xref: /inferno-os/appl/lib/random.b (revision 37da2899f40661e3e9631e497da8dc59b971cbd0)
1*37da2899SCharles.Forsythimplement Random;
2*37da2899SCharles.Forsyth
3*37da2899SCharles.Forsythinclude "sys.m";
4*37da2899SCharles.Forsythinclude "draw.m";
5*37da2899SCharles.Forsythinclude "keyring.m";
6*37da2899SCharles.Forsythinclude "security.m";
7*37da2899SCharles.Forsyth
8*37da2899SCharles.Forsythsys: Sys;
9*37da2899SCharles.Forsyth
10*37da2899SCharles.Forsythrandfd(which: int): ref sys->FD
11*37da2899SCharles.Forsyth{
12*37da2899SCharles.Forsyth	file: string;
13*37da2899SCharles.Forsyth
14*37da2899SCharles.Forsyth	sys = load Sys Sys->PATH;
15*37da2899SCharles.Forsyth	case(which){
16*37da2899SCharles.Forsyth	ReallyRandom =>
17*37da2899SCharles.Forsyth		file = "/dev/random";
18*37da2899SCharles.Forsyth	NotQuiteRandom =>
19*37da2899SCharles.Forsyth		file = "/dev/notquiterandom";
20*37da2899SCharles.Forsyth	}
21*37da2899SCharles.Forsyth	fd := sys->open(file, sys->OREAD);
22*37da2899SCharles.Forsyth	if(fd == nil){
23*37da2899SCharles.Forsyth		sys->print("can't open /dev/random\n");
24*37da2899SCharles.Forsyth		return nil;
25*37da2899SCharles.Forsyth	}
26*37da2899SCharles.Forsyth	return fd;
27*37da2899SCharles.Forsyth}
28*37da2899SCharles.Forsyth
29*37da2899SCharles.Forsythrandomint(which: int): int
30*37da2899SCharles.Forsyth{
31*37da2899SCharles.Forsyth	fd := randfd(which);
32*37da2899SCharles.Forsyth	if(fd == nil)
33*37da2899SCharles.Forsyth		return 0;
34*37da2899SCharles.Forsyth	buf := array[4] of byte;
35*37da2899SCharles.Forsyth	sys->read(fd, buf, 4);
36*37da2899SCharles.Forsyth	rand := 0;
37*37da2899SCharles.Forsyth	for(i := 0; i < 4; i++)
38*37da2899SCharles.Forsyth		rand = (rand<<8) | int buf[i];
39*37da2899SCharles.Forsyth	return rand;
40*37da2899SCharles.Forsyth}
41*37da2899SCharles.Forsyth
42*37da2899SCharles.Forsythrandombuf(which, n: int): array of byte
43*37da2899SCharles.Forsyth{
44*37da2899SCharles.Forsyth	buf := array[n] of byte;
45*37da2899SCharles.Forsyth	fd := randfd(which);
46*37da2899SCharles.Forsyth	if(fd == nil)
47*37da2899SCharles.Forsyth		return buf;
48*37da2899SCharles.Forsyth	sys->read(fd, buf, n);
49*37da2899SCharles.Forsyth	return buf;
50*37da2899SCharles.Forsyth}
51