/*
* Copyright (C) Igor Sysoev
* Copyright (C) NGINX, Inc.
*/
#ifndef _NXT_LEVEL_HASH_H_INCLUDED_
#define _NXT_LEVEL_HASH_H_INCLUDED_
typedef struct nxt_lvlhsh_query_s nxt_lvlhsh_query_t;
typedef nxt_int_t (*nxt_lvlhsh_test_t)(nxt_lvlhsh_query_t *lhq, void *data);
typedef void *(*nxt_lvlhsh_alloc_t)(void *ctx, size_t size);
typedef void (*nxt_lvlhsh_free_t)(void *ctx, void *p);
#if (NXT_64BIT)
#define NXT_LVLHSH_DEFAULT_BUCKET_SIZE 128
#define NXT_LVLHSH_ENTRY_SIZE 3
#define NXT_LVLHSH_BATCH_ALLOC 16
/* 3 is shift of 64-bit pointer. */
#define NXT_LVLHSH_MEMALIGN_SHIFT (NXT_MAX_MEMALIGN_SHIFT - 3)
#else
#define NXT_LVLHSH_DEFAULT_BUCKET_SIZE 64
#define NXT_LVLHSH_ENTRY_SIZE 2
#define NXT_LVLHSH_BATCH_ALLOC 8
/* 2 is shift of 32-bit pointer. */
#define NXT_LVLHSH_MEMALIGN_SHIFT (NXT_MAX_MEMALIGN_SHIFT - 2)
#endif
#if (NXT_LVLHSH_MEMALIGN_SHIFT < 10)
#define NXT_LVLHSH_MAX_MEMALIGN_SHIFT NXT_LVLHSH_MEMALIGN_SHIFT
#else
#define NXT_LVLHSH_MAX_MEMALIGN_SHIFT 10
#endif
#define NXT_LVLHSH_BUCKET_END(bucket_size) \
(((bucket_size) - sizeof(void *)) \
/ (NXT_LVLHSH_ENTRY_SIZE * sizeof(uint32_t)) \
* NXT_LVLHSH_ENTRY_SIZE)
#define NXT_LVLHSH_BUCKET_SIZE(bucket_size) \
NXT_LVLHSH_BUCKET_END(bucket_size), bucket_size, (bucket_size - 1)
#define NXT_LVLHSH_DEFAULT \
NXT_LVLHSH_BUCKET_SIZE(NXT_LVLHSH_DEFAULT_BUCKET_SIZE), \
{ 4, 4, 4, 4, 4, 4, 4, 0 }
#define NXT_LVLHSH_LARGE_SLAB \
NXT_LVLHSH_BUCKET_SIZE(NXT_LVLHSH_DEFAULT_BUCKET_SIZE), \
{ 10, 4, 4, 4, 4, 4, 4, 0 }
#define NXT_LVLHSH_LARGE_MEMALIGN \
NXT_LVLHSH_BUCKET_SIZE(NXT_LVLHSH_DEFAULT_BUCKET_SIZE), \
{ NXT_LVLHSH_MAX_MEMALIGN_SHIFT, 4, 4, 4, 4, 0, 0, 0 }
typedef struct {
uint32_t bucket_end;
uint32_t bucket_size;
uint32_t bucket_mask;
uint8_t shift[8];
nxt_lvlhsh_test_t test;
nxt_lvlhsh_alloc_t alloc;
nxt_lvlhsh_free_t free;
} nxt_lvlhsh_proto_t;
typedef struct {
void *slot;
} nxt_lvlhsh_t;
struct nxt_lvlhsh_query_s {
uint32_t key_hash;
uint32_t replace; /* 1 bit */
nxt_str_t key;
void *value;
const nxt_lvlhsh_proto_t *proto;
void *pool;
/* Opaque data passed for the test function. */
void *data;
};
typedef struct {
const nxt_lvlhsh_proto_t *proto;
/*
* Fields to store current bucket entry position. They cannot be
* combined in a single bucket pointer with number of entries in low
* bits, because entry positions are not aligned. A current level is
* stored as key bit path from the root.
