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33858ce2 AT |
1 | |
2 | /*-------------------------------------------------------------------------*/ | |
3 | /** | |
4 | @file dictionary.h | |
5 | @author N. Devillard | |
6 | @brief Implements a dictionary for string variables. | |
7 | ||
8 | This module implements a simple dictionary object, i.e. a list | |
9 | of string/string associations. This object is useful to store e.g. | |
10 | informations retrieved from a configuration file (ini files). | |
11 | */ | |
12 | /*--------------------------------------------------------------------------*/ | |
13 | ||
14 | #ifndef _DICTIONARY_H_ | |
15 | #define _DICTIONARY_H_ | |
16 | ||
17 | /*--------------------------------------------------------------------------- | |
18 | Includes | |
19 | ---------------------------------------------------------------------------*/ | |
20 | ||
21 | #include <stdio.h> | |
22 | #include <stdlib.h> | |
23 | #include <string.h> | |
24 | #include <unistd.h> | |
25 | ||
26 | #ifdef __cplusplus | |
27 | extern "C" { | |
28 | #endif | |
29 | ||
30 | /*--------------------------------------------------------------------------- | |
31 | New types | |
32 | ---------------------------------------------------------------------------*/ | |
33 | ||
34 | ||
35 | /*-------------------------------------------------------------------------*/ | |
36 | /** | |
37 | @brief Dictionary object | |
38 | ||
39 | This object contains a list of string/string associations. Each | |
40 | association is identified by a unique string key. Looking up values | |
41 | in the dictionary is speeded up by the use of a (hopefully collision-free) | |
42 | hash function. | |
43 | */ | |
44 | /*-------------------------------------------------------------------------*/ | |
45 | typedef struct _dictionary_ { | |
46 | int n ; /** Number of entries in dictionary */ | |
47 | ssize_t size ; /** Storage size */ | |
48 | char ** val ; /** List of string values */ | |
49 | char ** key ; /** List of string keys */ | |
50 | unsigned * hash ; /** List of hash values for keys */ | |
51 | } dictionary ; | |
52 | ||
53 | ||
54 | /*--------------------------------------------------------------------------- | |
55 | Function prototypes | |
56 | ---------------------------------------------------------------------------*/ | |
57 | ||
58 | /*-------------------------------------------------------------------------*/ | |
59 | /** | |
60 | @brief Compute the hash key for a string. | |
61 | @param key Character string to use for key. | |
62 | @return 1 unsigned int on at least 32 bits. | |
63 | ||
64 | This hash function has been taken from an Article in Dr Dobbs Journal. | |
65 | This is normally a collision-free function, distributing keys evenly. | |
66 | The key is stored anyway in the struct so that collision can be avoided | |
67 | by comparing the key itself in last resort. | |
68 | */ | |
69 | /*--------------------------------------------------------------------------*/ | |
70 | unsigned dictionary_hash(const char * key); | |
71 | ||
72 | /*-------------------------------------------------------------------------*/ | |
73 | /** | |
74 | @brief Create a new dictionary object. | |
75 | @param size Optional initial size of the dictionary. | |
76 | @return 1 newly allocated dictionary objet. | |
77 | ||
78 | This function allocates a new dictionary object of given size and returns | |
79 | it. If you do not know in advance (roughly) the number of entries in the | |
80 | dictionary, give size=0. | |
81 | */ | |
82 | /*--------------------------------------------------------------------------*/ | |
83 | dictionary * dictionary_new(size_t size); | |
84 | ||
85 | /*-------------------------------------------------------------------------*/ | |
86 | /** | |
87 | @brief Delete a dictionary object | |
88 | @param d dictionary object to deallocate. | |
89 | @return void | |
90 | ||
91 | Deallocate a dictionary object and all memory associated to it. | |
92 | */ | |
93 | /*--------------------------------------------------------------------------*/ | |
94 | void dictionary_del(dictionary * vd); | |
95 | ||
96 | /*-------------------------------------------------------------------------*/ | |
97 | /** | |
98 | @brief Get a value from a dictionary. | |
99 | @param d dictionary object to search. | |
100 | @param key Key to look for in the dictionary. | |
101 | @param def Default value to return if key not found. | |
102 | @return 1 pointer to internally allocated character string. | |
103 | ||
104 | This function locates a key in a dictionary and returns a pointer to its | |
105 | value, or the passed 'def' pointer if no such key can be found in | |
106 | dictionary. The returned character pointer points to data internal to the | |
107 | dictionary object, you should not try to free it or modify it. | |
108 | */ | |
109 | /*--------------------------------------------------------------------------*/ | |
110 | const char * dictionary_get(const dictionary * d, const char * key, const char * def); | |
111 | ||
112 | ||
113 | /*-------------------------------------------------------------------------*/ | |
114 | /** | |
115 | @brief Set a value in a dictionary. | |
116 | @param d dictionary object to modify. | |
117 | @param key Key to modify or add. | |
118 | @param val Value to add. | |
119 | @return int 0 if Ok, anything else otherwise | |
120 | ||
121 | If the given key is found in the dictionary, the associated value is | |
122 | replaced by the provided one. If the key cannot be found in the | |
123 | dictionary, it is added to it. | |
124 | ||
125 | It is Ok to provide a NULL value for val, but NULL values for the dictionary | |
126 | or the key are considered as errors: the function will return immediately | |
127 | in such a case. | |
128 | ||
129 | Notice that if you dictionary_set a variable to NULL, a call to | |
130 | dictionary_get will return a NULL value: the variable will be found, and | |
131 | its value (NULL) is returned. In other words, setting the variable | |
132 | content to NULL is equivalent to deleting the variable from the | |
133 | dictionary. It is not possible (in this implementation) to have a key in | |
134 | the dictionary without value. | |
135 | ||
136 | This function returns non-zero in case of failure. | |
137 | */ | |
138 | /*--------------------------------------------------------------------------*/ | |
139 | int dictionary_set(dictionary * vd, const char * key, const char * val); | |
140 | ||
141 | /*-------------------------------------------------------------------------*/ | |
142 | /** | |
143 | @brief Delete a key in a dictionary | |
144 | @param d dictionary object to modify. | |
145 | @param key Key to remove. | |
146 | @return void | |
147 | ||
148 | This function deletes a key in a dictionary. Nothing is done if the | |
149 | key cannot be found. | |
150 | */ | |
151 | /*--------------------------------------------------------------------------*/ | |
152 | void dictionary_unset(dictionary * d, const char * key); | |
153 | ||
154 | ||
155 | /*-------------------------------------------------------------------------*/ | |
156 | /** | |
157 | @brief Dump a dictionary to an opened file pointer. | |
158 | @param d Dictionary to dump | |
159 | @param f Opened file pointer. | |
160 | @return void | |
161 | ||
162 | Dumps a dictionary onto an opened file pointer. Key pairs are printed out | |
163 | as @c [Key]=[Value], one per line. It is Ok to provide stdout or stderr as | |
164 | output file pointers. | |
165 | */ | |
166 | /*--------------------------------------------------------------------------*/ | |
167 | void dictionary_dump(const dictionary * d, FILE * out); | |
168 | ||
169 | #ifdef __cplusplus | |
170 | } | |
171 | #endif | |
172 | ||
173 | #endif |