X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Fhmap.c;h=6bc5ea74bd79482897a353d5ad8361a7f360fe0c;hb=a23aab1fc2f66b63ba9b7e4b9c9a8f6d58c367d0;hp=1b4816d9ddbeeb60cedb10723cf8c0da4c6d96ee;hpb=f2f7be8696e030dbe6f7c859c4e2bd76fd363036;p=openvswitch

diff --git a/lib/hmap.c b/lib/hmap.c
index 1b4816d9..6bc5ea74 100644
--- a/lib/hmap.c
+++ b/lib/hmap.c
@@ -18,6 +18,7 @@
 #include "hmap.h"
 #include <assert.h>
 #include <stdint.h>
+#include <string.h>
 #include "coverage.h"
 #include "random.h"
 #include "util.h"
@@ -42,6 +43,22 @@ hmap_destroy(struct hmap *hmap)
     }
 }
 
+/* Removes all node from 'hmap', leaving it ready to accept more nodes.  Does
+ * not free memory allocated for 'hmap'.
+ *
+ * This function is appropriate when 'hmap' will soon have about as many
+ * elements as it before.  If 'hmap' will likely have fewer elements than
+ * before, use hmap_destroy() followed by hmap_clear() to save memory and
+ * iteration time. */
+void
+hmap_clear(struct hmap *hmap)
+{
+    if (hmap->n > 0) {
+        hmap->n = 0;
+        memset(hmap->buckets, 0, (hmap->mask + 1) * sizeof *hmap->buckets);
+    }
+}
+
 /* Exchanges hash maps 'a' and 'b'. */
 void
 hmap_swap(struct hmap *a, struct hmap *b)