LegoStream and implementations 100% match (#77)

* MxFile and implementations 100% match

* Add MxFile and it's implementations, MxSystemFile and MxMemoryFile.
  The names are chosen by me, we don't know their original naming.

* These expose a Read/Write/Seek/Tell interface for reading and writing
  data, either from a file on disk or memory buffer.

* 100% match all functions.

* Change name to LegoStream

* Use p_ convention

* Assert size

LEGO1/legostream.h

@@ -0,0 +1,73 @@
+#ifndef LEGOSTREAM_H
+#define LEGOSTREAM_H
+
+#include "decomp.h"
+#include "mxtypes.h"
+
+#include <iosfwd>
+
+#define LEGOSTREAM_MODE_READ 1
+#define LEGOSTREAM_MODE_WRITE 2
+
+// VTABLE 0x100d7d80
+class LegoStream
+{
+public:
+  LegoStream() : m_mode(0) {}
+  inline virtual ~LegoStream() {};
+
+  virtual MxResult Read(char* p_buffer, MxU32 p_size) = 0;
+  virtual MxResult Write(char* p_buffer, MxU32 p_size) = 0;
+  virtual MxResult Tell(MxU32* p_offset) = 0;
+  virtual MxResult Seek(MxU32 p_offset) = 0;
+
+  virtual MxBool IsWriteMode();
+  virtual MxBool IsReadMode();
+
+  enum OpenFlags
+  {
+    ReadBit = 1,
+    WriteBit = 2,
+    BinaryBit = 4,
+  };
+
+protected:
+  MxU8 m_mode;
+};
+
+// VTABLE 0x100db730
+class LegoFileStream : public LegoStream
+{
+public:
+  LegoFileStream();
+  virtual ~LegoFileStream();
+
+  MxResult Read(char* p_buffer, MxU32 p_size) override;
+  MxResult Write(char* p_buffer, MxU32 p_size) override;
+  MxResult Tell(MxU32* p_offset) override;
+  MxResult Seek(MxU32 p_offset) override;
+
+  MxResult Open(const char* p_filename, OpenFlags p_mode);
+
+private:
+  FILE *m_hFile;
+};
+
+// VTABLE 0x100db710
+class LegoMemoryStream : public LegoStream
+{
+public:
+  LegoMemoryStream(char* p_buffer);
+  ~LegoMemoryStream() {}
+
+  MxResult Read(char* p_buffer, MxU32 p_size) override;
+  MxResult Write(char* p_buffer, MxU32 p_size) override;
+  MxResult Tell(MxU32* p_offset) override;
+  MxResult Seek(MxU32 p_offset) override;
+
+private:
+  char *m_buffer;
+  MxU32 m_offset;
+};
+
+#endif // LEGOSTREAM_H