#include <assert.h>
#include "hash.h"
+static struct shash_node *shash_find__(const struct shash *,
+ const char *name, size_t hash);
+
static size_t
hash_name(const char *name)
{
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 *
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, 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 hash)
{
struct shash_node *node;
- HMAP_FOR_EACH_WITH_HASH (node, struct shash_node, node,
- hash_name(name), &sh->map) {
+ HMAP_FOR_EACH_WITH_HASH (node, node, hash, &sh->map) {
if (!strcmp(node->name, name)) {
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, hash_name(name));
+}
+
void *
shash_find_data(const struct shash *sh, const char *name)
{
}
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);
+}