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 cbeb0b26 2006-04-01 devnull /* convert an mpint into a big endian byte array (most significant byte first) */
 6 cbeb0b26 2006-04-01 devnull /*   return number of bytes converted */
 7 cbeb0b26 2006-04-01 devnull /*   if p == nil, allocate and result array */
 8 b3f61791 2004-03-21 devnull int
 9 b3f61791 2004-03-21 devnull mptobe(mpint *b, uchar *p, uint n, uchar **pp)
10 b3f61791 2004-03-21 devnull {
11 b3f61791 2004-03-21 devnull 	int i, j, suppress;
12 b3f61791 2004-03-21 devnull 	mpdigit x;
13 b3f61791 2004-03-21 devnull 	uchar *e, *s, c;
14 b3f61791 2004-03-21 devnull 
15 b3f61791 2004-03-21 devnull 	if(p == nil){
16 b3f61791 2004-03-21 devnull 		n = (b->top+1)*Dbytes;
17 b3f61791 2004-03-21 devnull 		p = malloc(n);
18 b3f61791 2004-03-21 devnull 	}
19 b3f61791 2004-03-21 devnull 	if(p == nil)
20 b3f61791 2004-03-21 devnull 		return -1;
21 b3f61791 2004-03-21 devnull 	if(pp != nil)
22 b3f61791 2004-03-21 devnull 		*pp = p;
23 b3f61791 2004-03-21 devnull 	memset(p, 0, n);
24 b3f61791 2004-03-21 devnull 
25 cbeb0b26 2006-04-01 devnull 	/* special case 0 */
26 b3f61791 2004-03-21 devnull 	if(b->top == 0){
27 b3f61791 2004-03-21 devnull 		if(n < 1)
28 b3f61791 2004-03-21 devnull 			return -1;
29 b3f61791 2004-03-21 devnull 		else
30 b3f61791 2004-03-21 devnull 			return 1;
31 b3f61791 2004-03-21 devnull 	}
32 fa325e9b 2020-01-10 cross 
33 b3f61791 2004-03-21 devnull 	s = p;
34 b3f61791 2004-03-21 devnull 	e = s+n;
35 b3f61791 2004-03-21 devnull 	suppress = 1;
36 b3f61791 2004-03-21 devnull 	for(i = b->top-1; i >= 0; i--){
37 b3f61791 2004-03-21 devnull 		x = b->p[i];
38 b3f61791 2004-03-21 devnull 		for(j = Dbits-8; j >= 0; j -= 8){
39 b3f61791 2004-03-21 devnull 			c = x>>j;
40 b3f61791 2004-03-21 devnull 			if(c == 0 && suppress)
41 b3f61791 2004-03-21 devnull 				continue;
42 b3f61791 2004-03-21 devnull 			if(p >= e)
43 b3f61791 2004-03-21 devnull 				return -1;
44 b3f61791 2004-03-21 devnull 			*p++ = c;
45 b3f61791 2004-03-21 devnull 			suppress = 0;
46 b3f61791 2004-03-21 devnull 		}
47 b3f61791 2004-03-21 devnull 	}
48 b3f61791 2004-03-21 devnull 
49 cbeb0b26 2006-04-01 devnull 	/* guarantee at least one byte */
50 b3f61791 2004-03-21 devnull 	if(s == p){
51 b3f61791 2004-03-21 devnull 		if(p >= e)
52 b3f61791 2004-03-21 devnull 			return -1;
53 b3f61791 2004-03-21 devnull 		*p++ = 0;
54 b3f61791 2004-03-21 devnull 	}
55 b3f61791 2004-03-21 devnull 
56 b3f61791 2004-03-21 devnull 	return p - s;
57 b3f61791 2004-03-21 devnull }