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Diffstat (limited to 'include/dictionary.h')
| -rw-r--r-- | include/dictionary.h | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/include/dictionary.h b/include/dictionary.h new file mode 100644 index 0000000..c7d1790 --- /dev/null +++ b/include/dictionary.h @@ -0,0 +1,174 @@ + +/*-------------------------------------------------------------------------*/ +/** + @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 |