Method withinStyle

app/src/main/java/eu/faircode/email/HtmlEx.java:550–591

(StringBuilder out, CharSequence text,
                                          int start, int end)

    //@UnsupportedAppUsage
    private /* static */ void withinStyle(StringBuilder out, CharSequence text,
                                          int start, int end) {
        for (int i = start; i < end; i++) {
            try {
                char c = text.charAt(i);

                if (c == '<') {
                    out.append("&lt;");
                } else if (c == '>') {
                    out.append("&gt;");
                } else if (c == '&') {
                    out.append("&amp;");
                } else if (c >= 0xD800 && c <= 0xDFFF) {
                    if (c < 0xDC00 && i + 1 < end) {
                        char d = text.charAt(i + 1);
                        if (d >= 0xDC00 && d <= 0xDFFF) {
                            i++;
                            int codepoint = 0x010000 | (int) c - 0xD800 << 10 | (int) d - 0xDC00;
                            out.append("&#").append(codepoint).append(";");
                        }
                    }
                } else if (c > 0x7E || c < ' ') {
                    out.append("&#").append((int) c).append(";");
                } else if (c == ' ') {
                    boolean img = (i - 1 >= 0 && text.charAt(i - i) == '\uFFFC');

                    while (i + 1 < end && text.charAt(i + 1) == ' ') {
                        out.append("&nbsp;");
                        i++;
                    }

                    out.append(img ? "&nbsp;" : ' ');
                } else {
                    out.append(c);
                }
            } catch (Throwable ex) {
                Log.e("withinStyle " + start + "..." + end + "/" + text.length() + " i=" + i +
                        "\n" + android.util.Log.getStackTraceString(ex));
                throw ex;
            }
        }
    }

    private static int nextSpanTransition(Spanned text, int start, int limit, Class type) {
        try {