1#!/usr/sbin/dtrace -wqs
2/*
3 * guess.d - guessing game in D (DTrace)
4 *
5 * $Id: guess.d 32 2007-09-15 05:08:49Z brendan $
6 *
7 * USAGE: guess.d
8 *
9 * SEE: http://www.brendangregg.com/guessinggame.html
10 *
11 * This is written to demonstrate this language versus the same program
12 * written in other languages.
13 *
14 * 11-May-2005	Brendan Gregg	Created this.
15 */
16
17inline string scorefile = "highscores_d";
18
19dtrace:::BEGIN
20{
21	printf("guess.d - Guess a number between 1 and 100\n\n");
22	num = 1;
23	state = 1;
24
25	/* Generate random number */
26	answer = (rand() % 100) + 1;
27	answer = answer > 0 ? answer : - answer;
28}
29
30syscall::write:entry
31/state == 1 && pid == $pid/
32{
33	state = 2;
34	printf("Enter guess %d: ", num);
35	system("read guess");
36	pos = 0;
37}
38
39syscall::read:entry
40/state == 2 && ppid == $pid && arg0 == 3/
41{
42	self->inguess = 1;
43	self->buf = arg1;
44}
45
46syscall::read:return
47/self->inguess/
48{
49	key = copyin(self->buf, arg0);
50	keys[pos] = *(char *)key;
51	self->buf = 0;
52	pos++;
53}
54
55syscall::read:return
56/self->inguess && keys[pos-1] == '\n'/
57{
58	pos -= 2;
59	fac = 1;
60	guess = fac * (keys[pos] - '0');
61	pos--;
62	fac *= 10;
63	guess = pos >= 0 ? guess + fac * (keys[pos] - '0') : guess;
64	pos--;
65	fac *= 10;
66	guess = pos >= 0 ? guess + fac * (keys[pos] - '0') : guess;
67	self->doneguess = 1;
68}
69
70syscall::read:return
71/self->inguess/
72{
73	self->inguess = 0;
74}
75
76/* Play game */
77syscall::read:return
78/self->doneguess && guess == answer/
79{
80	printf("Correct! That took %d guesses.\n\n", num);
81	self->doneguess = 0;
82	state = 3;
83	printf("Please enter your name: ");
84	system("/usr/bin/read name");
85}
86
87syscall::read:return
88/self->doneguess && guess != answer/
89{
90	num++;
91
92	printf("%s...\n", guess < answer ? "Higher" : "Lower");
93
94	printf("Enter guess %d: ", num);
95	system("read line");
96	pos = 0;
97}
98
99syscall::read:entry
100/state == 3 && curthread->t_procp->p_parent->p_ppid == $pid && arg0 == 0/
101{
102	self->inname = 1;
103	self->buf = arg1;
104}
105
106/* Save high score */
107syscall::read:return
108/self->inname/
109{
110	self->inname = 0;
111	name = stringof(copyin(self->buf, arg0 - 1));
112	system("echo %s %d >> %s", name, num, scorefile);
113
114	/* Print high scores */
115	printf("\nPrevious high scores,\n");
116	system("cat %s", scorefile);
117	exit(0);
118}
119