--- libelwix/src/ring.c	2026/02/11 13:36:09	1.6
+++ libelwix/src/ring.c	2026/02/18 11:41:47	1.8
@@ -3,7 +3,7 @@
 *  by Michael Pounov <misho@elwix.org>
 *
 * $Author: misho $
-* $Id: ring.c,v 1.6 2026/02/11 13:36:09 misho Exp $
+* $Id: ring.c,v 1.8 2026/02/18 11:41:47 misho Exp $
 *
 **************************************************************************
 The ELWIX and AITNET software is distributed under the following
@@ -61,6 +61,7 @@ rbuf_init(ringbuf_t *rbuf, int num)
 
 	atomic_store_explicit((atomic_int*) &rbuf->rb_head, 0, memory_order_relaxed);
 	atomic_store_explicit((atomic_int*) &rbuf->rb_tail, 0, memory_order_relaxed);
+	atomic_store_explicit((atomic_int*) &rbuf->rb_full, 0, memory_order_relaxed);
 
 	rbuf->rb_buffer = e_calloc(num, sizeof(struct iovec));
 	if (!rbuf->rb_buffer)
@@ -92,6 +93,7 @@ rbuf_free(ringbuf_t *rbuf)
 
 	atomic_store_explicit((atomic_int*) &rbuf->rb_head, 0, memory_order_relaxed);
 	atomic_store_explicit((atomic_int*) &rbuf->rb_tail, 0, memory_order_relaxed);
+	atomic_store_explicit((atomic_int*) &rbuf->rb_full, 0, memory_order_relaxed);
 }
 
 /*
@@ -111,6 +113,7 @@ rbuf_purge(ringbuf_t *rbuf)
 
 	atomic_store_explicit((atomic_int*) &rbuf->rb_head, 0, memory_order_relaxed);
 	atomic_store_explicit((atomic_int*) &rbuf->rb_tail, 0, memory_order_relaxed);
+	atomic_store_explicit((atomic_int*) &rbuf->rb_full, 0, memory_order_relaxed);
 }
 
 /*
@@ -122,11 +125,14 @@ rbuf_purge(ringbuf_t *rbuf)
 int
 rbuf_isempty(ringbuf_t *rbuf)
 {
-	if (!rbuf)
+	if (!rbuf || !rbuf->rb_bufnum)
 		return -1;
 
+	if (atomic_load_explicit((atomic_int*) &rbuf->rb_full, memory_order_acquire))
+		return 0;
+
 	return (atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_acquire) ==
-		atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire));
+			atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire));
 }
 
 /*
@@ -140,16 +146,14 @@ rbuf_isfull(ringbuf_t *rbuf)
 {
 	int h, t;
 
-	if (!rbuf)
+	if (!rbuf || !rbuf->rb_bufnum)
 		return -1;
-	if (!rbuf->rb_bufnum)
-		return 1;
 
-	t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
-	h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_relaxed) + 1;
-	if (h >= rbuf->rb_bufnum)
-		h ^= h;
+	if (!atomic_load_explicit((atomic_int*) &rbuf->rb_full, memory_order_acquire))
+		return 0;
 
+	t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
+	h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_acquire);
 	return (h == t);
 }
 
@@ -159,31 +163,49 @@ rbuf_isfull(ringbuf_t *rbuf)
  * @rbuf = Ring buffer
  * @data = Data
  * @len = Length
+ * @lost = Permit to lost data
  * return: -1 error, 1 buffer is full or 0 ok
  */
 int
-rbuf_enqueue(ringbuf_t *rbuf, void *data, size_t len)
+rbuf_enqueue(ringbuf_t *rbuf, void *data, size_t len, int lost)
 {
-	int h, t, n;
+	int h, t, f, n, t2, drop = 0;
 	struct iovec *iov;
 
-	if (!rbuf || !rbuf->rb_buffer)
+	if (!rbuf || !rbuf->rb_buffer || !rbuf->rb_bufnum)
 		return -1;
-	if (!rbuf->rb_bufnum)
-		return 1;
 
-	h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_relaxed);
+	f = atomic_load_explicit((atomic_int*) &rbuf->rb_full, memory_order_acquire);
 	t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
-	n = (h + 1) % rbuf->rb_bufnum;
+	h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_acquire);
 
-	if (n == t)
-		return 1;
+	if (f && h == t) {
+		if (!lost)
+			return 1;
+		else
+			drop = 1;
+	}
 
+	n = (h + 1) % rbuf->rb_bufnum;
+
 	iov = rbuf->rb_buffer + h;
 	iov->iov_len = len;
 	iov->iov_base = data;
 
 	atomic_store_explicit((atomic_int*) &rbuf->rb_head, n, memory_order_release);
+	if (drop) {
+		t2 = (t + 1) % rbuf->rb_bufnum;
+		while (42) {
+			drop = t;
+			if (atomic_compare_exchange_weak_explicit((atomic_int*) &rbuf->rb_tail,
+						&drop, t2, memory_order_release, memory_order_relaxed))
+				break;
+			t = drop;
+			t2 = (t + 1) % rbuf->rb_bufnum;
+		}
+	} else
+		t2 = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
+	atomic_store_explicit((atomic_int*) &rbuf->rb_full, (n == t2), memory_order_release);
 	return 0;
 }
 
