--- a/src/lib-imap/imap-envelope.c	Wed Oct 26 23:44:47 2016 +0200
+++ b/src/lib-imap/imap-envelope.c	Thu Dec 29 14:02:05 2016 +0100
@@ -214,3 +214,45 @@
 	*envlp_r = envlp;
 	return TRUE;
 }
+
+bool imap_envelope_parse(const char *envelope,
+	pool_t pool, struct message_part_envelope **envlp_r,
+	const char **error_r)
+{
+	struct istream *input;
+	struct imap_parser *parser;
+	const struct imap_arg *args;
+	char *error;
+	int ret;
+
+	input = i_stream_create_from_data(envelope, strlen(envelope));
+	(void)i_stream_read(input);
+
+	parser = imap_parser_create(input, NULL, (size_t)-1);
+	ret = imap_parser_finish_line(parser, 0,
+				      IMAP_PARSE_FLAG_LITERAL_TYPE, &args);
+	if (ret < 0) {
+		*error_r = t_strdup_printf("IMAP parser failed: %s",
+					   imap_parser_get_error(parser, NULL));
+	} else if (ret == 0) {
+		*error_r = "Empty envelope";
+		ret = -1;
+	} else {
+		T_BEGIN {
+			if (!imap_envelope_parse_args
+				(args, pool, envlp_r, error_r)) {
+				error = i_strdup(*error_r);
+				ret = -1;
+			}
+		} T_END;
+
+		if (ret < 0) {
+			*error_r = t_strdup(error);
+			i_free(error);
+		}
+	}
+
+	imap_parser_unref(&parser);
+	i_stream_destroy(&input);
+	return (ret >= 0);
+}
\ No newline at end of file

--- a/src/lib-imap/imap-envelope.h	Wed Oct 26 23:44:47 2016 +0200
+++ b/src/lib-imap/imap-envelope.h	Thu Dec 29 14:02:05 2016 +0100
@@ -12,5 +12,9 @@
 bool imap_envelope_parse_args(const struct imap_arg *args,
 	pool_t pool, struct message_part_envelope **envlp_r,
 	const char **error_r);
+/* Parse envelope from string */
+bool imap_envelope_parse(const char *envelope,
+	pool_t pool, struct message_part_envelope **envlp_r,
+	const char **error_r);
 
 #endif