From f26b50bdf866d704dcb721ed9ed2b9dc79b5dad7 Mon Sep 17 00:00:00 2001
From: Anna Schumaker <Anna@OcarinaProject.net>
Date: Tue, 1 Dec 2015 13:55:20 -0500
Subject: [PATCH] core/containers/queue: Add _q_iter_set() and _q_iter_val()

This patch implements basic queue iterator functions for accessing
specific positions on the queue.

Signed-off-by: Anna Schumaker <Anna@OcarinaProject.net>
---
 include/core/containers/queue.h | 21 +++++++++++++++++++++
 tests/core/containers/queue.c   | 18 ++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/include/core/containers/queue.h b/include/core/containers/queue.h
index dbaf0d48..d0dcb87b 100644
--- a/include/core/containers/queue.h
+++ b/include/core/containers/queue.h
@@ -10,6 +10,27 @@ struct _queue {
 	GQueue _queue;
 };
 
+struct _q_iter {
+	guint  it_pos;
+	GList *it_iter;
+};
+
+
+/* Called to set a queue iterator to a specific position. */
+static inline void _q_iter_set(struct _queue *queue, struct _q_iter *it,
+			       unsigned int pos)
+{
+	it->it_iter = g_queue_peek_nth_link(&queue->_queue, pos);
+	it->it_pos  = pos;
+}
+
+/* Called to access the value of a queue iterator. */
+static inline gpointer _q_iter_val(struct _q_iter *it)
+{
+	return (it->it_iter) ? it->it_iter->data : NULL;
+}
+
+
 #define _Q_INIT()				\
 	{					\
 		._queue = G_QUEUE_INIT,	\
diff --git a/tests/core/containers/queue.c b/tests/core/containers/queue.c
index d9e4111b..4cc38e4e 100644
--- a/tests/core/containers/queue.c
+++ b/tests/core/containers/queue.c
@@ -14,9 +14,15 @@ static inline unsigned int test_q_last(struct _queue *queue)
 	return GPOINTER_TO_INT(g_queue_peek_tail(&queue->_queue));
 }
 
+static inline unsigned int test_q_iter_val(struct _q_iter *it)
+{
+	return GPOINTER_TO_INT(_q_iter_val(it));
+}
+
 static void test_stress(unsigned int N)
 {
 	struct _queue queue = _Q_INIT();
+	struct _q_iter it;
 	unsigned int i;
 
 	/* _q_init() */
@@ -39,6 +45,18 @@ static void test_stress(unsigned int N)
 		test_loop_equal(test_q_last(&queue), i, i);
 	} test_loop_passed();
 	test_equal(_q_size(&queue), 2 * N);
+
+	/* _q_iter_set() */
+	for (i = 0; i < (2 * N); i += N) {
+		_q_iter_set(&queue, &it, i);
+		test_loop_not_equal((void *)it.it_iter, NULL, i);
+		test_loop_equal(it.it_pos, i, i);
+		if (i == N) {
+			test_loop_equal(test_q_iter_val(&it), 0, i);
+		} else {
+			test_loop_equal(test_q_iter_val(&it), N - 1, i);
+		}
+	} test_loop_passed();
 }
 
 static void test_basics()      { test_stress(10);     }