nghttp2/lib/nghttp2_ksl.h

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2020-07-26 07:00:45 +02:00
/*
* nghttp2 - HTTP/2 C Library
*
* Copyright (c) 2020 nghttp2 contributors
* Copyright (c) 2018 ngtcp2 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 NGHTTP2_KSL_H
#define NGHTTP2_KSL_H
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif /* HAVE_CONFIG_H */
#include <stdlib.h>
#include <nghttp2/nghttp2.h>
/*
* Skip List using single key instead of range.
*/
#define NGHTTP2_KSL_DEGR 16
/* NGHTTP2_KSL_MAX_NBLK is the maximum number of nodes which a single
block can contain. */
#define NGHTTP2_KSL_MAX_NBLK (2 * NGHTTP2_KSL_DEGR - 1)
/* NGHTTP2_KSL_MIN_NBLK is the minimum number of nodes which a single
block other than root must contains. */
#define NGHTTP2_KSL_MIN_NBLK (NGHTTP2_KSL_DEGR - 1)
/*
* nghttp2_ksl_key represents key in nghttp2_ksl.
*/
typedef void nghttp2_ksl_key;
struct nghttp2_ksl_node;
typedef struct nghttp2_ksl_node nghttp2_ksl_node;
struct nghttp2_ksl_blk;
typedef struct nghttp2_ksl_blk nghttp2_ksl_blk;
/*
* nghttp2_ksl_node is a node which contains either nghttp2_ksl_blk or
* opaque data. If a node is an internal node, it contains
* nghttp2_ksl_blk. Otherwise, it has data. The key is stored at the
* location starting at key.
*/
struct nghttp2_ksl_node {
union {
nghttp2_ksl_blk *blk;
void *data;
};
union {
uint64_t align;
/* key is a buffer to include key associated to this node.
Because the length of key is unknown until nghttp2_ksl_init is
called, the actual buffer will be allocated after this
field. */
uint8_t key[1];
};
};
/*
* nghttp2_ksl_blk contains nghttp2_ksl_node objects.
*/
struct nghttp2_ksl_blk {
/* next points to the next block if leaf field is nonzero. */
nghttp2_ksl_blk *next;
/* prev points to the previous block if leaf field is nonzero. */
nghttp2_ksl_blk *prev;
/* n is the number of nodes this object contains in nodes. */
size_t n;
/* leaf is nonzero if this block contains leaf nodes. */
int leaf;
union {
uint64_t align;
/* nodes is a buffer to contain NGHTTP2_KSL_MAX_NBLK
nghttp2_ksl_node objects. Because nghttp2_ksl_node object is
allocated along with the additional variable length key
storage, the size of buffer is unknown until nghttp2_ksl_init is
called. */
uint8_t nodes[1];
};
};
/*
* nghttp2_ksl_compar is a function type which returns nonzero if key
* |lhs| should be placed before |rhs|. It returns 0 otherwise.
*/
typedef int (*nghttp2_ksl_compar)(const nghttp2_ksl_key *lhs,
const nghttp2_ksl_key *rhs);
struct nghttp2_ksl;
typedef struct nghttp2_ksl nghttp2_ksl;
struct nghttp2_ksl_it;
typedef struct nghttp2_ksl_it nghttp2_ksl_it;
/*
* nghttp2_ksl_it is a forward iterator to iterate nodes.
*/
struct nghttp2_ksl_it {
const nghttp2_ksl *ksl;
nghttp2_ksl_blk *blk;
size_t i;
};
/*
* nghttp2_ksl is a deterministic paged skip list.
*/
struct nghttp2_ksl {
/* head points to the root block. */
nghttp2_ksl_blk *head;
/* front points to the first leaf block. */
nghttp2_ksl_blk *front;
/* back points to the last leaf block. */
nghttp2_ksl_blk *back;
nghttp2_ksl_compar compar;
size_t n;
/* keylen is the size of key */
size_t keylen;
/* nodelen is the actual size of nghttp2_ksl_node including key
storage. */
size_t nodelen;
nghttp2_mem *mem;
};
/*
* nghttp2_ksl_init initializes |ksl|. |compar| specifies compare
* function. |keylen| is the length of key.
*
* It returns 0 if it succeeds, or one of the following negative error
* codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
*/
int nghttp2_ksl_init(nghttp2_ksl *ksl, nghttp2_ksl_compar compar, size_t keylen,
nghttp2_mem *mem);
/*
* nghttp2_ksl_free frees resources allocated for |ksl|. If |ksl| is
* NULL, this function does nothing. It does not free the memory
* region pointed by |ksl| itself.
*/
void nghttp2_ksl_free(nghttp2_ksl *ksl);
/*
* nghttp2_ksl_insert inserts |key| with its associated |data|. On
* successful insertion, the iterator points to the inserted node is
* stored in |*it|.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_NOMEM
* Out of memory.
* NGHTTP2_ERR_INVALID_ARGUMENT
* |key| already exists.
*/
int nghttp2_ksl_insert(nghttp2_ksl *ksl, nghttp2_ksl_it *it,
const nghttp2_ksl_key *key, void *data);
/*
* nghttp2_ksl_remove removes the |key| from |ksl|.
