* called by the {@link #escape(String)} method when it discovers that escaping is required. It is
   * protected to allow subclasses to override the fastpath escaping function to inline their
   * escaping test. See {@link CharEscaperBuilder} for an example usage.
   *
   * @param s the literal string to be escaped
   * @param index the index to start escaping from
   * @return the escaped form of {@code string}

 * general way.
 *
 * <p>A good example of usage of this class is for HTML escaping where the replacement array
 * contains information about the named HTML entities such as {@code &amp;} and {@code &quot;} while
 * {@link #escapeUnsafe} is overridden to handle general escaping of the form {@code &#NNNNN;}.
 *
 * <p>The size of the data structure used by {@link ArrayBasedUnicodeEscaper} is proportional to the

   * form parameter names and values</a>. Escaping is performed with the UTF-8 character encoding.
   * The caller is responsible for <a
   * href="https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#multipart-form-data">replacing
   * any unpaired carriage return or line feed characters with a CR+LF pair</a> on any non-file
   * inputs before escaping them with this escaper.
   *

 * elements' text contents. When possible, avoid manual escaping by using templating systems and
 * high-level APIs that provide autoescaping. For example, consider <a
 * href="http://www.xom.nu/">XOM</a>.
 *
 * <p><b>Note:</b> Currently the escapers provided by this class do not escape any characters
 * outside the ASCII character range. Unlike HTML escaping the XML escapers will not escape

 * array contains information about special ASCII characters such as {@code \\t} and {@code \\n}
 * while {@link #escapeUnsafe} is overridden to handle general escaping of the form {@code \\uxxxx}.
 *
 * <p>The size of the data structure used by {@link ArrayBasedCharEscaper} is proportional to the
 * highest valued character that requires escaping. For example a replacement map containing the

   * called by the {@link #escape(String)} method when it discovers that escaping is required. It is
   * protected to allow subclasses to override the fastpath escaping function to inline their
   * escaping test. See {@link CharEscaperBuilder} for an example usage.
   *
   * @param s the literal string to be escaped
   * @param index the index to start escaping from
   * @return the escaped form of {@code string}

   * form parameter names and values</a>. Escaping is performed with the UTF-8 character encoding.
   * The caller is responsible for <a
   * href="https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#multipart-form-data">replacing
   * any unpaired carriage return or line feed characters with a CR+LF pair</a> on any non-file
   * inputs before escaping them with this escaper.
   *

 * general way.
 *
 * <p>A good example of usage of this class is for HTML escaping where the replacement array
 * contains information about the named HTML entities such as {@code &amp;} and {@code &quot;} while
 * {@link #escapeUnsafe} is overridden to handle general escaping of the form {@code &#NNNNN;}.
 *
 * <p>The size of the data structure used by {@link ArrayBasedUnicodeEscaper} is proportional to the

      ImmutableMap.of(
          '\n', "<newline>",
          '\t', "<tab>",
          '&', "<and>");

  public void testSafeRange() throws IOException {
    // Basic escaping of unsafe chars (wrap them in {,}'s)
    CharEscaper wrappingEscaper =
        new ArrayBasedCharEscaper(NO_REPLACEMENTS, 'A', 'Z') {
          @Override
          protected char[] escapeUnsafe(char c) {

@GwtCompatible
public final class Escapers {
  private Escapers() {}

  /**
   * Returns an {@link Escaper} that does no escaping, passing all character data through unchanged.
   */
  public static Escaper nullEscaper() {
    return NULL_ESCAPER;
  }

  // An Escaper that efficiently performs no escaping.
  // Extending CharEscaper (instead of Escaper) makes Escapers.compose() easier.
  private static final Escaper NULL_ESCAPER =