From 8eeb6f5836ee772e3cdc8967d20444d84261373e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20Andr=C3=A9=20Tanner?= <mat@brain-dump.org>
Date: Thu, 29 Dec 2016 01:34:58 +0100
Subject: map: implement map_first

---
 map.c | 22 ++++++++++++++++++++++
 map.h |  2 ++
 2 files changed, 24 insertions(+)

diff --git a/map.c b/map.c
index 10d39de..f6e5c64 100644
--- a/map.c
+++ b/map.c
@@ -232,6 +232,28 @@ void map_iterate(const Map *map, bool (*handle)(const char *, void *, void *), c
 	iterate(*map, handle, data);
 }
 
+typedef struct {
+	const char *key;
+	void *value;
+} KeyValue;
+
+static bool first(const char *key, void *value, void *data)
+{
+	KeyValue *kv = data;
+	kv->key = key;
+	kv->value = value;
+	return false;
+}
+
+void *map_first(const Map *map, const char **key)
+{
+	KeyValue kv = { 0 };
+	map_iterate(map, first, &kv);
+	if (key && kv.key)
+		*key = kv.key;
+	return kv.value;
+}
+
 const Map *map_prefix(const Map *map, const char *prefix)
 {
 	const Map *n, *top;
diff --git a/map.h b/map.h
index 816e537..ca7bd44 100644
--- a/map.h
+++ b/map.h
@@ -9,6 +9,8 @@ typedef struct Map Map;
 Map *map_new(void);
 /* Retrieves a value, or NULL if it isn't in the map */
 void *map_get(const Map*, const char *key);
+/* Get first element of the map, or NULL if empty */
+void *map_first(const Map*, const char **key);
 /* Returns the corresponding value if the given prefix is unique.
  * Otherwise NULL, if no such prefix exists then errno is set to ENOENT. */
 void *map_closest(const Map*, const char *prefix);
-- 
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