1 files changed, 59 insertions, 0 deletions
diff --git a/core/include/mbox.h b/core/include/mbox.h
new file mode 100644
index 00000000..3c35ce4e
--- /dev/null
+++ b/core/include/mbox.h
@@ -0,0 +1,59 @@
+/*
+ * mbox.h
+ *
+ * Simple thread mailbox interface
+ */
+
+#ifndef _MBOX_H
+#define _MBOX_H
+
+#include "thread.h"
+
+/*
+ * If a mailbox is allocated statically (as a struct mailbox), this
+ * is the number of slots it gets.
+ */
+#define MAILBOX_STATIC_SIZE	512
+
+struct mailbox {
+    struct semaphore prod_sem;	/* Producer semaphore (empty slots) */
+    struct semaphore cons_sem;	/* Consumer semaphore (data slots) */
+    struct semaphore head_sem;	/* Head pointer semaphore */
+    struct semaphore tail_sem;	/* Tail pointer semaphore */
+    void **wrap;		/* Where pointers wrap */
+    void **head;		/* Head pointer */
+    void **tail;		/* Tail pointer */
+
+    void *data[MAILBOX_STATIC_SIZE]; /* Data array */
+};
+
+/* The number of bytes for an mailbox of size s */
+#define MBOX_BYTES(s) (sizeof(struct mailbox) + \
+		       ((s)-MAILBOX_STATIC_SIZE)*sizeof(void *))
+
+void mbox_init(struct mailbox *mbox, size_t size);
+int mbox_post(struct mailbox *mbox, void *msg, mstime_t timeout);
+mstime_t mbox_fetch(struct mailbox *mbox, void **msg, mstime_t timeout);
+
+/*
+ * This marks a mailbox object as unusable; it will remain unusable
+ * until sem_init() is called on it again.  This DOES NOT clear the
+ * list of blocked processes on this mailbox!
+ *
+ * It is also possible to mark the mailbox invalid by zeroing its
+ * memory structure.
+ */
+static inline void mbox_set_invalid(struct mailbox *mbox)
+{
+    sem_set_invalid(&mbox->prod_sem);
+}
+
+/*
+ * Ask if a mailbox object has been initialized.
+ */
+static inline bool mbox_is_valid(struct mailbox *mbox)
+{
+    return sem_is_valid(&mbox->prod_sem);
+}
+
+#endif /* _MBOX_H */