#include <u.h>#include <libc.h> #include "git.h" enum {	Minchunk	= 128,	Maxchunk	= 8192,	Splitmask	= (1<<8)-1,}; static u32int geartab[] = {    0x67ed26b7, 0x32da500c, 0x53d0fee0, 0xce387dc7, 0xcd406d90, 0x2e83a4d4, 0x9fc9a38d, 0xb67259dc,    0xca6b1722, 0x6d2ea08c, 0x235cea2e, 0x3149bb5f, 0x1beda787, 0x2a6b77d5, 0x2f22d9ac, 0x91fc0544,    0xe413acfa, 0x5a30ff7a, 0xad6fdde0, 0x444fd0f5, 0x7ad87864, 0x58c5ff05, 0x8d2ec336, 0x2371f853,    0x550f8572, 0x6aa448dd, 0x7c9ddbcf, 0x95221e14, 0x2a82ec33, 0xcbec5a78, 0xc6795a0d, 0x243995b7,    0x1c909a2f, 0x4fded51c, 0x635d334b, 0x0e2b9999, 0x2702968d, 0x856de1d5, 0x3325d60e, 0xeb6a7502,    0xec2a9844, 0x0905835a, 0xa1820375, 0xa4be5cab, 0x96a6c058, 0x2c2ccd70, 0xba40fce3, 0xd794c46b,    0x8fbae83e, 0xc3aa7899, 0x3d3ff8ed, 0xa0d42b5b, 0x571c0c97, 0xd2811516, 0xf7e7b96c, 0x4fd2fcbd,    0xe2fdec94, 0x282cc436, 0x78e8e95c, 0x80a3b613, 0xcfbee20c, 0xd4a32d1c, 0x2a12ff13, 0x6af82936,    0xe5630258, 0x8efa6a98, 0x294fb2d1, 0xdeb57086, 0x5f0fddb3, 0xeceda7ce, 0x4c87305f, 0x3a6d3307,    0xe22d2942, 0x9d060217, 0x1e42ed02, 0xb6f63b52, 0x4367f39f, 0x055cf262, 0x03a461b2, 0x5ef9e382,    0x386bc03a, 0x2a1e79c7, 0xf1a0058b, 0xd4d2dea9, 0x56baf37d, 0x5daff6cc, 0xf03a951d, 0xaef7de45,    0xa8f4581e, 0x3960b555, 0xffbfff6d, 0xbe702a23, 0x8f5b6d6f, 0x061739fb, 0x98696f47, 0x3fd596d4,    0x151eac6b, 0xa9fcc4f5, 0x69181a12, 0x3ac5a107, 0xb5198fe7, 0x96bcb1da, 0x1b5ddf8e, 0xc757d650,    0x65865c3a, 0x8fc0a41a, 0x87435536, 0x99eda6f2, 0x41874794, 0x29cff4e8, 0xb70efd9a, 0x3103f6e7,    0x84d2453b, 0x15a450bd, 0x74f49af1, 0x60f664b1, 0xa1c86935, 0xfdafbce1, 0xe36353e3, 0x5d9ba739,    0xbc0559ba, 0x708b0054, 0xd41d808c, 0xb2f31723, 0x9027c41f, 0xf136d165, 0xb5374b12, 0x9420a6ac,    0x273958b6, 0xe6c2fad0, 0xebdc1f21, 0xfb33af8b, 0xc71c25cd, 0xe9a2d8e5, 0xbeb38a50, 0xbceb7cc2,    0x4e4e73f0, 0xcd6c251d, 0xde4c032c, 0x4b04ac30, 0x725b8b21, 0x4eb8c33b, 0x20d07b75, 0x0567aa63,    0xb56b2bb7, 0xc1f5fd3a, 0xcafd35ca, 0x470dd4da, 0xfe4f94cd, 0xfb8de424, 0xe8dbcf40, 0xfe50a37a,    0x62db5b5d, 0xf32f4ab6, 0x2c4a8a51, 0x18473dc0, 0xfe0cbb6e, 0xfe399efd, 0xdf34ecc9, 0x6ccd5055,    0x46097073, 0x139135c2, 0x721c76f6, 0x1c6a94b4, 0x6eee014d, 0x8a508e02, 0x3da538f5, 0x280d394f,    0x5248a0c4, 0x3ce94c6c, 0x9a71ad3a, 0x8493dd05, 0xe43f0ab6, 0x18e4ed42, 0x6c5c0e09, 0x42b06ec9,    0x8d330343, 0xa45b6f59, 0x2a573c0c, 0xd7fd3de6, 0xeedeab68, 0x5c84dafc, 0xbbd1b1a8, 0xa3ce1ad1,    0x85b70bed, 0xb6add07f, 0xa531309c, 0x8f8ab852, 0x564de332, 0xeac9ed0c, 0x73da402c, 0x3ec52761,    0x43af2f4d, 0xd6ff45c8, 0x4c367462, 0xd553bd6a, 0x44724855, 0x3b2aa728, 0x56e5eb65, 0xeaf16173,    0x33fa42ff, 0xd714bb5d, 0xfbd0a3b9, 0xaf517134, 0x9416c8cd, 0x534cf94f, 0x548947c2, 0x34193569,    0x32f4389a, 0xfe7028bc, 0xed73b1ed, 0x9db95770, 0x468e3922, 0x0440c3cd, 0x60059a62, 0x33504562,    0x2b229fbd, 0x5174dca5, 0xf7028752, 0xd63c6aa8, 0x31276f38, 0x0646721c, 0xb0191da8, 0xe00e6de0,    0x9eac1a6e, 0x9f7628a5, 0xed6c06ea, 0x0bb8af15, 