From e32fe06efdc2c1e0c0a9a9f0b470d8550b9e9901 Mon Sep 17 00:00:00 2001
From: Steffen Vogel <post@steffenvogel.de>
Date: Mon, 26 Mar 2018 12:52:04 +0200
Subject: [PATCH] list: added new list_index() function

---
 include/villas/list.h |  7 +++++++
 lib/list.c            | 24 ++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/villas/list.h b/include/villas/list.h
index f6ba29dae..aa674d25e 100644
--- a/include/villas/list.h
+++ b/include/villas/list.h
@@ -110,3 +110,10 @@ void list_sort(struct list *l, cmp_cb_t cmp);
 
 /** Set single element in list */
 int list_set(struct list *l, int index, void *value);
+
+/** Return index in list for value.
+ *
+ * @retval <0 No list entry  matching \p value was found.
+ * @retval >=0 Entry \p value was found at returned index.
+ */
+ssize_t list_index(struct list *l, void *value);
diff --git a/lib/list.c b/lib/list.c
index 2842c4223..34a4838a2 100644
--- a/lib/list.c
+++ b/lib/list.c
@@ -198,3 +198,27 @@ int list_set(struct list *l, int index, void *value)
 
 	return 0;
 }
+
+ssize_t list_index(struct list *l, void *p)
+{
+	void *e;
+	ssize_t f;
+
+	pthread_mutex_lock(&l->lock);
+
+	assert(l->state == STATE_INITIALIZED);
+
+	for (size_t i = 0; i < list_length(l); i++) {
+		e = list_at(l, i);
+		if (e == p) {
+			f = i;
+			goto found;
+		}
+	}
+
+	f = -1;
+
+found:	pthread_mutex_unlock(&l->lock);
+
+	return f;
+}