Method detect

app/src/main/java/eu/faircode/email/CharsetHelper.java:222–263

(String text, Charset ref)

    }

    public static Charset detect(String text, Charset ref) {
        if (text == null)
            return null;

        try {
            byte[] octets = text.getBytes(StandardCharsets.ISO_8859_1);

            byte[] sample;
            if (octets.length < MAX_SAMPLE_SIZE)
                sample = octets;
            else {
                sample = new byte[MAX_SAMPLE_SIZE];
                System.arraycopy(octets, 0, sample, 0, MAX_SAMPLE_SIZE);
            }

            Log.i("compact_enc_det sample=" + sample.length);
            DetectResult detected = jni_detect_charset(sample,
                    ref == null ? StandardCharsets.ISO_8859_1.name() : ref.name(),
                    Locale.getDefault().getLanguage());

            if (TextUtils.isEmpty(detected.charset)) {
                Log.e("compact_enc_det result=" + detected);
                return null;
            } else if (COMMON.contains(detected.charset) || LESS_COMMON.contains(detected.charset))
                Log.i("compact_enc_det result=" + detected);
            else if ("UTF-7".equals(detected.charset))
                return null;
            else if ("GB18030".equals(detected.charset)) {
                boolean chinese = Locale.getDefault().getLanguage().equals(CHINESE);
                // https://github.com/google/compact_enc_det/issues/8
                Log.e("compact_enc_det result=" + detected + " chinese=" + chinese);
                if (!chinese)
                    return null;
            } else
                Log.e("compact_enc_det result=" + detected);

            return Charset.forName(detected.charset);
        } catch (Throwable ex) {
            Log.w(ex);
            return null;
        }
    }

    private static class DetectResult {
        String charset;