@@ -197,24 +219,32 @@ rbuf_enqueue(ringbuf_t *rbuf, void *data, size_t len)
 int
 rbuf_dequeue(ringbuf_t *rbuf, struct iovec **out)
 {
-	int h, t, n;
+	int h, t, n, f;
 
-	if (!rbuf || !rbuf->rb_buffer)
+	if (!rbuf || !rbuf->rb_buffer || !rbuf->rb_bufnum)
 		return -1;
-	if (!rbuf->rb_bufnum)
-		return 1;
 
-	h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_acquire);
-	t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_relaxed);
-	n = (t + 1) % rbuf->rb_bufnum;
+	while (42) {
+		h = atomic_load_explicit((atomic_int*) &rbuf->rb_head, memory_order_acquire);
+		f = atomic_load_explicit((atomic_int*) &rbuf->rb_full, memory_order_acquire);
+		t = atomic_load_explicit((atomic_int*) &rbuf->rb_tail, memory_order_acquire);
 
-	if (h == t)
-		return 1;
+		if (!f && h == t)
+			return 1;
 
-	if (out)
-		*out = rbuf->rb_buffer + t;
+		n = (t + 1) % rbuf->rb_bufnum;
 
-	atomic_store_explicit((atomic_int*) &rbuf->rb_tail, n, memory_order_release);
+		f = t;
+		if (atomic_compare_exchange_weak_explicit((atomic_int*) &rbuf->rb_tail,
+					&f, n, memory_order_release, memory_order_relaxed)) {
+			if (out)
+				*out = rbuf->rb_buffer + t;
+
+			atomic_store_explicit((atomic_int*) &rbuf->rb_full, 0, memory_order_release);
+			break;
+		}
+	}
+
 	return 0;
 }
 
@@ -234,6 +264,7 @@ lrb_init(lrbuf_t *lrb, u_int size)
 
 	atomic_store_explicit((atomic_int*) &lrb->lrb_head, 0, memory_order_relaxed);
 	atomic_store_explicit((atomic_int*) &lrb->lrb_tail, 0, memory_order_relaxed);
+	atomic_store_explicit((atomic_int*) &lrb->lrb_full, 0, memory_order_relaxed);
 
 	lrb->lrb_data = e_malloc(size);
 	if (!lrb->lrb_data)
@@ -265,6 +296,7 @@ lrb_free(lrbuf_t *lrb)
 
 	atomic_store_explicit((atomic_int*) &lrb->lrb_head, 0, memory_order_relaxed);
 	atomic_store_explicit((atomic_int*) &lrb->lrb_tail, 0, memory_order_relaxed);
+	atomic_store_explicit((atomic_int*) &lrb->lrb_full, 0, memory_order_relaxed);
 }
 
 /*
@@ -296,12 +328,14 @@ lrb_purge(lrbuf_t *lrb)
 int
 lrb_isempty(lrbuf_t *lrb)
 {
-	if (!lrb)
+	if (!lrb || !lrb->lrb_size)
 		return -1;
 
-	return (!atomic_load_explicit((atomic_int*) &lrb->lrb_full, memory_order_acquire) &&
-			(atomic_load_explicit((atomic_int*) &lrb->lrb_head, memory_order_acquire) ==
-			atomic_load_explicit((atomic_int*) &lrb->lrb_tail, memory_order_acquire)));
+	if (atomic_load_explicit((atomic_int*) &lrb->lrb_full, memory_order_acquire))
+		return 0;
+
+	return (atomic_load_explicit((atomic_int*) &lrb->lrb_head, memory_order_acquire) ==
+			atomic_load_explicit((atomic_int*) &lrb->lrb_tail, memory_order_acquire));
 }
 
 /*
@@ -315,10 +349,8 @@ lrb_isfull(lrbuf_t *lrb)
 {
 	int h, t;
 
-	if (!lrb)
+	if (!lrb || !lrb->lrb_size)
 		return -1;
-	if (!lrb->lrb_size)
-		return 1;
 
 	if (!atomic_load_explicit((atomic_int*) &lrb->lrb_full, memory_order_acquire))
 		return 0;
@@ -366,9 +398,9 @@ lrb_enqueue(lrbuf_t *lrb, void *data, size_t len, int 
 {
 	int h, t = 0, n, t2 = 0, unused, drop = 0;
 
-	if (!lrb || !lrb->lrb_data)
+	if (!lrb || !lrb->lrb_data || !lrb->lrb_size)
 		return -1;
-	if (!lrb->lrb_size || lrb->lrb_size <= len)
+	if (lrb->lrb_size <= len)
 		return 1;
 
 	lrb_unused(lrb, unused);
@@ -453,9 +485,9 @@ lrb_dequeue(lrbuf_t *lrb, void *data, size_t len)
 {
 	int h, t, t2, n, l, f;
 
-	if (!lrb)
+	if (!lrb || !lrb->lrb_size)
 		return -1;
-	if (!lrb->lrb_size || !len || lrb_isempty(lrb))
+	if (!len || lrb_isempty(lrb))
 		return 0;
 	if (lrb->lrb_size <= len)
 		len = lrb->lrb_size - 1;
@@ -484,7 +516,7 @@ lrb_dequeue(lrbuf_t *lrb, void *data, size_t len)
 		} else {
 			if (data) {
 				memcpy(data, lrb->lrb_data + t, n);
-				memcpy(data + n, lrb->lrb_data, l - n);
+				memcpy(((u_char*) data) + n, lrb->lrb_data, l - n);
 			}
 			t2 = l - n;
 		}