character.java

gcc的组建

               | (1 << LOWERCASE_LETTER)
               | (1 << TITLECASE_LETTER)
               | (1 << MODIFIER_LETTER)
               | (1 << OTHER_LETTER)
               | (1 << LETTER_NUMBER))) != 0;
  }

  /**
   * Determines if a character can follow the first letter in
   * a Unicode identifier. This includes letters, connecting punctuation,
   * digits, numeric letters, combining marks, non-spacing marks, and
   * isIdentifierIgnorable.
   * <br>
   * Unicode identifier extender =
   *   [Lu]|[Ll]|[Lt]|[Lm]|[Lo]|[Nl]|[Mn]|[Mc]|[Nd]|[Pc]|[Cf]|
   *   |U+0000-U+0008|U+000E-U+001B|U+007F-U+009F
   *
   * @param ch character to test
   * @return true if ch can follow the first letter in a Unicode identifier
   * @see #isIdentifierIgnorable(char)
   * @see #isJavaIdentifierPart(char)
   * @see #isLetterOrDigit(char)
   * @see #isUnicodeIdentifierStart(char)
   * @since 1.1
   */
  public static boolean isUnicodeIdentifierPart(char ch)
  {
    int category = getType(ch);
    return ((1 << category)
            & ((1 << UPPERCASE_LETTER)
               | (1 << LOWERCASE_LETTER)
               | (1 << TITLECASE_LETTER)
               | (1 << MODIFIER_LETTER)
               | (1 << OTHER_LETTER)
               | (1 << NON_SPACING_MARK)
               | (1 << COMBINING_SPACING_MARK)
               | (1 << DECIMAL_DIGIT_NUMBER)
               | (1 << LETTER_NUMBER)
               | (1 << CONNECTOR_PUNCTUATION)
               | (1 << FORMAT))) != 0
      || (category == CONTROL && isIdentifierIgnorable(ch));
  }

  /**
   * Determines if a character is ignorable in a Unicode identifier. This
   * includes the non-whitespace ISO control characters (<code>'\u0000'</code>
   * through <code>'\u0008'</code>, <code>'\u000E'</code> through
   * <code>'\u001B'</code>, and <code>'\u007F'</code> through
   * <code>'\u009F'</code>), and FORMAT characters.
   * <br>
   * Unicode identifier ignorable = [Cf]|U+0000-U+0008|U+000E-U+001B
   *    |U+007F-U+009F
   *
   * @param ch character to test
   * @return true if ch is ignorable in a Unicode or Java identifier
   * @see #isJavaIdentifierPart(char)
   * @see #isUnicodeIdentifierPart(char)
   * @since 1.1
   */
  public static boolean isIdentifierIgnorable(char ch)
  {
    return (ch <= '\u009F' && (ch < '\t' || ch >= '\u007F'
                               || (ch <= '\u001B' && ch >= '\u000E')))
      || getType(ch) == FORMAT;
  }

  /**
   * Converts a Unicode character into its lowercase equivalent mapping.
   * If a mapping does not exist, then the character passed is returned.
   * Note that isLowerCase(toLowerCase(ch)) does not always return true.
   *
   * @param ch character to convert to lowercase
   * @return lowercase mapping of ch, or ch if lowercase mapping does
   *         not exist
   * @see #isLowerCase(char)
   * @see #isUpperCase(char)
   * @see #toTitleCase(char)
   * @see #toUpperCase(char)
   */
  public static char toLowerCase(char ch)
  {
    // Signedness doesn't matter, as result is cast back to char.
    return (char) (ch + lower[readChar(ch) >> 7]);
  }

  /**
   * Converts a Unicode character into its uppercase equivalent mapping.
   * If a mapping does not exist, then the character passed is returned.
   * Note that isUpperCase(toUpperCase(ch)) does not always return true.
   *
   * @param ch character to convert to uppercase
   * @return uppercase mapping of ch, or ch if uppercase mapping does
   *         not exist
   * @see #isLowerCase(char)
   * @see #isUpperCase(char)
   * @see #toLowerCase(char)
   * @see #toTitleCase(char)
   */
  public static char toUpperCase(char ch)
  {
    // Signedness doesn't matter, as result is cast back to char.
    return (char) (ch + upper[readChar(ch) >> 7]);
  }

