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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==*/
//////////////////////////////////////////////////////////////////////////////
//
// plBSDiffBuffer - A utility class for writing and applying a difference
// buffer--i.e. a buffer containing a series of modifications
// 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 copied in structure (not substance) from
// plDiffBuffer. It is based on bsdiff-4.1 from BSD
// Linux (http://www.daemonology.org/bsdiff). It's *extremely*
// hard to read code (written by a PhD), but it works well. The
// original BSD code has been modified to have the bzip2 pipes
// it used to compress data removed. It has also been converted
// to work a C++ utility class.
//
// There isn't really an Add or Copy command in bsdiff. It just
// uses three control numbers and two diff/data buffers.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef _plBSDiffBuffer_h
#define _plBSDiffBuffer_h
#include "hsTypes.h"
#include "hsStream.h"
//// Class Definition ////////////////////////////////////////////////////////
class hsRAMStream;
class plBSDiffBuffer
{
protected:
hsBool fWriting;
UInt32 fNewLength, fPatchLength;
unsigned char* fPatchBuffer;
public:
plBSDiffBuffer( UInt32 newLength, UInt32 oldLength = 0 ); // Constructor for writing new buffers. oldLength isn't required but helpful for optimizations
plBSDiffBuffer( void *buffer, UInt32 length ); // Constructor for applying a given diff set
// to an old buffer
virtual ~plBSDiffBuffer();
/// Creation/write functions
// Diff() creates the diff buffer from the new and old.
UInt32 Diff( UInt32 oldLength, void *oldBuffer, UInt32 newLength, void *newBuffer );
// 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() is another way to call Patch().
UInt32 Apply( UInt32 oldLength, void *oldBuffer, UInt32 &newLength, void *&newBuffer )
{ return Patch(oldLength, oldBuffer, newLength, newBuffer); };
// Patch() 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.
UInt32 Patch( UInt32 oldLength, void *oldBuffer, UInt32 &newLength, void *&newBuffer );
private:
UInt32 IReadUnsignedInt8(unsigned char *buf);
void IWriteUnsignedInt8(UInt32 x,unsigned char *buf);
void ISafeMemcpy(unsigned char *dest, unsigned char *src, size_t nbytes,
unsigned char *destend, unsigned char *srcend);
void ISplit(Int32 *I,Int32 *V,UInt32 start,UInt32 len,UInt32 h);
void IQSuffixSort(Int32 *I,Int32 *V,unsigned char *old,UInt32 oldsize);
UInt32 IMatchLen( unsigned char *oldBuffer, UInt32 oldLength,
unsigned char *newBuffer, UInt32 newLength);
UInt32 ISearch( Int32 *I,
unsigned char *oldBuffer, UInt32 oldLength,
unsigned char *newBuffer, UInt32 newLength,
UInt32 st, UInt32 en, Int32 *pos);
};
#endif // _plBSDiffBuffer_h