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authorSander Vrijders <sander.vrijders@ugent.be>2017-09-14 13:43:09 +0200
committerSander Vrijders <sander.vrijders@ugent.be>2017-09-15 11:30:40 +0200
commit26d4a6072cbf59708071dac8393c88ddacd69a37 (patch)
tree40d3dd4c9e955528e770325f5e59b84c61316d2c /src/lib/rq.c
parent07a2d315205fccf42e891e2bb46db44401b29153 (diff)
downloadouroboros-26d4a6072cbf59708071dac8393c88ddacd69a37.tar.gz
ouroboros-26d4a6072cbf59708071dac8393c88ddacd69a37.zip
lib: Add reordering queue to FRCT
This adds a reordering queue to FRCT so that SDUs can be delivered in-order when requested.
Diffstat (limited to 'src/lib/rq.c')
-rw-r--r--src/lib/rq.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/src/lib/rq.c b/src/lib/rq.c
new file mode 100644
index 00000000..bd0594b5
--- /dev/null
+++ b/src/lib/rq.c
@@ -0,0 +1,157 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * Reordering queue
+ *
+ * Dimitri Staessens <dimitri.staessens@ugent.be>
+ * Sander Vrijders <sander.vrijders@ugent.be>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#include <ouroboros/rq.h>
+
+#include <assert.h>
+
+struct pdu {
+ uint64_t seqno;
+ size_t idx;
+};
+
+struct rq {
+ struct pdu * items;
+ int n_items;
+ int size;
+};
+
+struct rq * rq_create(int size)
+{
+ struct rq * rq;
+
+ rq = malloc(sizeof(*rq));
+ if (rq == NULL)
+ return NULL;
+
+ rq->items = malloc(sizeof(struct pdu) * (size + 1));
+ if (rq->items == NULL) {
+ free(rq);
+ return NULL;
+ }
+
+ rq->size = size;
+ rq->n_items = 0;
+
+ return rq;
+}
+
+void rq_destroy(struct rq * rq)
+{
+ assert(rq);
+
+ free(rq->items);
+ free(rq);
+}
+
+int rq_push(struct rq * rq,
+ uint64_t seqno,
+ size_t idx)
+{
+ int i;
+ int j;
+
+ assert(rq);
+
+ /* Queue is full. */
+ if (rq->n_items == rq->size)
+ return -1;
+
+ i = ++rq->n_items;
+ j = i / 2;
+ while (i > 1 && rq->items[j].seqno > seqno) {
+ rq->items[i] = rq->items[j];
+ i = j;
+ j = j / 2;
+ }
+
+ rq->items[i].seqno = seqno;
+ rq->items[i].idx = idx;
+
+ return 0;
+}
+
+uint64_t rq_peek(struct rq * rq)
+{
+ assert(rq);
+
+ return rq->items[1].seqno;
+}
+
+bool rq_is_empty(struct rq * rq)
+{
+ assert(rq);
+
+ return (rq->n_items == 0);
+}
+
+size_t rq_pop(struct rq * rq)
+{
+ size_t idx;
+ int i;
+ int j;
+ int k;
+
+ assert(rq);
+
+ idx = rq->items[1].idx;
+
+ rq->items[1] = rq->items[rq->n_items];
+ rq->n_items--;
+
+ i = 1;
+ while (true) {
+ k = i;
+ j = 2 * i;
+
+ if (j <= rq->n_items && rq->items[j].seqno < rq->items[k].seqno)
+ k = j;
+
+ if (j + 1 <= rq->n_items &&
+ rq->items[j + 1].seqno < rq->items[k].seqno)
+ k = j + 1;
+
+ if (k == i)
+ break;
+
+ rq->items[i] = rq->items[k];
+ i = k;
+ }
+
+ rq->items[i] = rq->items[rq->n_items + 1];
+
+ return idx;
+}
+
+bool rq_has(struct rq * rq,
+ uint64_t seqno)
+{
+ int i;
+
+ assert(rq);
+
+ for (i = 1; i <= rq->n_items; i++)
+ if (rq->items[i].seqno == seqno)
+ return true;
+
+ return false;
+}