From 0d6a64fa06ce6aae729fa05a539eadd88fa59007 Mon Sep 17 00:00:00 2001
From: Mole Shang <135e2@135e2.dev>
Date: Wed, 17 Jan 2024 11:33:39 +0800
Subject: lab util: finish
---
user/primes.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 74 insertions(+)
create mode 100644 user/primes.c
(limited to 'user/primes.c')
diff --git a/user/primes.c b/user/primes.c
new file mode 100644
index 0000000..b359524
--- /dev/null
+++ b/user/primes.c
@@ -0,0 +1,74 @@
+#include "kernel/types.h"
+#include "user/user.h"
+
+#define MAX 36
+#define FIRST_PRIME 2
+
+int
+generate_natural(); // -> out_fd
+int
+prime_filter(int in_fd, int prime); // -> out_fd
+
+int
+main(int argc, char* argv[])
+{
+ int prime;
+
+ int in = generate_natural();
+ while (read(in, &prime, sizeof(int))) {
+ // printf("prime %d: in_fd: %d\n", prime, in); // debug
+ printf("prime %d\n", prime);
+ in = prime_filter(in, prime);
+ }
+
+ close(in);
+
+ exit(0);
+}
+
+int
+generate_natural()
+{
+ int out_pipe[2];
+
+ pipe(out_pipe);
+
+ if (!fork()) {
+ for (int i = FIRST_PRIME; i < MAX; i++) {
+ write(out_pipe[1], &i, sizeof(int));
+ }
+ close(out_pipe[1]);
+
+ exit(0);
+ }
+
+ close(out_pipe[1]);
+
+ return out_pipe[0];
+}
+
+int
+prime_filter(int in_fd, int prime)
+{
+ int num;
+ int out_pipe[2];
+
+ pipe(out_pipe);
+
+ if (!fork()) {
+ while (read(in_fd, &num, sizeof(int))) {
+ if (num % prime) {
+ write(out_pipe[1], &num, sizeof(int));
+ }
+ }
+ close(in_fd);
+ close(out_pipe[1]);
+
+ exit(0);
+ }
+
+ close(in_fd);
+ close(out_pipe[1]);
+
+ return out_pipe[0];
+}
--
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