mirror of https://github.com/0intro/conterm
43 lines
584 B
C
43 lines
584 B
C
#include "os.h"
|
|
#include <mp.h>
|
|
#include <libsec.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;
|
|
}
|