nghttp2/lib/nghttp2_pq.c

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/*
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* nghttp2 - HTTP/2.0 C Library
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*
* Copyright (c) 2012 Tatsuhiro Tsujikawa
*
* 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.
*/
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#include "nghttp2_pq.h"
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int nghttp2_pq_init(nghttp2_pq *pq, nghttp2_compar compar)
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{
pq->capacity = 4096;
pq->q = malloc(pq->capacity * sizeof(void*));
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if(pq->q == NULL) {
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return NGHTTP2_ERR_NOMEM;
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}
pq->length = 0;
pq->compar = compar;
return 0;
}
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void nghttp2_pq_free(nghttp2_pq *pq)
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{
free(pq->q);
pq->q = NULL;
}
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static void swap(nghttp2_pq *pq, size_t i, size_t j)
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{
void *t = pq->q[i];
pq->q[i] = pq->q[j];
pq->q[j] = t;
}
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static void bubble_up(nghttp2_pq *pq, size_t index)
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{
if(index == 0) {
return;
} else {
size_t parent = (index-1)/2;
if(pq->compar(pq->q[parent], pq->q[index]) > 0) {
swap(pq, parent, index);
bubble_up(pq, parent);
}
}
}
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int nghttp2_pq_push(nghttp2_pq *pq, void *item)
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{
if(pq->capacity <= pq->length) {
void *nq;
nq = realloc(pq->q, (pq->capacity*2) * sizeof(void*));
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if(nq == NULL) {
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return NGHTTP2_ERR_NOMEM;
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}
pq->capacity *= 2;
pq->q = nq;
}
pq->q[pq->length] = item;
++pq->length;
bubble_up(pq, pq->length-1);
return 0;
}
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void* nghttp2_pq_top(nghttp2_pq *pq)
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{
if(pq->length == 0) {
return NULL;
} else {
return pq->q[0];
}
}
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static void bubble_down(nghttp2_pq *pq, size_t index)
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{
size_t lchild = index*2+1;
size_t minindex = index;
size_t i, j;
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for(i = 0; i < 2; ++i) {
j = lchild+i;
if(j >= pq->length) {
break;
}
if(pq->compar(pq->q[minindex], pq->q[j]) > 0) {
minindex = j;
}
}
if(minindex != index) {
swap(pq, index, minindex);
bubble_down(pq, minindex);
}
}
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void nghttp2_pq_pop(nghttp2_pq *pq)
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{
if(pq->length > 0) {
pq->q[0] = pq->q[pq->length-1];
--pq->length;
bubble_down(pq, 0);
}
}
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int nghttp2_pq_empty(nghttp2_pq *pq)
{
return pq->length == 0;
}
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size_t nghttp2_pq_size(nghttp2_pq *pq)
{
return pq->length;
}
void nghttp2_pq_update(nghttp2_pq *pq, nghttp2_pq_item_cb fun, void *arg)
{
size_t i;
int rv = 0;
if(pq->length == 0) {
return;
}
for(i = 0; i < pq->length; ++i) {
rv |= (*fun)(pq->q[i], arg);
}
if(rv) {
for(i = pq->length; i > 0; --i) {
bubble_down(pq, i - 1);
}
}
}