dict: add av_dict_parse_string()

Can be used to set multiple key/value pairs from a string.
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>

doc/APIchanges

@@ -13,6 +13,10 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2013-xx-xx - xxxxxxx - lavu 52.7.0 - dict.h
+  Add av_dict_parse_string() to set multiple key/value pairs at once from a
+  string.
+
 2013-01-xx - xxxxxxx - lavu 52.6.0 - avstring.h
   Add av_strnstr()
 

libavutil/dict.c

@@ -110,6 +110,53 @@ int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags
     return 0;
 }
 
+static int parse_key_value_pair(AVDictionary **pm, const char **buf,
+                                const char *key_val_sep, const char *pairs_sep,
+                                int flags)
+{
+    char *key = av_get_token(buf, key_val_sep);
+    char *val = NULL;
+    int ret;
+
+    if (key && *key && strspn(*buf, key_val_sep)) {
+        (*buf)++;
+        val = av_get_token(buf, pairs_sep);
+    }
+
+    if (key && *key && val && *val)
+        ret = av_dict_set(pm, key, val, flags);
+    else
+        ret = AVERROR(EINVAL);
+
+    av_freep(&key);
+    av_freep(&val);
+
+    return ret;
+}
+
+int av_dict_parse_string(AVDictionary **pm, const char *str,
+                         const char *key_val_sep, const char *pairs_sep,
+                         int flags)
+{
+    int ret;
+
+    if (!str)
+        return 0;
+
+    /* ignore STRDUP flags */
+    flags &= ~(AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
+
+    while (*str) {
+        if ((ret = parse_key_value_pair(pm, &str, key_val_sep, pairs_sep, flags)) < 0)
+            return ret;
+
+        if (*str)
+            str++;
+    }
+
+    return 0;
+}
+
 void av_dict_free(AVDictionary **pm)
 {
     AVDictionary *m = *pm;

libavutil/dict.h

@@ -106,6 +106,23 @@ int av_dict_count(const AVDictionary *m);
  */
 int av_dict_set(AVDictionary **pm, const char *key, const char *value, int flags);
 
+/**
+ * Parse the key/value pairs list and add to a 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 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.
  * @param dst pointer to a pointer to a AVDictionary struct. If *dst is NULL,

libavutil/version.h

@@ -37,7 +37,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 52
-#define LIBAVUTIL_VERSION_MINOR  6
+#define LIBAVUTIL_VERSION_MINOR  7
 #define LIBAVUTIL_VERSION_MICRO  0
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \