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guess.d revision 1.1.1.1 
      1 #!/usr/sbin/dtrace -wqs
      2 /*
      3  * guess.d - guessing game in D (DTrace)
      4  *
      5  * $Id: guess.d,v 1.1.1.1 2015/09/30 22:01:07 christos Exp $
      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 
     17 inline string scorefile = "highscores_d";
     18 
     19 dtrace:::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 
     30 syscall::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 
     39 syscall::read:entry
     40 /state == 2 && ppid == $pid && arg0 == 3/
     41 {
     42 	self->inguess = 1;
     43 	self->buf = arg1;
     44 }
     45 
     46 syscall::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 
     55 syscall::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 
     70 syscall::read:return
     71 /self->inguess/
     72 {
     73 	self->inguess = 0;
     74 }
     75 
     76 /* Play game */
     77 syscall::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 
     87 syscall::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 
     99 syscall::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 */
    107 syscall::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