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/*-------------------------------------------------------------------------*/
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/**
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@file dictionary.h
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@author N. Devillard
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@brief Implements a dictionary for string variables.
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This module implements a simple dictionary object, i.e. a list
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of string/string associations. This object is useful to store e.g.
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informations retrieved from a configuration file (ini files).
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*/
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/*--------------------------------------------------------------------------*/
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#ifndef _DICTIONARY_H_
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#define _DICTIONARY_H_
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/*---------------------------------------------------------------------------
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Includes
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---------------------------------------------------------------------------*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*---------------------------------------------------------------------------
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New types
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---------------------------------------------------------------------------*/
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/*-------------------------------------------------------------------------*/
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/**
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@brief Dictionary object
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This object contains a list of string/string associations. Each
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association is identified by a unique string key. Looking up values
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in the dictionary is speeded up by the use of a (hopefully collision-free)
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hash function.
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*/
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/*-------------------------------------------------------------------------*/
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typedef struct _dictionary_ {
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int n ; /** Number of entries in dictionary */
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ssize_t size ; /** Storage size */
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char ** val ; /** List of string values */
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char ** key ; /** List of string keys */
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unsigned * hash ; /** List of hash values for keys */
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} dictionary ;
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/*---------------------------------------------------------------------------
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Function prototypes
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---------------------------------------------------------------------------*/
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/*-------------------------------------------------------------------------*/
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/**
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@brief Compute the hash key for a string.
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@param key Character string to use for key.
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@return 1 unsigned int on at least 32 bits.
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This hash function has been taken from an Article in Dr Dobbs Journal.
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This is normally a collision-free function, distributing keys evenly.
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The key is stored anyway in the struct so that collision can be avoided
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by comparing the key itself in last resort.
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*/
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/*--------------------------------------------------------------------------*/
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unsigned dictionary_hash(const char * key);
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/*-------------------------------------------------------------------------*/
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/**
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@brief Create a new dictionary object.
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@param size Optional initial size of the dictionary.
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@return 1 newly allocated dictionary objet.
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This function allocates a new dictionary object of given size and returns
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it. If you do not know in advance (roughly) the number of entries in the
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dictionary, give size=0.
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*/
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/*--------------------------------------------------------------------------*/
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dictionary * dictionary_new(size_t size);
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/*-------------------------------------------------------------------------*/
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/**
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@brief Delete a dictionary object
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@param d dictionary object to deallocate.
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@return void
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Deallocate a dictionary object and all memory associated to it.
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*/
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/*--------------------------------------------------------------------------*/
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void dictionary_del(dictionary * vd);
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/*-------------------------------------------------------------------------*/
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/**
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@brief Get a value from a dictionary.
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@param d dictionary object to search.
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@param key Key to look for in the dictionary.
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@param def Default value to return if key not found.
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@return 1 pointer to internally allocated character string.
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This function locates a key in a dictionary and returns a pointer to its
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value, or the passed 'def' pointer if no such key can be found in
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dictionary. The returned character pointer points to data internal to the
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dictionary object, you should not try to free it or modify it.
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*/
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/*--------------------------------------------------------------------------*/
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const char * dictionary_get(const dictionary * d, const char * key, const char * def);
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|
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/*-------------------------------------------------------------------------*/
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/**
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@brief Set a value in a dictionary.
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@param d dictionary object to modify.
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@param key Key to modify or add.
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@param val Value to add.
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@return int 0 if Ok, anything else otherwise
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If the given key is found in the dictionary, the associated value is
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replaced by the provided one. If the key cannot be found in the
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dictionary, it is added to it.
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It is Ok to provide a NULL value for val, but NULL values for the dictionary
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or the key are considered as errors: the function will return immediately
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in such a case.
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Notice that if you dictionary_set a variable to NULL, a call to
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dictionary_get will return a NULL value: the variable will be found, and
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its value (NULL) is returned. In other words, setting the variable
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content to NULL is equivalent to deleting the variable from the
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dictionary. It is not possible (in this implementation) to have a key in
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the dictionary without value.
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This function returns non-zero in case of failure.
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*/
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/*--------------------------------------------------------------------------*/
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int dictionary_set(dictionary * vd, const char * key, const char * val);
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/*-------------------------------------------------------------------------*/
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/**
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@brief Delete a key in a dictionary
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@param d dictionary object to modify.
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@param key Key to remove.
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@return void
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This function deletes a key in a dictionary. Nothing is done if the
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key cannot be found.
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*/
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/*--------------------------------------------------------------------------*/
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void dictionary_unset(dictionary * d, const char * key);
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|
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/*-------------------------------------------------------------------------*/
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/**
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@brief Dump a dictionary to an opened file pointer.
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@param d Dictionary to dump
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@param f Opened file pointer.
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@return void
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Dumps a dictionary onto an opened file pointer. Key pairs are printed out
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as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as
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output file pointers.
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*/
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/*--------------------------------------------------------------------------*/
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void dictionary_dump(const dictionary * d, FILE * out);
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#ifdef __cplusplus
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}
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#endif
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#endif
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