AVDictionary

Simple key:value store. Подробнее...

Граф связей класса AVDictionary:

Классы
struct	AVDictionaryEntry

Определения типов
typedef struct AVDictionaryEntry	AVDictionaryEntry
typedef struct AVDictionary	AVDictionary

Функции
AVDictionaryEntry *	av_dict_get (const AVDictionary *m, const char *key, const AVDictionaryEntry *prev, int flags)
int	av_dict_count (const AVDictionary *m)
int	av_dict_set (AVDictionary **pm, const char *key, const char *value, int flags)
int	av_dict_set_int (AVDictionary **pm, const char *key, int64_t value, int flags)
int	av_dict_parse_string (AVDictionary **pm, const char *str, const char *key_val_sep, const char *pairs_sep, int flags)
int	av_dict_copy (AVDictionary **dst, const AVDictionary *src, int flags)
void	av_dict_free (AVDictionary **m)
int	av_dict_get_string (const AVDictionary *m, char **buffer, const char key_val_sep, const char pairs_sep)

Подробное описание

Simple key:value store.

Dictionaries are used for storing key:value pairs. To create an AVDictionary, simply pass an address of a NULL pointer to av_dict_set(). NULL can be used as an empty dictionary wherever a pointer to an AVDictionary is required. Use av_dict_get() to retrieve an entry or iterate over all entries and finally av_dict_free() to free the dictionary and all its contents.

AVDictionary *d = NULL;           // "create" an empty dictionary
AVDictionaryEntry *t = NULL;
 
av_dict_set(&d, "foo", "bar", 0); // add an entry
 
char *k = av_strdup("key");       // if your strings are already allocated,
char *v = av_strdup("value");     // you can avoid copying them like this
av_dict_set(&d, k, v, AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
 
while (t = av_dict_get(d, "", t, AV_DICT_IGNORE_SUFFIX)) {
    <....>                             // iterate over all entries in d
}
av_dict_free(&d);

Типы

AVDictionaryEntry

typedef struct AVDictionaryEntry AVDictionaryEntry

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

AVDictionary

typedef struct AVDictionary AVDictionary

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

См. определение в файле dict.h строка 86

Функции

av_dict_get()

AVDictionaryEntry* av_dict_get	(	const AVDictionary *	m,
		const char *	key,
		const AVDictionaryEntry *	prev,
		int	flags
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Get a dictionary entry with matching key.

The returned entry key or value must not be changed, or it will cause undefined behavior.

To iterate through all the dictionary entries, you can set the matching key to the null string "" and set the AV_DICT_IGNORE_SUFFIX flag.

Аргументы

prev	Set to the previous matching element to find the next. If set to NULL the first matching element is returned.
key	matching key
flags	a collection of AV_DICT_* flags controlling how the entry is retrieved

Возвращает

found entry or NULL in case no matching entry was found in the dictionary

av_dict_count()

int av_dict_count

(

const AVDictionary *

m

)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Get number of entries in dictionary.

Аргументы

m	dictionary

Возвращает

number of entries in dictionary

av_dict_set()

int av_dict_set	(	AVDictionary **	pm,
		const char *	key,
		const char *	value,
		int	flags
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Set the given entry in *pm, overwriting an existing entry.

Note: If AV_DICT_DONT_STRDUP_KEY or AV_DICT_DONT_STRDUP_VAL is set, these arguments will be freed on error.

Warning: Adding a new entry to a dictionary invalidates all existing entries previously returned with av_dict_get.

Аргументы

pm	pointer to a pointer to a dictionary struct. If *pm is NULL a dictionary struct is allocated and put in *pm.
key	entry key to add to *pm (will either be av_strduped or added as a new key depending on flags)
value	entry value to add to *pm (will be av_strduped or added as a new key depending on flags). Passing a NULL value will cause an existing entry to be deleted.

Возвращает

>= 0 on success otherwise an error code <0

av_dict_set_int()

int av_dict_set_int	(	AVDictionary **	pm,
		const char *	key,
		int64_t	value,
		int	flags
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Convenience wrapper for av_dict_set that converts the value to a string and stores it.

Note: If AV_DICT_DONT_STRDUP_KEY is set, key will be freed on error.

av_dict_parse_string()

int av_dict_parse_string	(	AVDictionary **	pm,
		const char *	str,
		const char *	key_val_sep,
		const char *	pairs_sep,
		int	flags
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Parse the key/value pairs list and add the parsed entries to a dictionary.

In case of failure, all the successfully set entries are stored in *pm. You may need to manually free the created dictionary.

Аргументы

key_val_sep	a 0-terminated list of characters used to separate key from value
pairs_sep	a 0-terminated list of characters used to separate two pairs from each other
flags	flags to use when adding to dictionary. AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL are ignored since the key/value tokens will always be duplicated.

Возвращает

0 on success, negative AVERROR code on failure

av_dict_copy()

int av_dict_copy	(	AVDictionary **	dst,
		const AVDictionary *	src,
		int	flags
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Copy entries from one AVDictionary struct into another.

Аргументы

dst	pointer to a pointer to a AVDictionary struct. If *dst is NULL, this function will allocate a struct for you and put it in *dst
src	pointer to source AVDictionary struct
flags	flags to use when setting entries in *dst

Заметки

metadata is read using the AV_DICT_IGNORE_SUFFIX flag

Возвращает

0 on success, negative AVERROR code on failure. If dst was allocated by this function, callers should free the associated memory.

av_dict_free()

void av_dict_free

(

AVDictionary **

m

)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Free all the memory allocated for an AVDictionary struct and all keys and values.

av_dict_get_string()

int av_dict_get_string	(	const AVDictionary *	m,
		char **	buffer,
		const char	key_val_sep,
		const char	pairs_sep
	)

#include <C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavutil/dict.h>

Get dictionary entries as a string.

Create a string containing dictionary's entries. Such string may be passed back to av_dict_parse_string().

Заметки

String is escaped with backslashes ('\').

Аргументы

[in]	m	dictionary
[out]	buffer	Pointer to buffer that will be allocated with string containg entries. Buffer must be freed by the caller when is no longer needed.
[in]	key_val_sep	character used to separate key from value
[in]	pairs_sep	character used to separate two pairs from each other

Возвращает

>= 0 on success, negative on error

Предупреждения

Separators cannot be neither '\' nor '\0'. They also cannot be the same.