69 lines
2.1 KiB
C++
69 lines
2.1 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.
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//Compression results
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// are not aggresive as other alogrithms, but gets 2:1 on most
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//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 \
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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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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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public:
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unsigned char *Compress(const unsigned char *pInput, int inputlen,
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unsigned int *pOutputSize);
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unsigned char *CompressNoAlloc(const unsigned char *pInput, int inputlen,
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unsigned char *pOutput,
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unsigned int *pOutputSize);
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unsigned int Uncompress(const unsigned char *pInput,
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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,
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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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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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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) { m_nWindowSize = nWindowSize; }
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#endif
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