ref: 94916808dd9a53ac297ab537851791894b919828
dir: /sys/src/cmd/ip/ppp/thwack.h/
typedef struct Thwack Thwack; typedef struct Unthwack Unthwack; typedef struct ThwBlock ThwBlock; typedef struct UnthwBlock UnthwBlock; enum { ThwStats = 8, ThwErrLen = 64, /* max length of error message from thwack or unthwack */ ThwMaxBlock = 1600, /* max size of compressible block */ HashLog = 12, HashSize = 1<<HashLog, HashMask = HashSize - 1, MinMatch = 3, /* shortest match possible */ MaxOff = 8, OffBase = 6, MinDecode = 8, /* minimum bits to decode a match or lit; >= 8 */ CompBlocks = 10, /* max blocks used to encode data */ EWinBlocks = 64, /* blocks held in encoder window */ DWinBlocks = EWinBlocks, /* blocks held in decoder window */ MaxSeqMask = 8, /* number of bits in coding block mask */ MaxSeqStart = 256 /* max offset of initial coding block */ }; struct ThwBlock { ulong seq; /* sequence number for this data */ uchar acked; /* ok to use this block; the decoder has it */ ushort begin; /* time of first byte in hash */ uchar *edata; /* last byte of valid data */ ushort maxoff; /* time of last valid hash entry */ ushort *hash; uchar *data; }; struct Thwack { QLock acklock; /* locks slot, blocks[].(acked|seq) */ int slot; /* next block to use */ ThwBlock blocks[EWinBlocks]; ushort hash[EWinBlocks][HashSize]; Block *data[EWinBlocks]; }; struct UnthwBlock { ulong seq; /* sequence number for this data */ ushort maxoff; /* valid data in each block */ uchar *data; }; struct Unthwack { int slot; /* next block to use */ char err[ThwErrLen]; UnthwBlock blocks[DWinBlocks]; uchar data[DWinBlocks][ThwMaxBlock]; }; void thwackinit(Thwack*); void thwackcleanup(Thwack *tw); void unthwackinit(Unthwack*); int thwack(Thwack*, int mustadd, uchar *dst, int ndst, Block *bsrc, ulong seq, ulong stats[ThwStats]); void thwackack(Thwack*, ulong seq, ulong mask); int unthwack(Unthwack*, uchar *dst, int ndst, uchar *src, int nsrc, ulong seq); ulong unthwackstate(Unthwack *ut, uchar *mask); int unthwackadd(Unthwack *ut, uchar *src, int nsrc, ulong seq);