115 lines
4.2 KiB
C
115 lines
4.2 KiB
C
/*
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Public dictionary API.
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*/
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#ifndef AVUTIL_DICT_H
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#define AVUTIL_DICT_H
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/**
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* @defgroup dict_api Public Dictionary API
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* @{
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* Dictionaries are used for storing key:value pairs. To create
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* an AVDictionary, simply pass an address of a NULL pointer to
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* av_dict_set(). NULL can be used as an empty dictionary wherever
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* a pointer to an AVDictionary is required.
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* Use av_dict_get() to retrieve an entry or iterate over all
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* entries and finally av_dict_free() to free the dictionary
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* and all its contents.
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*
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* @code
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* AVDictionary *d = NULL; // "create" an empty dictionary
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* av_dict_set(&d, "foo", "bar", 0); // add an entry
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*
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* char *k = av_strdup("key"); // if your strings are already allocated,
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* char *v = av_strdup("value"); // you can avoid copying them like this
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* av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
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*
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* AVDictionaryEntry *t = NULL;
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* while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
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* <....> // iterate over all entries in d
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* }
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*
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* av_dict_free(&d);
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* @endcode
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*
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* @}
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*/
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#define AV_DICT_MATCH_CASE 1
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#define AV_DICT_IGNORE_SUFFIX 2
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#define AV_DICT_DONT_STRDUP_KEY 4 /**< Take ownership of a key that's been
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allocated with av_malloc() and children. */
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#define AV_DICT_DONT_STRDUP_VAL 8 /**< Take ownership of a value that's been
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allocated with av_malloc() and chilren. */
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#define AV_DICT_DONT_OVERWRITE 16 ///< Don't overwrite existing entries.
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#define AV_DICT_APPEND 32 /**< If the entry already exists, append to it. Note that no
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delimiter is added, the strings are simply concatenated. */
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typedef struct {
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char *key;
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char *value;
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} AVDictionaryEntry;
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typedef struct AVDictionary AVDictionary;
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/**
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* Get a dictionary entry with matching key.
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*
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* @param prev Set to the previous matching element to find the next.
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* If set to NULL the first matching element is returned.
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* @param flags Allows case as well as suffix-insensitive comparisons.
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* @return Found entry or NULL, changing key or value leads to undefined behavior.
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*/
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AVDictionaryEntry *
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av_dict_get(AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags);
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/**
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* Set the given entry in *pm, overwriting an existing entry.
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*
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* @param pm pointer to a pointer to a dictionary struct. If *pm is NULL
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* a dictionary struct is allocated and put in *pm.
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* @param key entry key to add to *pm (will be av_strduped depending on flags)
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* @param value entry value to add to *pm (will be av_strduped depending on flags).
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* Passing a NULL value will cause an existing tag to be deleted.
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* @return >= 0 on success otherwise an error code <0
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*/
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int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
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/**
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* Copy entries from one AVDictionary struct into another.
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* @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,
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* this function will allocate a struct for you and put it in *dst
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* @param src pointer to source AVDictionary struct
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* @param flags flags to use when setting entries in *dst
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* @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
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*/
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void av_dict_copy(AVDictionary **dst, AVDictionary *src, int flags);
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/**
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* Free all the memory allocated for an AVDictionary struct
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* and all keys and values.
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*/
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void av_dict_free(AVDictionary **m);
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#endif // AVUTIL_DICT_H
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