till you come to the end:  then stop.'

  These were the verses the White Rabbit read:--

        `They told me you had been to her,
          And mentioned me to him:
        She gave me a good character,
          But said I could not swim.

        He sent them word I had not gone
          (We know it to be true):
        If she should push the matter on,
          What would become of you?

 *
 * <ul>
 *   <li>All specified safe characters remain unchanged.
 *   <li>If {@code plusForSpace} was specified, the space character " " is converted into a plus
 *       sign {@code "+"}.
 *   <li>All other characters are converted into one or more bytes using UTF-8 encoding and each
 *       byte is then represented by the 3-character string "%XX", where "XX" is the two-digit,

        throw new DecodingException("Unrecognized character: 0x" + Integer.toHexString(ch));
      }
      int result = decodabet[ch];
      if (result == -1) {
        if (ch <= 0x20 || ch == Ascii.MAX) {
          throw new DecodingException("Unrecognized character: 0x" + Integer.toHexString(ch));
        } else {
          throw new DecodingException("Unrecognized character: " + ch);
        }
      }
      return result;

 * when more than one escaper is created using the same character replacement mapping to allow the
 * underlying (implementation specific) data structures to be shared.
 *
 * <p>The size of the data structure used by ArrayBasedCharEscaper and ArrayBasedUnicodeEscaper is
 * proportional to the highest valued character that has a replacement. For example a replacement
 * map containing the single character '{@literal \}u1000' will require approximately 16K of memory.

    String msg = "plusForSpace cannot be specified when space is a 'safe' character";
    try {
      new PercentEscaper(" ", true);
      fail(msg);
    } catch (IllegalArgumentException expected) {
      assertThat(expected).hasMessageThat().isEqualTo(msg);
    }
  }

  /** Helper to manually escape a 7-bit ascii character */
  private String escapeAscii(char c) {
    Preconditions.checkArgument(c < 128);

  }

  public void testBuilderInitialStateNoReplacement() {
    // Unsafe characters aren't modified by default (unsafeReplacement == null).
    Escaper escaper = Escapers.builder().setSafeRange('a', 'z').build();
    assertEquals("The Quick Brown Fox", escaper.escape("The Quick Brown Fox"));
  }

  public void testBuilderInitialStateNoneUnsafe() {
    // No characters are unsafe by default (safeMin == 0, safeMax == 0xFFFF).

    String[] BAD_STRINGS = {
      String.valueOf(Character.MIN_LOW_SURROGATE),
      Character.MIN_LOW_SURROGATE + "xyz",
      "abc" + Character.MIN_LOW_SURROGATE,
      "abc" + Character.MIN_LOW_SURROGATE + "xyz",
      String.valueOf(Character.MAX_LOW_SURROGATE),
      Character.MAX_LOW_SURROGATE + "xyz",
      "abc" + Character.MAX_LOW_SURROGATE,
      "abc" + Character.MAX_LOW_SURROGATE + "xyz",
    };

    assertFailsToDecode(base16(), "\n\n", "Unrecognized character: 0xa");
    assertFailsToDecode(base16(), "EFGH", "Unrecognized character: G");
    // Valid base16 strings always have an even length.
    assertFailsToDecode(base16(), "A", "Invalid input length 1");
    assertFailsToDecode(base16(), "ABC");
    // These have a combination of invalid length and unrecognized characters.

    return asByteSource(url).read();
  }

  /**
   * Reads all characters from a URL into a {@link String}, using the given character set.
   *
   * @param url the URL to read from
   * @param charset the charset used to decode the input stream; see {@link Charsets} for helpful
   *     predefined constants
   * @return a string containing all the characters from the URL
   * @throws IOException if an I/O error occurs.
   */

    assertFalse(table.containsValue(null));
  }

  public void testGet() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertEquals((Character) 'a', table.get("foo", 1));
    assertEquals((Character) 'b', table.get("bar", 1));
    assertEquals((Character) 'c', table.get("foo", 3));
    assertNull(table.get("foo", 2));
    assertNull(table.get("bar", 3));
    assertNull(table.get("cat", 1));