+++ /dev/null
-/*
- * 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.
- */
-#include <vppinfra/fheap.h>
-
-/* Fibonacci heaps. */
-always_inline fheap_node_t *
-fheap_get_node (fheap_t * f, u32 i)
-{
- return i != ~0 ? vec_elt_at_index (f->nodes, i) : 0;
-}
-
-always_inline fheap_node_t *
-fheap_get_root (fheap_t * f)
-{
- return fheap_get_node (f, f->min_root);
-}
-
-static void
-fheap_validate (fheap_t * f)
-{
- fheap_node_t *n, *m;
- uword ni, si;
-
- if (!CLIB_DEBUG || !f->enable_validate)
- return;
-
- vec_foreach_index (ni, f->nodes)
- {
- n = vec_elt_at_index (f->nodes, ni);
-
- if (!n->is_valid)
- continue;
-
- /* Min root must have minimal key. */
- m = vec_elt_at_index (f->nodes, f->min_root);
- ASSERT (n->key >= m->key);
-
- /* Min root must have no parent. */
- if (ni == f->min_root)
- ASSERT (n->parent == ~0);
-
- /* Check sibling linkages. */
- if (n->next_sibling == ~0)
- ASSERT (n->prev_sibling == ~0);
- else if (n->prev_sibling == ~0)
- ASSERT (n->next_sibling == ~0);
- else
- {
- fheap_node_t *prev, *next;
- u32 si = n->next_sibling, si_start = si;
- do
- {
- m = vec_elt_at_index (f->nodes, si);
- prev = vec_elt_at_index (f->nodes, m->prev_sibling);
- next = vec_elt_at_index (f->nodes, m->next_sibling);
- ASSERT (prev->next_sibling == si);
- ASSERT (next->prev_sibling == si);
- si = m->next_sibling;
- }
- while (si != si_start);
- }
-
- /* Loop through all siblings. */
- {
- u32 n_siblings = 0;
-
- foreach_fheap_node_sibling (f, si, n->next_sibling, (
- {
- m =
- vec_elt_at_index
- (f->nodes, si);
- /* All siblings must have same parent. */
- ASSERT (m->parent
- ==
- n->
- parent);
- n_siblings += 1;}
- ));
-
- /* Either parent is non-empty or there are siblings present. */
- if (n->parent == ~0 && ni != f->min_root)
- ASSERT (n_siblings > 0);
- }
-
- /* Loop through all children. */
- {
- u32 found_first_child = n->first_child == ~0;
- u32 n_children = 0;
-
- foreach_fheap_node_sibling (f, si, n->first_child, (
- {
- m =
- vec_elt_at_index
- (f->nodes, si);
- /* Children must have larger keys than their parent. */
- ASSERT (m->key >=
- n->key);
- if
- (!found_first_child)
- found_first_child =
- si ==
- n->first_child;
- n_children += 1;}
- ));
-
- /* Check that first child is present on list. */
- ASSERT (found_first_child);
-
- /* Make sure rank is correct. */
- ASSERT (n->rank == n_children);
- }
- }
-
- /* Increment serial number for each successful validate.
