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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.
*/
#ifndef NGTCP2_PQ_H
#define NGTCP2_PQ_H
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <ngtcp2/ngtcp2.h>
#include "ngtcp2_mem.h"
/* Implementation of priority queue */
/* NGTCP2_PQ_BAD_INDEX is the priority queue index which indicates
that an entry is not queued. Assigning this value to
ngtcp2_pq_entry.index can check that the entry is queued or not. */
#define NGTCP2_PQ_BAD_INDEX SIZE_MAX
typedef struct ngtcp2_pq_entry {
size_t index;
} ngtcp2_pq_entry;
/* "less" function, return nonzero if |lhs| is less than |rhs|. */
typedef int (*ngtcp2_less)(const ngtcp2_pq_entry *lhs,
const ngtcp2_pq_entry *rhs);
typedef struct ngtcp2_pq {
/* The pointer to the pointer to the item stored */
ngtcp2_pq_entry **q;
/* Memory allocator */
const ngtcp2_mem *mem;
/* The number of items stored */
size_t length;
/* The maximum number of items this pq can store. This is
automatically extended when length is reached to this value. */
size_t capacity;
/* The less function between items */
ngtcp2_less less;
} ngtcp2_pq;
/*
* Initializes priority queue |pq| with compare function |cmp|.
*/
void ngtcp2_pq_init(ngtcp2_pq *pq, ngtcp2_less less, const ngtcp2_mem *mem);
/*
* Deallocates any resources allocated for |pq|. The stored items are
* not freed by this function.
*/
void ngtcp2_pq_free(ngtcp2_pq *pq);
/*
* Adds |item| to the priority queue |pq|.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGTCP2_ERR_NOMEM
* Out of memory.
*/
int ngtcp2_pq_push(ngtcp2_pq *pq, ngtcp2_pq_entry *item);
/*
* Returns item at the top of the queue |pq|. It is undefined if the
* queue is empty.
*/
ngtcp2_pq_entry *ngtcp2_pq_top(ngtcp2_pq *pq);
/*
* Pops item at the top of the queue |pq|. The popped item is not
* freed by this function.
*/
void ngtcp2_pq_pop(ngtcp2_pq *pq);
/*
* Returns nonzero if the queue |pq| is empty.
*/
int ngtcp2_pq_empty(ngtcp2_pq *pq);
/*
* Returns the number of items in the queue |pq|.
*/
size_t ngtcp2_pq_size(ngtcp2_pq *pq);
typedef int (*ngtcp2_pq_item_cb)(ngtcp2_pq_entry *item, void *arg);
/*
* Applies |fun| to each item in |pq|. The |arg| is passed as arg
* parameter to callback function. This function must not change the
* ordering key. If the return value from callback is nonzero, this
* function returns 1 immediately without iterating remaining items.
* Otherwise this function returns 0.
*/
int ngtcp2_pq_each(ngtcp2_pq *pq, ngtcp2_pq_item_cb fun, void *arg);
/*
* Removes |item| from priority queue.
*/
void ngtcp2_pq_remove(ngtcp2_pq *pq, ngtcp2_pq_entry *item);
#endif /* NGTCP2_PQ_H */
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