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/*
* ngtcp2
*
* Copyright (c) 2017 ngtcp2 contributors
* Copyright (c) 2012 nghttp2 contributors
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include "ngtcp2_pq.h"
#include <assert.h>
#include "ngtcp2_macro.h"
void ngtcp2_pq_init(ngtcp2_pq *pq, ngtcp2_less less, const ngtcp2_mem *mem) {
pq->mem = mem;
pq->capacity = 0;
pq->q = NULL;
pq->length = 0;
pq->less = less;
}
void ngtcp2_pq_free(ngtcp2_pq *pq) {
ngtcp2_mem_free(pq->mem, pq->q);
pq->q = NULL;
}
static void swap(ngtcp2_pq *pq, size_t i, size_t j) {
ngtcp2_pq_entry *a = pq->q[i];
ngtcp2_pq_entry *b = pq->q[j];
pq->q[i] = b;
b->index = i;
pq->q[j] = a;
a->index = j;
}
static void bubble_up(ngtcp2_pq *pq, size_t index) {
size_t parent;
while (index != 0) {
parent = (index - 1) / 2;
if (!pq->less(pq->q[index], pq->q[parent])) {
return;
}
swap(pq, parent, index);
index = parent;
}
}
int ngtcp2_pq_push(ngtcp2_pq *pq, ngtcp2_pq_entry *item) {
if (pq->capacity <= pq->length) {
void *nq;
size_t ncapacity;
ncapacity = ngtcp2_max_size(4, pq->capacity * 2);
nq = ngtcp2_mem_realloc(pq->mem, pq->q,
ncapacity * sizeof(ngtcp2_pq_entry *));
if (nq == NULL) {
return NGTCP2_ERR_NOMEM;
}
pq->capacity = ncapacity;
pq->q = nq;
}
pq->q[pq->length] = item;
item->index = pq->length;
++pq->length;
bubble_up(pq, pq->length - 1);
return 0;
}
ngtcp2_pq_entry *ngtcp2_pq_top(ngtcp2_pq *pq) {
assert(pq->length);
return pq->q[0];
}
static void bubble_down(ngtcp2_pq *pq, size_t index) {
size_t i, j, minindex;
for (;;) {
j = index * 2 + 1;
minindex = index;
for (i = 0; i < 2; ++i, ++j) {
if (j >= pq->length) {
break;
}
if (pq->less(pq->q[j], pq->q[minindex])) {
minindex = j;
}
}
if (minindex == index) {
return;
}
swap(pq, index, minindex);
index = minindex;
}
}
void ngtcp2_pq_pop(ngtcp2_pq *pq) {
if (pq->length > 0) {
pq->q[0] = pq->q[pq->length - 1];
pq->q[0]->index = 0;
--pq->length;
bubble_down(pq, 0);
}
}
void ngtcp2_pq_remove(ngtcp2_pq *pq, ngtcp2_pq_entry *item) {
assert(pq->q[item->index] == item);
if (item->index == 0) {
ngtcp2_pq_pop(pq);
return;
}
if (item->index == pq->length - 1) {
--pq->length;
return;
}
pq->q[item->index] = pq->q[pq->length - 1];
pq->q[item->index]->index = item->index;
--pq->length;
if (pq->less(item, pq->q[item->index])) {
bubble_down(pq, item->index);
} else {
bubble_up(pq, item->index);
}
}
int ngtcp2_pq_empty(ngtcp2_pq *pq) { return pq->length == 0; }
size_t ngtcp2_pq_size(ngtcp2_pq *pq) { return pq->length; }
int ngtcp2_pq_each(ngtcp2_pq *pq, ngtcp2_pq_item_cb fun, void *arg) {
size_t i;
if (pq->length == 0) {
return 0;
}
for (i = 0; i < pq->length; ++i) {
if ((*fun)(pq->q[i], arg)) {
return 1;
}
}
return 0;
}
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