  /**
   * Converts a Unicode character into its titlecase equivalent mapping.
   * If a mapping does not exist, then the character passed is returned.
   * Note that isTitleCase(toTitleCase(ch)) does not always return true.
   *
   * @param ch character to convert to titlecase
   * @return titlecase mapping of ch, or ch if titlecase mapping does
   *         not exist
   * @see #isTitleCase(char)
   * @see #toLowerCase(char)
   * @see #toUpperCase(char)
   */
  public static char toTitleCase(char ch)
  {
    // As title is short, it doesn't hurt to exhaustively iterate over it.
    for (int i = title.length - 2; i >= 0; i -= 2)
      if (title[i] == ch)
        return title[i + 1];
    return toUpperCase(ch);
  }

  /**
   * Converts a character into a digit of the specified radix. If the radix
   * exceeds MIN_RADIX or MAX_RADIX, or if the result of getNumericValue(ch)
   * exceeds the radix, or if ch is not a decimal digit or in the case
   * insensitive set of 'a'-'z', the result is -1.
   * <br>
   * character argument boundary = [Nd]|U+0041-U+005A|U+0061-U+007A
   *    |U+FF21-U+FF3A|U+FF41-U+FF5A
   *
   * @param ch character to convert into a digit
   * @param radix radix in which ch is a digit
   * @return digit which ch represents in radix, or -1 not a valid digit
   * @see #MIN_RADIX
   * @see #MAX_RADIX
   * @see #forDigit(int, int)
   * @see #isDigit(char)
   * @see #getNumericValue(char)
   */
  public static int digit(char ch, int radix)
  {
    if (radix < MIN_RADIX || radix > MAX_RADIX)
      return -1;
    char attr = readChar(ch);
    if (((1 << (attr & TYPE_MASK))
         & ((1 << UPPERCASE_LETTER)
            | (1 << LOWERCASE_LETTER)
            | (1 << DECIMAL_DIGIT_NUMBER))) != 0)
      {
        // Signedness doesn't matter; 0xffff vs. -1 are both rejected.
        int digit = numValue[attr >> 7];
        return (digit < radix) ? digit : -1;
      }
    return -1;
  }

  /**
   * Returns the Unicode numeric value property of a character. For example,
   * <code>'\\u216C'</code> (the Roman numeral fifty) returns 50.
   *
   * <p>This method also returns values for the letters A through Z, (not
   * specified by Unicode), in these ranges: <code>'\u0041'</code>
   * through <code>'\u005A'</code> (uppercase); <code>'\u0061'</code>
   * through <code>'\u007A'</code> (lowercase); and <code>'\uFF21'</code>
   * through <code>'\uFF3A'</code>, <code>'\uFF41'</code> through
   * <code>'\uFF5A'</code> (full width variants).
   *
   * <p>If the character lacks a numeric value property, -1 is returned.
   * If the character has a numeric value property which is not representable
   * as a nonnegative integer, such as a fraction, -2 is returned.
   *
   * character argument boundary = [Nd]|[Nl]|[No]|U+0041-U+005A|U+0061-U+007A
   *    |U+FF21-U+FF3A|U+FF41-U+FF5A
   *
   * @param ch character from which the numeric value property will
   *        be retrieved
   * @return the numeric value property of ch, or -1 if it does not exist, or
   *         -2 if it is not representable as a nonnegative integer
   * @see #forDigit(int, int)
   * @see #digit(char, int)
   * @see #isDigit(char)
   * @since 1.1
   */
  public static int getNumericValue(char ch)
  {
    // Treat numValue as signed.
    return (short) numValue[readChar(ch) >> 7];
  }

