1 b3f61791 2004-03-21 devnull #include "os.h"
 2 b3f61791 2004-03-21 devnull #include <mp.h>
 3 b3f61791 2004-03-21 devnull #include "dat.h"
 4 b3f61791 2004-03-21 devnull 
 5 b3f61791 2004-03-21 devnull mpint*
 6 b3f61791 2004-03-21 devnull mprand(int bits, void (*gen)(uchar*, int), mpint *b)
 7 b3f61791 2004-03-21 devnull {
 8 b3f61791 2004-03-21 devnull 	int n, m;
 9 b3f61791 2004-03-21 devnull 	mpdigit mask;
10 b3f61791 2004-03-21 devnull 	uchar *p;
11 b3f61791 2004-03-21 devnull 
12 b3f61791 2004-03-21 devnull 	n = DIGITS(bits);
13 b3f61791 2004-03-21 devnull 	if(b == nil)
14 b3f61791 2004-03-21 devnull 		b = mpnew(bits);
15 b3f61791 2004-03-21 devnull 	else
16 b3f61791 2004-03-21 devnull 		mpbits(b, bits);
17 b3f61791 2004-03-21 devnull 
18 b3f61791 2004-03-21 devnull 	p = malloc(n*Dbytes);
19 b3f61791 2004-03-21 devnull 	if(p == nil)
20 b3f61791 2004-03-21 devnull 		return nil;
21 b3f61791 2004-03-21 devnull 	(*gen)(p, n*Dbytes);
22 b3f61791 2004-03-21 devnull 	betomp(p, n*Dbytes, b);
23 b3f61791 2004-03-21 devnull 	free(p);
24 b3f61791 2004-03-21 devnull 
25 cbeb0b26 2006-04-01 devnull 	/* make sure we don't give too many bits */
26 b3f61791 2004-03-21 devnull 	m = bits%Dbits;
27 b3f61791 2004-03-21 devnull 	n--;
28 b3f61791 2004-03-21 devnull 	if(m > 0){
29 b3f61791 2004-03-21 devnull 		mask = 1;
30 b3f61791 2004-03-21 devnull 		mask <<= m;
31 b3f61791 2004-03-21 devnull 		mask--;
32 b3f61791 2004-03-21 devnull 		b->p[n] &= mask;
33 b3f61791 2004-03-21 devnull 	}
34 b3f61791 2004-03-21 devnull 
35 b3f61791 2004-03-21 devnull 	for(; n >= 0; n--)
36 b3f61791 2004-03-21 devnull 		if(b->p[n] != 0)
37 b3f61791 2004-03-21 devnull 			break;
38 b3f61791 2004-03-21 devnull 	b->top = n+1;
39 b3f61791 2004-03-21 devnull 	b->sign = 1;
40 b3f61791 2004-03-21 devnull 	return b;
41 b3f61791 2004-03-21 devnull }