1 files changed, 126 insertions, 0 deletions
diff --git a/vppinfra/vppinfra/fheap.h b/vppinfra/vppinfra/fheap.h
new file mode 100644
index 00000000000..974eb1fc698
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+++ b/vppinfra/vppinfra/fheap.h
@@ -0,0 +1,126 @@
+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef included_clib_fheap_h
+#define included_clib_fheap_h
+
+/* Fibonacci Heaps Fredman, M. L.; Tarjan (1987).
+   "Fibonacci heaps and their uses in improved network optimization algorithms" */
+
+#include <vppinfra/vec.h>
+
+typedef struct {
+  /* Node index of parent. */
+  u32 parent;
+
+  /* Node index of first child. */
+  u32 first_child;
+
+  /* Next and previous nodes in doubly linked list of siblings. */
+  u32 next_sibling, prev_sibling;
+
+  /* Key (distance) for this node.  Parent always has key
+     <= than keys of children. */
+  u32 key;
+
+  /* Number of children (as opposed to descendents). */
+  u32 rank;
+
+  u32 is_marked;
+
+  /* Set to one when node is inserted; zero when deleted. */
+  u32 is_valid;
+} fheap_node_t;
+
+#define foreach_fheap_node_sibling(f,ni,first_ni,body)			\
+do {									\
+  u32 __fheap_foreach_first_ni = (first_ni);				\
+  u32 __fheap_foreach_ni = __fheap_foreach_first_ni;			\
+  u32 __fheap_foreach_next_ni;						\
+  fheap_node_t * __fheap_foreach_n;					\
+  if (__fheap_foreach_ni != ~0)						\
+    while (1)								\
+      {									\
+	__fheap_foreach_n = fheap_get_node ((f), __fheap_foreach_ni);	\
+	__fheap_foreach_next_ni = __fheap_foreach_n -> next_sibling;	\
+	(ni) = __fheap_foreach_ni;					\
+									\
+	body;								\
+									\
+	/* End of circular list? */					\
+	if (__fheap_foreach_next_ni == __fheap_foreach_first_ni)	\
+	  break;							\
+									\
+	__fheap_foreach_ni = __fheap_foreach_next_ni;			\
+									\
+      }									\
+} while (0)
+
+typedef struct {
+  u32 min_root;
+
+  /* Vector of nodes. */
+  fheap_node_t * nodes;
+
+  u32 * root_list_by_rank;
+
+  u32 enable_validate;
+
+  u32 validate_serial;
+} fheap_t;
+
+/* Initialize empty heap. */
+always_inline void
+fheap_init (fheap_t * f, u32 n_nodes)
+{
+  fheap_node_t * save_nodes = f->nodes;
+  u32 * save_root_list = f->root_list_by_rank;
+
+  memset (f, 0, sizeof (f[0]));
+
+  f->nodes = save_nodes;
+  f->root_list_by_rank = save_root_list;
+
+  vec_validate (f->nodes, n_nodes - 1);
+  vec_reset_length (f->root_list_by_rank);
+
+  f->min_root = ~0;
+}
+
+always_inline void
+fheap_free (fheap_t * f)
+{
+  vec_free (f->nodes);
+  vec_free (f->root_list_by_rank);
+}
+
+always_inline u32
+fheap_find_min (fheap_t * f)
+{ return f->min_root; }
+
+always_inline u32
+fheap_is_empty (fheap_t * f)
+{ return f->min_root == ~0; }
+
+/* Add/delete nodes. */
+void fheap_add (fheap_t * f, u32 ni, u32 key);
+void fheap_del (fheap_t * f, u32 ni);
+
+/* Delete and return minimum. */
+u32 fheap_del_min (fheap_t * f, u32 * min_key);
+
+/* Change key value. */
+void fheap_decrease_key (fheap_t * f, u32 ni, u32 new_key);
+
+#endif /* included_clib_fheap_h */