1 /* 2 * Copyright 2015 Rockchip Electronics Co. LTD 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 /*-------------------------------------------------------------------------*/ 18 /** 19 @file dictionary.h 20 @author N. Devillard 21 @brief Implements a dictionary for string variables. 22 23 This module implements a simple dictionary object, i.e. a list 24 of string/string associations. This object is useful to store e.g. 25 informations retrieved from a configuration file (ini files). 26 */ 27 /*--------------------------------------------------------------------------*/ 28 29 #ifndef _DICTIONARY_H_ 30 #define _DICTIONARY_H_ 31 32 /*--------------------------------------------------------------------------- 33 Includes 34 ---------------------------------------------------------------------------*/ 35 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 41 #ifdef __cplusplus 42 extern "C" { 43 #endif 44 45 /*--------------------------------------------------------------------------- 46 New types 47 ---------------------------------------------------------------------------*/ 48 49 50 /*-------------------------------------------------------------------------*/ 51 /** 52 @brief Dictionary object 53 54 This object contains a list of string/string associations. Each 55 association is identified by a unique string key. Looking up values 56 in the dictionary is speeded up by the use of a (hopefully collision-free) 57 hash function. 58 */ 59 /*-------------------------------------------------------------------------*/ 60 typedef struct _dictionary_ { 61 int n ; /** Number of entries in dictionary */ 62 ssize_t size ; /** Storage size */ 63 char ** val ; /** List of string values */ 64 char ** key ; /** List of string keys */ 65 unsigned * hash ; /** List of hash values for keys */ 66 } dictionary ; 67 68 69 /*--------------------------------------------------------------------------- 70 Function prototypes 71 ---------------------------------------------------------------------------*/ 72 73 /*-------------------------------------------------------------------------*/ 74 /** 75 @brief Compute the hash key for a string. 76 @param key Character string to use for key. 77 @return 1 unsigned int on at least 32 bits. 78 79 This hash function has been taken from an Article in Dr Dobbs Journal. 80 This is normally a collision-free function, distributing keys evenly. 81 The key is stored anyway in the struct so that collision can be avoided 82 by comparing the key itself in last resort. 83 */ 84 /*--------------------------------------------------------------------------*/ 85 unsigned dictionary_hash(const char * key); 86 87 /*-------------------------------------------------------------------------*/ 88 /** 89 @brief Create a new dictionary object. 90 @param size Optional initial size of the dictionary. 91 @return 1 newly allocated dictionary objet. 92 93 This function allocates a new dictionary object of given size and returns 94 it. If you do not know in advance (roughly) the number of entries in the 95 dictionary, give size=0. 96 */ 97 /*--------------------------------------------------------------------------*/ 98 dictionary * dictionary_new(size_t size); 99 100 /*-------------------------------------------------------------------------*/ 101 /** 102 @brief Delete a dictionary object 103 @param d dictionary object to deallocate. 104 @return void 105 106 Deallocate a dictionary object and all memory associated to it. 107 */ 108 /*--------------------------------------------------------------------------*/ 109 void dictionary_del(dictionary * vd); 110 111 /*-------------------------------------------------------------------------*/ 112 /** 113 @brief Get a value from a dictionary. 114 @param d dictionary object to search. 115 @param key Key to look for in the dictionary. 116 @param def Default value to return if key not found. 117 @return 1 pointer to internally allocated character string. 118 119 This function locates a key in a dictionary and returns a pointer to its 120 value, or the passed 'def' pointer if no such key can be found in 121 dictionary. The returned character pointer points to data internal to the 122 dictionary object, you should not try to free it or modify it. 123 */ 124 /*--------------------------------------------------------------------------*/ 125 const char * dictionary_get(const dictionary * d, const char * key, const char * def); 126 127 128 /*-------------------------------------------------------------------------*/ 129 /** 130 @brief Set a value in a dictionary. 131 @param d dictionary object to modify. 132 @param key Key to modify or add. 133 @param val Value to add. 134 @return int 0 if Ok, anything else otherwise 135 136 If the given key is found in the dictionary, the associated value is 137 replaced by the provided one. If the key cannot be found in the 138 dictionary, it is added to it. 139 140 It is Ok to provide a NULL value for val, but NULL values for the dictionary 141 or the key are considered as errors: the function will return immediately 142 in such a case. 143 144 Notice that if you dictionary_set a variable to NULL, a call to 145 dictionary_get will return a NULL value: the variable will be found, and 146 its value (NULL) is returned. In other words, setting the variable 147 content to NULL is equivalent to deleting the variable from the 148 dictionary. It is not possible (in this implementation) to have a key in 149 the dictionary without value. 150 151 This function returns non-zero in case of failure. 152 */ 153 /*--------------------------------------------------------------------------*/ 154 int dictionary_set(dictionary * vd, const char * key, const char * val); 155 156 /*-------------------------------------------------------------------------*/ 157 /** 158 @brief Delete a key in a dictionary 159 @param d dictionary object to modify. 160 @param key Key to remove. 161 @return void 162 163 This function deletes a key in a dictionary. Nothing is done if the 164 key cannot be found. 165 */ 166 /*--------------------------------------------------------------------------*/ 167 void dictionary_unset(dictionary * d, const char * key); 168 169 170 /*-------------------------------------------------------------------------*/ 171 /** 172 @brief Dump a dictionary to an opened file pointer. 173 @param d Dictionary to dump 174 @param f Opened file pointer. 175 @return void 176 177 Dumps a dictionary onto an opened file pointer. Key pairs are printed out 178 as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as 179 output file pointers. 180 */ 181 /*--------------------------------------------------------------------------*/ 182 void dictionary_dump(const dictionary * d, FILE * out); 183 184 #ifdef __cplusplus 185 } 186 #endif 187 188 #endif 189