doc/wfcqueue: cds_wfcq_splice

[urcu.git] / doc / examples / wfcqueue / cds_wfcq_splice.c

diff --git a/doc/examples/wfcqueue/cds_wfcq_splice.c b/doc/examples/wfcqueue/cds_wfcq_splice.c
new file mode 100644 (file)
index 0000000..bb2e512
--- /dev/null
+++ b/doc/examples/wfcqueue/cds_wfcq_splice.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2013  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
+ * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
+ *
+ * Permission is hereby granted to use or copy this program for any
+ * purpose,  provided the above notices are retained on all copies.
+ * Permission to modify the code and to distribute modified code is
+ * granted, provided the above notices are retained, and a notice that
+ * the code was modified is included with the above copyright notice.
+ *
+ * This example shows how to splice nodes from a source wfcqueue A into
+ * a destination wfcqueue B.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <urcu/wfcqueue.h>     /* Wait-free concurrent queue */
+#include <urcu/compiler.h>     /* For CAA_ARRAY_SIZE */
+
+/*
+ * Nodes populated into the queue.
+ */
+struct mynode {
+       int value;                      /* Node content */
+       struct cds_wfcq_node node;      /* Chaining in queue */
+};
+
+static
+int enqueue_values(struct cds_wfcq_head *head,
+               struct cds_wfcq_tail *tail,
+               int *values,
+               size_t nr_values)
+{
+       int ret = 0;
+       unsigned int i;
+
+       for (i = 0; i < nr_values; i++) {
+               struct mynode *node;
+
+               node = malloc(sizeof(*node));
+               if (!node) {
+                       ret = -1;
+                       goto end;
+               }
+               cds_wfcq_node_init(&node->node);
+               node->value = values[i];
+               cds_wfcq_enqueue(head, tail, &node->node);
+       }
+end:
+       return ret;
+}
+
+static
+void print_queue(struct cds_wfcq_head *head,
+               struct cds_wfcq_tail *tail,
+               const char *qname)
+{
+       struct cds_wfcq_node *qnode;
+
+       printf("%s:", qname);
+       __cds_wfcq_for_each_blocking(head, tail, qnode) {
+               struct mynode *node =
+                       caa_container_of(qnode, struct mynode, node);
+               printf(" %d", node->value);
+       }
+       printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+       int values_A[] = { -5, 42, 36, 24, };
+       int values_B[] = { 200, 300, 400, };
+       struct cds_wfcq_head head_A;    /* Queue A head */
+       struct cds_wfcq_tail tail_A;    /* Queue A tail */
+       struct cds_wfcq_head head_B;    /* Queue B head */
+       struct cds_wfcq_tail tail_B;    /* Queue B tail */
+       int ret = 0;
+
+       cds_wfcq_init(&head_A, &tail_A);
+       /* Enqueue nodes into A. */
+       ret = enqueue_values(&head_A, &tail_A, values_A,
+                       CAA_ARRAY_SIZE(values_A));
+       if (ret)
+               goto end;
+       cds_wfcq_init(&head_B, &tail_B);
+       /* Enqueue nodes into B. */
+       ret = enqueue_values(&head_B, &tail_B, values_B,
+                       CAA_ARRAY_SIZE(values_B));
+       if (ret)
+               goto end;
+
+       print_queue(&head_A, &tail_A, "queue A content before splice");
+       print_queue(&head_B, &tail_B, "queue B content before splice");
+
+       /*
+        * Splice nodes from A into B.
+        */
+       printf("Splicing queue A into queue B\n");
+       (void) cds_wfcq_splice_blocking(&head_B, &tail_B,
+                       &head_A, &tail_A);
+
+       print_queue(&head_A, &tail_A, "queue A content after splice");
+       print_queue(&head_B, &tail_B, "queue B content after splice");
+end:
+       return ret;
+}