From ca2c7bdfa64a30c0013598f0718dcfe7e6d98b2a Mon Sep 17 00:00:00 2001
From: Florian Dold <florian.dold@gmail.com>
Date: Tue, 5 Nov 2013 00:08:13 +0000
Subject: - implemented missing set functionality - secretsharing api changes

---
 src/util/container_multihashmap32.c | 121 ++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

(limited to 'src/util/container_multihashmap32.c')

diff --git a/src/util/container_multihashmap32.c b/src/util/container_multihashmap32.c
index afb0e3653..365333de2 100644
--- a/src/util/container_multihashmap32.c
+++ b/src/util/container_multihashmap32.c
@@ -73,6 +73,41 @@ struct GNUNET_CONTAINER_MultiHashMap32
    * Length of the "map" array.
    */
   unsigned int map_length;
+
+  /**
+   * Counts the destructive modifications (grow, remove)
+   * to the map, so that iterators can check if they are still valid.
+   */
+  unsigned int modification_counter;
+};
+
+
+/**
+ * Cursor into a multihashmap.
+ * Allows to enumerate elements asynchronously.
+ */
+struct GNUNET_CONTAINER_MultiHashMap32Iterator
+{
+  /**
+   * Position in the bucket 'idx'
+   */
+  struct MapEntry *me;
+
+  /**
+   * Current bucket index.
+   */
+  unsigned int idx;
+
+  /**
+   * Modification counter as observed on the map when the iterator
+   * was created.
+   */
+  unsigned int modification_counter;
+
+  /**
+   * Map that we are iterating over.
+   */
+  const struct GNUNET_CONTAINER_MultiHashMap32 *map;
 };
 
 
@@ -239,6 +274,8 @@ GNUNET_CONTAINER_multihashmap32_remove (struct GNUNET_CONTAINER_MultiHashMap32
   struct MapEntry *p;
   unsigned int i;
 
+  map->modification_counter++;
+
   i = idx_of (map, key);
   p = NULL;
   e = map->map[i];
@@ -280,6 +317,8 @@ GNUNET_CONTAINER_multihashmap32_remove_all (struct
   unsigned int i;
   int ret;
 
+  map->modification_counter++;
+
   ret = 0;
   i = idx_of (map, key);
   p = NULL;
@@ -383,6 +422,8 @@ grow (struct GNUNET_CONTAINER_MultiHashMap32 *map)
   unsigned int idx;
   unsigned int i;
 
+  map->modification_counter++;
+
   old_map = map->map;
   old_len = map->map_length;
   new_len = old_len * 2;
@@ -492,4 +533,84 @@ GNUNET_CONTAINER_multihashmap32_get_multiple (const struct
 }
 
 
+/**
+ * Create an iterator for a multihashmap.
+ * The iterator can be used to retrieve all the elements in the multihashmap
+ * one by one, without having to handle all elements at once (in contrast to
+ * GNUNET_CONTAINER_multihashmap_iterate()).  Note that the iterator can not be
+ * used anymore if elements have been removed from 'map' after the creation of
+ * the iterator, or 'map' has been destroyed.  Adding elements to 'map' may
+ * result in skipped or repeated elements.
+ *
+ * @param map the map to create an iterator for
+ * @return an iterator over the given multihashmap 'map'
+ */
+struct GNUNET_CONTAINER_MultiHashMap32Iterator *
+GNUNET_CONTAINER_multihashmap32_iterator_create (const struct GNUNET_CONTAINER_MultiHashMap32 *map)
+{
+  struct GNUNET_CONTAINER_MultiHashMap32Iterator *iter;
+
+  iter = GNUNET_new (struct GNUNET_CONTAINER_MultiHashMap32Iterator);
+  iter->map = map;
+  iter->modification_counter = map->modification_counter;
+  iter->me = map->map[0];
+  return iter;
+}
+
+
+/**
+ * Retrieve the next element from the hash map at the iterator's position.
+ * If there are no elements left, GNUNET_NO is returned, and 'key' and 'value'
+ * are not modified.
+ * This operation is only allowed if no elements have been removed from the
+ * multihashmap since the creation of 'iter', and the map has not been destroyed.
+ * Adding elements may result in repeating or skipping elements.
+ *
+ * @param iter the iterator to get the next element from
+ * @param key pointer to store the key in, can be NULL
+ * @param value pointer to store the value in, can be NULL
+ * @return #GNUNET_YES we returned an element,
+ *         #GNUNET_NO if we are out of elements
+ */
+int
+GNUNET_CONTAINER_multihashmap32_iterator_next (struct GNUNET_CONTAINER_MultiHashMap32Iterator *iter,
+                                               uint32_t *key,
+                                               const void **value)
+{
+  /* make sure the map has not been modified */
+  GNUNET_assert (iter->modification_counter == iter->map->modification_counter);
+
+  /* look for the next entry, skipping empty buckets */
+  while (1)
+  {
+    if (iter->idx >= iter->map->map_length)
+      return GNUNET_NO;
+    if (NULL != iter->me)
+    {
+      if (NULL != key)
+        *key = iter->me->key;
+      if (NULL != value)
+        *value = iter->me->value;
+      iter->me = iter->me->next;
+      return GNUNET_YES;
+    }
+    iter->idx += 1;
+    if (iter->idx < iter->map->map_length)
+      iter->me = iter->map->map[iter->idx];
+  }
+}
+
+
+/**
+ * Destroy a multihashmap iterator.
+ *
+ * @param iter the iterator to destroy
+ */
+void
+GNUNET_CONTAINER_multihashmap32_iterator_destroy (struct GNUNET_CONTAINER_MultiHashMapIterator *iter)
+{
+  GNUNET_free (iter);
+}
+
+
 /* end of container_multihashmap.c */
-- 
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