void cinv22(COMPLEX *a,COMPLEX *b){
double tmp = 1/(a->re*(a+3)->im - (a+1)->im*(a+2)->re);
COMPLEX res1,res2,res3,res4,one;
cmult((a),(a+3),&res1);
cmult((a+1),(a+2),&res2);
res2.re *= -1;
res2.im *= -1;
cadd(&res1,&res2,&res3);
one.re = 1;
one.im = 0;
cdev(&one,&res3,&res4);
cmult(&res4,a+3,b);
cmult(&res4,a+1,b+1);
(b+1)->re *= -1;
(b+1)->im *= -1;
cmult(&res4,a+2,b+2);
(b+2)->re *= -1;
(b+2)->im *= -1;
cmult(&res4,a,b+3);
}
void
cwrite(Chan* c, uchar *buf, int len, vlong off)
{
int o, eo;
Mntcache *m;
ulong eblock, ee;
Extent *p, *f, *e, *tail;
ulong offset;
if(off > maxcache || len == 0)
return;
m = c->mcp;
if(m == 0)
return;
qlock(m);
if(cdev(m, c) == 0) {
qunlock(m);
return;
}
offset = off;
m->qid.vers++;
c->qid.vers++;
p = 0;
for(f = m->list; f; f = f->next) {
if(f->start >= offset)
break;
p = f;
}
if(p != 0) {
ee = p->start+p->len;
eo = offset - p->start;
/* pack in predecessor if there is space */
if(offset <= ee && eo < BY2PG) {
o = len;
if(o > BY2PG - eo)
o = BY2PG - eo;
if(cpgmove(p, buf, eo, o)) {
if(eo+o > p->len)
p->len = eo+o;
buf += o;
len -= o;
offset += o;
}
}
}
/* free the overlap -- it's a rare case */
eblock = offset+len;
while(f && f->start < eblock) {
e = f->next;
extentfree(f);
f = e;
}
/* link the block (if any) into the middle */
e = cchain(buf, offset, len, &tail);
if(e != 0) {
tail->next = f;
f = e;
}
if(p == 0)
m->list = f;
else
p->next = f;
qunlock(m);
}
void
cupdate(Chan *c, uchar *buf, int len, vlong off)
{
Mntcache *m;
Extent *tail;
Extent *e, *f, *p;
int o, ee, eblock;
ulong offset;
if(off > maxcache || len == 0)
return;
m = c->mcp;
if(m == 0)
return;
qlock(m);
if(cdev(m, c) == 0) {
qunlock(m);
return;
}
/*
* Find the insertion point
*/
offset = off;
p = 0;
for(f = m->list; f; f = f->next) {
if(f->start > offset)
break;
p = f;
}
/* trim if there is a successor */
eblock = offset+len;
if(f != 0 && eblock > f->start) {
len -= (eblock - f->start);
if(len <= 0) {
qunlock(m);
return;
}
}
if(p == 0) { /* at the head */
e = cchain(buf, offset, len, &tail);
if(e != 0) {
m->list = e;
tail->next = f;
}
qunlock(m);
return;
}
/* trim to the predecessor */
ee = p->start+p->len;
if(offset < ee) {
o = ee - offset;
len -= o;
if(len <= 0) {
qunlock(m);
return;
}
buf += o;
offset += o;
}
/* try and pack data into the predecessor */
if(offset == ee && p->len < BY2PG) {
o = len;
if(o > BY2PG - p->len)
o = BY2PG - p->len;
if(cpgmove(p, buf, p->len, o)) {
p->len += o;
buf += o;
len -= o;
offset += o;
if(len <= 0) {
if(f && p->start + p->len > f->start) print("CACHE: p->start=%uld p->len=%d f->start=%uld\n", p->start, p->len, f->start);
qunlock(m);
return;
}
}
}
e = cchain(buf, offset, len, &tail);
if(e != 0) {
p->next = e;
tail->next = f;
}
qunlock(m);
}
int
cread(Chan *c, uchar *buf, int len, vlong off)
{
KMap *k;
Page *p;
Mntcache *m;
Extent *e, **t;
int o, l, total;
ulong offset;
if(off+len > maxcache)
return 0;
m = c->mcp;
if(m == 0)
return 0;
qlock(m);
if(cdev(m, c) == 0) {
qunlock(m);
return 0;
}
offset = off;
t = &m->list;
for(e = *t; e; e = e->next) {
if(offset >= e->start && offset < e->start+e->len)
break;
t = &e->next;
}
if(e == 0) {
qunlock(m);
return 0;
}
total = 0;
while(len) {
p = cpage(e);
if(p == 0) {
*t = e->next;
extentfree(e);
qunlock(m);
return total;
}
o = offset - e->start;
l = len;
if(l > e->len-o)
l = e->len-o;
k = kmap(p);
if(waserror()) {
kunmap(k);
putpage(p);
qunlock(m);
nexterror();
}
memmove(buf, (uchar*)VA(k) + o, l);
poperror();
kunmap(k);
putpage(p);
buf += l;
len -= l;
offset += l;
total += l;
t = &e->next;
e = e->next;
if(e == 0 || e->start != offset)
break;
}
qunlock(m);
return total;
}
