1*8ccd4a63SDavid du Colombier #include "os.h"
2*8ccd4a63SDavid du Colombier #include <mp.h>
3*8ccd4a63SDavid du Colombier #include "dat.h"
4*8ccd4a63SDavid du Colombier
5*8ccd4a63SDavid du Colombier // convert an mpint into a big endian byte array (most significant byte first)
6*8ccd4a63SDavid du Colombier // return number of bytes converted
7*8ccd4a63SDavid du Colombier // if p == nil, allocate and result array
8*8ccd4a63SDavid du Colombier int
mptobe(mpint * b,uchar * p,uint n,uchar ** pp)9*8ccd4a63SDavid du Colombier mptobe(mpint *b, uchar *p, uint n, uchar **pp)
10*8ccd4a63SDavid du Colombier {
11*8ccd4a63SDavid du Colombier int i, j, suppress;
12*8ccd4a63SDavid du Colombier mpdigit x;
13*8ccd4a63SDavid du Colombier uchar *e, *s, c;
14*8ccd4a63SDavid du Colombier
15*8ccd4a63SDavid du Colombier if(p == nil){
16*8ccd4a63SDavid du Colombier n = (b->top+1)*Dbytes;
17*8ccd4a63SDavid du Colombier p = malloc(n);
18*8ccd4a63SDavid du Colombier }
19*8ccd4a63SDavid du Colombier if(p == nil)
20*8ccd4a63SDavid du Colombier return -1;
21*8ccd4a63SDavid du Colombier if(pp != nil)
22*8ccd4a63SDavid du Colombier *pp = p;
23*8ccd4a63SDavid du Colombier memset(p, 0, n);
24*8ccd4a63SDavid du Colombier
25*8ccd4a63SDavid du Colombier // special case 0
26*8ccd4a63SDavid du Colombier if(b->top == 0){
27*8ccd4a63SDavid du Colombier if(n < 1)
28*8ccd4a63SDavid du Colombier return -1;
29*8ccd4a63SDavid du Colombier else
30*8ccd4a63SDavid du Colombier return 1;
31*8ccd4a63SDavid du Colombier }
32*8ccd4a63SDavid du Colombier
33*8ccd4a63SDavid du Colombier s = p;
34*8ccd4a63SDavid du Colombier e = s+n;
35*8ccd4a63SDavid du Colombier suppress = 1;
36*8ccd4a63SDavid du Colombier for(i = b->top-1; i >= 0; i--){
37*8ccd4a63SDavid du Colombier x = b->p[i];
38*8ccd4a63SDavid du Colombier for(j = Dbits-8; j >= 0; j -= 8){
39*8ccd4a63SDavid du Colombier c = x>>j;
40*8ccd4a63SDavid du Colombier if(c == 0 && suppress)
41*8ccd4a63SDavid du Colombier continue;
42*8ccd4a63SDavid du Colombier if(p >= e)
43*8ccd4a63SDavid du Colombier return -1;
44*8ccd4a63SDavid du Colombier *p++ = c;
45*8ccd4a63SDavid du Colombier suppress = 0;
46*8ccd4a63SDavid du Colombier }
47*8ccd4a63SDavid du Colombier }
48*8ccd4a63SDavid du Colombier
49*8ccd4a63SDavid du Colombier // guarantee at least one byte
50*8ccd4a63SDavid du Colombier if(s == p){
51*8ccd4a63SDavid du Colombier if(p >= e)
52*8ccd4a63SDavid du Colombier return -1;
53*8ccd4a63SDavid du Colombier *p++ = 0;
54*8ccd4a63SDavid du Colombier }
55*8ccd4a63SDavid du Colombier
56*8ccd4a63SDavid du Colombier return p - s;
57*8ccd4a63SDavid du Colombier }
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