Method isUTF8

app/src/main/java/eu/faircode/email/CharsetHelper.java:73–77

(String text)

    private static native DetectResult jni_detect_charset(byte[] octets, String ref, String lang);

    static boolean isUTF8(String text) {
        // Get extended ASCII characters
        byte[] octets = text.getBytes(StandardCharsets.ISO_8859_1);
        return isUTF8(octets);
    }

    static boolean isUTF8(byte[] octets) {
        return isValid(octets, StandardCharsets.UTF_8);