- Failure can be used as condition for gdb breakpoints. */
- f->validate_serial++;
-}
-
-always_inline void
-fheap_node_add_sibling (fheap_t * f, u32 ni, u32 ni_to_add)
-{
- fheap_node_t *n = vec_elt_at_index (f->nodes, ni);
- fheap_node_t *n_to_add = vec_elt_at_index (f->nodes, ni_to_add);
- fheap_node_t *n_next = fheap_get_node (f, n->next_sibling);
- fheap_node_t *parent;
-
- /* Empty list? */
- if (n->next_sibling == ~0)
- {
- ASSERT (n->prev_sibling == ~0);
- n->next_sibling = n->prev_sibling = ni_to_add;
- n_to_add->next_sibling = n_to_add->prev_sibling = ni;
- }
- else
- {
- /* Add node after existing node. */
- n_to_add->prev_sibling = ni;
- n_to_add->next_sibling = n->next_sibling;
-
- n->next_sibling = ni_to_add;
- n_next->prev_sibling = ni_to_add;
- }
-
- n_to_add->parent = n->parent;
- parent = fheap_get_node (f, n->parent);
- if (parent)
- parent->rank += 1;
-}
-
-void
-fheap_add (fheap_t * f, u32 ni, u32 key)
-{
- fheap_node_t *r, *n;
- u32 ri;
-
- n = vec_elt_at_index (f->nodes, ni);
-
- clib_memset (n, 0, sizeof (n[0]));
- n->parent = n->first_child = n->next_sibling = n->prev_sibling = ~0;
- n->key = key;
-
- r = fheap_get_root (f);
- ri = f->min_root;
- if (!r)
- {
- /* No root? Add node as new root. */
- f->min_root = ni;
- }
- else
- {
- /* Add node as sibling of current root. */
- fheap_node_add_sibling (f, ri, ni);
-
- /* New node may become new root. */
- if (r->key > n->key)
- f->min_root = ni;
- }
-
- fheap_validate (f);
-}
-
-always_inline u32
-fheap_node_remove_internal (fheap_t * f, u32 ni, u32 invalidate)
-{
- fheap_node_t *n = vec_elt_at_index (f->nodes, ni);
- u32 prev_ni = n->prev_sibling;
- u32 next_ni = n->next_sibling;
- u32 list_has_single_element = prev_ni == ni;
- fheap_node_t *prev = fheap_get_node (f, prev_ni);
- fheap_node_t *next = fheap_get_node (f, next_ni);
- fheap_node_t *p = fheap_get_node (f, n->parent);
-
- if (p)
- {
- ASSERT (p->rank > 0);
- p->rank -= 1;
- p->first_child = list_has_single_element ? ~0 : next_ni;
- }
-
- if (prev)
- {
- ASSERT (prev->next_sibling == ni);
- prev->next_sibling = next_ni;
- }
- if (next)
- {
- ASSERT (next->prev_sibling == ni);
- next->prev_sibling = prev_ni;
- }
-
- n->prev_sibling = n->next_sibling = ni;
- n->parent = ~0;
- n->is_valid = invalidate == 0;
-
- return list_has_single_element ? ~0 : next_ni;
-}
-
-always_inline u32
-fheap_node_remove (fheap_t * f, u32 ni)
-{
- return fheap_node_remove_internal (f, ni, /* invalidate */ 0);
-}
-
-always_inline u32
-fheap_node_remove_and_invalidate (fheap_t * f, u32 ni)
-{
- return fheap_node_remove_internal (f, ni, /* invalidate */ 1);
-}
-
-static void
-fheap_link_root (fheap_t * f, u32 ni)
-{
- fheap_node_t *n = vec_elt_at_index (f->nodes, ni);
- fheap_node_t *r, *lo, *hi;
- u32 ri, lo_i, hi_i, k;
-
- while (1)
- {
- k = n->rank;
- vec_validate_init_empty (f->root_list_by_rank, k, ~0);
- ri = f->root_list_by_rank[k];
- r = fheap_get_node (f, ri);
- if (!r)
- {
- f->root_list_by_rank[k] = ni;
- return;
- }
-
- f->root_list_by_rank[k] = ~0;
-
- /* Sort n/r into lo/hi by their keys. */
- lo = r, lo_i = ri;
- hi = n, hi_i = ni;
- if (hi->key < lo->key)
- {
- u32 ti;
- fheap_node_t *tn;
- ti = lo_i, tn = lo;
- lo = hi, lo_i = hi_i;
- hi = tn, hi_i = ti;
- }
-
- /* Remove larger key. */
- fheap_node_remove (f, hi_i);
-
- /* Add larger key as child of smaller one. */
- if (lo->first_child == ~0)
- {
- hi->parent = lo_i;
- lo->first_child = hi_i;
- lo->rank = 1;
- }
- else
- fheap_node_add_sibling (f, lo->first_child, hi_i);
-
- /* Following Fredman & Trajan: "When making a root node X a child of another node in a linking step,
