diff options
Diffstat (limited to 'include/lzsscomprs.h')
| -rw-r--r-- | include/lzsscomprs.h | 61 |
1 files changed, 12 insertions, 49 deletions
diff --git a/include/lzsscomprs.h b/include/lzsscomprs.h index 67732a3..b960a55 100644 --- a/include/lzsscomprs.h +++ b/include/lzsscomprs.h @@ -1,9 +1,11 @@ /****************************************************************************** - * lzsscomprs.h - definition of Class SWCompress used for data compression * - * $Id: lzsscomprs.h 1688 2005-01-01 04:42:26Z scribe $ + * lzsscomprs.h - definition of Class SWCompress used for data + * compression * - * Copyright 1998 CrossWire Bible Society (http://www.crosswire.org) + * $Id: lzsscomprs.h 2935 2013-08-02 11:06:30Z scribe $ + * + * Copyright 1999-2013 CrossWire Bible Society (http://www.crosswire.org) * CrossWire Bible Society * P. O. Box 2528 * Tempe, AZ 85280-2528 @@ -28,54 +30,15 @@ SWORD_NAMESPACE_START -// The following are constant sizes used by the compression algorithm. -// -// N - This is the size of the ring buffer. It is set -// to 4K. It is important to note that a position -// within the ring buffer requires 12 bits. -// -// F - This is the maximum length of a character sequence -// that can be taken from the ring buffer. It is set -// to 18. Note that a length must be 3 before it is -// worthwhile to store a position/length pair, so the -// length can be encoded in only 4 bits. Or, put yet -// another way, it is not necessary to encode a length -// of 0-18, it is necessary to encode a length of -// 3-18, which requires 4 bits. -// -// THRESHOLD - It takes 2 bytes to store an offset and -// a length. If a character sequence only -// requires 1 or 2 characters to store -// uncompressed, then it is better to store -// it uncompressed than as an offset into -// the ring buffer. -// -// Note that the 12 bits used to store the position and the 4 bits -// used to store the length equal a total of 16 bits, or 2 bytes. - -#define N 4096 -#define F 18 -#define THRESHOLD 3 -#define NOT_USED N - - - -class SWDLLEXPORT LZSSCompress:public SWCompress +class SWDLLEXPORT LZSSCompress : public SWCompress { - static unsigned char m_ring_buffer[N + F - 1]; - static short int m_match_position; - static short int m_match_length; - static short int m_lson[N + 1]; - static short int m_rson[N + 257]; - static short int m_dad[N + 1]; - void InitTree (); - void InsertNode (short int Pos); - void DeleteNode (short int Node); +class Private; + Private *p; public: - LZSSCompress (); - virtual ~ LZSSCompress (); - virtual void Encode (void); - virtual void Decode (void); + LZSSCompress (); + virtual ~LZSSCompress(); + virtual void Encode(void); + virtual void Decode(void); }; SWORD_NAMESPACE_END |