Add wmem_tree_count.

There are cases where wmem_tree needs to know its number of nodes.

Change-Id: I6411cf4275fd4d85a1d76382e1922d236be3b176
Reviewed-on: https://code.wireshark.org/review/20005
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Michael Mann <mmann78@netscape.net>

epan/wmem/wmem_test.c

@@ -1147,6 +1147,7 @@ wmem_test_tree(void)
         g_assert(wmem_tree_lookup32(tree, i) == GINT_TO_POINTER(i));
         g_assert(!wmem_tree_is_empty(tree));
     }
+    g_assert(wmem_tree_count(tree) == CONTAINER_ITERS);
     wmem_free_all(allocator);
 
     tree = wmem_tree_new(allocator);
@@ -1155,6 +1156,7 @@ wmem_test_tree(void)
         wmem_tree_insert32(tree, rand_int, GINT_TO_POINTER(i));
         g_assert(wmem_tree_lookup32(tree, rand_int) == GINT_TO_POINTER(i));
     }
+    g_assert(wmem_tree_count(tree) == CONTAINER_ITERS);
     wmem_free_all(allocator);
 
     /* test auto-reset functionality */
@@ -1164,7 +1166,9 @@ wmem_test_tree(void)
         wmem_tree_insert32(tree, i, GINT_TO_POINTER(i));
         g_assert(wmem_tree_lookup32(tree, i) == GINT_TO_POINTER(i));
     }
+    g_assert(wmem_tree_count(tree) == CONTAINER_ITERS);
     wmem_free_all(extra_allocator);
+    g_assert(wmem_tree_count(tree) == 0);
     for (i=0; i<CONTAINER_ITERS; i++) {
         g_assert(wmem_tree_lookup32(tree, i) == NULL);
         g_assert(wmem_tree_lookup32_le(tree, i) == NULL);

epan/wmem/wmem_tree.c

@@ -271,6 +271,27 @@ wmem_tree_is_empty(wmem_tree_t *tree)
     return tree->root == NULL;
 }
 
+static gboolean
+count_nodes(const void *key _U_, void *value _U_, void *userdata)
+{
+    guint* count = (guint*)userdata;
+    (*count)++;
+    return FALSE;
+}
+
+guint
+wmem_tree_count(wmem_tree_t* tree)
+{
+    guint count = 0;
+
+    /* Recursing through the tree counting each node is the simplest approach.
+       We don't keep track of the count within the tree because it can get
+       complicated with subtrees within the tree */
+    wmem_tree_foreach(tree, count_nodes, &count);
+
+    return count;
+}
+
 static wmem_tree_node_t *
 create_node(wmem_allocator_t *allocator, wmem_tree_node_t *parent, const void *key,
         void *data, wmem_node_color_t color, gboolean is_subtree)

epan/wmem/wmem_tree.h

@@ -77,6 +77,11 @@ WS_DLL_PUBLIC
 gboolean
 wmem_tree_is_empty(wmem_tree_t *tree);
 
+/** Returns number of nodes in tree */
+WS_DLL_PUBLIC
+guint
+wmem_tree_count(wmem_tree_t* tree);
+
 /** Insert a node indexed by a guint32 key value.
  *
  * Data is a pointer to the structure you want to be able to retrieve by