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libwget-hashmap(3) wget2 libwget-hashmap(3)

libwget-hashmap - Hashmap functions


wget_hashmap_t * wget_hashmap_create (int max, wget_hashmap_hash_t hash, wget_hashmap_compare_t cmp)
int wget_hashmap_put_noalloc (wget_hashmap_t *h, const void *key, const void *value)
int wget_hashmap_put (wget_hashmap_t *h, const void *key, size_t keysize, const void *value, size_t valuesize)
int wget_hashmap_get_null (const wget_hashmap_t *h, const void *key, void **value)
void * wget_hashmap_get (const wget_hashmap_t *h, const void *key)
int wget_hashmap_contains (const wget_hashmap_t *h, const void *key)
int wget_hashmap_remove (wget_hashmap_t *h, const void *key)
int wget_hashmap_remove_nofree (wget_hashmap_t *h, const void *key)
void wget_hashmap_free (wget_hashmap_t **h)
void wget_hashmap_clear (wget_hashmap_t *h)
int wget_hashmap_size (const wget_hashmap_t *h)
int wget_hashmap_browse (const wget_hashmap_t *h, wget_hashmap_browse_t browse, void *ctx)
void wget_hashmap_setcmpfunc (wget_hashmap_t *h, wget_hashmap_compare_t cmp)
void wget_hashmap_sethashfunc (wget_hashmap_t *h, wget_hashmap_hash_t hash)
void wget_hashmap_set_key_destructor (wget_hashmap_t *h, wget_hashmap_key_destructor_t destructor)
void wget_hashmap_set_value_destructor (wget_hashmap_t *h, wget_hashmap_value_destructor_t destructor)
void wget_hashmap_setloadfactor (wget_hashmap_t *h, float factor)
void wget_hashmap_set_growth_policy (wget_hashmap_t *h, int off)

Hashmaps are key/value stores that perform at O(1) for insertion, searching and removing.

Parameters

max Initial number of pre-allocated entries
hash Hash function to build hashes from elements
cmp Comparison function used to find elements

Returns

New hashmap instance

Create a new hashmap instance with initial size max. It should be free'd after use with wget_hashmap_free().

Before the first insertion of an element, hash and cmp must be set. So if you use NULL values here, you have to call wget_hashmap_setcmpfunc() and/or wget_hashmap_hashcmpfunc() with appropriate function pointers. No doing so will result in undefined behavior (likely you'll see a segmentation fault).

Parameters

h Hashmap to put data into
key Key to insert into h
value Value to insert into h

Returns

0 if inserted a new entry, 1 if entry existed

Insert a key/value pair into hashmap h.

key and value are not cloned, the hashmap takes 'ownership' of both.

If key already exists and the pointer values the old and the new key differ, the old key will be destroyed by calling the key destructor function (default is free()).

To realize a hashset (just keys without values), value may be NULL.

Neither h nor key must be NULL.

Parameters

h Hashmap to put data into
key Key to insert into h
keysize Size of key
value Value to insert into h
valuesize Size of value

Returns

0 if inserted a new entry, 1 if entry existed

Insert a key/value pair into hashmap h.

If key already exists it will not be cloned. In this case the value destructor function will be called with the old value and the new value will be shallow cloned.

If doesn't exist, both key and value will be shallow cloned.

To realize a hashset (just keys without values), value may be NULL.

Neither h nor key must be NULL.

Parameters

h Hashmap
key Key to search for
value Value to be returned

Returns

1 if key has been found, 0 if not found

Get the value for a given key.

If there are NULL values in the hashmap, you should use this function to distinguish between 'not found' and 'found NULL value'.

Neither h nor key must be NULL.

Parameters

h Hashmap
key Key to search for

Returns

Found value or NULL if not found

Get the value for a given key.

If there are NULL values in the hashmap, you should use wget_hashmap_get_null() to distinguish between 'not found' and 'found NULL value'.

Neither h nor key must be NULL.

Parameters

h Hashmap
key Key to search for

Returns

1 if key has been found, 0 if not found

Check if key exists in h.

Parameters

h Hashmap
key Key to be removed

Returns

1 if key has been removed, 0 if not found

Remove key from hashmap h.

If key is found, the key and value destructor functions are called when removing the entry from the hashmap.

Parameters

h Hashmap
key Key to be removed

Returns

1 if key has been removed, 0 if not found

Remove key from hashmap h.

Key and value destructor functions are not called when removing the entry from the hashmap.

Parameters

h Hashmap to be free'd

Remove all entries from hashmap h and free the hashmap instance.

Key and value destructor functions are called for each entry in the hashmap.

Parameters

h Hashmap to be cleared

Remove all entries from hashmap h.

Key and value destructor functions are called for each entry in the hashmap.

Parameters

h Hashmap

Returns

Number of entries in hashmap h

Return the number of entries in the hashmap h.

Parameters

h Hashmap
browse Function to be called for each element of h
ctx Context variable use as param to browse

Returns

Return value of the last call to browse

Call function browse for each element of hashmap h or until browse returns a value not equal to zero.

browse is called with ctx and the pointer to the current element.

The return value of the last call to browse is returned or 0 if either h or browse is NULL.

Parameters

h Hashmap
cmp Comparison function used to find keys

Set the comparison function.

Parameters

h Hashmap
hash Hash function used to hash keys

Set the key hash function.

The keys of all entries in the hashmap will be hashed again.

Parameters

h Hashmap
destructor Destructor function for keys

Set the key destructor function.

Default is free().

Parameters

h Hashmap
destructor Destructor function for values

Set the value destructor function.

Default is free().

Parameters

h Hashmap
factor The load factor

Set the load factor function.

The load factor is determines when to resize the internal memory. 0.75 means 'resize if 75% or more of all slots are used'.

The resize strategy is set by wget_hashmap_set_growth_policy().

The resize (and rehashing) occurs earliest on the next insertion of a new key.

Default is 0.75.

Parameters

h Hashmap
off Hashmap growth mode: positive values: increase size by off entries on each resize negative values: increase size by multiplying -off, e.g. -2 doubles the size on each resize

Set the growth policy for internal memory.

Default is -2.

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Tue Jan 26 2021 Version 1.99.1