cp_hashtable(3) - Linux man page

Name

cp_hashtable - a general purpose hashtable implementation

Description

cp_hashtable is a general purpose hashtable implementation. Instances may be created with a specifiable degree of internal or external synchronization and entry memory management. It is also possible to specify the load factors controlling when internal table resizes occur.

Interface

the following is a summary of functions provided by <cprops/hashtable.h>.

CONSTRUCTOR FUNCTIONS

cp_hashtable *cp_hashtable_create(unsigned long size_hint,

cp_hashfunction hash_fn, cp_compare_fn compare_fn);
cp_hashtable *cp_hashtable_create_by_mode(int mode,

int size_hint, cp_hashfunction hash_fn, cp_compare_fn compare_fn);
cp_hashtable *

cp_hashtable_create_copy_mode(unsigned long size_hint,

cp_hashfunction cp_hashfn, cp_compare_fn compare_fn, cp_copy_fn copy_key, cp_destructor_fn free_key); cp_copy_fn copy_value cp_destructor_fn free_value);
cp_hashtable *

cp_hashtable_create_by_option(int mode,

unsigned long size_hint, cp_hashfunction hash_fn, cp_compare_fn compare_fn, cp_copy_fn copy_key, cp_destructor_fn free_key); cp_copy_fn copy_value cp_destructor_fn free_value);

DESTRUCTOR FUNCTIONS

void cp_hashtable_destroy(cp_hashtable *table); void cp_hashtable_destroy_shallow(cp_hashtable *table); void cp_hashtable_destroy_deep(cp_hashtable *table); void cp_hashtable_destroy_custom(cp_hashtable *table,

cp_destructor_fn dk, cp_destructor_fn dv);

ITEM INSERTION

void *cp_hashtable_put(cp_hashtable *table, void *key, void *value); void *cp_hashtable_put_by_option(cp_hashtable *table, void *key,

void *value, int mode);

void *cp_hashtable_put_safe(cp_hashtable *table, void * key,

void *value);

void *cp_hashtable_put_copy(cp_hashtable *table, void *key,

void *value);

ITEM RETRIEVAL

void *cp_hashtable_get(cp_hashtable *table, void *key); void *cp_hashtable_get_by_option(cp_hashtable *table, void *key,

int mode);

void **cp_hashtable_get_keys(cp_hashtable *table);
void **cp_hashtable_get_values(cp_hashtable *table);
int cp_hashtable_contains(cp_hashtable *table, void *key);

ITEM REMOVAL

void *cp_hashtable_remove(cp_hashtable *table, void *key); int cp_hashtable_remove_deep(cp_hashtable *table, void *key); int cp_hashtable_remove_all(cp_hashtable *table);

BEHAVIOR

int cp_hashtable_set_mode(cp_hashtable *table, int mode);
int cp_hashtable_unset_mode(cp_hashtable *table, int mode);
int cp_hashtable_set_min_size(cp_hashtable *table, int size);
int cp_hashtable_set_min_fill_factor(cp_hashtable *table, int factor);
int cp_hashtable_set_max_fill_factor(cp_hashtable *table, int factor);

SYNCHRONIZATION

int cp_hashtable_lock(cp_hashtable *table, int type);
int cp_hashtable_unlock(cp_hashtable *table);
int cp_hashtable_rdlock(cp_hashtable *table);
int cp_hashtable_wrlock(cp_hashtable *table);

OTHER

unsigned long cp_hashtable_count(cp_hashtable *table); cp_hashtable_is_empty(cp_hashtable *table);

HASH- and COMPARISON FUNCTIONS

libcprops provides the following hash function implementations for primitives and null terminated strings:

unsigned long cp_hash_char(void *key);
int cp_hash_compare_char(void *a, void *b);
unsigned long cp_hash_int(void *key);
int cp_hash_compare_int(void *a, void *b);
unsigned long cp_hash_long(void *key);
int cp_hash_compare_long(void *a, void *b);
unsigned long cp_hash_float(void *key);
int cp_hash_compare_float(void *a, void *b);
unsigned long cp_hash_double(void *key);
int cp_hash_compare_double(void *a, void *b);
unsigned long cp_hash_addr(void *key);
int cp_hash_compare_addr(void *a, void *b);
unsigned long cp_hash_string(void *key);
int cp_hash_compare_string(void *a, void *b);
unsigned long cp_hash_istring(void *key);
int cp_hash_compare_istring(void *a, void *b);

Example

The following code creates a hashtable mapping names to phone numbers. The hash function used is cp_hash_istring, a case insensitive hash function for null terminated strings.

#include <stdio.h>

#include <string.h>

/* for strdup */

#include <strings.h>

/* for strcasecmp */

#include <stdlib.h>

/* for free */

#include <cprops/hashtable.h>

int main()
{
cp_hashtable *t =
cp_hashtable_create_by_option(COLLECTION_MODE_NOSYNC |
COLLECTION_MODE_COPY |
COLLECTION_MODE_DEEP,
10,
cp_hash_istring,
(cp_compare_fn) strcasecmp,
(cp_copy_fn) strdup,
(cp_destructor_fn) free,
(cp_copy_fn) strdup,
(cp_destructor_fn) free);

cp_hashtable_put(t, "ed", "123");
cp_hashtable_put(t, "zed", "345");
cp_hashtable_put(t, "fred", "789");

while (1)
{
char name[80];
char *number;

printf("enter name [quit]: ");
name[0] = '\0';
fgets(name, 80, stdin);
name[strlen(name) - 1] = '\0'; /* chop newline */
if (name[0] == '\0') break;

if ((number = cp_hashtable_get(t, name)) != NULL)
printf("%s: %s\n", name, number);
else
printf("no entry for %s\n", name);
}

cp_hashtable_destroy(t);
return 0;
}

for notes on compiling and linking see cprops(3).

Referenced By