libmisc

2 files changed, 91 insertions, 0 deletions

diff --git a/libmisc/include/libmisc/net.h b/libmisc/include/libmisc/net.h
new file mode 100644
index 0000000..bb5999b
--- /dev/null
+++ b/libmisc/include/libmisc/net.h
@@ -0,0 +1,64 @@
+/* libmisc/net.h - Base definitions for network interfaces
+ *
+ * Copyright (C) 2024  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-Licence-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _LIBMISC_NET_H_
+#define _LIBMISC_NET_H_
+
+#include <stdbool.h>   /* for bool */
+#include <stddef.h>    /* for size_t */
+#include <sys/types.h> /* for ssize_t */
+
+struct net_ip4_addr {
+	unsigned char   octets[4];
+};
+
+struct net_eth_addr {
+	unsigned char   octets[6];
+};
+
+struct net_conn;
+struct net_listener;
+
+struct net_listener_vtable {
+	/**
+	 * It is invalid to accept() a new connection if an existing
+	 * connection is still open.
+	 */
+	struct net_conn         *(*accept)(struct net_listener *self);
+};
+
+struct net_conn_vtable {
+	/**
+	 * Return bytes-read on success, 0 on EOF, -errno on error; a
+	 * short read is *not* an error.
+	 */
+	ssize_t                  (*read)(struct net_conn *self, void *buf, size_t count);
+
+	/**
+	 * Return `count` on success, -errno on error; a short write *is* an
+	 * error.
+	 *
+	 * Writes are *not* guaranteed to be atomic (as this would be
+	 * expensive to implement), so if you have concurrent writers then you
+	 * should arrange for a mutex to protect the connection.
+	 */
+	ssize_t                  (*write)(struct net_conn *self, void *buf, size_t count);
+
+	/**
+	 * Return 0 on success, -errno on error.
+	 */
+	int                      (*close)(struct net_conn *self, bool rd, bool wr);
+};
+
+typedef struct net_listener {
+	struct net_listener_vtable      *vtable;
+} implements_net_listener;
+
+typedef struct net_conn {
+	struct net_conn_vtable          *vtable;
+} implements_net_conn;
+
+#endif /* _LIBMISC_NET_H_ */
diff --git a/libmisc/include/libmisc/vcall.h b/libmisc/include/libmisc/vcall.h
new file mode 100644
index 0000000..c3562ee
--- /dev/null
+++ b/libmisc/include/libmisc/vcall.h
@@ -0,0 +1,27 @@
+/* libmisc/vcall.h - A simple Go-ish object system built on GCC -fplan9-extensions
+ *
+ * Copyright (C) 2024  Luke T. Shumaker <lukeshu@lukeshu.com>
+ * SPDX-Licence-Identifier: AGPL-3.0-or-later
+ */
+
+#ifndef _LIBMISC_VCALL_H_
+#define _LIBMISC_VCALL_H_
+
+#include <assert.h> /* for assert() and static_assert() */
+#include <stddef.h> /* for offsetof() */
+
+#define VCALL(o, m, ...)                                     \
+	({                                                   \
+		assert(o);                                   \
+		(o)->vtable->m(o __VA_OPT__(,) __VA_ARGS__); \
+	})
+
+#define VCALL_SELF(obj_typ, iface_typ, iface_ptr)                              \
+	({                                                                     \
+		static_assert(_Generic(iface_ptr, iface_typ *: 1, default: 0), \
+		              "typeof("#iface_ptr") != "#iface_typ);           \
+		assert(iface_ptr);                                             \
+		((obj_typ*)(((void*)iface_ptr)-offsetof(obj_typ,iface_typ)));  \
+	})
+
+#endif /* _LIBMISC_VCALL_H_ */