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engines/scumm/resource.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 SCUMM_RESOURCE_H
+#define SCUMM_RESOURCE_H
+
+#include "common/array.h"
+#include "scumm/scumm.h"	// for ResType
+
+namespace Scumm {
+
+// Extra space allocated for every resource. Originaly a safety area to make
+// "precaching" of bytes in the gdi drawer easier. Now also taken into
+// consideration when doing bounds checking in o5_stringOps().
+#define SAFETY_AREA 2
+
+enum {
+	OF_OWNER_MASK = 0x0F,
+	OF_STATE_MASK = 0xF0,
+
+	OF_STATE_SHL = 4
+};
+
+class ResourceIterator {
+	uint32 _size;
+	uint32 _pos;
+	const byte *_ptr;
+	bool _smallHeader;
+public:
+	ResourceIterator(const byte *searchin, bool smallHeader);
+	const byte *findNext(uint32 tag);
+};
+
+enum : uint {
+	RES_INVALID_OFFSET = 0xFFFFFFFF
+};
+
+class ScummEngine;
+
+/**
+ * The mode of a resource type indicates whether the resource can be restored
+ * from the game data files or not.
+ * This affects for example whether the resource is stored in savestates.
+ *
+ * Note that we treat sound resources somewhat differently: On the one hand,
+ * these behave mostly like a kStaticResTypeMode res type. However, when we
+ * create a savestate, we do save *some* information about them: Namely, which
+ * sound resources are loaded in memory at the time the save is made. And when
+ * loading, we invoke ensureResourceLoaded() for each sound resource that was
+ * marked in this way.
+ */
+enum ResTypeMode {
+	kDynamicResTypeMode = 0,	///< Resource is generated during runtime and may change
+	kStaticResTypeMode = 1,		///< Resource comes from data files, does not change
+	kSoundResTypeMode = 2		///< Resource comes from data files, but may change
+};
+
+/**
+ * The 'resource manager' class. Currently doesn't really deserve to be called
+ * a 'class', at least until somebody gets around to OOfying this more.
+ */
+class ResourceManager {
+	//friend class ScummDebugger;
+	//friend class ScummEngine;
+protected:
+	ScummEngine *_vm;
+	Common::Mutex *_mutex;
+
+public:
+	class Resource {
+	public:
+		/**
+		 * Pointer to the data contained in this resource
+		 */
+		byte *_address;
+
+		/**
+		 * Size of this resource, i.e. of the data contained in it.
+		 */
+		uint32 _size;
+
+	protected:
+		/**
+		 * The uppermost bit indicates whether the resources is locked.
+		 * The lower 7 bits contain a counter. This counter measures roughly
+		 * how old the resource is; it starts out with a count of 1 and can go
+		 * as high as 127. When memory falls low resp. when the engine decides
+		 * that it should throw out some unused stuff, then it begins by
+		 * removing the resources with the highest counter (excluding locked
+		 * resources and resources that are known to be in use).
+		 */
+		byte _flags;
+
+		/**
+		 * The status of the resource. Currently only one bit is used, which
+		 * indicates whether the resource is modified.
+		 */
+		byte _status;
+
+	public:
+		/**
+		 * The id of the room (resp. the disk) the resource is contained in.
+		 */
+		byte _roomno;
+
+		/**
+		 * The offset (in bytes) where the data for this resources can be found
+		 * in the game data file(s), relative to the start of the room the
+		 * resource is contained in.
+		 *
+		 * A value of RES_INVALID_OFFSET indicates a resources that is not contained
+		 * in the game data files.
+		 */
+		uint32 _roomoffs;
+
+	public:
+		Resource();
+		~Resource();
+
+		void nuke();
+
+		inline void setResourceCounter(byte counter);
+		inline byte getResourceCounter() const;
+
+		void lock();
+		void unlock();
+		bool isLocked() const;
+
+		// HE specific
+		void setModified();
+		bool isModified() const;
+		void setOffHeap();
+		void setOnHeap();
+		bool isOffHeap() const;
+	};
+
+	/**
+	 * This struct represents a resource type and all resource of that type.
+	 */
+	class ResTypeData : public Common::Array<Resource> {
+	friend class ResourceManager;
+	public:
+		/**
+		 * The mode of this res type.
+		 */
+		ResTypeMode _mode;
+
+		/**
+		 * The 4-byte tag or chunk type associated to this resource type, if any.
+		 * Only applies to resources that are loaded from the game data files.
+		 * This value is only used for debugging purposes.
+		 */
+		uint32 _tag;
+
+	public:
+		ResTypeData();
+		~ResTypeData();
+	};
+	ResTypeData _types[rtLast + 1];
+
+protected:
+	uint32 _allocatedSize;
+	uint32 _maxHeapThreshold, _minHeapThreshold;
+	byte _expireCounter;
+
+public:
+	ResourceManager(ScummEngine *vm);
+	~ResourceManager();
+
+	void setHeapThreshold(int min, int max);
+	uint32 getHeapSize() { return _allocatedSize; }
+
+	void allocResTypeData(ResType type, uint32 tag, int num, ResTypeMode mode);
+	void freeResources();
+
+	byte *createResource(ResType type, ResId idx, uint32 size);
+	void nukeResource(ResType type, ResId idx);
+
+//	inline Resource &getRes(ResType type, ResId idx) { return _types[type][idx]; }
+//	inline const Resource &getRes(ResType type, ResId idx) const { return _types[type][idx]; }
+
+	bool isResourceLoaded(ResType type, ResId idx) const;
+
+	void lock(ResType type, ResId idx);
+	void unlock(ResType type, ResId idx);
+	bool isLocked(ResType type, ResId idx) const;
+
+	// HE Specific
+	void setModified(ResType type, ResId idx);
+	bool isModified(ResType type, ResId idx) const;
+	void setOffHeap(ResType type, ResId idx);
+	bool isOffHeap(ResType type, ResId idx) const;
+	void setOnHeap(ResType type, ResId idx);
+
+	/**
+	 * This method increments the _expireCounter, and if it overflows (which happens
+	 * after at most 256 calls), it calls increaseResourceCounter.
+	 * It is invoked in the engine's main loop ScummEngine::scummLoop().
+	 */
+	void increaseExpireCounter();
+
+	/**
+	 * Update the specified resource's counter.
+	 */
+	void setResourceCounter(ResType type, ResId idx, byte counter);
+
+	/**
+	 * Increment the counter of all unlocked loaded resources.
+	 * The maximal count is 255.
+	 * This is called by increaseExpireCounter and expireResources,
+	 * but also by ScummEngine::startScene.
+	 */
+	void increaseResourceCounters();
+
+	void resourceStats();
+
+//protected:
+	bool validateResource(const char *str, ResType type, ResId idx) const;
+protected:
+	void expireResources(uint32 size);
+};
+
+} // End of namespace Scumm
+
+#endif