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engines/glk/level9/detection.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef GLK_LEVEL9_DETECTION
+#define GLK_LEVEL9_DETECTION
+
+#include "common/fs.h"
+#include "common/hash-str.h"
+#include "engines/game.h"
+#include "glk/detection.h"
+
+namespace Glk {
+namespace Level9 {
+
+enum L9GameTypes { L9_V1, L9_V2, L9_V3, L9_V4 };
+
+struct gln_game_table_t {
+	const size_t length;        ///< Datafile length in bytes
+	const byte checksum;        ///< 8-bit checksum, last datafile byte
+	const uint16 crc;           ///< 16-bit CRC, L9cut-internal
+	const char *const gameId;   ///< Game Id
+	const char *const name;     ///< Game title
+	const char *const extra;    ///< Disk number, platform, etc.
+};
+typedef const gln_game_table_t *gln_game_tableref_t;
+
+struct gln_patch_table_t {
+	const size_t length;        ///< Datafile length in bytes
+	const byte orig_checksum;   ///< 8-bit checksum, last datafile byte
+	const uint16 orig_crc;      ///< 16-bit CRC, L9cut-internal
+	const byte patch_checksum;  ///< 8-bit checksum, last datafile byte
+	const uint16 patch_crc;     ///< 16-bit CRC, L9cut-internal
+};
+typedef const gln_patch_table_t *gln_patch_tableref_t;
+
+struct L9V1GameInfo {
+	byte dictVal1, dictVal2;
+	int dictStart, L9Ptrs[5], absData, msgStart, msgLen;
+};
+
+/**
+ * Scanner for game data
+ */
+class Scanner {
+private:
+	long scan(byte *StartFile, uint32 size);
+	long ScanV2(byte *StartFile, uint32 size);
+	long ScanV1(byte *StartFile, uint32 size);
+
+	bool ValidateSequence(byte *Base, byte *Image, uint32 iPos, uint32 acode, uint32 *Size, uint32 size, uint32 *Min, uint32 *Max, bool Rts, bool *JumpKill, bool *DriverV4);
+	uint16 scanmovewa5d0(byte *Base, uint32 *Pos);
+	uint32 scangetaddr(int Code, byte *Base, uint32 *Pos, uint32 acode, int *Mask);
+	void scangetcon(int Code, uint32 *Pos, int *Mask);
+	bool CheckCallDriverV4(byte *Base, uint32 Pos);
+#ifdef FULLSCAN
+	void Scanner::fullScan(byte *StartFile, uint32 size);
+#endif
+private:
+	byte **_dictData;
+	byte **_aCodePtr;
+public:
+	L9GameTypes _gameType;
+	int _l9V1Game;
+public:
+	Scanner() : _dictData(nullptr), _aCodePtr(nullptr), _gameType(L9_V1), _l9V1Game(-1) {}
+
+	/**
+	 * Scan passed file for a valid game, and if found return it's offset
+	 */
+	long scanner(byte *StartFile, uint32 size, byte **dictData = nullptr,
+		byte **aCodePtr = nullptr);
+
+	/**
+	 * Returns the info for a V1 game
+	 */
+	const L9V1GameInfo &v1Game() const;
+};
+
+/**
+ * Detection manager for specific games
+ */
+class GameDetection : public Scanner {
+private:
+	byte *&_startData;
+	uint32 &_fileSize;
+	bool _crcInitialized;
+	uint16 _crcTable[256];
+public:
+	const char *_gameName;
+public:
+	/**
+	 * Constructor
+	 */
+	GameDetection(byte *&startData, uint32 &fileSize);
+
+	/**
+	 * Identify a game from its data length, checksum, and CRC.  Returns the
+	 * entry of the game in the game table, or nullptr if not found.
+	 *
+	 * This function uses startdata and FileSize from the core interpreter.
+	 * These aren't advertised symbols, so be warned.
+	 */
+	gln_game_tableref_t gln_gameid_identify_game();
+
+	/**
+	 * Return the CRC of the bytes buffer[0..length-1].
+	 *
+	 * This algorithm is selected to match the CRCs used in L9cut.  Because of
+	 * the odd way CRCs are padded when L9cut calculates the CRC, this function
+	 * allows a count of NUL padding bytes to be included within the return CRC.
+	 */
+	uint16 gln_get_buffer_crc(const void *void_buffer, size_t length, size_t padding = 0);
+
+	/*
+	 * Look up and return game table and patch table entries given a game's
+	 * length, checksum, and CRC.  Returns the entry, or nullptr if not found.
+	 */
+	gln_game_tableref_t gln_gameid_lookup_game(uint16 length, byte checksum, uint16 crc, int ignore_crc) const;
+
+	/**
+	 * Look up and return patch table entries given a game's length, checksum, and CRC.
+	 * Returns the entry, or nullptr if not found
+	 */
+	gln_patch_tableref_t gln_gameid_lookup_patch(uint16 length, byte checksum, uint16 crc) const;
+
+	/**
+	 * Return the name of the game, or nullptr if not identifiable.
+	 *
+	 * This function uses startdata from the core interpreter.  This isn't an
+	 * advertised symbol, so be warned.
+	 */
+	const char *gln_gameid_get_game_name();
+
+	/**
+	 * Clear the saved game name, forcing a new lookup when next queried.  This
+	 * function should be called by actions that may cause the interpreter to
+	 * change game file, for example os_set_filenumber().
+	 */
+	void gln_gameid_game_name_reset();
+};
+
+/**
+ * Meta engine for Level 9 interpreter
+ */
+class Level9MetaEngine {
+public:
+	/**
+	 * Get a list of supported games
+	 */
+	static void getSupportedGames(PlainGameList &games);
+
+	/**
+	 * Get the detection entries
+	 */
+	static const GlkDetectionEntry* getDetectionEntries();
+
+	/**
+	 * Returns a game description for the given game Id, if it's supported
+	 */
+	static GameDescriptor findGame(const char *gameId);
+
+	/**
+	 * Detect supported games
+	 */
+	static bool detectGames(const Common::FSList &fslist, DetectedGames &gameList);
+
+	/**
+	 * Check for game Id clashes with other sub-engines
+	 */
+	static void detectClashes(Common::StringMap &map);
+};
+
+} // End of namespace Level9
+} // End of namespace Glk
+
+#endif