fd9e5ef7b7
Even though "hashtab_key_t" is an alias for "char *", "const hashtab_key_t" is not an alias for "(const char) *" but means "(char *) const". Introduce const_hashtab_key_t to map "(const char) *" and use it in hashtab_search() and hashtab key comparison functions. Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
143 lines
4.4 KiB
C
143 lines
4.4 KiB
C
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/* Author : Stephen Smalley, <sds@epoch.ncsc.mil> */
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/* FLASK */
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/*
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* A hash table (hashtab) maintains associations between
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* key values and datum values. The type of the key values
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* and the type of the datum values is arbitrary. The
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* functions for hash computation and key comparison are
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* provided by the creator of the table.
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*/
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#ifndef _NEWROLE_HASHTAB_H_
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#define _NEWROLE_HASHTAB_H_
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#include <stdint.h>
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#include <errno.h>
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#include <stdio.h>
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typedef char *hashtab_key_t; /* generic key type */
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typedef const char *const_hashtab_key_t; /* constant generic key type */
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typedef void *hashtab_datum_t; /* generic datum type */
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typedef struct hashtab_node *hashtab_ptr_t;
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typedef struct hashtab_node {
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hashtab_key_t key;
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hashtab_datum_t datum;
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hashtab_ptr_t next;
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} hashtab_node_t;
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typedef struct hashtab_val {
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hashtab_ptr_t *htable; /* hash table */
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unsigned int size; /* number of slots in hash table */
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uint32_t nel; /* number of elements in hash table */
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unsigned int (*hash_value) (struct hashtab_val * h, const_hashtab_key_t key); /* hash function */
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int (*keycmp) (struct hashtab_val * h, const_hashtab_key_t key1, const_hashtab_key_t key2); /* key comparison function */
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} hashtab_val_t;
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typedef hashtab_val_t *hashtab_t;
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/* Define status codes for hash table functions */
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#define HASHTAB_SUCCESS 0
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#define HASHTAB_OVERFLOW -ENOMEM
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#define HASHTAB_PRESENT -EEXIST
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#define HASHTAB_MISSING -ENOENT
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/*
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Creates a new hash table with the specified characteristics.
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Returns NULL if insufficent space is available or
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the new hash table otherwise.
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*/
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extern hashtab_t hashtab_create(unsigned int (*hash_value) (hashtab_t h,
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const_hashtab_key_t
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key),
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int (*keycmp) (hashtab_t h,
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const_hashtab_key_t key1,
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const_hashtab_key_t key2),
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unsigned int size);
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/*
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Inserts the specified (key, datum) pair into the specified hash table.
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Returns HASHTAB_OVERFLOW if insufficient space is available or
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HASHTAB_PRESENT if there is already an entry with the same key or
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HASHTAB_SUCCESS otherwise.
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*/
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extern int hashtab_insert(hashtab_t h, hashtab_key_t k, hashtab_datum_t d);
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/*
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Removes the entry with the specified key from the hash table.
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Applies the specified destroy function to (key,datum,args) for
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the entry.
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Returns HASHTAB_MISSING if no entry has the specified key or
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HASHTAB_SUCCESS otherwise.
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*/
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extern int hashtab_remove(hashtab_t h, hashtab_key_t k,
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void (*destroy) (hashtab_key_t k,
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hashtab_datum_t d,
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void *args), void *args);
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/*
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Insert or replace the specified (key, datum) pair in the specified
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hash table. If an entry for the specified key already exists,
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then the specified destroy function is applied to (key,datum,args)
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for the entry prior to replacing the entry's contents.
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Returns HASHTAB_OVERFLOW if insufficient space is available or
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HASHTAB_SUCCESS otherwise.
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*/
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extern int hashtab_replace(hashtab_t h, hashtab_key_t k, hashtab_datum_t d,
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void (*destroy) (hashtab_key_t k,
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hashtab_datum_t d,
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void *args), void *args);
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/*
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Searches for the entry with the specified key in the hash table.
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Returns NULL if no entry has the specified key or
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the datum of the entry otherwise.
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*/
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extern hashtab_datum_t hashtab_search(hashtab_t h, const_hashtab_key_t k);
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/*
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Destroys the specified hash table.
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*/
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extern void hashtab_destroy(hashtab_t h);
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/*
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Applies the specified apply function to (key,datum,args)
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for each entry in the specified hash table.
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The order in which the function is applied to the entries
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is dependent upon the internal structure of the hash table.
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If apply returns a non-zero status, then hashtab_map will cease
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iterating through the hash table and will propagate the error
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return to its caller.
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*/
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extern int hashtab_map(hashtab_t h,
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int (*apply) (hashtab_key_t k,
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hashtab_datum_t d,
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void *args), void *args);
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/*
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Same as hashtab_map, except that if apply returns a non-zero status,
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then the (key,datum) pair will be removed from the hashtab and the
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destroy function will be applied to (key,datum,args).
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*/
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extern void hashtab_map_remove_on_error(hashtab_t h,
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int (*apply) (hashtab_key_t k,
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hashtab_datum_t d,
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void *args),
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void (*destroy) (hashtab_key_t k,
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hashtab_datum_t d,
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void *args),
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void *args);
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extern void hashtab_hash_eval(hashtab_t h, char *tag);
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#endif
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