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| -rw-r--r-- | lib/ngtcp2_ksl.h | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/lib/ngtcp2_ksl.h b/lib/ngtcp2_ksl.h new file mode 100644 index 0000000..312a151 --- /dev/null +++ b/lib/ngtcp2_ksl.h @@ -0,0 +1,345 @@ +/* + * ngtcp2 + * + * 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 NGTCP2_KSL_H +#define NGTCP2_KSL_H + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif /* HAVE_CONFIG_H */ + +#include <stdlib.h> + +#include <ngtcp2/ngtcp2.h> + +#include "ngtcp2_objalloc.h" + +/* + * Skip List using single key instead of range. + */ + +#define NGTCP2_KSL_DEGR 16 +/* NGTCP2_KSL_MAX_NBLK is the maximum number of nodes which a single + block can contain. */ +#define NGTCP2_KSL_MAX_NBLK (2 * NGTCP2_KSL_DEGR - 1) +/* NGTCP2_KSL_MIN_NBLK is the minimum number of nodes which a single + block other than root must contains. */ +#define NGTCP2_KSL_MIN_NBLK (NGTCP2_KSL_DEGR - 1) + +/* + * ngtcp2_ksl_key represents key in ngtcp2_ksl. + */ +typedef void ngtcp2_ksl_key; + +typedef struct ngtcp2_ksl_node ngtcp2_ksl_node; + +typedef struct ngtcp2_ksl_blk ngtcp2_ksl_blk; + +/* + * ngtcp2_ksl_node is a node which contains either ngtcp2_ksl_blk or + * opaque data. If a node is an internal node, it contains + * ngtcp2_ksl_blk. Otherwise, it has data. The key is stored at the + * location starting at key. + */ +struct ngtcp2_ksl_node { + union { + ngtcp2_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 ngtcp2_ksl_init is + called, the actual buffer will be allocated after this + field. */ + uint8_t key[1]; + }; +}; + +/* + * ngtcp2_ksl_blk contains ngtcp2_ksl_node objects. + */ +struct ngtcp2_ksl_blk { + union { + struct { + /* next points to the next block if leaf field is nonzero. */ + ngtcp2_ksl_blk *next; + /* prev points to the previous block if leaf field is nonzero. */ + ngtcp2_ksl_blk *prev; + /* n is the number of nodes this object contains in nodes. */ + uint32_t n; + /* leaf is nonzero if this block contains leaf nodes. */ + uint32_t leaf; + union { + uint64_t align; + /* nodes is a buffer to contain NGTCP2_KSL_MAX_NBLK + ngtcp2_ksl_node objects. Because ngtcp2_ksl_node object is + allocated along with the additional variable length key + storage, the size of buffer is unknown until ngtcp2_ksl_init is + called. */ + uint8_t nodes[1]; + }; + }; + + ngtcp2_opl_entry oplent; + }; +}; + +ngtcp2_objalloc_def(ksl_blk, ngtcp2_ksl_blk, oplent); + +/* + * ngtcp2_ksl_compar is a function type which returns nonzero if key + * |lhs| should be placed before |rhs|. It returns 0 otherwise. + */ +typedef int (*ngtcp2_ksl_compar)(const ngtcp2_ksl_key *lhs, + const ngtcp2_ksl_key *rhs); + +typedef struct ngtcp2_ksl ngtcp2_ksl; + +typedef struct ngtcp2_ksl_it ngtcp2_ksl_it; + +/* + * ngtcp2_ksl_it is a forward iterator to iterate nodes. + */ +struct ngtcp2_ksl_it { + const ngtcp2_ksl *ksl; + ngtcp2_ksl_blk *blk; + size_t i; +}; + +/* + * ngtcp2_ksl is a deterministic paged skip list. + */ +struct ngtcp2_ksl { + ngtcp2_objalloc blkalloc; + /* head points to the root block. */ + ngtcp2_ksl_blk *head; + /* front points to the first leaf block. */ + ngtcp2_ksl_blk *front; + /* back points to the last leaf block. */ + ngtcp2_ksl_blk *back; + ngtcp2_ksl_compar compar; + size_t n; + /* keylen is the size of key */ + size_t keylen; + /* nodelen is the actual size of ngtcp2_ksl_node including key + storage. */ + size_t nodelen; +}; + +/* + * ngtcp2_ksl_init initializes |ksl|. |compar| specifies compare + * function. |keylen| is the length of key. + */ +void ngtcp2_ksl_init(ngtcp2_ksl *ksl, ngtcp2_ksl_compar compar, size_t keylen, + const ngtcp2_mem *mem); + +/* + * ngtcp2_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 ngtcp2_ksl_free(ngtcp2_ksl *ksl); + +/* + * ngtcp2_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: + * + * NGTCP2_ERR_NOMEM + * Out of memory. + * NGTCP2_ERR_INVALID_ARGUMENT + * |key| already exists. + */ +int ngtcp2_ksl_insert(ngtcp2_ksl *ksl, ngtcp2_ksl_it *it, + const ngtcp2_ksl_key *key, void *data); + +/* + * ngtcp2_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 ngtcp2_ksl_end(ksl) is assigned to |*it|. + * + * This function returns 0 if it succeeds, or one of the following + * negative error codes: + * + * NGTCP2_ERR_INVALID_ARGUMENT + * |key| does not exist. + */ +int ngtcp2_ksl_remove(ngtcp2_ksl *ksl, ngtcp2_ksl_it *it, + const ngtcp2_ksl_key *key); + +/* + * ngtcp2_ksl_remove_hint removes the |key| from |ksl|. |hint| must + * point to the same node denoted by |key|. |hint| is used to remove + * a node efficiently in some cases. Other than that, it behaves + * exactly like ngtcp2_ksl_remove. |it| and |hint| can point to the + * same object. + */ +int ngtcp2_ksl_remove_hint(ngtcp2_ksl *ksl, ngtcp2_ksl_it *it, + const ngtcp2_ksl_it *hint, + const ngtcp2_ksl_key *key); + +/* + * ngtcp2_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 ngtcp2_ksl_it_end(it) + * != 0. + */ +ngtcp2_ksl_it ngtcp2_ksl_lower_bound(ngtcp2_ksl *ksl, + const ngtcp2_ksl_key *key); + +/* + * ngtcp2_ksl_lower_bound_compar works like ngtcp2_ksl_lower_bound, + * but it takes custom function |compar| to do lower bound search. + */ +ngtcp2_ksl_it ngtcp2_ksl_lower_bound_compar(ngtcp2_ksl *ksl, + const ngtcp2_ksl_key *key, + ngtcp2_ksl_compar compar); + +/* + * ngtcp2_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 ngtcp2_ksl_update_key(ngtcp2_ksl *ksl, const ngtcp2_ksl_key *old_key, + const ngtcp2_ksl_key *new_key); + +/* + * ngtcp2_ksl_begin returns the iterator which points to the first + * node. If there is no node in |ksl|, it returns the iterator which + * satisfies ngtcp2_ksl_it_end(it) != 0. + */ +ngtcp2_ksl_it ngtcp2_ksl_begin(const ngtcp2_ksl *ksl); + +/* + * ngtcp2_ksl_end returns the iterator which points to the node + * following the last node. The returned object satisfies + * ngtcp2_ksl_it_end(). If there is no node in |ksl|, it returns the + * iterator which satisfies ngtcp2_ksl_it_begin(it) != 0. + */ +ngtcp2_ksl_it