DTT/Misc/guess.d

#!/usr/sbin/dtrace -wqs
/*
 * guess.d - guessing game in D (DTrace)
 *
 * $Id: guess.d 32 2007-09-15 05:08:49Z brendan $
 *
 * USAGE: guess.d
 *
 * SEE: http://www.brendangregg.com/guessinggame.html
 *
 * This is written to demonstrate this language versus the same program
 * written in other languages.
 *
 * 11-May-2005  Brendan Gregg   Created this.
 */

inline string scorefile = "highscores_d";

dtrace:::BEGIN
{
    printf("guess.d - Guess a number between 1 and 100\n\n");
    num = 1;
    state = 1;

    /* Generate random number */
    answer = (rand() % 100) + 1;
    answer = answer > 0 ? answer : - answer;
}

syscall::write:entry
/state == 1 && pid == $pid/
{
    state = 2;
    printf("Enter guess %d: ", num);
    system("read guess");
    pos = 0;
}

syscall::read:entry
/state == 2 && ppid == $pid && arg0 == 3/
{
    self->inguess = 1;
    self->buf = arg1;
}

syscall::read:return
/self->inguess/
{
    key = copyin(self->buf, arg0);
    keys[pos] = *(char *)key;
    self->buf = 0;
    pos++;
}

syscall::read:return
/self->inguess && keys[pos-1] == '\n'/
{
    pos -= 2;
    fac = 1;
    guess = fac * (keys[pos] - '0');
    pos--;
    fac *= 10;
    guess = pos >= 0 ? guess + fac * (keys[pos] - '0') : guess;
    pos--;
    fac *= 10;
    guess = pos >= 0 ? guess + fac * (keys[pos] - '0') : guess;
    self->doneguess = 1;
}

syscall::read:return
/self->inguess/
{
    self->inguess = 0;
}

/* Play game */
syscall::read:return
/self->doneguess && guess == answer/
{
    printf("Correct! That took %d guesses.\n\n", num);
    self->doneguess = 0;
    state = 3;
    printf("Please enter your name: ");
    system("/usr/bin/read name");
}

syscall::read:return
/self->doneguess && guess != answer/
{
    num++;

    printf("%s...\n", guess < answer ? "Higher" : "Lower");

    printf("Enter guess %d: ", num);
    system("read line");
    pos = 0;
}

syscall::read:entry
/state == 3 && curthread->t_procp->p_parent->p_ppid == $pid && arg0 == 0/
{
    self->inname = 1;
    self->buf = arg1;
}

/* Save high score */
syscall::read:return
/self->inname/
{
    self->inname = 0;
    name = stringof(copyin(self->buf, arg0 - 1));
    system("echo %s %d >> %s", name, num, scorefile);

    /* Print high scores */
    printf("\nPrevious high scores,\n");
    system("cat %s", scorefile);
    exit(0);
}