernel/intern/pointcache.c
index 9891a8c..d2ef59b 100644
--- a/source/blender/blenkernel/intern/pointcache.c
+++ b/source/blender/blenkernel/intern/pointcache.c
@@ -1769,7 +1769,7 @@ static void ptcache_file_pointers_init(PTCacheFile *pf)
 /* Check to see if point number "index" is in pm, uses binary search for index data. */
 int BKE_ptcache_mem_index_find(PTCacheMem *pm, unsigned int index)
 {
-	if (pm->data[BPHYS_DATA_INDEX]) {
+	if (pm->totpoint > 0 && pm->data[BPHYS_DATA_INDEX]) {
 		unsigned int *data = pm->data[BPHYS_DATA_INDEX];
 		unsigned int mid, low = 0, high = pm->totpoint - 1;