Add swap function for maps

1 files changed, 26 insertions, 0 deletions

diff --git a/collections/map/map.adoc b/collections/map/map.adoc
index c42a99a..740df3c 100644
--- a/collections/map/map.adoc
+++ b/collections/map/map.adoc
@@ -119,6 +119,32 @@ assert(strcmp(tmp, "FOUR") == 0);
 free(tmp);
 ----
 
+[[map_swap]]
++void map_swap(map *self, void *i, void *j)+
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Swaps values at keys +i+ and +j+, does nothing if +i+ or +j+ are invalid keys.
+
+Examples
+^^^^^^^^
+[source,c]
+----
+#include "map.h"
+#include <string.h>
+
+char *str1 = "ONE";
+char *str2 = "TWO";
+
+map *dict = map_new((cmp_func) strcmp);
+
+map_insert(dict, str1, strdup(str2));
+map_insert(dict, str2, strdup(str3));
+
+map_swap(dict, str1, str2);
+
+assert(strcmp(str1, map_index(dict, str1)) == 0);
+assert(strcmp(str2, map_index(dict, str2)) == 0);
+----
+
 [[map_set_val]]
 +void* map_set_val(map *self, void *key, void *val)+
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~