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/*
* 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 */
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