*
* This function assigns the iterator to |*it|, which points to the
* node which is located at the right next of the removed node if |it|
* is not NULL. If |key| is not found, no deletion takes place and
* the return value of nghttp2_ksl_end(ksl) is assigned to |*it|.
*
* This function returns 0 if it succeeds, or one of the following
* negative error codes:
*
* NGHTTP2_ERR_INVALID_ARGUMENT
* |key| does not exist.
*/
int nghttp2_ksl_remove(nghttp2_ksl *ksl, nghttp2_ksl_it *it,
const nghttp2_ksl_key *key);
/*
* nghttp2_ksl_lower_bound returns the iterator which points to the
* first node which has the key which is equal to |key| or the last
* node which satisfies !compar(&node->key, key). If there is no such
* node, it returns the iterator which satisfies nghttp2_ksl_it_end(it)
* != 0.
*/
nghttp2_ksl_it nghttp2_ksl_lower_bound(nghttp2_ksl *ksl,
const nghttp2_ksl_key *key);
/*
* nghttp2_ksl_lower_bound_compar works like nghttp2_ksl_lower_bound,
* but it takes custom function |compar| to do lower bound search.
*/
nghttp2_ksl_it nghttp2_ksl_lower_bound_compar(nghttp2_ksl *ksl,
const nghttp2_ksl_key *key,
nghttp2_ksl_compar compar);
/*
* nghttp2_ksl_update_key replaces the key of nodes which has |old_key|
* with |new_key|. |new_key| must be strictly greater than the
* previous node and strictly smaller than the next node.
*/
void nghttp2_ksl_update_key(nghttp2_ksl *ksl, const nghttp2_ksl_key *old_key,
const nghttp2_ksl_key *new_key);
/*
* nghttp2_ksl_begin returns the iterator which points to the first
* node. If there is no node in |ksl|, it returns the iterator which
* satisfies nghttp2_ksl_it_end(it) != 0.
*/
nghttp2_ksl_it nghttp2_ksl_begin(const nghttp2_ksl *ksl);
/*
* nghttp2_ksl_end returns the iterator which points to the node
* following the last node. The returned object satisfies
* nghttp2_ksl_it_end(). If there is no node in |ksl|, it returns the
* iterator which satisfies nghttp2_ksl_it_begin(it) != 0.
*/
nghttp2_ksl_it nghttp2_ksl_end(const nghttp2_ksl *ksl);
/*
* nghttp2_ksl_len returns the number of elements stored in |ksl|.
*/
size_t nghttp2_ksl_len(nghttp2_ksl *ksl);
/*
* nghttp2_ksl_clear removes all elements stored in |ksl|.
*/
void nghttp2_ksl_clear(nghttp2_ksl *ksl);
/*
* nghttp2_ksl_nth_node returns the |n|th node under |blk|.
*/
#define nghttp2_ksl_nth_node(KSL, BLK, N) \
((nghttp2_ksl_node *)(void *)((BLK)->nodes + (KSL)->nodelen * (N)))
/*
* nghttp2_ksl_print prints its internal state in stderr. It assumes
* that the key is of type int64_t. This function should be used for
* the debugging purpose only.
*/
void nghttp2_ksl_print(nghttp2_ksl *ksl);
/*
* nghttp2_ksl_it_init initializes |it|.
*/
void nghttp2_ksl_it_init(nghttp2_ksl_it *it, const nghttp2_ksl *ksl,
nghttp2_ksl_blk *blk, size_t i);
/*
* nghttp2_ksl_it_get returns the data associated to the node which
* |it| points to. It is undefined to call this function when
* nghttp2_ksl_it_end(it) returns nonzero.
*/
void *nghttp2_ksl_it_get(const nghttp2_ksl_it *it);
/*
* nghttp2_ksl_it_next advances the iterator by one. It is undefined
* if this function is called when nghttp2_ksl_it_end(it) returns
* nonzero.
*/
#define nghttp2_ksl_it_next(IT) \
(++(IT)->i == (IT)->blk->n && (IT)->blk->next \
? ((IT)->blk = (IT)->blk->next, (IT)->i = 0) \
: 0)
/*
* nghttp2_ksl_it_prev moves backward the iterator by one. It is
* undefined if this function is called when nghttp2_ksl_it_begin(it)
* returns nonzero.
*/
void nghttp2_ksl_it_prev(nghttp2_ksl_it *it);
/*
* nghttp2_ksl_it_end returns nonzero if |it| points to the beyond the
* last node.
*/
#define nghttp2_ksl_it_end(IT) \
((IT)->blk->n == (IT)->i && (IT)->blk->next == NULL)
/*
* nghttp2_ksl_it_begin returns nonzero if |it| points to the first
* node. |it| might satisfy both nghttp2_ksl_it_begin(&it) and
* nghttp2_ksl_it_end(&it) if the skip list has no node.
*/
int nghttp2_ksl_it_begin(const nghttp2_ksl_it *it);
/*
* nghttp2_ksl_key returns the key of the node which |it| points to.
* It is undefined to call this function when nghttp2_ksl_it_end(it)
* returns nonzero.
*/
#define nghttp2_ksl_it_key(IT) \
((nghttp2_ksl_key *)nghttp2_ksl_nth_node((IT)->ksl, (IT)->blk, (IT)->i)->key)
#endif /* NGHTTP2_KSL_H */