}
  }

  private static class DontStringMeBro implements CharSequence {
    @Override
    public int length() {
      return 3;
    }

    @Override
    public char charAt(int index) {
      return "foo".charAt(index);
    }

    @Override
    public CharSequence subSequence(int start, int end) {
      return "foo".subSequence(start, end);
    }

    @Override

   *
   * @throws IOException if an I/O error occurs
   */
  @Override
  public void writeChars(String s) throws IOException {
    for (int i = 0; i < s.length(); i++) {
      writeChar(s.charAt(i));
    }
  }

  /**
   * Writes a {@code double} as specified by {@link DataOutputStream#writeDouble(double)}, except
   * using little-endian byte order.
   *

   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableListMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableListMultimap.Builder<Character, String>()

   *
   * <pre>{@code
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     Stream.of("banana", "apple", "carrot", "asparagus", "cherry")
   *         .collect(toImmutableSetMultimap(str -> str.charAt(0), str -> str.substring(1)));
   *
   * // is equivalent to
   *
   * static final Multimap<Character, String> FIRST_LETTER_MULTIMAP =
   *     new ImmutableSetMultimap.Builder<Character, String>()

  public static CharMatcher anyOf(final CharSequence sequence) {
    switch (sequence.length()) {
      case 0:
        return none();
      case 1:
        return is(sequence.charAt(0));
      case 2:
        return isEither(sequence.charAt(0), sequence.charAt(1));
      default:
        // TODO(lowasser): is it potentially worth just going ahead and building a precomputed
        // matcher?
        return new AnyOf(sequence);
    }

   *       use {@link String#getChars(int, int, char[], int)} instead of copying characters one by
   *       one with {@link CharSequence#charAt(int)}.
   *   <li>use {@link Appendable#append(CharSequence)} in {@link #copyTo(Appendable)} and {@link
   *       #copyTo(CharSink)}. We know this is correct since strings are immutable and so the length

      new Function<@Nullable String, @Nullable Character>() {
        @Override
        public @Nullable Character apply(@Nullable String input) {
          return input == null ? null : input.charAt(0);
        }
      };

  abstract static class ColumnMapTests extends MapMapTests {
    ColumnMapTests(
        boolean allowsNullValues,
        boolean supportsRemove,
        boolean supportsClear,

  @Generates
  Byte generateByteObject() {
    return new Byte(generateByte());
  }

  @Generates
  char generateChar() {
    return generateString().charAt(0);
  }

  @SuppressWarnings("removal") // b/321209431 -- maybe just use valueOf here?
  @Generates
  Character generateCharacter() {
    return new Character(generateChar());
  }

  @Generates

    int utf8Length = utf16Length;
    int i = 0;

    // This loop optimizes for pure ASCII.
    while (i < utf16Length && sequence.charAt(i) < 0x80) {
      i++;
    }

    // This loop optimizes for chars less than 0x800.
    for (; i < utf16Length; i++) {
      char c = sequence.charAt(i);
      if (c < 0x800) {
        utf8Length += ((0x7f - c) >>> 31); // branch free!
      } else {

                positions:
                for (int p = start, last = toSplit.length() - separatorLength; p <= last; p++) {
                  for (int i = 0; i < separatorLength; i++) {
                    if (toSplit.charAt(i + p) != separator.charAt(i)) {
                      continue positions;
                    }
                  }
                  return p;
                }
                return -1;
              }