* Reader#skip(long) skip} to the end of the stream, and return the total number of chars that
   * were skipped.
   *
   * <p>Note that for sources that implement {@link #lengthIfKnown} to provide a more efficient
   * implementation, it is <i>possible</i> that this method will return a different number of chars
   * than would be returned by reading all of the chars.
   *

   * Reader#skip(long) skip} to the end of the stream, and return the total number of chars that
   * were skipped.
   *
   * <p>Note that for sources that implement {@link #lengthIfKnown} to provide a more efficient
   * implementation, it is <i>possible</i> that this method will return a different number of chars
   * than would be returned by reading all of the chars.
   *

      // Start with "%--" and fill in the blanks
      char[] dest = new char[3];
      dest[0] = '%';
      dest[2] = upperHexDigits[cp & 0xF];
      dest[1] = upperHexDigits[cp >>> 4];
      return dest;
    } else if (cp <= 0x7ff) {
      // Two byte UTF-8 characters [cp >= 0x80 && cp <= 0x7ff]
      // Start with "%--%--" and fill in the blanks
      char[] dest = new char[6];
      dest[0] = '%';
      dest[3] = '%';

  }

  public void testCharsIgnored() {
    for (char c : IGNORED.toCharArray()) {
      String str = String.valueOf(c);
      assertEquals(str, c, Ascii.toLowerCase(c));
      assertEquals(str, c, Ascii.toUpperCase(c));
      assertFalse(str, Ascii.isLowerCase(c));
      assertFalse(str, Ascii.isUpperCase(c));
    }
  }

  public void testCharsLower() {
    for (char c : LOWER.toCharArray()) {
      String str = String.valueOf(c);

    scratch.putLong(l);
    return update(scratch, Longs.BYTES);
  }

  @Override
  @CanIgnoreReturnValue
  public Hasher putChar(char c) {
    ByteBuffer scratch = scratch();
    scratch.putChar(c);
    return update(scratch, Chars.BYTES);
  }

  private ByteBuffer scratch() {
    if (scratch == null) {
      scratch = ByteBuffer.allocate(8).order(ByteOrder.LITTLE_ENDIAN);
    }

        // Test extended ASCII characters (not valid URL chars without encoding)
        assertFalse(CharUtil.isUrlChar('\u00A0')); // non-breaking space
        assertFalse(CharUtil.isUrlChar('\u00FF')); // ÿ
    }

    public void test_isUrlChar_unicode() {
        // Test Unicode characters (not valid URL chars without encoding)
        assertFalse(CharUtil.isUrlChar('\u3042')); // あ (Hiragana)

    String expected = "abcdabcd";

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice
    // TODO(cgdecker): Add CharSource.slice?
    StringBuilder builder = new StringBuilder();
    Reader reader = concatenated.openStream(); // no need to worry about closing
    for (int i = 0; i < 8; i++) {
      builder.append((char) reader.read());
    }
    assertEquals(expected, builder.toString());

   */
  private static char[] growBuffer(char[] dest, int index, int size) {
    if (size < 0) { // overflow - should be OutOfMemoryError but GWT/j2cl don't support it
      throw new AssertionError("Cannot increase internal buffer any further");
    }
    char[] copy = new char[size];
    if (index > 0) {
      System.arraycopy(dest, 0, copy, 0, index);
    }

    String expected = "abcdabcd";

    // read the first 8 chars manually, since there's no equivalent to ByteSource.slice
    // TODO(cgdecker): Add CharSource.slice?
    StringBuilder builder = new StringBuilder();
    Reader reader = concatenated.openStream(); // no need to worry about closing
    for (int i = 0; i < 8; i++) {
      builder.append((char) reader.read());
    }
    assertEquals(expected, builder.toString());

          a: String,
          b: String,
        ): Int {
          var i = 4
          val limit = minOf(a.length, b.length)
          while (i < limit) {
            val charA = a[i]
            val charB = b[i]
            if (charA != charB) return if (charA < charB) -1 else 1
            i++
          }
          val lengthA = a.length
          val lengthB = b.length