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authorFox Caminiti <fox@foxcam.net>2022-12-16 20:16:43 -0500
committerFox Caminiti <fox@foxcam.net>2022-12-16 20:16:43 -0500
commitbedd6906eabdd513042d6a178d4dc56a3a41d1d3 (patch)
tree2bcbd3e46ae61e583707a2ccc5b3f5cfeacb61a8 /dependencies/include/libavutil/dict.h
parentcdb9e1f7240cb0716b7d99df5e1fd7c3fc3407a8 (diff)
v3, file/build organization
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+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Public dictionary API.
+ * @deprecated
+ * AVDictionary is provided for compatibility with libav. It is both in
+ * implementation as well as API inefficient. It does not scale and is
+ * extremely slow with large dictionaries.
+ * It is recommended that new code uses our tree container from tree.c/h
+ * where applicable, which uses AVL trees to achieve O(log n) performance.
+ */
+
+#ifndef AVUTIL_DICT_H
+#define AVUTIL_DICT_H
+
+#include <stdint.h>
+
+/**
+ * @addtogroup lavu_dict AVDictionary
+ * @ingroup lavu_data
+ *
+ * @brief 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.
+ * - To **insert an entry**, use av_dict_set().
+ * - Use av_dict_get() to **retrieve an entry**.
+ * - To **iterate over all entries**, use av_dict_iterate().
+ * - In order to **free the dictionary and all its contents**, use av_dict_free().
+ *
+ @code
+ 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_iterate(d, t))) {
+ <....> // iterate over all entries in d
+ }
+ av_dict_free(&d);
+ @endcode
+ */
+
+/**
+ * @name AVDictionary Flags
+ * Flags that influence behavior of the matching of keys or insertion to the dictionary.
+ * @{
+ */
+#define AV_DICT_MATCH_CASE 1 /**< Only get an entry with exact-case key match. Only relevant in av_dict_get(). */
+#define AV_DICT_IGNORE_SUFFIX 2 /**< Return first entry in a dictionary whose first part corresponds to the search key,
+ ignoring the suffix of the found key string. Only relevant in av_dict_get(). */
+#define AV_DICT_DONT_STRDUP_KEY 4 /**< Take ownership of a key that's been
+ allocated with av_malloc() or another memory allocation function. */
+#define AV_DICT_DONT_STRDUP_VAL 8 /**< Take ownership of a value that's been
+ allocated with av_malloc() or another memory allocation function. */
+#define AV_DICT_DONT_OVERWRITE 16 /**< Don't overwrite existing entries. */
+#define AV_DICT_APPEND 32 /**< If the entry already exists, append to it. Note that no
+ delimiter is added, the strings are simply concatenated. */
+#define AV_DICT_MULTIKEY 64 /**< Allow to store several equal keys in the dictionary */
+/**
+ * @}
+ */
+
+typedef struct AVDictionaryEntry {
+ char *key;
+ char *value;
+} AVDictionaryEntry;
+
+typedef struct AVDictionary AVDictionary;
+
+/**
+ * Get a dictionary entry with matching key.
+ *
+ * The returned entry key or value must not be changed, or it will
+ * cause undefined behavior.
+ *
+ * @param prev Set to the previous matching element to find the next.
+ * If set to NULL the first matching element is returned.
+ * @param key Matching key
+ * @param flags A collection of AV_DICT_* flags controlling how the
+ * entry is retrieved
+ *
+ * @return Found entry or NULL in case no matching entry was found in the dictionary
+ */
+AVDictionaryEntry *av_dict_get(const AVDictionary *m, const char *key,
+ const AVDictionaryEntry *prev, int flags);
+
+/**
+ * Iterate over a dictionary
+ *
+ * Iterates through all entries in the dictionary.
+ *
+ * @warning The returned AVDictionaryEntry key/value must not be changed.
+ *
+ * @warning As av_dict_set() invalidates all previous entries returned
+ * by this function, it must not be called while iterating over the dict.
+ *
+ * Typical usage:
+ * @code
+ * const AVDictionaryEntry *e = NULL;
+ * while ((e = av_dict_iterate(m, e))) {
+ * // ...
+ * }
+ * @endcode
+ *
+ * @param m The dictionary to iterate over
+ * @param prev Pointer to the previous AVDictionaryEntry, NULL initially
+ *
+ * @retval AVDictionaryEntry* The next element in the dictionary
+ * @retval NULL No more elements in the dictionary
+ */
+const AVDictionaryEntry *av_dict_iterate(const AVDictionary *m,
+ const AVDictionaryEntry *prev);
+
+/**
+ * Get number of entries in dictionary.
+ *
+ * @param m dictionary
+ * @return number of entries in dictionary
+ */
+int av_dict_count(const AVDictionary *m);
+
+/**
+ * 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() or av_dict_iterate().
+ *
+ * @param pm Pointer to a pointer to a dictionary struct. If *pm is NULL
+ * a dictionary struct is allocated and put in *pm.
+ * @param key Entry key to add to *pm (will either be av_strduped or added as a new key depending on flags)
+ * @param 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.
+ *
+ * @return >= 0 on success otherwise an error code <0
+ */
+int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
+
+/**
+ * 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.
+ */
+int av_dict_set_int(AVDictionary **pm, const char *key, int64_t value, int flags);
+
+/**
+ * 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.
+ *
+ * @param key_val_sep A 0-terminated list of characters used to separate
+ * key from value
+ * @param pairs_sep A 0-terminated list of characters used to separate
+ * two pairs from each other
+ * @param flags Flags to use when adding to the dictionary.
+ * ::AV_DICT_DONT_STRDUP_KEY and ::AV_DICT_DONT_STRDUP_VAL
+ * are ignored since the key/value tokens will always
+ * be duplicated.
+ *
+ * @return 0 on success, negative AVERROR code on failure
+ */
+int av_dict_parse_string(AVDictionary **pm, const char *str,
+ const char *key_val_sep, const char *pairs_sep,
+ int flags);
+
+/**
+ * Copy entries from one AVDictionary struct into another.
+ *
+ * @note Metadata is read using the ::AV_DICT_IGNORE_SUFFIX flag
+ *
+ * @param dst Pointer to a pointer to a AVDictionary struct to copy into. If *dst is NULL,
+ * this function will allocate a struct for you and put it in *dst
+ * @param src Pointer to the source AVDictionary struct to copy items from.
+ * @param flags Flags to use when setting entries in *dst
+ *
+ * @return 0 on success, negative AVERROR code on failure. If dst was allocated
+ * by this function, callers should free the associated memory.
+ */
+int av_dict_copy(AVDictionary **dst, const AVDictionary *src, int flags);
+
+/**
+ * Free all the memory allocated for an AVDictionary struct
+ * and all keys and values.
+ */
+void av_dict_free(AVDictionary **m);
+
+/**
+ * Get dictionary entries as a string.
+ *
+ * Create a string containing dictionary's entries.
+ * Such string may be passed back to av_dict_parse_string().
+ * @note String is escaped with backslashes ('\').
+ *
+ * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
+ *
+ * @param[in] m The dictionary
+ * @param[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.
+ * @param[in] key_val_sep Character used to separate key from value
+ * @param[in] pairs_sep Character used to separate two pairs from each other
+ *
+ * @return >= 0 on success, negative on error
+ */
+int av_dict_get_string(const AVDictionary *m, char **buffer,
+ const char key_val_sep, const char pairs_sep);
+
+/**
+ * @}
+ */
+
+#endif /* AVUTIL_DICT_H */