*       which operate only on the ASCII characters of a string.
 * </ul>
 *
 * @author Catherine Berry
 * @author Gregory Kick
 * @since 7.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Ascii {

  private Ascii() {}

  /* The ASCII control characters, per RFC 20. */
  /**

 *       which operate only on the ASCII characters of a string.
 * </ul>
 *
 * @author Catherine Berry
 * @author Gregory Kick
 * @since 7.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Ascii {

  private Ascii() {}

  /* The ASCII control characters, per RFC 20. */
  /**

Kurt Kluever <******@****.***> 1372373349 -0400

zhenghua <******@****.***> 1492724018 -0700

    assertEquals(LOWER, Ascii.toLowerCase(UPPER));
    assertSame(LOWER, Ascii.toLowerCase(LOWER));
    assertEquals(IGNORED, Ascii.toLowerCase(IGNORED));
    assertEquals("foobar", Ascii.toLowerCase("fOobaR"));
  }

  public void testToUpperCase() {
    assertEquals(UPPER, Ascii.toUpperCase(LOWER));
    assertSame(UPPER, Ascii.toUpperCase(UPPER));
    assertEquals(IGNORED, Ascii.toUpperCase(IGNORED));

    assertEquals(LOWER, Ascii.toLowerCase(UPPER));
    assertSame(LOWER, Ascii.toLowerCase(LOWER));
    assertEquals(IGNORED, Ascii.toLowerCase(IGNORED));
    assertEquals("foobar", Ascii.toLowerCase("fOobaR"));
  }

  public void testToUpperCase() {
    assertEquals(UPPER, Ascii.toUpperCase(LOWER));
    assertSame(UPPER, Ascii.toUpperCase(UPPER));
    assertEquals(IGNORED, Ascii.toUpperCase(IGNORED));

    return NONALPHA.charAt(random.nextInt(NONALPHA.length()));
  }

  @Benchmark
  int asciiStringToUpperCase(int reps) {
    String string = noWorkToDo ? Ascii.toUpperCase(testString) : testString;

    int dummy = 0;
    for (int i = 0; i < reps; i++) {
      dummy += Ascii.toUpperCase(string).length();
    }
    return dummy;
  }

  @Benchmark
  int asciiCharSequenceToUpperCase(int reps) {

  }

  public void testToString() throws IOException {
    File asciiFile = getTestFile("ascii.txt");
    File i18nFile = getTestFile("i18n.txt");
    assertEquals(ASCII, Files.toString(asciiFile, Charsets.US_ASCII));
    assertEquals(I18N, Files.toString(i18nFile, Charsets.UTF_8));
    assertThat(Files.toString(i18nFile, Charsets.US_ASCII)).isNotEqualTo(I18N);
  }

  public void testWriteString() throws IOException {

  public void testWhyUsAsciiIsDangerous() {
    byte[] b1 = "朝日新聞".getBytes(Charsets.US_ASCII);
    byte[] b2 = "聞朝日新".getBytes(Charsets.US_ASCII);
    byte[] b3 = "????".getBytes(Charsets.US_ASCII);
    byte[] b4 = "ニュース".getBytes(Charsets.US_ASCII);
    byte[] b5 = "スューー".getBytes(Charsets.US_ASCII);
    // Assert they are all equal (using the transitive property)
    assertTrue(Arrays.equals(b1, b2));

 *
 * <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
 * non-ASCII characters to their numeric entity replacements. These XML escapers provide the minimal
 * level of escaping to ensure that the output can be safely included in a Unicode XML document.
 *