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/*
LICENSE INFORMATION:
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Copyright (c) 2002 Bruno T. C. de Oliveira
INFORMAES DE LICENA:
Este programa um software de livre distribuio; voc pode
redistribu-lo e/ou modific-lo sob os termos da GNU General
Public License, conforme publicado pela Free Software Foundation,
pela verso 2 da licena ou qualquer verso posterior.
Este programa distribudo na esperana de que ele ser til
aos seus usurios, porm, SEM QUAISQUER GARANTIAS; sem sequer
a garantia implcita de COMERCIABILIDADE ou DE ADEQUAO A
QUALQUER FINALIDADE ESPECFICA. Consulte a GNU General Public
License para obter mais detalhes (uma cpia acompanha este
programa, armazenada no arquivo COPYING).
*/
/* hashdict.h
* A general purpose dictionary implemented by means of a hashtable.
* This dictionary maps string keys to values of arbitrary type.
* It allows the specification of a value-destroy function that will
* be called whenever values are to be overwritten or deleted.
*
* Restrictions:
*
* - keys must be strings of positive length, and must of course be
* unique.
*
* - values may not be NULL, because NULL is used as a
* return value to indicate absense of keys, and because when writing/reading
* to a file handling of NULL values would complicate things.
*
* Copyright (c) 2003 by Bruno T. C. de Oliveira
* All rights reserved.
*
* 2003.01.07
*/
#ifndef btco_bores_hashdict_h
#define btco_bores_hashdict_h
#include <stdio.h>
#include <stdbool.h>
/* opaque dictionary handle */
struct HashDict_;
typedef struct HashDict_ HashDict;
/* iterator type */
struct HashDictIt_ {
/* indicates whether this iterator is past the end of the dictionary */
bool pastend;
/* key and value of entry iterator is currently pointing to. Read only. */
const char *key;
const void *value;
/* internal data. Do not tamper with. */
HashDict* dict; /* the dictionary this iterator pertains to */
int nextbucket; /* the next bucket to be visited after this one ends */
void *nextnode; /* the next node in this bucket to be visited. If
NULL, next advancement will cause the iterator
to go to the next nonempty bucket */
};
typedef struct HashDictIt_ HashDictIt;
/* Creates a new dictionary with default bucketcount and no value destroyer
* function. */
HashDict* hashdict_create(void);
/* Creates a new dictionary given bucketcount and a value destroyer function.*/
HashDict* hashdict_create_ex(int bucketcount, void (*valuedestroyer)(void*));
/* Destroy a dictionary previously created by hashdict_create */
void hashdict_destroy(HashDict* hd);
/* Look up key <key> in the dictionary. Returns the associated value,
* or NULL if the value is not found. */
void* hashdict_get(HashDict* hd, const char *key);
/* Sets the value associated to the given key. If the key already exists,
* the value associated to it will be overwritten (and the value-
* destroyer function will be called); otherwise, a new entry will be added.
*
* As a convenience, if value is NULL, this function is equivalent
* to hashdict_unset(hd, key) */
void hashdict_set(HashDict* hd, const char *key, const void *value);
/* Removes from the dictionary the entry whose key is <key>, if it exists.
* If it was removed, returns true; if it was not found, returns false */
bool hashdict_unset(HashDict* hd, const char *key);
/* Writes dictionary to file f in a binary format. valuewriter is a
* function that will be used to write the values onto the stream. */
void hashdict_write(HashDict *hd, FILE *f, void (*valuewriter)(void*, FILE*));
/* Reads a dictionary previously saved with hashdict_write.
* valuereader is a function that will be used to read values from
* the stream. If valuereader returns NULL at any time, this
* function will interpret it as an error. If this happens,
* or if any other error occurs, this function will return NULL. */
HashDict* hashdict_read(HashDict *hd, FILE *f, void* (*valuereader)(FILE*));
/* Returns a new hash dict iterator that points BEFORE the first entry
* in the dictionary. Iterators are lightweight objects, i.e.,
* they don't need to be deallocated. That's why there is no
* hashdict_it_destroy function.
*
* Please note that the iterator returned is not in a valid position
* (it is BEFORE the start). You must advance it before using the value.
* This behavior is useful because you can write neat loops:
*
* it = hashdict_it_start(hd);
* while (hashdict_it_advance(it)) {
* // use it->key and it->value here
* }
*/
HashDictIt hashdict_it_start(HashDict *hd);
/* Advances the given iterator. Returns true if advancement was successful,
* or false if the end of the dictionary was reached. */
bool hashdict_it_advance(HashDictIt *hdi);
#endif
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