70 lines
1.9 KiB
C++
70 lines
1.9 KiB
C++
//========= Copyright Valve Corporation, All rights reserved. ============//
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//
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// LZSS Codec. Designed for fast cheap gametime encoding/decoding. Compression results
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// are not aggresive as other alogrithms, but gets 2:1 on most arbitrary uncompressed data.
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//
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//=====================================================================================//
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#ifndef _LZSS_H
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#define _LZSS_H
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#pragma once
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#define LZSS_ID uint32( BigLong( ('L'<<24)|('Z'<<16)|('S'<<8)|('S') ) )
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#define SNAPPY_ID uint32( BigLong( ('S'<<24)|('N'<<16)|('A'<<8)|('P') ) )
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// bind the buffer for correct identification
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struct lzss_header_t
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{
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unsigned int id;
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unsigned int actualSize; // always little endian
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};
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class CUtlBuffer;
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#define DEFAULT_LZSS_WINDOW_SIZE 4096
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class CLZSS
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{
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public:
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unsigned char* Compress( const unsigned char *pInput, int inputlen, unsigned int *pOutputSize );
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unsigned char* CompressNoAlloc( const unsigned char *pInput, int inputlen, unsigned char *pOutput, unsigned int *pOutputSize );
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unsigned int Uncompress( const unsigned char *pInput, unsigned char *pOutput );
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//unsigned int Uncompress( unsigned char *pInput, CUtlBuffer &buf );
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unsigned int SafeUncompress( const unsigned char *pInput, unsigned char *pOutput, unsigned int unBufSize );
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static bool IsCompressed( const unsigned char *pInput );
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static unsigned int GetActualSize( const unsigned char *pInput );
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// windowsize must be a power of two.
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FORCEINLINE CLZSS( int nWindowSize = DEFAULT_LZSS_WINDOW_SIZE );
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private:
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// expected to be sixteen bytes
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struct lzss_node_t
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{
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const unsigned char *pData;
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lzss_node_t *pPrev;
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lzss_node_t *pNext;
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char empty[4];
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};
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struct lzss_list_t
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{
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lzss_node_t *pStart;
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lzss_node_t *pEnd;
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};
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void BuildHash( const unsigned char *pData );
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lzss_list_t *m_pHashTable;
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lzss_node_t *m_pHashTarget;
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int m_nWindowSize;
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};
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FORCEINLINE CLZSS::CLZSS( int nWindowSize )
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{
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m_nWindowSize = nWindowSize;
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}
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#endif
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