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typedef struct Thwack Thwack;
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typedef struct Unthwack Unthwack;
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typedef struct ThwBlock ThwBlock;
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typedef struct UnthwBlock UnthwBlock;
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enum
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{
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ThwStats = 8,
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ThwErrLen = 64, /* max length of error message from thwack or unthwack */
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ThwMaxBlock = 1600, /* max size of compressible block */
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HashLog = 12,
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HashSize = 1<<HashLog,
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HashMask = HashSize - 1,
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MinMatch = 3, /* shortest match possible */
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MaxOff = 8,
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OffBase = 6,
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MinDecode = 8, /* minimum bits to decode a match or lit; >= 8 */
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CompBlocks = 10, /* max blocks used to encode data */
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EWinBlocks = 64, /* blocks held in encoder window */
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DWinBlocks = EWinBlocks, /* blocks held in decoder window */
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MaxSeqMask = 8, /* number of bits in coding block mask */
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MaxSeqStart = 256 /* max offset of initial coding block */
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};
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struct ThwBlock
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{
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ulong seq; /* sequence number for this data */
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uchar acked; /* ok to use this block; the decoder has it */
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ushort begin; /* time of first byte in hash */
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uchar *edata; /* last byte of valid data */
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ushort maxoff; /* time of last valid hash entry */
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ushort *hash;
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uchar *data;
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};
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struct Thwack
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{
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QLock acklock; /* locks slot, blocks[].(acked|seq) */
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int slot; /* next block to use */
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ThwBlock blocks[EWinBlocks];
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ushort hash[EWinBlocks][HashSize];
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Block *data[EWinBlocks];
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};
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struct UnthwBlock
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{
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ulong seq; /* sequence number for this data */
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ushort maxoff; /* valid data in each block */
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uchar *data;
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};
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struct Unthwack
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{
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int slot; /* next block to use */
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char err[ThwErrLen];
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UnthwBlock blocks[DWinBlocks];
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uchar data[DWinBlocks][ThwMaxBlock];
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};
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void thwackinit(Thwack*);
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void thwackcleanup(Thwack *tw);
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void unthwackinit(Unthwack*);
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int thwack(Thwack*, int mustadd, uchar *dst, int ndst, Block *bsrc, ulong seq, ulong stats[ThwStats]);
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void thwackack(Thwack*, ulong seq, ulong mask);
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int unthwack(Unthwack*, uchar *dst, int ndst, uchar *src, int nsrc, ulong seq);
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ulong unthwackstate(Unthwack *ut, uchar *mask);
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int unthwackadd(Unthwack *ut, uchar *src, int nsrc, ulong seq);
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