/*-------------------------------------------------------------------------*/ /** @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 #include #include #include /*--------------------------------------------------------------------------- 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
