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engines/glk/zcode/mem.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_ZCODE_MEM
+#define GLK_ZCODE_MEM
+
+#include "glk/zcode/frotz_types.h"
+#include "glk/zcode/config.h"
+
+namespace Glk {
+namespace ZCode {
+
+#define SET_WORD(addr,v)  zmp[addr] = hi(v); zmp[addr+1] = lo(v)
+#define LOW_WORD(addr,v)  v = READ_BE_UINT16(&zmp[addr])
+#define HIGH_WORD(addr,v) v = READ_BE_UINT16(&zmp[addr])
+#define HIGH_LONG(addr,v) v = READ_BE_UINT32(&zmp[addr])
+#define SET_BYTE(addr,v)   zmp[addr] = v
+#define LOW_BYTE(addr,v)   v = zmp[addr]
+
+typedef uint offset_t;
+
+/**
+ * Stores undo information
+ */
+struct undo_struct {
+	undo_struct *next;
+	undo_struct *prev;
+	offset_t pc;
+	long diff_size;
+	zword frame_count;
+	zword stack_size;
+	zword frame_offset;
+	// undo diff and stack data follow
+};
+typedef undo_struct undo_t;
+
+/**
+ * Handles the memory, header, and user options
+ */
+class Mem : public Header, public virtual UserOptions {
+protected:
+	Common::SeekableReadStream *story_fp;
+	uint story_size;
+	byte *pcp;
+	byte *zmp;
+
+	undo_t *first_undo, *last_undo, *curr_undo;
+	zbyte *undo_mem, *prev_zmp, *undo_diff;
+	int undo_count;
+	int reserve_mem;
+private:
+	/**
+	 * Handles setting the story file, parsing it if it's a Blorb file
+	 */
+	void initializeStoryFile();
+
+	/**
+	 * Handles loading the game header
+	 */
+	void loadGameHeader();
+
+	/**
+	 * Initializes memory and loads the story data
+	 */
+	void loadMemory();
+
+	/**
+	 * Setup undo data
+	 */
+	void initializeUndo();
+protected:
+	/**
+	 * Read a value from the header extension (former mouse table).
+	 */
+	zword get_header_extension(int entry);
+
+	/**
+	 * Set an entry in the header extension (former mouse table).
+	 */
+	void set_header_extension(int entry, zword val);
+
+	/**
+	 * Set all header fields which hold information about the interpreter.
+	 */
+	void restart_header();
+
+	/**
+	 * Write a byte value to the dynamic Z-machine memory.
+	 */
+	void storeb(zword addr, zbyte value);
+
+	/**
+	 * Write a word value to the dynamic Z-machine memory.
+	 */
+	void storew(zword addr, zword value);
+
+	/**
+	 * Free count undo blocks from the beginning of the undo list
+	 */
+	void free_undo(int count);
+
+	/**
+	 * Generates a runtime error
+	 */
+	virtual void runtimeError(ErrorCode errNum) = 0;
+
+	/**
+	 * Called when the flags are changed
+	 */
+	virtual void flagsChanged(zbyte value) = 0;
+
+	/**
+	 * Close the story file and deallocate memory.
+	 */
+	void reset_memory();
+
+	/**
+	 * Set diff to a Quetzal-like difference between a and b,
+	 * copying a to b as we go.  It is assumed that diff points to a
+	 * buffer which is large enough to hold the diff.
+	 * mem_size is the number of bytes to compare.
+	 * Returns the number of bytes copied to diff.
+	 *
+	 */
+	long mem_diff(zbyte *a, zbyte *b, zword mem_size, zbyte *diff);
+
+	/**
+	 * Applies a quetzal-like diff to dest
+	 */
+	void mem_undiff(zbyte *diff, long diff_length, zbyte *dest);
+public:
+	/**
+	 * Constructor
+	 */
+	Mem();
+
+	/**
+	 * Destructor
+	 */
+	virtual ~Mem() {}
+
+	/**
+	 * Initialize
+	 */
+	void initialize();
+};
+
+} // End of namespace ZCode
+} // End of namespace Glk
+
+#endif