ngtcp2_ksl_end(const ngtcp2_ksl *ksl); + +/* + * ngtcp2_ksl_len returns the number of elements stored in |ksl|. + */ +size_t ngtcp2_ksl_len(ngtcp2_ksl *ksl); + +/* + * ngtcp2_ksl_clear removes all elements stored in |ksl|. + */ +void ngtcp2_ksl_clear(ngtcp2_ksl *ksl); + +/* + * ngtcp2_ksl_nth_node returns the |n|th node under |blk|. + */ +#define ngtcp2_ksl_nth_node(KSL, BLK, N) \ + ((ngtcp2_ksl_node *)(void *)((BLK)->nodes + (KSL)->nodelen * (N))) + +/* + * ngtcp2_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 ngtcp2_ksl_print(ngtcp2_ksl *ksl); + +/* + * ngtcp2_ksl_it_init initializes |it|. + */ +void ngtcp2_ksl_it_init(ngtcp2_ksl_it *it, const ngtcp2_ksl *ksl, + ngtcp2_ksl_blk *blk, size_t i); + +/* + * ngtcp2_ksl_it_get returns the data associated to the node which + * |it| points to. It is undefined to call this function when + * ngtcp2_ksl_it_end(it) returns nonzero. + */ +#define ngtcp2_ksl_it_get(IT) \ + ngtcp2_ksl_nth_node((IT)->ksl, (IT)->blk, (IT)->i)->data + +/* + * ngtcp2_ksl_it_next advances the iterator by one. It is undefined + * if this function is called when ngtcp2_ksl_it_end(it) returns + * nonzero. + */ +#define ngtcp2_ksl_it_next(IT) \ + (++(IT)->i == (IT)->blk->n && (IT)->blk->next \ + ? ((IT)->blk = (IT)->blk->next, (IT)->i = 0) \ + : 0) + +/* + * ngtcp2_ksl_it_prev moves backward the iterator by one. It is + * undefined if this function is called when ngtcp2_ksl_it_begin(it) + * returns nonzero. + */ +void ngtcp2_ksl_it_prev(ngtcp2_ksl_it *it); + +/* + * ngtcp2_ksl_it_end returns nonzero if |it| points to the beyond the + * last node. + */ +#define ngtcp2_ksl_it_end(IT) \ + ((IT)->blk->n == (IT)->i && (IT)->blk->next == NULL) + +/* + * ngtcp2_ksl_it_begin returns nonzero if |it| points to the first + * node. |it| might satisfy both ngtcp2_ksl_it_begin(&it) and + * ngtcp2_ksl_it_end(&it) if the skip list has no node. + */ +int ngtcp2_ksl_it_begin(const ngtcp2_ksl_it *it); + +/* + * ngtcp2_ksl_key returns the key of the node which |it| points to. + * It is undefined to call this function when ngtcp2_ksl_it_end(it) + * returns nonzero. + */ +#define ngtcp2_ksl_it_key(IT) \ + ((ngtcp2_ksl_key *)ngtcp2_ksl_nth_node((IT)->ksl, (IT)->blk, (IT)->i)->key) + +/* + * ngtcp2_ksl_range_compar is an implementation of ngtcp2_ksl_compar. + * lhs->ptr and rhs->ptr must point to ngtcp2_range object and the + * function returns nonzero if (const ngtcp2_range *)(lhs->ptr)->begin + * < (const ngtcp2_range *)(rhs->ptr)->begin. + */ +int ngtcp2_ksl_range_compar(const ngtcp2_ksl_key *lhs, + const ngtcp2_ksl_key *rhs); + +/* + * ngtcp2_ksl_range_exclusive_compar is an implementation of + * ngtcp2_ksl_compar. lhs->ptr and rhs->ptr must point to + * ngtcp2_range object and the function returns nonzero if (const + * ngtcp2_range *)(lhs->ptr)->begin < (const ngtcp2_range + * *)(rhs->ptr)->begin and the 2 ranges do not intersect. + */ +int ngtcp2_ksl_range_exclusive_compar(const ngtcp2_ksl_key *lhs, + const ngtcp2_ksl_key *rhs); + +#endif /* NGTCP2_KSL_H */ |