Snap for 5637155 from 66b2b04145b1d1007f03356e0106b16ad5e8fa46 to qt-qpr1-release

Change-Id: Id3f09f9707ed92c047d85f517eb8bffd682b9b6f
diff --git a/Parcel.cpp b/Parcel.cpp
index 4b61738..d6ea481 100644
--- a/Parcel.cpp
+++ b/Parcel.cpp
@@ -1324,8 +1324,8 @@
 
 const char* Parcel::readCString() const
 {
-    const size_t avail = mDataSize-mDataPos;
-    if (avail > 0) {
+    if (mDataPos < mDataSize) {
+        const size_t avail = mDataSize-mDataPos;
         const char* str = reinterpret_cast<const char*>(mData+mDataPos);
         // is the string's trailing NUL within the parcel's valid bounds?
         const char* eos = reinterpret_cast<const char*>(memchr(str, 0, avail));