From 56b6cf5b7f5648ab071bd24136006b9d84066005 Mon Sep 17 00:00:00 2001
From: Chad Brubaker <cbrubaker@google.com>
Date: Wed, 23 Sep 2015 16:21:54 -0700
Subject: Fix benign overflow in ToneGenerator.cpp

while (count--) causes an unsigned overflow when count = 0, refactor the
condition to avoid this.

Change-Id: I91a8c93e6be715d80070a4c94c1de712cb659265
---
 media/libmedia/ToneGenerator.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'media/libmedia')

diff --git a/media/libmedia/ToneGenerator.cpp b/media/libmedia/ToneGenerator.cpp
index 53b229e..d738ea7 100644
--- a/media/libmedia/ToneGenerator.cpp
+++ b/media/libmedia/ToneGenerator.cpp
@@ -1586,7 +1586,8 @@ void ToneGenerator::WaveGenerator::getSamples(short *outBuffer,
         }
         long dec = lAmplitude/count;
         // loop generation
-        while (count--) {
+        while (count) {
+            count--;
             Sample = ((lA1 * lS1) >> S_Q14) - lS2;
             // shift delay
             lS2 = lS1;
@@ -1597,7 +1598,8 @@ void ToneGenerator::WaveGenerator::getSamples(short *outBuffer,
         }
     } else {
         // loop generation
-        while (count--) {
+        while (count) {
+            count--;
             Sample = ((lA1 * lS1) >> S_Q14) - lS2;
             // shift delay
             lS2 = lS1;
-- 
cgit v1.1