decoder/DsdLib: check size before seeking

src/decoder/plugins/DsdLib.cxx

@@ -112,19 +112,18 @@ dsdlib_tag_id3(InputStream &is,
 	if (tagoffset == 0 || !is.KnownSize())
 		return;
 
-	if (!dsdlib_skip_to(nullptr, is, tagoffset))
-		return;
-
 	/* Prevent broken files causing problems */
 	const auto size = is.GetSize();
 	if (tagoffset >= size)
 		return;
 
 	const id3_length_t count = size - tagoffset;
-
 	if (count < 10 || count > 1024 * 1024)
 		return;
 
+	if (!dsdlib_skip_to(nullptr, is, tagoffset))
+		return;
+
 	id3_byte_t *const id3_buf = new id3_byte_t[count];
 	if (id3_buf == nullptr)
 		return;