commit f6ff9714c00c2c38a4498bbdf9a2cb17e8033cf3
author danilchap <danilchap@webrtc.org> Wed Feb 24 09:23:37 2016 -0800
committer Commit bot <commit-bot@chromium.org> Wed Feb 24 17:23:57 2016 +0000
tree d2b435e5b38f1e27c193c1e9ddb34f54dcc85743
parent 07fb9be37faac543299432605f31c77940333268

Fix division by zero in FindTMMBRBoundingSet

BUG=webrtc:5490

Review URL: https://codereview.webrtc.org/1727273003

Cr-Commit-Position: refs/heads/master@{#11749}

webrtc/modules/rtp_rtcp/source/tmmbr_help.cc

diff --git a/webrtc/modules/rtp_rtcp/source/tmmbr_help.cc b/webrtc/modules/rtp_rtcp/source/tmmbr_help.cc
index 5c09050..1001bf4 100644
--- a/webrtc/modules/rtp_rtcp/source/tmmbr_help.cc
+++ b/webrtc/modules/rtp_rtcp/source/tmmbr_help.cc
@@ -15,6 +15,7 @@
 
 #include <limits>
 
+#include "webrtc/base/checks.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_rtcp_config.h"
 
 namespace webrtc {
@@ -300,6 +301,7 @@
                   && j != currentMinIndexTMMBR)
                 {
                     candidateSet.ClearEntry(j);
+                    numCandidates--;
                 }
             }
         }
@@ -336,9 +338,15 @@
     // set intersection value
     _ptrIntersectionBoundingSet[numBoundingSet] = 0;
     // calculate its maximum packet rate (where its line crosses x-axis)
-    _ptrMaxPRBoundingSet[numBoundingSet]
-        = _boundingSet.Tmmbr(numBoundingSet) * 1000
-        / float(8 * _boundingSet.PacketOH(numBoundingSet));
+    uint32_t packet_overhead_bits = 8 * _boundingSet.PacketOH(numBoundingSet);
+    if (packet_overhead_bits == 0) {
+      // Avoid division by zero.
+      _ptrMaxPRBoundingSet[numBoundingSet] = std::numeric_limits<float>::max();
+    } else {
+      _ptrMaxPRBoundingSet[numBoundingSet] =
+          _boundingSet.Tmmbr(numBoundingSet) * 1000 /
+          static_cast<float>(packet_overhead_bits);
+    }
     numBoundingSet++;
     // remove from candidate list
     candidateSet.ClearEntry(minIndexTMMBR);
@@ -364,10 +372,10 @@
     }
 
     bool getNewCandidate = true;
-    int curCandidateTMMBR = 0;
-    int curCandidateIndex = 0;
-    int curCandidatePacketOH = 0;
-    int curCandidateSSRC = 0;
+    uint32_t curCandidateTMMBR = 0;
+    size_t curCandidateIndex = 0;
+    uint32_t curCandidatePacketOH = 0;
+    uint32_t curCandidateSSRC = 0;
     do
     {
         if (getNewCandidate)
@@ -389,6 +397,8 @@
 
         // 6. Calculate packet rate and intersection of the current
         // line with line of last tuple in selected list
+        RTC_DCHECK_NE(curCandidatePacketOH,
+                      _boundingSet.PacketOH(numBoundingSet - 1));
         float packetRate
             = float(curCandidateTMMBR
                     - _boundingSet.Tmmbr(numBoundingSet-1))*1000
@@ -418,9 +428,12 @@
                                       curCandidatePacketOH,
                                       curCandidateSSRC);
                 _ptrIntersectionBoundingSet[numBoundingSet] = packetRate;
-                _ptrMaxPRBoundingSet[numBoundingSet]
-                    = _boundingSet.Tmmbr(numBoundingSet)*1000
-                    / float(8*_boundingSet.PacketOH(numBoundingSet));
+                float packet_overhead_bits =
+                    8 * _boundingSet.PacketOH(numBoundingSet);
+                RTC_DCHECK_NE(packet_overhead_bits, 0.0f);
+                _ptrMaxPRBoundingSet[numBoundingSet] =
+                    _boundingSet.Tmmbr(numBoundingSet) * 1000 /
+                    packet_overhead_bits;
                 numBoundingSet++;
             }
             numCandidates--;