ccan/ccan/ciniparser/dictionary.h

#ifndef _DICTIONARY_H_
#define _DICTIONARY_H_

/* Copyright (c) 2000-2007 by Nicolas Devillard.
 * Copyright (x) 2009 by Tim Post <tinkertim@gmail.com>
 * MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

/** @addtogroup ciniparser
 * @{
 */
/**
 * @file    dictionary.h
 * @author  N. Devillard
 * @date    Sep 2007
 * @version $Revision: 1.12 $
 * @brief   Implements a dictionary for string variables.
 *
 * This module implements a simple dictionary object, i.e. a list
 * of string/string associations. This object is useful to store e.g.
 * information retrieved from a configuration file (ini files).
 */


/**
 * @brief Dictionary object
 * @param n Number of entries in the dictionary
 * @param size Storage size
 * @param val List of string values
 * @param key List of string keys
 * @param hash List of hash values for keys
 *
 * This object contains a list of string/string associations. Each
 * association is identified by a unique string key. Looking up values
 * in the dictionary is speeded up by the use of a (hopefully collision-free)
 * hash function.
 */
typedef struct _dictionary_ {
	int n;
	int size;
	char **val;
	char **key;
	unsigned *hash;
} dictionary;

/**
 * @brief Compute the hash key for a string.
 * @param key Character string to use for key.
 * @return 1 unsigned int on at least 32 bits.
 *
 * This hash function has been taken from an Article in Dr Dobbs Journal.
 * This is normally a collision-free function, distributing keys evenly.
 * The key is stored anyway in the struct so that collision can be avoided
 * by comparing the key itself in last resort.
 */
unsigned dictionary_hash(char *key);

/**
 * @brief Create a new dictionary object.
 * @param size Optional initial size of the dictionary.
 * @return allocated dictionary object on success, NULL on failure
 *
 * This function allocates a new dictionary object of given size and returns
 * it. If you do not know in advance (roughly) the number of entries in the
 * dictionary, give size=0.
 */
dictionary *dictionary_new(int size);

/**
 * @brief Delete a dictionary object
 * @param d dictionary object to deallocate.
 * @return void
 *
 * Deallocate a dictionary object and all memory associated to it.
 */
void dictionary_del(dictionary *vd);

/**
 * @brief Get a value from a dictionary.
 * @param d dictionary object to search.
 * @param key Key to look for in the dictionary.
 * @param def Default value to return if key not found.
 * @return 1 pointer to internally allocated character string.
 *
 * This function locates a key in a dictionary and returns a pointer to its
 * value, or the passed 'def' pointer if no such key can be found in
 * dictionary. The returned character pointer points to data internal to the
 * dictionary object, you should not try to free it or modify it.
 */
char *dictionary_get(dictionary *d, char *key, char *def);

/**
 * @brief Set a value in a dictionary.
 * @param d dictionary object to modify.
 * @param key Key to modify or add.
 * @param val Value to add.
 * @return int 0 if Ok, anything else otherwise
 *
 * If the given key is found in the dictionary, the associated value is
 * replaced by the provided one. If the key cannot be found in the
 * dictionary, it is added to it.
 *
 * It is Ok to provide a NULL value for val, but NULL values for the dictionary
 * or the key are considered as errors: the function will return immediately
 * in such a case.
 *
 * Notice that if you dictionary_set a variable to NULL, a call to
 * dictionary_get will return a NULL value: the variable will be found, and
 * its value (NULL) is returned. In other words, setting the variable
 * content to NULL is equivalent to deleting the variable from the
 * dictionary. It is not possible (in this implementation) to have a key in
 * the dictionary without value.
 *
 * This function returns non-zero in case of failure.
 */
int dictionary_set(dictionary *vd, char *key, char *val);

/**
 * @brief Delete a key in a dictionary
 * @param d dictionary object to modify.
 * @param key Key to remove.
 * @return void
 *
 * This function deletes a key in a dictionary. Nothing is done if the
 * key cannot be found.
 */
void dictionary_unset(dictionary *d, char *key);

/**
 * @brief Dump a dictionary to an opened file pointer.
 * @param d Dictionary to dump
 * @param out Opened file pointer
 * @return void
 *
 * Dumps a dictionary onto an opened file pointer. Key pairs are printed out
 * as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as
 * output file pointers.
 */
void dictionary_dump(dictionary *d, FILE *out);

#endif
/** @}
 */