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/*==LICENSE==*
CyanWorlds.com Engine - MMOG client, server and tools
Copyright (C) 2011 Cyan Worlds, Inc.
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/>.
You can contact Cyan Worlds, Inc. by email legal@cyan.com
or by snail mail at:
Cyan Worlds, Inc.
14617 N Newport Hwy
Mead, WA 99021
*==LICENSE==*/
//////////////////////////////////////////////////////////////////////////////
//
// plDiffBuffer - A utility class for writing and applying a difference
// buffer--i.e. a buffer containing a series of modifications
// (specifically, adds and copys) that will modify an old
// data buffer to match a new one. It's a useful utility
// class when doing binary file patching, for example, as you
// can write out the changes to this class, get back a data
// buffer suitable for writing, then use this class again
// later to reconstruct the new buffer.
//
// This class is meant to construct diff buffers using two
// ops: add and copy. Basically, the syntax is defined so
// that to reconstruct the new buffer, you run through the
// list of ops sequentially, each one defining the next
// chunk of data in the new buffer. Add ops will add new data
// to the buffer that didn't exist in the old buffer, and
// copy ops will copy data that existed in the old buffer
// (from an arbitrary offset, to facilitate encoding data
// shuffling). Delete ops are implicit, as they simply aren't
// defined in the stream of ops.
//
//// History /////////////////////////////////////////////////////////////////
//
// 7.24.2002 mcn - Created (Happy late b-day to me!)
//
//////////////////////////////////////////////////////////////////////////////
#ifndef _plDiffBuffer_h
#define _plDiffBuffer_h
#include "hsTypes.h"
#include "hsStream.h"
//// Class Definition ////////////////////////////////////////////////////////
class hsRAMStream;
class plBSDiffBuffer;
class plDiffBuffer
{
protected:
hsBool fWriting, f16BitMode;
UInt32 fNewLength;
hsRAMStream *fStream;
// Support for BSDiff patch buffers (Patching only)
plBSDiffBuffer *fBSDiffBuffer;
hsBool fIsBSDiff;
public:
plDiffBuffer( UInt32 newLength, UInt32 oldLength = 0 ); // Constructor for writing new buffers. oldLength isn't required but helpful for optimizations
plDiffBuffer( void *buffer, UInt32 length ); // Constructor for applying a given diff set
// to an old buffer
virtual ~plDiffBuffer();
/// Creation/write functions
// Add() appends an Add-New-Data operation to the diff buffer. The data supplied will be copied internally.
void Add( Int32 length, void *newData );
// Copy() appends a Copy-Data-From-Old operation to the diff buffer
void Copy( Int32 length, UInt32 oldOffset );
// GetBuffer() will copy the diff stream into a new buffer and return it. You are responsible for freeing the buffer.
void GetBuffer( UInt32 &length, void *&bufferPtr );
/// Apply functions
// Apply() will take this diff buffer and apply it to the given old buffer, allocating and producing a new buffer. You are responsible for freeing the new buffer.
void Apply( UInt32 oldLength, void *oldBuffer, UInt32 &newLength, void *&newBuffer );
};
#endif // _plDiffBuffer_h