rculfhash: document algorithms

[urcu.git] / urcu / rculfhash.h

diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index 2e50beb27a5711c855a03f4689e11ae8c033e8ea..b98b4932922e02fab3cd53e6630a46ca3b848a06 100644 (file)
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -4,15 +4,21 @@
 #include <stdint.h>
 #include <urcu-call-rcu.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct _rcu_ht_node {
+       struct rcu_ht_node *next;       /* ptr | DUMMY_FLAG | REMOVED_FLAG */
+       unsigned long reverse_hash;
+};
+
 struct rcu_ht_node {
        /* cache-hot for iteration */
-       struct rcu_ht_node *next;
-       unsigned long reverse_hash;
+       struct _rcu_ht_node p;          /* needs to be first field */
        void *key;
        unsigned int key_len;
-       unsigned int dummy;
        /* cache-cold for iteration */
-       unsigned long hash;
        struct rcu_head head;
 };
 
@@ -34,7 +40,6 @@ void ht_node_init(struct rcu_ht_node *node, void *key,
 {
        node->key = key;
        node->key_len = key_len;
-       node->dummy = 0;
 }
 
 /*
@@ -59,12 +64,21 @@ struct rcu_ht_node *ht_lookup(struct rcu_ht *ht, void *key, size_t key_len);
 /* Call with rcu_read_lock held. */
 void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node);
 
-/* Call with rcu_read_lock held. */
-int ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node);
+/*
+ * Call with rcu_read_lock held.
+ * Returns the node added upon success.
+ * Returns the unique node already present upon failure. If ht_add_unique fails,
+ * the node passed as parameter should be freed by the caller.
+ */
+struct rcu_ht_node *ht_add_unique(struct rcu_ht *ht, struct rcu_ht_node *node);
 
 /* Call with rcu_read_lock held. */
 int ht_remove(struct rcu_ht *ht, struct rcu_ht_node *node);
 
 void ht_resize(struct rcu_ht *ht, int growth);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* _URCU_RCULFHASH_H */