blob: 95a01ccbf082a38d27d72d92513f4a033f97d84a [file] [log] [blame]
#include "os.h"
#include <mp.h>
#include "dat.h"
mpint*
mprand(int bits, void (*gen)(uchar*, int), mpint *b)
{
int n, m;
mpdigit mask;
uchar *p;
n = DIGITS(bits);
if(b == nil)
b = mpnew(bits);
else
mpbits(b, bits);
p = malloc(n*Dbytes);
if(p == nil)
return nil;
(*gen)(p, n*Dbytes);
betomp(p, n*Dbytes, b);
free(p);
/* make sure we don't give too many bits */
m = bits%Dbits;
n--;
if(m > 0){
mask = 1;
mask <<= m;
mask--;
b->p[n] &= mask;
}
for(; n >= 0; n--)
if(b->p[n] != 0)
break;
b->top = n+1;
b->sign = 1;
return b;
}