From 87775d35e0d7cff7c7563c1cbddffb817f01752e Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@audacityteam.org>
Date: Thu, 16 Mar 2017 19:24:36 -0400
Subject: [PATCH] null pointer checks on all uses of WaveTrackCache::Get

---
 src/Mix.cpp      | 20 ++++++++++++++++----
 src/WaveClip.cpp | 10 +++++++---
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/src/Mix.cpp b/src/Mix.cpp
index db4477f56..96b8089a4 100644
--- a/src/Mix.cpp
+++ b/src/Mix.cpp
@@ -456,7 +456,10 @@ size_t Mixer::MixVariableRates(int *channelFlags, WaveTrackCache &cache,
          if (getLen > 0) {
             if (backwards) {
                auto results = cache.Get(floatSample, *pos - (getLen - 1), getLen);
-               memcpy(&queue[*queueLen], results, sizeof(float) * getLen);
+               if (results)
+                  memcpy(&queue[*queueLen], results, sizeof(float) * getLen);
+               else
+                  memset(&queue[*queueLen], 0, sizeof(float) * getLen);
 
                track->GetEnvelopeValues(mEnvValues,
                                         getLen,
@@ -465,7 +468,10 @@ size_t Mixer::MixVariableRates(int *channelFlags, WaveTrackCache &cache,
             }
             else {
                auto results = cache.Get(floatSample, *pos, getLen);
-               memcpy(&queue[*queueLen], results, sizeof(float) * getLen);
+               if (results)
+                  memcpy(&queue[*queueLen], results, sizeof(float) * getLen);
+               else
+                  memset(&queue[*queueLen], 0, sizeof(float) * getLen);
 
                track->GetEnvelopeValues(mEnvValues,
                                         getLen,
@@ -571,7 +577,10 @@ size_t Mixer::MixSameRate(int *channelFlags, WaveTrackCache &cache,
 
    if (backwards) {
       auto results = cache.Get(floatSample, *pos - (slen - 1), slen);
-      memcpy(mFloatBuffer, results, sizeof(float) * slen);
+      if (results)
+         memcpy(mFloatBuffer, results, sizeof(float) * slen);
+      else
+         memset(mFloatBuffer, 0, sizeof(float) * slen);
       track->GetEnvelopeValues(mEnvValues, slen, t - (slen - 1) / mRate);
       for(decltype(slen) i = 0; i < slen; i++)
          mFloatBuffer[i] *= mEnvValues[i]; // Track gain control will go here?
@@ -581,7 +590,10 @@ size_t Mixer::MixSameRate(int *channelFlags, WaveTrackCache &cache,
    }
    else {
       auto results = cache.Get(floatSample, *pos, slen);
-      memcpy(mFloatBuffer, results, sizeof(float) * slen);
+      if (results)
+         memcpy(mFloatBuffer, results, sizeof(float) * slen);
+      else
+         memset(mFloatBuffer, 0, sizeof(float) * slen);
       track->GetEnvelopeValues(mEnvValues, slen, t);
       for(decltype(slen) i = 0; i < slen; i++)
          mFloatBuffer[i] *= mEnvValues[i]; // Track gain control will go here?
diff --git a/src/WaveClip.cpp b/src/WaveClip.cpp
index 9e7859475..00c7ef09a 100644
--- a/src/WaveClip.cpp
+++ b/src/WaveClip.cpp
@@ -854,12 +854,16 @@ bool SpecCache::CalculateOneSpectrum
                myLen)
             );
 
-            if (copy)
-               memcpy(adj, useBuffer, myLen * sizeof(float));
+            if (copy) {
+               if (useBuffer)
+                  memcpy(adj, useBuffer, myLen * sizeof(float));
+               else
+                  memset(adj, 0, myLen * sizeof(float));
+            }
          }
       }
 
-      if (copy)
+      if (copy || !useBuffer)
          useBuffer = scratch;
 
       if (autocorrelation) {