  /**
   * Determines if a character is a ISO-LATIN-1 space. This is only the five
   * characters <code>'\t'</code>, <code>'\n'</code>, <code>'\f'</code>,
   * <code>'\r'</code>, and <code>' '</code>.
   * <br>
   * Java space = U+0020|U+0009|U+000A|U+000C|U+000D
   *
   * @param ch character to test
   * @return true if ch is a space, else false
   * @deprecated Replaced by {@link #isWhitespace(char)}
   * @see #isSpaceChar(char)
   * @see #isWhitespace(char)
   */
  public static boolean isSpace(char ch)
  {
    // Performing the subtraction up front alleviates need to compare longs.
    return ch-- <= ' ' && ((1 << ch)
                           & ((1 << (' ' - 1))
                              | (1 << ('\t' - 1))
                              | (1 << ('\n' - 1))
                              | (1 << ('\r' - 1))
                              | (1 << ('\f' - 1)))) != 0;
  }

  /**
   * Determines if a character is a Unicode space character. This includes
   * SPACE_SEPARATOR, LINE_SEPARATOR, and PARAGRAPH_SEPARATOR.
   * <br>
   * Unicode space = [Zs]|[Zp]|[Zl]
   *
   * @param ch character to test
   * @return true if ch is a Unicode space, else false
   * @see #isWhitespace(char)
   * @since 1.1
   */
  public static boolean isSpaceChar(char ch)
  {
    return ((1 << getType(ch))
            & ((1 << SPACE_SEPARATOR)
               | (1 << LINE_SEPARATOR)
               | (1 << PARAGRAPH_SEPARATOR))) != 0;
  }

  /**
   * Determines if a character is Java whitespace. This includes Unicode
   * space characters (SPACE_SEPARATOR, LINE_SEPARATOR, and
   * PARAGRAPH_SEPARATOR) except the non-breaking spaces
   * (<code>'\u00A0'</code>, <code>'\u2007'</code>, and <code>'\u202F'</code>);
   * and these characters: <code>'\u0009'</code>, <code>'\u000A'</code>,
   * <code>'\u000B'</code>, <code>'\u000C'</code>, <code>'\u000D'</code>,
   * <code>'\u001C'</code>, <code>'\u001D'</code>, <code>'\u001E'</code>,
   * and <code>'\u001F'</code>.
   * <br>
   * Java whitespace = ([Zs] not Nb)|[Zl]|[Zp]|U+0009-U+000D|U+001C-U+001F
   *
   * @param ch character to test
   * @return true if ch is Java whitespace, else false
   * @see #isSpaceChar(char)
   * @since 1.1
   */
  public static boolean isWhitespace(char ch)
  {
    int attr = readChar(ch);
    return ((((1 << (attr & TYPE_MASK))
              & ((1 << SPACE_SEPARATOR)
                 | (1 << LINE_SEPARATOR)
                 | (1 << PARAGRAPH_SEPARATOR))) != 0)
            && (attr & NO_BREAK_MASK) == 0)
      || (ch <= '\u001F' && ((1 << ch)
                             & ((1 << '\t')
                                | (1 << '\n')
                                | (1 << '\u000B')
                                | (1 << '\u000C')
                                | (1 << '\r')
                                | (1 << '\u001C')
                                | (1 << '\u001D')
                                | (1 << '\u001E')
                                | (1 << '\u001F'))) != 0);
  }

  /**
   * Determines if a character has the ISO Control property.
   * <br>
   * ISO Control = [Cc]
   *
   * @param ch character to test
   * @return true if ch is an ISO Control character, else false
   * @see #isSpaceChar(char)
   * @see #isWhitespace(char)
   * @since 1.1
   */
  public static boolean isISOControl(char ch)
  {
    return getType(ch) == CONTROL;
  }

