Buffer::CopyData (uint8_t*, uint32_t) does not return the total number of bytes copied. I'm not sure of the best way to fix it, but my suggestion is to keep a copy of the original buffer pointer, increment buffer after the final memcpy(), and return the difference between the final and original values of buffer. Eg,

uint32_t 
Buffer::CopyData (uint8_t *buffer, uint32_t size) const
{
  /**
   * ALU CHANGE: Calculate the copied byte count as the difference
   * between the final value of "buffer" and the original value.
   */
  uint8_t* originalBuffer = buffer;
  if (size > 0)
    {
      uint32_t tmpsize = std::min (m_zeroAreaStart-m_start, size);
      memcpy (buffer, (const char*)(m_data->m_data + m_start), tmpsize);
      buffer += tmpsize;
      if (size > tmpsize) 
        { 
          size -= m_zeroAreaStart-m_start;
          tmpsize = std::min (m_zeroAreaEnd - m_zeroAreaStart, size);
          uint32_t left = tmpsize;
          while (left > 0)
            {
              uint32_t toWrite = std::min (left, g_zeroes.size);
              memcpy (buffer, g_zeroes.buffer, toWrite);
              left -= toWrite;
              buffer += toWrite;
            }
          if (size > tmpsize)
            {
              size -= tmpsize;
              tmpsize = std::min (m_end - m_zeroAreaEnd, size);
              memcpy (buffer, (const char*)(m_data->m_data + m_zeroAreaStart), tmpsize);
              buffer += tmpsize; // ALU: Added this statement
            }
        }
    }
  return buffer - originalBuffer;  // ALU: was originalSize - size.
}