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BeefySysLib/sound/Common/AkDefaultLowLevelIODispatcher.h

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+//////////////////////////////////////////////////////////////////////
+//
+// AkDefaultLowLevelIODispatcher.h
+//
+// Canvas for implementation of the AK::StreamMgr::IAkFileLocationResolver,
+// meant to be used in a multiple streaming devices system. It is this
+// object that should be registered as the one and only 
+// AK::StreamMgr::IAkFileLocationResolver of the Stream Manager
+// (by calling AK::StreamMgr::SetFileLocationResolver()).
+// 
+// It forwards the calls to Open() to one of the low level I/O devices 
+// that were added to it using AddDevice(). These devices must thus also 
+// implement AK::StreamMgr::IAkFileLocationResolver.
+// 
+// The strategy for device dispatching is that of a chain of responsibility:
+// the dispatcher asks the first file resolver hook to open the file. If it 
+// fails, then it tries with the second, and so on, until a hook succeeds. 
+// This is inefficient. In your game, you should implement a strategy of 
+// your own (see CAkDefaultLowLevelIODispatcher::Open()). 
+//
+// Copyright (c) 2006 Audiokinetic Inc. / All Rights Reserved
+//
+//////////////////////////////////////////////////////////////////////
+
+#ifndef _AK_DEFAULT_LOW_LEVEL_IO_DISPATCHER_H_
+#define _AK_DEFAULT_LOW_LEVEL_IO_DISPATCHER_H_
+
+#include <AK/SoundEngine/Common/AkStreamMgrModule.h>
+
+#define AK_MAX_IO_DEVICES	(3)
+
+//-----------------------------------------------------------------------------
+// Name: class CAkDefaultLowLevelIODispatcher.
+// Desc: Register this object to the Stream Manager as the File Location Resolver.
+//		 You need to implement dispatching calls to Open() to separate devices,
+//		 according to your specific requirements.
+//-----------------------------------------------------------------------------
+class CAkDefaultLowLevelIODispatcher : public AK::StreamMgr::IAkFileLocationResolver
+{
+public:
+
+    CAkDefaultLowLevelIODispatcher( );
+    virtual ~CAkDefaultLowLevelIODispatcher( );
+
+    // Returns a file descriptor for a given file name (string).
+    virtual AKRESULT Open( 
+        const AkOSChar*			in_pszFileName,		// File name.
+		AkOpenMode				in_eOpenMode,		// Open mode.
+        AkFileSystemFlags *		in_pFlags,			// Special flags. Can pass NULL.
+		bool &					io_bSyncOpen,		// If true, the file must be opened synchronously. Otherwise it is left at the File Location Resolver's discretion. Return false if Open needs to be deferred.
+        AkFileDesc &			out_fileDesc        // Returned file descriptor.
+        );
+
+    // Returns a file descriptor for a given file ID.
+    virtual AKRESULT Open( 
+        AkFileID				in_fileID,          // File ID.
+        AkOpenMode				in_eOpenMode,       // Open mode.
+        AkFileSystemFlags *		in_pFlags,			// Special flags. Can pass NULL.
+		bool &					io_bSyncOpen,		// If true, the file must be opened synchronously. Otherwise it is left at the File Location Resolver's discretion. Return false if Open needs to be deferred.
+        AkFileDesc &			out_fileDesc        // Returned file descriptor.
+        );
+
+
+	// 
+	// Default dispatcher services.
+	//-----------------------------------------------------------------------------
+
+	// Add a "device" (actually, a File Location Resolver) to the dispatcher's list. 
+	// The first device added will be the first device queried.
+    virtual AKRESULT AddDevice(
+		AK::StreamMgr::IAkFileLocationResolver *	in_pHook
+        );
+
+	// Remove all devices from the dispatcher's array.
+	virtual void RemoveAllDevices();
+    
+protected:
+
+	// List of devices.
+	AK::StreamMgr::IAkFileLocationResolver *	m_arDevices[AK_MAX_IO_DEVICES];
+	AkUInt32									m_uNumDevices;
+};
+
+#endif //_AK_DEFAULT_LOW_LEVEL_IO_DISPATCHER_H_