1 2 /*-------------------------------------------------------------------------*/ 3 /** 4 @file dictionary.h 5 @author N. Devillard 6 @date Sep 2007 7 @version Revision: 1.12 8 @brief Implements a dictionary for string variables. 9 10 This module implements a simple dictionary object, i.e. a list 11 of string/string associations. This object is useful to store e.g. 12 informations retrieved from a configuration file (ini files). 13 */ 14 /*--------------------------------------------------------------------------*/ 15 16 /* 17 Id: dictionary.h,v 1.12 2007-11-23 21:37:00 ndevilla Exp 18 Author: ndevilla 19 Date: 2007-11-23 21:37:00 20 Revision: 1.12 21 */ 22 23 #ifndef _DICTIONARY_H_ 24 #define _DICTIONARY_H_ 25 26 /*--------------------------------------------------------------------------- 27 Includes 28 ---------------------------------------------------------------------------*/ 29 30 #include <stdio.h> 31 #include <stdlib.h> 32 #include <string.h> 33 #include <unistd.h> 34 35 /*--------------------------------------------------------------------------- 36 New types 37 ---------------------------------------------------------------------------*/ 38 39 40 /*-------------------------------------------------------------------------*/ 41 /** 42 @brief Dictionary object 43 44 This object contains a list of string/string associations. Each 45 association is identified by a unique string key. Looking up values 46 in the dictionary is speeded up by the use of a (hopefully collision-free) 47 hash function. 48 */ 49 /*-------------------------------------------------------------------------*/ 50 typedef struct _dictionary_ { 51 int n ; /** Number of entries in dictionary */ 52 int size ; /** Storage size */ 53 char ** val ; /** List of string values */ 54 char ** key ; /** List of string keys */ 55 unsigned * hash ; /** List of hash values for keys */ 56 } dictionary ; 57 58 59 /*--------------------------------------------------------------------------- 60 Function prototypes 61 ---------------------------------------------------------------------------*/ 62 63 /*-------------------------------------------------------------------------*/ 64 /** 65 @brief Compute the hash key for a string. 66 @param key Character string to use for key. 67 @return 1 unsigned int on at least 32 bits. 68 69 This hash function has been taken from an Article in Dr Dobbs Journal. 70 This is normally a collision-free function, distributing keys evenly. 71 The key is stored anyway in the struct so that collision can be avoided 72 by comparing the key itself in last resort. 73 */ 74 /*--------------------------------------------------------------------------*/ 75 unsigned dictionary_hash(char * key); 76 77 /*-------------------------------------------------------------------------*/ 78 /** 79 @brief Create a new dictionary object. 80 @param size Optional initial size of the dictionary. 81 @return 1 newly allocated dictionary objet. 82 83 This function allocates a new dictionary object of given size and returns 84 it. If you do not know in advance (roughly) the number of entries in the 85 dictionary, give size=0. 86 */ 87 /*--------------------------------------------------------------------------*/ 88 dictionary * dictionary_new(int size); 89 90 /*-------------------------------------------------------------------------*/ 91 /** 92 @brief Delete a dictionary object 93 @param d dictionary object to deallocate. 94 @return void 95 96 Deallocate a dictionary object and all memory associated to it. 97 */ 98 /*--------------------------------------------------------------------------*/ 99 void dictionary_del(dictionary * vd); 100 101 /*-------------------------------------------------------------------------*/ 102 /** 103 @brief Get a value from a dictionary. 104 @param d dictionary object to search. 105 @param key Key to look for in the dictionary. 106 @param def Default value to return if key not found. 107 @return 1 pointer to internally allocated character string. 108 109 This function locates a key in a dictionary and returns a pointer to its 110 value, or the passed 'def' pointer if no such key can be found in 111 dictionary. The returned character pointer points to data internal to the 112 dictionary object, you should not try to free it or modify it. 113 */ 114 /*--------------------------------------------------------------------------*/ 115 char * dictionary_get(dictionary * d, char * key, char * def); 116 117 118 /*-------------------------------------------------------------------------*/ 119 /** 120 @brief Set a value in a dictionary. 121 @param d dictionary object to modify. 122 @param key Key to modify or add. 123 @param val Value to add. 124 @return int 0 if Ok, anything else otherwise 125 126 If the given key is found in the dictionary, the associated value is 127 replaced by the provided one. If the key cannot be found in the 128 dictionary, it is added to it. 129 130 It is Ok to provide a NULL value for val, but NULL values for the dictionary 131 or the key are considered as errors: the function will return immediately 132 in such a case. 133 134 Notice that if you dictionary_set a variable to NULL, a call to 135 dictionary_get will return a NULL value: the variable will be found, and 136 its value (NULL) is returned. In other words, setting the variable 137 content to NULL is equivalent to deleting the variable from the 138 dictionary. It is not possible (in this implementation) to have a key in 139 the dictionary without value. 140 141 This function returns non-zero in case of failure. 142 */ 143 /*--------------------------------------------------------------------------*/ 144 int dictionary_set(dictionary * vd, char * key, char * val); 145 146 /*-------------------------------------------------------------------------*/ 147 /** 148 @brief Delete a key in a dictionary 149 @param d dictionary object to modify. 150 @param key Key to remove. 151 @return void 152 153 This function deletes a key in a dictionary. Nothing is done if the 154 key cannot be found. 155 */ 156 /*--------------------------------------------------------------------------*/ 157 void dictionary_unset(dictionary * d, char * key); 158 159 160 /*-------------------------------------------------------------------------*/ 161 /** 162 @brief Dump a dictionary to an opened file pointer. 163 @param d Dictionary to dump 164 @param f Opened file pointer. 165 @return void 166 167 Dumps a dictionary onto an opened file pointer. Key pairs are printed out 168 as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as 169 output file pointers. 170 */ 171 /*--------------------------------------------------------------------------*/ 172 void dictionary_dump(dictionary * d, FILE * out); 173 174 #endif 175