0xf119fb12, 0x38693c1c, 0x732bc0fe, 0x84953275,    0xb82ec888, 0x33a4f1b3, 0x3099835e, 0x028a8782, 0x5fdd51d7, 0xc6c717b3, 0xb06caf71, 0x17c8c111,    0x61bad754, 0x9fd03061, 0xe09df1af, 0x3bc9eb73, 0x85878413, 0x9889aaf2, 0x3f5a9e46, 0x42c9f01f,    0x9984a4f4, 0xd5de43cc, 0xd294daed, 0xbecba2d2, 0xf1f6e72c, 0x5551128a, 0x83af87e2, 0x6f0342ba,}; static u64inthash(void *p, int n){	return murmurhash2(p, n);} static voidaddblk(Dtab *dt, void *buf, int len, int off, u64int h){	int i, sz, probe;	Dblock *db; 	probe = h % dt->sz;	while(dt->b[probe].buf != nil){		if(len == dt->b[probe].len && memcmp(buf, dt->b[probe].buf, len) == 0)			return;		probe = (probe + 1) % dt->sz;	}	assert(dt->b[probe].buf == nil);	dt->b[probe].buf = buf;	dt->b[probe].len = len;	dt->b[probe].off = off;	dt->b[probe].hash = h;	dt->nb++;	if(dt->sz < 2*dt->nb){		sz = dt->sz;		db = dt->b;		dt->sz *= 2;		dt->nb = 0;		dt->b = eamalloc(dt->sz, sizeof(Dblock));		for(i = 0; i < sz; i++)			if(db[i].buf != nil)				addblk(dt, db[i].buf, db[i].len, db[i].off, db[i].hash);		free(db);	}		} static Dblock*lookup(Dtab *dt, uchar *p, int n){	int probe;	u64int h; 	h = hash(p, n);	for(probe = h % dt->sz; dt->b[probe].buf != nil; probe = (probe + 1) % dt->sz){		if(dt->b[probe].hash != h)			continue;		if(n != dt->b[probe].len)			continue;		if(memcmp(p, dt->b[probe].buf, n) != 0)			continue;		return &dt->b[probe];	}	return nil;} static intnextblk(uchar *s, uchar *e){	u32int gh;	uchar *p; 	if((e - s) < Minchunk)		return e - s;	p = s + Minchunk;	if((e - s) > Maxchunk)		e = s + Maxchunk;	gh = 0;	while(p != e){		gh = (gh<<1) + geartab[*p++];		if((gh & Splitmask) == 0)			break;	}	return p - s;} voiddtinit(Dtab *dt, Object *obj){	uchar *s, *e;	u64int h;	vlong n, o;		o = 0;	s = (uchar*)obj->data;	e = s + obj->size;	dt->o = ref(obj);	dt->nb = 0;	dt->sz = 128;	dt->b = eamalloc(dt->sz, sizeof(Dblock));	dt->base = (uchar*)obj->data;	dt->nbase = obj->size;	while(s != e){		n = nextblk(s, e);		h = hash(s, n);		addblk(dt, s, n, o, h);		s += n;		o += n;	}} voiddtclear(Dtab *dt){	unref(dt->o);	free(dt->b);} static intemitdelta(Delta **pd, int *nd, int cpy, int off, int len){	Delta *d; 	*nd += 1;	*pd = earealloc(*pd, *nd, sizeof(Delta));	d = &(*pd)[*nd - 1];	d->cpy = cpy;	d->off = off;	d->len = len;	return len;} static intstretch(Dtab *dt, Dblock *b, uchar *s, uchar *e, int n){	uchar *p0, *p, *q, *eb; 	if(b == nil)		return n;	p = s + n;	q = dt->base + b->off + n;	p0 = p;	eb = dt->base + dt->nbase;	while(1){		if(p == e || q == eb)			break;		if(n+(p-p0) >= (1<<24)-1)			break;		if(*p != *q)			break;		p++;		q++;	}	return n + (p - p0);} Delta*deltify(Object *obj, Dtab *dt, int *pnd){	Delta *d;	Dblock *b;	uchar *s, *e;	vlong n, o;		o = 0;	d = nil;	s = (uchar*)obj->data;	e = s + obj->size;	*pnd = 0;	while(s != e){		n = nextblk(s, e);		b = lookup(dt, s, n);		n = stretch(dt, b, s, e, n);		if(b != nil)			emitdelta(&d, pnd, 1, b->off, n);		else			emitdelta(&d, pnd, 0, o, n);		s += n;		o += n;	}	return d;}