1 /*
2  *
3  * This file is part of FFmpeg.
4  *
5  * FFmpeg is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * FFmpeg is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with FFmpeg; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19 
20 /**
21  * @file
22  * Public dictionary API.
23  * @deprecated
24  *  AVDictionary is provided for compatibility with libav. It is both in
25  *  implementation as well as API inefficient. It does not scale and is
26  *  extremely slow with large dictionaries.
27  *  It is recommended that new code uses our tree container from tree.c/h
28  *  where applicable, which uses AVL trees to achieve O(log n) performance.
29  */
30 module ffmpeg.libavutil.dict;
31 
32 @nogc nothrow extern(C):
33 
34 /**
35  * @addtogroup lavu_dict AVDictionary
36  * @ingroup lavu_data
37  *
38  * @brief Simple key:value store
39  *
40  * @{
41  * Dictionaries are used for storing key:value pairs. To create
42  * an AVDictionary, simply pass an address of a NULL pointer to
43  * av_dict_set(). NULL can be used as an empty dictionary wherever
44  * a pointer to an AVDictionary is required.
45  * Use av_dict_get() to retrieve an entry or iterate over all
46  * entries and finally av_dict_free() to free the dictionary
47  * and all its contents.
48  *
49  @code
50    AVDictionary *d = NULL;           // "create" an empty dictionary
51    AVDictionaryEntry *t = NULL;
52 
53    av_dict_set(&d, "foo", "bar", 0); // add an entry
54 
55    char *k = av_strdup("key");       // if your strings are already allocated,
56    char *v = av_strdup("value");     // you can avoid copying them like this
57    av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
58 
59    while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
60        <....>                             // iterate over all entries in d
61    }
62    av_dict_free(&d);
63  @endcode
64  *
65  */
66 
67 enum AV_DICT_MATCH_CASE      = 1;   /**< Only get an entry with exact-case key match. Only relevant in av_dict_get(). */
68 enum AV_DICT_IGNORE_SUFFIX   = 2;/**< Return first entry in a dictionary whose first part corresponds to the search key,
69                                          ignoring the suffix of the found key string. Only relevant in av_dict_get(). */
70 enum AV_DICT_DONT_STRDUP_KEY = 4;   /**< Take ownership of a key that's been
71                                          allocated with av_malloc() and children. */
72 enum AV_DICT_DONT_STRDUP_VAL = 8;   /**< Take ownership of a value that's been
73                                          allocated with av_malloc() and chilren. */
74 enum AV_DICT_DONT_OVERWRITE = 16;   ///< Don't overwrite existing entries.
75 enum AV_DICT_APPEND         = 32;   /**< If the entry already exists, append to it.  Note that no
76                                       delimiter is added, the strings are simply concatenated. */
77 struct AVDictionaryEntry {
78     char *key;
79     char *value;
80 }
81 
82   struct AVDictionary;
83 
84 /**
85  * Get a dictionary entry with matching key.
86  *
87  * The returned entry key or value must not be changed, or it will
88  * cause undefined behavior.
89  *
90  * To iterate through all the dictionary entries, you can set the matching key
91  * to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag.
92  *
93  * @param prev Set to the previous matching element to find the next.
94  *             If set to NULL the first matching element is returned.
95  * @param key matching key
96  * @param flags a collection of AV_DICT_* flags controlling how the entry is retrieved
97  * @return found entry or NULL in case no matching entry was found in the dictionary
98  */
99 AVDictionaryEntry *av_dict_get(AVDictionary *m, const char *key, 
100                                const AVDictionaryEntry *prev, int flags);
101 
102 /**
103  * Get number of entries in dictionary.
104  *
105  * @param m dictionary
106  * @return  number of entries in dictionary
107  */
108 int av_dict_count(const AVDictionary *m);
109 
110 /**
111  * Set the given entry in *pm, overwriting an existing entry.
112  *
113  * Note: If AV_DICT_DONT_STRDUP_KEY or AV_DICT_DONT_STRDUP_VAL is set,
114  * these arguments will be freed on error.
115  *
116  * @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
117  * a dictionary struct is allocated and put in *pm.
118  * @param key entry key to add to *pm (will be av_strduped depending on flags)
119  * @param value entry value to add to *pm (will be av_strduped depending on flags).
120  *        Passing a NULL value will cause an existing entry to be deleted.
121  * @return >= 0 on success otherwise an error code <0
122  */
123 int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
124 
125 /**
126  * Convenience wrapper for av_dict_set that converts the value to a string
127  * and stores it.
128  *
129  * Note: If AV_DICT_DONT_STRDUP_KEY is set, key will be freed on error.
130  */
131 int av_dict_set_int(AVDictionary **pm, const char *key, long value, int flags);
132 
133 /**
134  * Parse the key/value pairs list and add the parsed entries to a dictionary.
135  *
136  * In case of failure, all the successfully set entries are stored in
137  * *pm. You may need to manually free the created dictionary.
138  *
139  * @param key_val_sep  a 0-terminated list of characters used to separate
140  *                     key from value
141  * @param pairs_sep    a 0-terminated list of characters used to separate
142  *                     two pairs from each other
143  * @param flags        flags to use when adding to dictionary.
144  *                     AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL
145  *                     are ignored since the key/value tokens will always
146  *                     be duplicated.
147  * @return             0 on success, negative AVERROR code on failure
148  */
149 int av_dict_parse_string(AVDictionary **pm, const char *str,
150                          const char *key_val_sep, const char *pairs_sep,
151                          int flags);
152 
153 /**
154  * Copy entries from one AVDictionary struct into another.
155  * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
156  *            this function will allocate a struct for you and put it in *dst
157  * @param src pointer to source AVDictionary struct
158  * @param flags flags to use when setting entries in *dst
159  * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
160  */
161 void av_dict_copy(AVDictionary **dst, AVDictionary *src, int flags);
162 
163 /**
164  * Free all the memory allocated for an AVDictionary struct
165  * and all keys and values.
166  */
167 void av_dict_free(AVDictionary **m);
168 
169 /**
170  * @}
171  */
172 
173 //#endif /* AVUTIL_DICT_H */