nghttp2/lib/nghttp2_pq.h

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/*
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* nghttp2 - HTTP/2 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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#ifndef NGHTTP2_PQ_H
#define NGHTTP2_PQ_H
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif /* HAVE_CONFIG_H */
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#include <nghttp2/nghttp2.h>
#include "nghttp2_int.h"
#include "nghttp2_mem.h"
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/* Implementation of priority queue */
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typedef struct {
size_t index;
} nghttp2_pq_entry;
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typedef struct {
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/* The pointer to the pointer to the item stored */
nghttp2_pq_entry **q;
/* Memory allocator */
nghttp2_mem *mem;
/* The number of items stored */
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size_t length;
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/* The maximum number of items this pq can store. This is
automatically extended when length is reached to this value. */
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size_t capacity;
/* The less function between items */
nghttp2_less less;
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} nghttp2_pq;
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/*
* Initializes priority queue |pq| with compare function |cmp|.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
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* NGHTTP2_ERR_NOMEM
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* Out of memory.
*/
int nghttp2_pq_init(nghttp2_pq *pq, nghttp2_less less, nghttp2_mem *mem);
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/*
* Deallocates any resources allocated for |pq|. The stored items are
* not freed by this function.
*/
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void nghttp2_pq_free(nghttp2_pq *pq);
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/*
* Adds |item| to the priority queue |pq|.
*
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* This function returns 0 if it succeeds, or one of the following
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* negative error codes:
*
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* NGHTTP2_ERR_NOMEM
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* Out of memory.
*/
int nghttp2_pq_push(nghttp2_pq *pq, nghttp2_pq_entry *item);
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/*
* Returns item at the top of the queue |pq|. If the queue is empty,
* this function returns NULL.
*/
nghttp2_pq_entry *nghttp2_pq_top(nghttp2_pq *pq);
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/*
* Pops item at the top of the queue |pq|. The popped item is not
* freed by this function.
*/
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void nghttp2_pq_pop(nghttp2_pq *pq);
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/*
* Returns nonzero if the queue |pq| is empty.
*/
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int nghttp2_pq_empty(nghttp2_pq *pq);
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/*
* Returns the number of items in the queue |pq|.
*/
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size_t nghttp2_pq_size(nghttp2_pq *pq);
typedef int (*nghttp2_pq_item_cb)(nghttp2_pq_entry *item, void *arg);
/*
* Updates each item in |pq| using function |fun| and re-construct
* priority queue. The |fun| must return non-zero if it modifies the
* item in a way that it affects ordering in the priority queue. The
* |arg| is passed to the 2nd parameter of |fun|.
*/
void nghttp2_pq_update(nghttp2_pq *pq, nghttp2_pq_item_cb fun, void *arg);
/*
* Applys |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 nghttp2_pq_each(nghttp2_pq *pq, nghttp2_pq_item_cb fun, void *arg);
/*
* Removes |item| from priority queue.
*/
void nghttp2_pq_remove(nghttp2_pq *pq, nghttp2_pq_entry *item);
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#endif /* NGHTTP2_PQ_H */