vp8: remove assertion in tree coder.

Cast the counter to uint64_t in case it overflows.

The assert was to prevent c[0] * Pfac being overflow beyong unsigned int
since Pfac could be 2^8. Thus c[0] needs to be smaller than 2^24.

In VP9, the assert was removed and c[0] was casted to uint64_t.

Bug: 805277
Change-Id: Ic46a3c5b4af2f267de4e32c1518b64e8d6e9d856

diff --git a/vp8/common/treecoder.c b/vp8/common/treecoder.c
index 9feb40a5a7c2a8f86e4149bbc483ea3049894dc1..8a94cdeec0df14bb67415d588b817375c7681d21 100644 (file)
--- a/vp8/common/treecoder.c
+++ b/vp8/common/treecoder.c
@@ -12,6 +12,7 @@
 #include <stdio.h>
 
 #include "vp8/common/treecoder.h"
+#include "vpx/vpx_integer.h"
 
 static void tree2tok(struct vp8_token_struct *const p, vp8_tree t, int i, int v,
                      int L) {
@@ -89,10 +90,9 @@ void vp8_tree_probs_from_distribution(int n, /* n = size of alphabet */
     const unsigned int *const c = branch_ct[t];
     const unsigned int tot = c[0] + c[1];
 
-    assert(tot < (1 << 24)); /* no overflow below */
-
     if (tot) {
-      const unsigned int p = ((c[0] * Pfac) + (rd ? tot >> 1 : 0)) / tot;
+      const unsigned int p =
+          (unsigned int)(((uint64_t)c[0] * Pfac) + (rd ? tot >> 1 : 0)) / tot;
       probs[t] = p < 256 ? (p ? p : 1) : 255; /* agree w/old version for now */
     } else {
       probs[t] = vp8_prob_half;