*/
uint32_t *bucket;
uint32_t current;
uint32_t entry;
uint32_t entries;
} nxt_lvlhsh_each_t;
#define nxt_lvlhsh_is_empty(lh) \
((lh)->slot == NULL)
#define nxt_lvlhsh_init(lh) \
(lh)->slot = NULL
/*
* nxt_lvlhsh_find() finds a hash element. If the element has been
* found then it is stored in the lhq->value and nxt_lvlhsh_find()
* returns NXT_OK. Otherwise NXT_DECLINED is returned.
*
* The required nxt_lvlhsh_query_t fields: key_hash, key, proto.
*/
NXT_EXPORT nxt_int_t nxt_lvlhsh_find(nxt_lvlhsh_t *lh, nxt_lvlhsh_query_t *lhq);
/*
* nxt_lvlhsh_insert() adds a hash element. If the element already
* presents in lvlhsh and the lhq->replace flag is zero, then lhq->value
* is updated with the old element and NXT_DECLINED is returned.
* If the element already presents in lvlhsh and the lhq->replace flag
* is non-zero, then the old element is replaced with the new element.
* lhq->value is updated with the old element, and NXT_OK is returned.
* If the element is not present in lvlhsh, then it is inserted and
* NXT_OK is returned. The lhq->value is not changed.
* On memory allocation failure NXT_ERROR is returned.
*
* The required nxt_lvlhsh_query_t fields: key_hash, key, proto, replace, value.
* The optional nxt_lvlhsh_query_t fields: pool.
*/
NXT_EXPORT nxt_int_t nxt_lvlhsh_insert(nxt_lvlhsh_t *lh,
nxt_lvlhsh_query_t *lhq);
/*
* nxt_lvlhsh_delete() deletes a hash element. If the element has been
* found then it is removed from lvlhsh and is stored in the lhq->value,
* and NXT_OK is returned. Otherwise NXT_DECLINED is returned.
*
* The required nxt_lvlhsh_query_t fields: key_hash, key, proto.
* The optional nxt_lvlhsh_query_t fields: pool.
*/
NXT_EXPORT nxt_int_t nxt_lvlhsh_delete(nxt_lvlhsh_t *lh,
nxt_lvlhsh_query_t *lhq);
/*
* nxt_lvlhsh_each_init() initializes iterator.
* It must be called before the first nxt_lvlhsh_each() call.
*/
#define nxt_lvlhsh_each_init(lhe, _proto) \
do { \
(lhe)->proto = _proto; \
(lhe)->bucket = NULL; \
} while (0)
/*
* nxt_lvlhsh_each() iterates over a lvlhsh.
* It returns NULL if there is no more elements.
*/
NXT_EXPORT void *nxt_lvlhsh_each(nxt_lvlhsh_t *lh, nxt_lvlhsh_each_t *lhe);
/*
* nxt_lvlhsh_peek() is used to iterate over a lvlhsh during the lvlhsh
* destruction. The returned hash element should be deleted from the lvlhsh,
* otherwise it will be returned again by the next nxt_lvlhsh_peek() call.
* The function returns NULL if there is no more elements in the lvlhsh.
*/
NXT_EXPORT void *nxt_lvlhsh_peek(nxt_lvlhsh_t *lh,
const nxt_lvlhsh_proto_t *proto);
/*
* nxt_lvlhsh_retrieve() is used to iterate over a lvlhsh during the lvlhsh
* destruction. As opposed to nxt_lvlhsh_peek() the returned hash element
* is deleted from the lvlhsh. The function returns NULL if there is no
* more elements in the lvlhsh.
*/
NXT_EXPORT void *nxt_lvlhsh_retrieve(nxt_lvlhsh_t *lh,
const nxt_lvlhsh_proto_t *proto, void *pool);
NXT_EXPORT void *nxt_lvlhsh_alloc(void *data, size_t size);
NXT_EXPORT void nxt_lvlhsh_free(void *data, void *p);
#endif /* _NXT_LEVEL_HASH_H_INCLUDED_ */
