From 2c0d472e87625000c71626fc965e7d1060f4ac7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marc=20Andr=C3=A9=20Tanner?= <mat@brain-dump.org>
Date: Tue, 12 Jan 2016 22:38:45 +0100
Subject: map: implement map_copy

Copies all entries from one map to another, overwriting existing entries.
---
 map.c | 22 ++++++++++++++++++++++
 map.h |  2 ++
 2 files changed, 24 insertions(+)

diff --git a/map.c b/map.c
index 5fde157..57dc761 100644
--- a/map.c
+++ b/map.c
@@ -284,6 +284,28 @@ void map_clear(Map *map)
 	map->v = NULL;
 }
 
+static bool copy(Map *dest, Map n)
+{
+	if (!n.v) {
+		return copy(dest, n.u.n->child[0]) &&
+		       copy(dest, n.u.n->child[1]);
+	} else {
+		if (!map_put(dest, n.u.s, n.v) && map_get(dest, n.u.s) != n.v) {
+			map_delete(dest, n.u.s);
+			return map_put(dest, n.u.s, n.v);
+		}
+		return true;
+	}
+}
+
+bool map_copy(Map *dest, Map *src)
+{
+	if (!src || !src->u.n)
+		return true;
+
+	return copy(dest, *src);
+}
+
 bool map_empty(const Map *map)
 {
 	return map->u.n == NULL;
diff --git a/map.h b/map.h
index 078c9c6..0540fab 100644
--- a/map.h
+++ b/map.h
@@ -21,6 +21,8 @@ bool map_put(Map*, const char *key, const void *value);
 /* Remove a member from the map. Returns the removed entry or NULL
  * if there was no entry found using the given key*/
 void *map_delete(Map*, const char *key);
+/* Copy all entries from `src' into `dest', overwrites existing entries in `dest' */
+bool map_copy(Map *dest, Map *src);
 /* Ordered iteration over a map, call handle for every entry. If handle
  * returns false, the iteration will stop. */
 void map_iterate(const Map*, bool (*handle)(const char *key, void *value, void *data), const void *data);
-- 
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