table of contents
| libwget-hashmap(3) | wget2 | libwget-hashmap(3) |
NAME¶
libwget-hashmap - Hashmap functions
SYNOPSIS¶
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)
Detailed Description¶
Hashmaps are key/value stores that perform at O(1) for insertion, searching and removing.
Function Documentation¶
wget_hashmap_t* wget_hashmap_create (int max, wget_hashmap_hash_t hash, wget_hashmap_compare_t cmp)¶
Parameters
hash Hash function to build hashes from elements
cmp Comparison function used to find elements
Returns
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).
int wget_hashmap_put_noalloc (wget_hashmap_t * h, const void * key, const void * value)¶
Parameters
key Key to insert into h
value Value to insert into h
Returns
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.
int wget_hashmap_put (wget_hashmap_t * h, const void * key, size_t keysize, const void * value, size_t valuesize)¶
Parameters
key Key to insert into h
keysize Size of key
value Value to insert into h
valuesize Size of value
Returns
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.
int wget_hashmap_get_null (const wget_hashmap_t * h, const void * key, void ** value)¶
Parameters
key Key to search for
value Value to be returned
Returns
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.
void* wget_hashmap_get (const wget_hashmap_t * h, const void * key)¶
Parameters
key Key to search for
Returns
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.
int wget_hashmap_contains (const wget_hashmap_t * h, const void * key)¶
Parameters
key Key to search for
Returns
Check if key exists in h.
int wget_hashmap_remove (wget_hashmap_t * h, const void * key)¶
Parameters
key Key to be removed
Returns
Remove key from hashmap h.
If key is found, the key and value destructor functions are called when removing the entry from the hashmap.
int wget_hashmap_remove_nofree (wget_hashmap_t * h, const void * key)¶
Parameters
key Key to be removed
Returns
Remove key from hashmap h.
Key and value destructor functions are not called when removing the entry from the hashmap.
void wget_hashmap_free (wget_hashmap_t ** h)¶
Parameters
Remove all entries from hashmap h and free the hashmap instance.
Key and value destructor functions are called for each entry in the hashmap.
void wget_hashmap_clear (wget_hashmap_t * h)¶
Parameters
Remove all entries from hashmap h.
Key and value destructor functions are called for each entry in the hashmap.
int wget_hashmap_size (const wget_hashmap_t * h)¶
Parameters
Returns
Return the number of entries in the hashmap h.
int wget_hashmap_browse (const wget_hashmap_t * h, wget_hashmap_browse_t browse, void * ctx)¶
Parameters
browse Function to be called for each element of h
ctx Context variable use as param to browse
Returns
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.
void wget_hashmap_setcmpfunc (wget_hashmap_t * h, wget_hashmap_compare_t cmp)¶
Parameters
cmp Comparison function used to find keys
Set the comparison function.
void wget_hashmap_sethashfunc (wget_hashmap_t * h, wget_hashmap_hash_t hash)¶
Parameters
hash Hash function used to hash keys
Set the key hash function.
The keys of all entries in the hashmap will be hashed again.
void wget_hashmap_set_key_destructor (wget_hashmap_t * h, wget_hashmap_key_destructor_t destructor)¶
Parameters
destructor Destructor function for keys
Set the key destructor function.
Default is free().
void wget_hashmap_set_value_destructor (wget_hashmap_t * h, wget_hashmap_value_destructor_t destructor)¶
Parameters
destructor Destructor function for values
Set the value destructor function.
Default is free().
void wget_hashmap_setloadfactor (wget_hashmap_t * h, float factor)¶
Parameters
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.
void wget_hashmap_set_growth_policy (wget_hashmap_t * h, int off)¶
Parameters
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.
Author¶
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| Tue Jan 26 2021 | Version 1.99.1 |