1 static char rcsid[] = "$Id: H:/drh/idioms/book/RCS/thread.doc,v 1.11 1997/02/21 19:50:51 drh Exp $";
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include "assert.h"
5 #include "fmt.h"
6 #include "thread.h"
7 #include "chan.h"
8 struct args {
9 Chan_T c;
10 int n, last;
11 };
source(void * cl)12 int source(void *cl) {
13 struct args *p = cl;
14 int i = 2;
15 if (Chan_send(p->c, &i, sizeof i))
16 for (i = 3; Chan_send(p->c, &i, sizeof i); )
17 i += 2;
18 return EXIT_SUCCESS;
19 }
filter(int primes[],Chan_T input,Chan_T output)20 void filter(int primes[], Chan_T input, Chan_T output) {
21 int j, x;
22 for (;;) {
23 Chan_receive(input, &x, sizeof x);
24 for (j = 0; primes[j] != 0 && x%primes[j] != 0; j++)
25 ;
26 if (primes[j] == 0)
27 if (Chan_send(output, &x, sizeof x) == 0)
28 break;
29 }
30 Chan_receive(input, &x, 0);
31 }
sink(void * cl)32 int sink(void *cl) {
33 struct args *p = cl;
34 Chan_T input = p->c;
35 int i = 0, j, x, primes[256];
36 primes[0] = 0;
37 for (;;) {
38 Chan_receive(input, &x, sizeof x);
39 for (j = 0; primes[j] != 0 && x%primes[j] != 0; j++)
40 ;
41 if (primes[j] == 0) {
42 if (x > p->last)
43 break;
44 Fmt_print(" %d", x);
45 primes[i++] = x;
46 primes[i] = 0;
47 if (i == p->n)
48 {
49 p->c = Chan_new();
50 Thread_new(sink, p, sizeof *p, NULL);
51 filter(primes, input, p->c);
52 return EXIT_SUCCESS;
53 }
54 }
55 }
56 Fmt_print("\n");
57 Chan_receive(input, &x, 0);
58 return EXIT_SUCCESS;
59 }
main(int argc,char * argv[])60 int main(int argc, char *argv[]) {
61 struct args args;
62 Thread_init(1, NULL);
63 args.c = Chan_new();
64 Thread_new(source, &args, sizeof args, NULL);
65 args.n = argc > 2 ? atoi(argv[2]) : 5;
66 args.last = argc > 1 ? atoi(argv[1]) : 1000;
67 Thread_new(sink, &args, sizeof args, NULL);
68 Thread_exit(EXIT_SUCCESS);
69 return EXIT_SUCCESS;
70 }
71