+
          // Three byte characters
          THREE_BYTE_ROUNDTRIPPABLE_CHARACTERS;

  // 1,048,576 [chars 0x10000L to 0x10FFFF]
  private static final long FOUR_BYTE_ROUNDTRIPPABLE_CHARACTERS = 0x10FFFF - 0x10000L + 1;

  // 289,571,839
  private static final long EXPECTED_FOUR_BYTE_ROUNDTRIPPABLE_COUNT =
      // All one byte characters

      mappings.binarySearch {
        when {
          it.sourceCodePoint1 < codePoint -> -1
          it.sourceCodePoint0 > codePoint -> 1
          else -> 0
        }
      }

    // Code points must be in 0..0x10ffff.
    require(index in mappings.indices) { "unexpected code point: $codePoint" }

    val mapping = mappings[index]
    var result = true

    when (mapping.type) {
      TYPE_IGNORED -> {
        Unit
      }

      val deltaN = i / (codePoints.size + 1)
      if (n > Int.MAX_VALUE - deltaN) return false // Prevent overflow.
      n += deltaN
      i %= (codePoints.size + 1)

      if (n > 0x10ffff) return false // Not a valid code point.

      codePoints.add(i, n)

      i++
    }

    for (codePoint in codePoints) {
      result.writeUtf8CodePoint(codePoint)
    }

    return true

 * <a href="http://www.unicode.org/glossary/#supplementary_code_point">supplementary Unicode code
 * points</a> in the range {@code 0x10000} to {@code 0x10FFFF} which includes the majority of
 * assigned characters, including important CJK characters and emoji.
 *
 * <p>Supplementary characters are <a

 * <a href="http://www.unicode.org/glossary/#supplementary_code_point">supplementary Unicode code
 * points</a> in the range {@code 0x10000} to {@code 0x10FFFF} which includes the majority of
 * assigned characters, including important CJK characters and emoji.
 *
 * <p>Supplementary characters are <a

0 and 255 inclusive.  Hexadecimal escapes satisfy this condition
by construction. The escapes <code>\u</code> and <code>\U</code>
represent Unicode code points so within them some values are illegal,
in particular those above <code>0x10FFFF</code> and surrogate halves.
</p>

<p>
After a backslash, certain single-character escapes represent special values:
</p>

<pre class="grammar">
\a   U+0007 alert or bell
\b   U+0008 backspace

      }
    }

    // Test that 0xFFFE and 0xFFFF are replaced with 0xFFFD
    assertEscaping(xmlEscaper, "\uFFFD", '\uFFFE');
    assertEscaping(xmlEscaper, "\uFFFD", '\uFFFF');

    assertWithMessage("0xFFFE is forbidden and should be replaced during escaping")
        .that(xmlEscaper.escape("[\ufffe]"))
        .isEqualTo("[\uFFFD]");
    assertWithMessage("0xFFFF is forbidden and should be replaced during escaping")

			h.Devmajor, h.Devminor = int64(major), int64(minor)
		case "darwin", "ios":
			// Copied from golang.org/x/sys/unix/dev_darwin.go.
			major := uint32((dev >> 24) & 0xff)
			minor := uint32(dev & 0xffffff)
			h.Devmajor, h.Devminor = int64(major), int64(minor)
		case "dragonfly":
			// Copied from golang.org/x/sys/unix/dev_dragonfly.go.
			major := uint32((dev >> 8) & 0xff)
			minor := uint32(dev & 0xffff00ff)

    assertThat(escaper.escape("The Quick Brown Fox")).isEqualTo("The Quick Brown Fox");
  }

  public void testBuilderInitialStateNoneUnsafe() {
    // No characters are unsafe by default (safeMin == 0, safeMax == 0xFFFF).
    Escaper escaper = Escapers.builder().setUnsafeReplacement("X").build();
    assertThat(escaper.escape("\0\uFFFF")).isEqualTo("\0\uFFFF");
  }

  public void testBuilderRetainsState() {

      }
    }

    // Test that 0xFFFE and 0xFFFF are replaced with 0xFFFD
    assertEscaping(xmlEscaper, "\uFFFD", '\uFFFE');
    assertEscaping(xmlEscaper, "\uFFFD", '\uFFFF');

    assertWithMessage("0xFFFE is forbidden and should be replaced during escaping")
        .that(xmlEscaper.escape("[\ufffe]"))
        .isEqualTo("[\uFFFD]");
    assertWithMessage("0xFFFF is forbidden and should be replaced during escaping")