- we unmark X". */
- hi->is_marked = 0;
-
- ni = lo_i;
- n = lo;
- }
-}
-
-u32
-fheap_del_min (fheap_t * f, u32 * min_key)
-{
- fheap_node_t *r = fheap_get_root (f);
- u32 to_delete_min_ri = f->min_root;
- u32 ri, ni;
-
- /* Empty heap? */
- if (!r)
- return ~0;
-
- /* Root's children become siblings. Call this step a; see below. */
- if (r->first_child != ~0)
- {
- u32 ci, cni, rni;
- fheap_node_t *c, *cn, *rn;
-
- /* Splice child & root circular lists together. */
- ci = r->first_child;
- c = vec_elt_at_index (f->nodes, ci);
-
- cni = c->next_sibling;
- rni = r->next_sibling;
- cn = vec_elt_at_index (f->nodes, cni);
- rn = vec_elt_at_index (f->nodes, rni);
-
- r->next_sibling = cni;
- c->next_sibling = rni;
- cn->prev_sibling = to_delete_min_ri;
- rn->prev_sibling = ci;
- }
-
- /* Remove min root. */
- ri = fheap_node_remove_and_invalidate (f, to_delete_min_ri);
-
- /* Find new min root from among siblings including the ones we've just added. */
- f->min_root = ~0;
- if (ri != ~0)
- {
- u32 ri_last, ri_next, i, min_ds;
-
- r = fheap_get_node (f, ri);
- ri_last = r->prev_sibling;
- while (1)
- {
- /* Step a above can put children (with r->parent != ~0) on root list. */
- r->parent = ~0;
-
- ri_next = r->next_sibling;
- fheap_link_root (f, ri);
- if (ri == ri_last)
- break;
- ri = ri_next;
- r = fheap_get_node (f, ri);
- }
-
- min_ds = ~0;
- vec_foreach_index (i, f->root_list_by_rank)
- {
- ni = f->root_list_by_rank[i];
- if (ni == ~0)
- continue;
- f->root_list_by_rank[i] = ~0;
- r = fheap_get_node (f, ni);
- if (r->key < min_ds)
- {
- f->min_root = ni;
- min_ds = r->key;
- ASSERT (r->parent == ~0);
- }
- }
- }
-
- /* Return deleted min root. */
- r = vec_elt_at_index (f->nodes, to_delete_min_ri);
- if (min_key)
- *min_key = r->key;
-
- fheap_validate (f);
-
- return to_delete_min_ri;
-}
-
-static void
-fheap_mark_parent (fheap_t * f, u32 pi)
-{
- fheap_node_t *p = vec_elt_at_index (f->nodes, pi);
-
- /* Parent is a root: do nothing. */
- if (p->parent == ~0)
- return;
-
- /* If not marked, mark it. */
- if (!p->is_marked)
- {
- p->is_marked = 1;
- return;
- }
-
- /* Its a previously marked, non-root parent.
- Cut edge to its parent and add to root list. */
- fheap_node_remove (f, pi);
- fheap_node_add_sibling (f, f->min_root, pi);
-
- /* Unmark it since its now a root node. */
- p->is_marked = 0;
-
- /* "Cascading cuts": check parent. */
- if (p->parent != ~0)
- fheap_mark_parent (f, p->parent);
-}
-
-/* Set key to new smaller value. */
-void
-fheap_decrease_key (fheap_t * f, u32 ni, u32 new_key)
-{
- fheap_node_t *n = vec_elt_at_index (f->nodes, ni);
- fheap_node_t *r = fheap_get_root (f);
-
- n->key = new_key;
-
- if (n->parent != ~0)
- {
- fheap_mark_parent (f, n->parent);
-
- /* Remove node and add to root list. */
- fheap_node_remove (f, ni);
- fheap_node_add_sibling (f, f->min_root, ni);
- }
-
- if (n->key < r->key)
- f->min_root = ni;
-
- fheap_validate (f);
-}
-
-void
-fheap_del (fheap_t * f, u32 ni)
-{
- fheap_node_t *n;
-
- n = vec_elt_at_index (f->nodes, ni);
-
- if (n->parent == ~0)
- {
- ASSERT (ni == f->min_root);
- fheap_del_min (f, 0);
- }
- else
- {
- u32 ci;
-
- fheap_mark_parent (f, n->parent);
-
- /* Add children to root list. */
- foreach_fheap_node_sibling (f, ci, n->first_child, (
- {
- fheap_node_remove
- (f, ci);
- fheap_node_add_sibling
- (f, f->min_root,
- ci);}
- ));
-
- fheap_node_remove_and_invalidate (f, ni);
- }
-
- fheap_validate (f);
-}
-
-/*
- * fd.io coding-style-patch-verification: ON
- *
- * Local Variables:
- * eval: (c-set-style "gnu")
- * End:
- */
Code Review / vpp.git / blobdiff