opengles emulator: dynamicaly grow ReadBuffer

In case we're receiving packets larger then the initial size
of the read buffer, we dynamicaly grow (X2 steps) the size of
the buffer. An example for this large buffer is a 4MB texture
in JetCarStunts.

Change-Id: I167caddb731583811c009321d4f8fb2f7eea032c

tools/emulator/opengl/host/libs/libOpenglRender/ReadBuffer.cpp

@@ -16,29 +16,48 @@
 #include "ReadBuffer.h"
 #include <string.h>
 #include <assert.h>
+#include <limits.h>
+#include "ErrorLog.h"
 
 ReadBuffer::ReadBuffer(IOStream *stream, size_t bufsize)
 {
     m_size = bufsize;
     m_stream = stream;
-    m_buf = new unsigned char[m_size];
+    m_buf = (unsigned char*)malloc(m_size*sizeof(unsigned char));
     m_validData = 0;
     m_readPtr = m_buf;
 }
 
 ReadBuffer::~ReadBuffer()
 {
-    delete m_buf;
+    free(m_buf);
 }
 
 int ReadBuffer::getData()
 {
-    if (m_validData > 0) {
+    if ((m_validData > 0) && (m_readPtr > m_buf)) {
         memcpy(m_buf, m_readPtr, m_validData);
     }
-    m_readPtr = m_buf;
     // get fresh data into the buffer;
     size_t len = m_size - m_validData;
+    if (len==0) {
+        //we need to inc our buffer
+        size_t new_size = m_size*2;
+        unsigned char* new_buf;
+        if (new_size < m_size) { // overflow check
+            new_size = INT_MAX;
+        }
+
+        new_buf = (unsigned char*)realloc(m_buf, new_size);
+        if (!new_buf) {
+            ERR("Failed to alloc %d bytes for ReadBuffer\n", new_size);
+            return -1;
+        }
+        m_size = new_size;
+        m_buf  = new_buf;
+        len    = m_size - m_validData;
+    }
+    m_readPtr = m_buf;
     if (NULL != m_stream->read(m_buf + m_validData, &len)) {
         m_validData += len;
         return len;