Added dining_philosophers.c coroutine example.

Fixed cco_stop() when in state 0.
Renamed cco_timer_with(msec) => cco_timer_from(msec)
Renamed cco_sem_with(val) => cco_sem_from(val)

1 files changed, 99 insertions, 0 deletions

diff --git a/misc/examples/dining_philosophers.c b/misc/examples/dining_philosophers.c
new file mode 100644
index 00000000..0bf421c6
--- /dev/null
+++ b/misc/examples/dining_philosophers.c
@@ -0,0 +1,99 @@
+// https://en.wikipedia.org/wiki/Dining_philosophers_problem
+#include <stdio.h>
+#include <stc/crand.h>
+#include <stc/algo/coroutine.h>
+ 
+// Define the number of philosophers and forks
+enum {
+    num_philosophers = 5,
+    num_forks = num_philosophers,
+};
+
+struct Philosopher {
+    int id;
+    cco_timer tm;
+    cco_sem* left_fork;
+    cco_sem* right_fork;
+    int cco_state; // required
+};
+
+struct Dining {
+    // Define semaphores for the forks
+    cco_sem forks[num_forks];
+    struct Philosopher ph[num_philosophers];
+    int ph_idx;
+    int cco_state; // required
+};
+
+ 
+// Philosopher coroutine
+void philosopher(struct Philosopher* p)
+{
+    cco_routine(p) {
+        while (1) {
+            int duration = (int)(1000 + crand() % 2000); // 1-3 seconds
+            printf("Philosopher %d is thinking for %d minutes...\n", p->id, duration/100);
+            cco_timer_await(&p->tm, duration);
+
+            printf("Philosopher %d is hungry...\n", p->id);
+            cco_sem_await(p->left_fork);
+            cco_sem_await(p->right_fork);
+            
+            duration = (int)(500 + crand() % 1000);
+            printf("Philosopher %d is eating for %d minutes...\n", p->id, duration/100);
+            cco_timer_await(&p->tm, duration);
+            
+            cco_sem_release(p->left_fork);
+            cco_sem_release(p->right_fork);
+        }
+        
+        cco_final:
+        printf("Philosopher %d finished\n", p->id);
+    }
+}
+
+
+// Dining coroutine
+void dining(struct Dining* d)
+{
+    cco_routine(d) {
+        for (int i = 0; i < num_forks; ++i)
+            cco_sem_set(&d->forks[i], 1); // all forks available
+        for (int i = 0; i < num_philosophers; ++i) {
+            cco_reset(&d->ph[i]);
+            d->ph[i].id = i + 1;
+            d->ph[i].left_fork = &d->forks[i];
+            d->ph[i].right_fork = &d->forks[(i + 1) % num_forks];
+        }
+
+        while (1) {
+            for (d->ph_idx = 0; d->ph_idx < num_philosophers; ++d->ph_idx) {
+                philosopher(&d->ph[d->ph_idx]);
+                cco_yield();
+            }
+        }
+
+        cco_final:
+        for (int i = 0; i < num_philosophers; ++i) {
+            cco_stop(&d->ph[i]);
+            philosopher(&d->ph[i]);
+        }
+        puts("Dining finished");
+    }
+}
+
+
+int main()
+{
+    struct Dining dine;
+    cco_reset(&dine);
+    cco_timer tm = cco_timer_from(10000);
+    csrand((uint64_t)time(NULL));
+
+    while (!cco_done(&dine)) {
+        if (cco_timer_expired(&tm))
+            cco_stop(&dine);
+        dining(&dine);
+        cco_sleep(1);
+    }
+}