src/dictionary.h

   1
   2 /*
   3  *
   4  * Copyright (c) 2000-2007 by Nicolas Devillard.
   5  * MIT License
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  23  * DEALINGS IN THE SOFTWARE.
  24  *
  25  */
  26
  27 /*-------------------------------------------------------------------------*/
  28 /**
  29    @file    dictionary.h
  30    @author  N. Devillard
  31    @date    Sep 2007
  32    @version $Revision: 1.12 $
  33    @brief   Implements a dictionary for string variables.
  34
  35    This module implements a simple dictionary object, i.e. a list
  36    of string/string associations. This object is useful to store e.g.
  37    informations retrieved from a configuration file (ini files).
  38 */
  39 /*--------------------------------------------------------------------------*/
  40
  41 /*
  42         $Id: dictionary.h,v 1.12 2007-11-23 21:37:00 ndevilla Exp $
  43         $Author: ndevilla $
  44         $Date: 2007-11-23 21:37:00 $
  45         $Revision: 1.12 $
  46 */
  47
  48 #ifndef _DICTIONARY_H_
  49 #define _DICTIONARY_H_
  50
  51 /*---------------------------------------------------------------------------
  52                                                                 Includes
  53  ---------------------------------------------------------------------------*/
  54
  55 #include <stdio.h>
  56 #include <stdlib.h>
  57 #include <string.h>
  58 #include <unistd.h>
  59
  60 /*---------------------------------------------------------------------------
  61                                                                 New types
  62  ---------------------------------------------------------------------------*/
  63
  64
  65 /*-------------------------------------------------------------------------*/
  66 /**
  67   @brief        Dictionary object
  68
  69   This object contains a list of string/string associations. Each
  70   association is identified by a unique string key. Looking up values
  71   in the dictionary is speeded up by the use of a (hopefully collision-free)
  72   hash function.
  73  */
  74 /*-------------------------------------------------------------------------*/
  75 typedef struct _dictionary_ {
  76         int                             n ;             /** Number of entries in dictionary */
  77         int                             size ;  /** Storage size */
  78         char            **      val ;   /** List of string values */
  79         char            **  key ;       /** List of string keys */
  80         unsigned         *      hash ;  /** List of hash values for keys */
  81 } dictionary ;
  82
  83
  84 /*---------------------------------------------------------------------------
  85                                                         Function prototypes
  86  ---------------------------------------------------------------------------*/
  87
  88 /*-------------------------------------------------------------------------*/
  89 /**
  90   @brief    Compute the hash key for a string.
  91   @param    key     Character string to use for key.
  92   @return   1 unsigned int on at least 32 bits.
  93
  94   This hash function has been taken from an Article in Dr Dobbs Journal.
  95   This is normally a collision-free function, distributing keys evenly.
  96   The key is stored anyway in the struct so that collision can be avoided
  97   by comparing the key itself in last resort.
  98  */
  99 /*--------------------------------------------------------------------------*/
 100 unsigned dictionary_hash(char * key);
 101
 102 /*-------------------------------------------------------------------------*/
 103 /**
 104   @brief    Create a new dictionary object.
 105   @param    size    Optional initial size of the dictionary.
 106   @return   1 newly allocated dictionary objet.
 107
 108   This function allocates a new dictionary object of given size and returns
 109   it. If you do not know in advance (roughly) the number of entries in the
 110   dictionary, give size=0.
 111  */
 112 /*--------------------------------------------------------------------------*/
 113 dictionary * dictionary_new(int size);
 114
 115 /*-------------------------------------------------------------------------*/
 116 /**
 117   @brief    Delete a dictionary object
 118   @param    d   dictionary object to deallocate.
 119   @return   void
 120
 121   Deallocate a dictionary object and all memory associated to it.
 122  */
 123 /*--------------------------------------------------------------------------*/
 124 void dictionary_del(dictionary * vd);
 125
 126 /*-------------------------------------------------------------------------*/
 127 /**
 128   @brief    Get a value from a dictionary.
 129   @param    d       dictionary object to search.
 130   @param    key     Key to look for in the dictionary.
 131   @param    def     Default value to return if key not found.
 132   @return   1 pointer to internally allocated character string.
 133
 134   This function locates a key in a dictionary and returns a pointer to its
 135   value, or the passed 'def' pointer if no such key can be found in
 136   dictionary. The returned character pointer points to data internal to the
 137   dictionary object, you should not try to free it or modify it.
 138  */
 139 /*--------------------------------------------------------------------------*/
 140 char * dictionary_get(dictionary * d, char * key, char * def);
 141
 142
 143 /*-------------------------------------------------------------------------*/
 144 /**
 145   @brief    Set a value in a dictionary.
 146   @param    d       dictionary object to modify.
 147   @param    key     Key to modify or add.
 148   @param    val     Value to add.
 149   @return   int     0 if Ok, anything else otherwise
 150
 151   If the given key is found in the dictionary, the associated value is
 152   replaced by the provided one. If the key cannot be found in the
 153   dictionary, it is added to it.
 154
 155   It is Ok to provide a NULL value for val, but NULL values for the dictionary
 156   or the key are considered as errors: the function will return immediately
 157   in such a case.
 158
 159   Notice that if you dictionary_set a variable to NULL, a call to
 160   dictionary_get will return a NULL value: the variable will be found, and
 161   its value (NULL) is returned. In other words, setting the variable
 162   content to NULL is equivalent to deleting the variable from the
 163   dictionary. It is not possible (in this implementation) to have a key in
 164   the dictionary without value.
 165
 166   This function returns non-zero in case of failure.
 167  */
 168 /*--------------------------------------------------------------------------*/
 169 int dictionary_set(dictionary * vd, char * key, char * val);
 170
 171 /*-------------------------------------------------------------------------*/
 172 /**
 173   @brief    Delete a key in a dictionary
 174   @param    d       dictionary object to modify.
 175   @param    key     Key to remove.
 176   @return   void
 177
 178   This function deletes a key in a dictionary. Nothing is done if the
 179   key cannot be found.
 180  */
 181 /*--------------------------------------------------------------------------*/
 182 void dictionary_unset(dictionary * d, char * key);
 183
 184
 185 /*-------------------------------------------------------------------------*/
 186 /**
 187   @brief    Dump a dictionary to an opened file pointer.
 188   @param    d   Dictionary to dump
 189   @param    f   Opened file pointer.
 190   @return   void
 191
 192   Dumps a dictionary onto an opened file pointer. Key pairs are printed out
 193   as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as
 194   output file pointers.
 195  */
 196 /*--------------------------------------------------------------------------*/
 197 void dictionary_dump(dictionary * d, FILE * out);
 198
 199 #endif