int
BigTochar (Big &x, char *c, int s)
{
int len = 0;
int totlen = sizeof (int);
// format: 4 bytes length, followed by the big
if (s <= sizeof (int))
return -1;
// Code assumes epoint contains either nulls or bigs > 0
s -= sizeof (int);
c += sizeof (int);
if (x.iszero()) {
len = 0;
} else {
len = to_binary (x, s, c, FALSE);
}
if (len < 0)
return -1;
memcpy ((char *)(c - sizeof(int)), (void *)&len, sizeof (int));
totlen += len;
s -= len;
c += len;
// cout << "Len1 " << len << " x " << x;
return totlen;
}
GF2m4x pow(const GF2m4x& a,const Big& k)
{
int i,j,nb,n,nbw,nzs;
GF2m4x u,u2,t[16];
if (k.iszero()) return (GF2m4x)1;
u=a;
if (k.isone()) return u;
//
// Prepare table for windowing
//
u2=(u*u);
t[0]=u;
for (i=1;i<16;i++)
t[i]=u2*t[i-1];
// Left to right method - with windows
nb=bits(k);
if (nb>1) for (i=nb-2;i>=0;)
{
n=window(k,i,&nbw,&nzs,5);
for (j=0;j<nbw;j++) u*=u;
if (n>0) u*=t[n/2];
i-=nbw;
if (nzs)
{
for (j=0;j<nzs;j++) u*=u;
i-=nzs;
}
}
return u;
}
ostream& operator<<(ostream& s,const Ps_Big& p)
{
BOOL first=TRUE;
Big a;
term_ps_big *ptr=p.start;
int pw;
if (ptr==NULL)
{
s << "0";
return s;
}
while (ptr!=NULL)
{
a=ptr->an;
if (a.iszero())
{
ptr=ptr->next;
continue;
}
if (a < (Big)0)
{
a=(-a);
s << " - ";
}
else if (!first) s << " + ";
first=FALSE;
pw=ptr->n*p.pwr-p.offset;
if (pw==0)
{
s << a;
ptr=ptr->next;
continue;
}
if (a==1) s << "x";
else s << a << "*x";
if (pw!=1) s << "^" << pw;
ptr=ptr->next;
}
return s;
}
ZZn2 powu(const ZZn2& x,const Big& e)
{
int i,j,nb,n,nbw,nzs;
ZZn2 u,u2,t[11];
Big k,k3;
if (e.iszero()) return (ZZn2)one();
k=e;
if (e<0) k=-k;
u=x;
if (k.isone())
{
if (e<0) u=conj(u);
return u;
}
//
// Prepare table for windowing
//
k3=3*k;
u2=(u*u);
t[0]=u;
for (i=1;i<=10;i++)
t[i]=u2*t[i-1];
nb=bits(k3);
for (i=nb-2;i>=1;)
{
n=naf_window(k,k3,i,&nbw,&nzs,11);
for (j=0;j<nbw;j++) u*=u;
if (n>0) u*=t[n/2];
if (n<0) u*=conj(t[(-n)/2]);
i-=nbw;
if (nzs)
{
for (j=0;j<nzs;j++) u*=u;
i-=nzs;
}
}
if (e<0) u=conj(u);
return u;
}
Ps_Big operator*(Ps_Big& a,Ps_Big& b)
{
Ps_Big prod;
Big t;
term_ps_big *aptr,*bptr,*pos;
int ka,kb,i,pa,pb,d,deg,g;
if (a.IsInt())
{
if (a.start==NULL) return prod;
else return (a.start->an*b);
}
if (b.IsInt())
{
if (b.start==NULL) return prod;
else return (b.start->an*a);
}
g=igcd(a.pwr,b.pwr);
deg=psN/g;
#ifdef FFT
if (deg>=FFT_BREAK_EVEN)
{ // use fast methods
big *A,*B,*C;
A=(big *)mr_alloc(deg,sizeof(big));
B=(big *)mr_alloc(deg,sizeof(big));
C=(big *)mr_alloc(deg,sizeof(big));
char *memc=(char *)memalloc(deg);
for (i=0;i<deg;i++) C[i]=mirvar_mem(memc,i);
ka=a.pwr/g;
a.decompress(ka);
aptr=a.start;
while (aptr!=NULL)
{
d=aptr->n;
if (d >= deg) break;
A[d]=(aptr->an).getbig();
aptr=aptr->next;
}
kb=b.pwr/g;
b.decompress(kb);
bptr=b.start;
while (bptr!=NULL)
{
d=bptr->n;
if (d >= deg) break;
B[d]=(bptr->an).getbig();
bptr=bptr->next;
}
mr_ps_big_mul(deg,A,B,C);
pos=NULL;
for (d=0;d<deg;d++)
{
t=C[d];
if (t.iszero()) continue;
pos=prod.addterm(t,d*g,pos);
}
memkill(memc,deg);
a.compress(ka); b.compress(kb);
mr_free(C); mr_free(B); mr_free(A);
}
else
{
#endif
bptr=b.start;
while (bptr!=NULL)
{
aptr=a.start;
pb=bptr->n*b.pwr-b.offset;
pos=NULL;
while (aptr!=NULL)
{
pa=aptr->n*a.pwr-a.offset;
if (pb+pa>=psN) break;
pos=prod.addterm(aptr->an*bptr->an,pa+pb,pos);
aptr=aptr->next;
}
bptr=bptr->next;
}
#ifdef FFT
}
#endif
if (prod.start!=NULL) prod.offset=a.offset+b.offset;
return prod;
}
