5 files changed, 70 insertions, 23 deletions

diff --git a/engines/glk/advsys/advsys.cpp b/engines/glk/advsys/advsys.cpp
index d5709d0619..5664bc8bc0 100644
--- a/engines/glk/advsys/advsys.cpp
+++ b/engines/glk/advsys/advsys.cpp
@@ -45,8 +45,7 @@ bool AdvSys::initialize() {
 		return false;
 
 	// Load the game's header
-	_header.load(&_gameFile);
-	if (!_header._valid)
+	if (!load(_gameFile))
 		return false;
 
 	return true;
diff --git a/engines/glk/advsys/advsys.h b/engines/glk/advsys/advsys.h
index 3fdf39f482..ea2558fa58 100644
--- a/engines/glk/advsys/advsys.h
+++ b/engines/glk/advsys/advsys.h
@@ -33,10 +33,9 @@ namespace AdvSys {
 /**
  * AdvSys game interpreter
  */
-class AdvSys : public GlkAPI {
+class AdvSys : public GlkAPI, public Game {
 private:
 	winid_t _window;
-	Header _header;
 private:
 	/**
 	 * Engine initialization
diff --git a/engines/glk/advsys/detection.cpp b/engines/glk/advsys/detection.cpp
index d3b376f0b6..921be4eef8 100644
--- a/engines/glk/advsys/detection.cpp
+++ b/engines/glk/advsys/detection.cpp
@@ -65,7 +65,7 @@ bool AdvSysMetaEngine::detectGames(const Common::FSList &fslist, DetectedGames &
 		if (!gameFile.open(*file))
 			continue;
 
-		Header hdr(&gameFile);
+		Header hdr(gameFile);
 		if (!hdr._valid)
 			continue;
 
diff --git a/engines/glk/advsys/game.cpp b/engines/glk/advsys/game.cpp
index ce1da29456..0b9db7e8aa 100644
--- a/engines/glk/advsys/game.cpp
+++ b/engines/glk/advsys/game.cpp
@@ -26,27 +26,34 @@
 namespace Glk {
 namespace AdvSys {
 
+void Decrypter::decrypt(byte *data, size_t size) {
+	for (; --size; ++data)
+		*data = ~(*data + 30);
+}
+
+/*--------------------------------------------------------------------------*/
+
 #define HEADER_SIZE 62
 
-void Header::load(Common::ReadStream *s) {
+bool Header::load(Common::ReadStream &s) {
 	_valid = false;
 	byte data[HEADER_SIZE];
 
 	// Read in the data
-	if (s->read(data, HEADER_SIZE) != HEADER_SIZE)
-		return;
-	Compression::decompress(data, HEADER_SIZE);
+	if (s.read(data, HEADER_SIZE) != HEADER_SIZE)
+		return false;
+	decrypt(data, HEADER_SIZE);
 	Common::MemoryReadStream ms(data, HEADER_SIZE, DisposeAfterUse::NO);
 
 	// Validate the header
 	_valid = !strncmp((const char*)data + 2, "ADVSYS", 6);
 	if (!_valid)
-		return;
+		return false;
 	
 	_size = ms.readUint16LE();
 	ms.skip(6);
 	_headerVersion = ms.readUint16LE();
-	_name = Common::String((const char*)data + 10, (const char*)data + 28);
+	_name = Common::String((const char *)data + 10, (const char *)data + 28);
 	ms.skip(18);
 	_version = ms.readUint16LE();
 	_wordTable = ms.readUint16LE();
@@ -65,11 +72,30 @@ void Header::load(Common::ReadStream *s) {
 	_errorHandler = ms.readUint16LE();
 	_saveArea = ms.readUint16LE();
 	_saveSize = ms.readUint16LE();
+
+	return true;
 }
 
-void Compression::decompress(byte *data, size_t size) {
-	for (; --size; ++data)
-		*data = ~(*data + 30);
+/*--------------------------------------------------------------------------*/
+
+#define MAX_VERSION 102
+
+bool Game::load(Common::SeekableReadStream &s) {
+	// Load the header
+	s.seek(0);
+	if (!Header::load(s))
+		return false;
+	
+	if (_headerVersion < 101 || _headerVersion > MAX_VERSION)
+		error("Wrong version number");
+
+	// Load the needed game data and decrypt it
+	_data.resize(_size);
+	if (!s.read(&_data[0], _size))
+		return false;
+	decrypt(&_data[0], _size);
+
+	return true;
 }
 
 } // End of namespace AdvSys
diff --git a/engines/glk/advsys/game.h b/engines/glk/advsys/game.h
index 9e2a6f759f..044d2642e7 100644
--- a/engines/glk/advsys/game.h
+++ b/engines/glk/advsys/game.h
@@ -23,27 +23,30 @@
 #ifndef GLK_ADVSYS_GAME
 #define GLK_ADVSYS_GAME
 
+#include "common/array.h"
 #include "common/stream.h"
 
 namespace Glk {
 namespace AdvSys {
 
 /**
- * Decompressor
+ * Data decryption
  */
-struct Compression {
+class Decrypter {
+public:
 	/**
-	 * Decompress a data block
+	 * Decrypt a data block
 	 */
-	static void decompress(byte* data, size_t size);
+	static void decrypt(byte* data, size_t size);
 };
 
 /**
  * AdvSys game header
  */
-struct Header {
+class Header : public Decrypter {
+public:
 	bool _valid;			///< Signals whether header is valid
-	size_t _size;			///< Header size in bytes
+	size_t _size;			///< Size in bytes
 	uint _headerVersion;	///< Header structure version
 	Common::String _name;	///< Adventure name
 	uint _version;			///< Adventure version			
@@ -63,7 +66,7 @@ struct Header {
 	uint _errorHandler;		///< Error handler code offset
 	uint _saveArea;			///< Save area offset
 	uint _saveSize;			///< Save area size
-
+public:
 	/**
 	 * Constructor
 	 */
@@ -76,14 +79,34 @@ struct Header {
 	/**
 	 * Constructor
 	 */
-	Header(Common::ReadStream* s) {
+	Header(Common::ReadStream &s) {
 		load(s);
 	}
 
 	/**
 	 * Load the header
 	 */
-	void load(Common::ReadStream *s);
+	bool load(Common::ReadStream &s);
+};
+
+/**
+ * Game abstraction class
+ */
+class Game : public Header {
+private:
+	uint _saveOffset;
+public:
+	Common::Array<byte> _data;
+public:
+	/**
+	 * Constructor
+	 */
+	Game() : Header(), _saveOffset(0) {}
+
+	/**
+	 * Load data for the game
+	 */
+	bool load(Common::SeekableReadStream &s);
 };
 
 } // End of namespace AdvSys