ofp-util: Work on decoding OF1.1 flow_mods.

[openvswitch] / lib / shash.c

diff --git a/lib/shash.c b/lib/shash.c
index c4d3ccb8daa524b586dc4471d1365e40e401c65d..74801763ecaf728442db9239fb190c8be41215f1 100644 (file)
--- a/lib/shash.c
+++ b/lib/shash.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2010 Nicira Networks.
+ * Copyright (c) 2009, 2010, 2011 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,10 @@
 #include <assert.h>
 #include "hash.h"
 
+static struct shash_node *shash_find__(const struct shash *,
+                                       const char *name, size_t name_len,
+                                       size_t hash);
+
 static size_t
 hash_name(const char *name)
 {
@@ -100,18 +104,24 @@ shash_count(const struct shash *shash)
     return hmap_count(&shash->map);
 }
 
-/* It is the caller's responsibility to avoid duplicate names, if that is
- * desirable. */
-struct shash_node *
-shash_add_nocopy(struct shash *sh, char *name, const void *data)
+static struct shash_node *
+shash_add_nocopy__(struct shash *sh, char *name, const void *data, size_t hash)
 {
     struct shash_node *node = xmalloc(sizeof *node);
     node->name = name;
     node->data = (void *) data;
-    hmap_insert(&sh->map, &node->node, hash_name(name));
+    hmap_insert(&sh->map, &node->node, hash);
     return node;
 }
 
+/* It is the caller's responsibility to avoid duplicate names, if that is
+ * desirable. */
+struct shash_node *
+shash_add_nocopy(struct shash *sh, char *name, const void *data)
+{
+    return shash_add_nocopy__(sh, name, data, hash_name(name));
+}
+
 /* It is the caller's responsibility to avoid duplicate names, if that is
  * desirable. */
 struct shash_node *
@@ -138,29 +148,76 @@ shash_add_assert(struct shash *sh, const char *name, const void *data)
     assert(added);
 }
 
+/* Searches for 'name' in 'sh'.  If it does not already exist, adds it along
+ * with 'data' and returns NULL.  If it does already exist, replaces its data
+ * by 'data' and returns the data that it formerly contained. */
+void *
+shash_replace(struct shash *sh, const char *name, const void *data)
+{
+    size_t hash = hash_name(name);
+    struct shash_node *node;
+
+    node = shash_find__(sh, name, strlen(name), hash);
+    if (!node) {
+        shash_add_nocopy__(sh, xstrdup(name), data, hash);
+        return NULL;
+    } else {
+        void *old_data = node->data;
+        node->data = (void *) data;
+        return old_data;
+    }
+}
+
+/* Deletes 'node' from 'sh' and frees the node's name.  The caller is still
+ * responsible for freeing the node's data, if necessary. */
 void
 shash_delete(struct shash *sh, struct shash_node *node)
 {
+    free(shash_steal(sh, node));
+}
+
+/* Deletes 'node' from 'sh'.  Neither the node's name nor its data is freed;
+ * instead, ownership is transferred to the caller.  Returns the node's
+ * name. */
+char *
+shash_steal(struct shash *sh, struct shash_node *node)
+{
+    char *name = node->name;
+
     hmap_remove(&sh->map, &node->node);
-    free(node->name);
     free(node);
+    return name;
 }
 
-/* If there are duplicates, returns a random element. */
-struct shash_node *
-shash_find(const struct shash *sh, const char *name)
+static struct shash_node *
+shash_find__(const struct shash *sh, const char *name, size_t name_len,
+             size_t hash)
 {
     struct shash_node *node;
 
-    HMAP_FOR_EACH_WITH_HASH (node, struct shash_node, node,
-                             hash_name(name), &sh->map) {
-        if (!strcmp(node->name, name)) {
+    HMAP_FOR_EACH_WITH_HASH (node, node, hash, &sh->map) {
+        if (!strncmp(node->name, name, name_len) && !node->name[name_len]) {
             return node;
         }
     }
     return NULL;
 }
 
+/* If there are duplicates, returns a random element. */
+struct shash_node *
+shash_find(const struct shash *sh, const char *name)
+{
+    return shash_find__(sh, name, strlen(name), hash_name(name));
+}
+
+/* Finds and returns a shash_node within 'sh' that has the given 'name' that is
+ * exactly 'len' bytes long.  Returns NULL if no node in 'sh' has that name. */
+struct shash_node *
+shash_find_len(const struct shash *sh, const char *name, size_t len)
+{
+    return shash_find__(sh, name, len, hash_bytes(name, len, 0));
+}
+
 void *
 shash_find_data(const struct shash *sh, const char *name)
 {
@@ -245,3 +302,14 @@ shash_equal_keys(const struct shash *a, const struct shash *b)
     }
     return true;
 }
+
+/* Chooses and returns a randomly selected node from 'sh', which must not be
+ * empty.
+ *
+ * I wouldn't depend on this algorithm to be fair, since I haven't analyzed it.
+ * But it does at least ensure that any node in 'sh' can be chosen. */
+struct shash_node *
+shash_random_node(struct shash *sh)
+{
+    return CONTAINER_OF(hmap_random_node(&sh->map), struct shash_node, node);
+}