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+
+/*-------------------------------------------------------------------------*/
+/**
+ @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.
+ informations retrieved from a configuration file (ini files).
+*/
+/*--------------------------------------------------------------------------*/
+
+/*
+ $Id: dictionary.h,v 1.12 2007-11-23 21:37:00 ndevilla Exp $
+ $Author: ndevilla $
+ $Date: 2007-11-23 21:37:00 $
+ $Revision: 1.12 $
+*/
+
+#ifndef _DICTIONARY_H_
+#define _DICTIONARY_H_
+
+/*---------------------------------------------------------------------------
+ Includes
+ ---------------------------------------------------------------------------*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/*---------------------------------------------------------------------------
+ New types
+ ---------------------------------------------------------------------------*/
+
+
+/*-------------------------------------------------------------------------*/
+/**
+ @brief Dictionary object
+
+ 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 ; /** Number of entries in dictionary */
+ int size ; /** Storage size */
+ char ** val ; /** List of string values */
+ char ** key ; /** List of string keys */
+ unsigned * hash ; /** List of hash values for keys */
+} dictionary ;
+
+
+/*---------------------------------------------------------------------------
+ Function prototypes
+ ---------------------------------------------------------------------------*/
+
+/*-------------------------------------------------------------------------*/
+/**
+ @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 1 newly allocated dictionary objet.
+
+ 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 f 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