avutil/dict: Improve documentation

Mostly consistent formatting and consistently ordering of
warnings/notes to be next to the description.

Additionally group the AV_DICT_* macros.

Signed-off-by: Anton Khirnov <anton@khirnov.net>

1 files changed, 55 insertions, 36 deletions

diff --git a/libavutil/dict.h b/libavutil/dict.h
index 9414cf61c0..713c9e361a 100644
--- a/libavutil/dict.h
+++ b/libavutil/dict.h
@@ -39,13 +39,15 @@
  * @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.
- * Use av_dict_get() to retrieve an entry and av_dict_iterate() to
- * iterate over all entries and finally av_dict_free() to free the
- * dictionary and all its contents.
+ * 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
@@ -57,13 +59,18 @@
    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)) {
+   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(). */
@@ -71,10 +78,13 @@
                                          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_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. */
+                                         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;
@@ -89,11 +99,13 @@ typedef struct AVDictionary AVDictionary;
  * 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
+ * @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);
@@ -142,20 +154,21 @@ int av_dict_count(const AVDictionary *m);
  * @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
+ * @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
+ * 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.
+ * 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);
 
@@ -165,14 +178,15 @@ int av_dict_set_int(AVDictionary **pm, const char *key, int64_t value, int flags
  * 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
+ * @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
+ * @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 dictionary.
- *                     AV_DICT_DONT_STRDUP_KEY and AV_DICT_DONT_STRDUP_VAL
+ * @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,
@@ -181,11 +195,14 @@ int av_dict_parse_string(AVDictionary **pm, const char *str,
 
 /**
  * Copy entries from one AVDictionary struct into another.
- * @param 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
- * @param src pointer to source AVDictionary struct
- * @param flags flags to use when setting entries in *dst
- * @note metadata is read using the AV_DICT_IGNORE_SUFFIX flag
+ *
+ * @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.
  */
@@ -204,13 +221,15 @@ void av_dict_free(AVDictionary **m);
  * Such string may be passed back to av_dict_parse_string().
  * @note String is escaped with backslashes ('\').
  *
- * @param[in]  m             dictionary
+ * @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
+ * @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
- * @warning Separators cannot be neither '\\' nor '\0'. They also cannot be the same.
  */
 int av_dict_get_string(const AVDictionary *m, char **buffer,
                        const char key_val_sep, const char pairs_sep);