gfxstream: make sure we consistently use uint32_t instead of int32_t to read the packet size.

A negative packet size doesn't make sense, and the code currently doesn't try to handle that scenario (ie: all 4 stream decoders do `ptr += packetLen` and as such would move backwards if the length was negative.

Further, on the encoder side, uint32_t is used (e.g.:
http://cs/android/device/generic/goldfish-opengl/system/vulkan_enc/VkEncoder.cpp;l=122;rcl=b0df973dd65f81645707f65a12e8a196a5310ef2)

Test: compiles, runs

Change-Id: Iaa0ac3fe57a3c20b419ceebe80d3b8ccec4083d7

1 files changed, 9 insertions, 11 deletions

diff --git a/stream-servers/ReadBuffer.cpp b/stream-servers/ReadBuffer.cpp
index 8bc52379..a108ccae 100644
--- a/stream-servers/ReadBuffer.cpp
+++ b/stream-servers/ReadBuffer.cpp
@@ -36,21 +36,21 @@ ReadBuffer::~ReadBuffer() {
     free(m_buf);
 }
 
-void ReadBuffer::setNeededFreeTailSize(int size) {
+void ReadBuffer::setNeededFreeTailSize(size_t size) {
     m_neededFreeTailSize = size;
 }
 
-int ReadBuffer::getData(IOStream* stream, int minSize) {
+int ReadBuffer::getData(IOStream* stream, size_t minSize) {
     assert(stream);
-    assert(minSize > (int)m_validData);
+    assert(minSize > m_validData);
 
-    const int minSizeToRead = minSize - m_validData;
-    const int neededFreeTailThisTime =
+    const size_t minSizeToRead = minSize - m_validData;
+    const size_t neededFreeTailThisTime =
         std::max(minSizeToRead,
                  m_neededFreeTailSize);
 
-    int maxSizeToRead;
-    const int freeTailSize = m_buf + m_size - (m_readPtr + m_validData);
+    size_t maxSizeToRead;
+    const size_t freeTailSize = m_buf + m_size - (m_readPtr + m_validData);
     if (freeTailSize >= neededFreeTailThisTime) {
         maxSizeToRead = freeTailSize;
     } else {
@@ -63,10 +63,8 @@ int ReadBuffer::getData(IOStream* stream, int minSize) {
             // Note: make sure we can fit at least two of the requested packets
             //  into the new buffer to minimize the reallocations and
             //  memmove()-ing stuff around.
-            size_t new_size = std::max<size_t>(
-                    2 * minSizeToRead + m_validData,
-                    2 * m_size);
-            if (new_size < m_size) {  // overflow check
+          size_t new_size = std::max(2 * minSizeToRead + m_validData, 2 * m_size);
+          if (new_size < m_size) {  // overflow check
                 new_size = INT_MAX;
             }