  /**
   * Returns the Unicode general category property of a character.
   *
   * @param ch character from which the general category property will
   *        be retrieved
   * @return the character category property of ch as an integer
   * @see #UNASSIGNED
   * @see #UPPERCASE_LETTER
   * @see #LOWERCASE_LETTER
   * @see #TITLECASE_LETTER
   * @see #MODIFIER_LETTER
   * @see #OTHER_LETTER
   * @see #NON_SPACING_MARK
   * @see #ENCLOSING_MARK
   * @see #COMBINING_SPACING_MARK
   * @see #DECIMAL_DIGIT_NUMBER
   * @see #LETTER_NUMBER
   * @see #OTHER_NUMBER
   * @see #SPACE_SEPARATOR
   * @see #LINE_SEPARATOR
   * @see #PARAGRAPH_SEPARATOR
   * @see #CONTROL
   * @see #FORMAT
   * @see #PRIVATE_USE
   * @see #SURROGATE
   * @see #DASH_PUNCTUATION
   * @see #START_PUNCTUATION
   * @see #END_PUNCTUATION
   * @see #CONNECTOR_PUNCTUATION
   * @see #OTHER_PUNCTUATION
   * @see #MATH_SYMBOL
   * @see #CURRENCY_SYMBOL
   * @see #MODIFIER_SYMBOL
   * @see #INITIAL_QUOTE_PUNCTUATION
   * @see #FINAL_QUOTE_PUNCTUATION
   * @since 1.1
   */
  public static int getType(char ch)
  {
    return readChar(ch) & TYPE_MASK;
  }

  /**
   * Converts a digit into a character which represents that digit
   * in a specified radix. If the radix exceeds MIN_RADIX or MAX_RADIX,
   * or the digit exceeds the radix, then the null character <code>'\0'</code>
   * is returned.  Otherwise the return value is in '0'-'9' and 'a'-'z'.
   * <br>
   * return value boundary = U+0030-U+0039|U+0061-U+007A
   *
   * @param digit digit to be converted into a character
   * @param radix radix of digit
   * @return character representing digit in radix, or '\0'
   * @see #MIN_RADIX
   * @see #MAX_RADIX
   * @see #digit(char, int)
   */
  public static char forDigit(int digit, int radix)
  {
    if (radix < MIN_RADIX || radix > MAX_RADIX
        || digit < 0 || digit >= radix)
      return '\0';
    return Number.digits[digit];
  }

  /**
   * Returns the Unicode directionality property of the character. This
   * is used in the visual ordering of text.
   *
   * @param ch the character to look up
   * @return the directionality constant, or DIRECTIONALITY_UNDEFINED
   * @see #DIRECTIONALITY_UNDEFINED
   * @see #DIRECTIONALITY_LEFT_TO_RIGHT
   * @see #DIRECTIONALITY_RIGHT_TO_LEFT
   * @see #DIRECTIONALITY_RIGHT_TO_LEFT_ARABIC
   * @see #DIRECTIONALITY_EUROPEAN_NUMBER
   * @see #DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR
   * @see #DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR
   * @see #DIRECTIONALITY_ARABIC_NUMBER
   * @see #DIRECTIONALITY_COMMON_NUMBER_SEPARATOR
   * @see #DIRECTIONALITY_NONSPACING_MARK
   * @see #DIRECTIONALITY_BOUNDARY_NEUTRAL
   * @see #DIRECTIONALITY_PARAGRAPH_SEPARATOR
   * @see #DIRECTIONALITY_SEGMENT_SEPARATOR
   * @see #DIRECTIONALITY_WHITESPACE
   * @see #DIRECTIONALITY_OTHER_NEUTRALS
   * @see #DIRECTIONALITY_LEFT_TO_RIGHT_EMBEDDING
   * @see #DIRECTIONALITY_LEFT_TO_RIGHT_OVERRIDE
   * @see #DIRECTIONALITY_RIGHT_TO_LEFT_EMBEDDING
   * @see #DIRECTIONALITY_RIGHT_TO_LEFT_OVERRIDE
   * @see #DIRECTIONALITY_POP_DIRECTIONAL_FORMAT
   * @since 1.4
   */
  public static byte getDirectionality(char ch)
  {
    // The result will correctly be signed.
    return (byte) (direction[readChar(ch) >> 7] >> 2);
  }

  /**
   * Determines whether the character is mirrored according to Unicode. For
   * example, <code>\u0028</code> (LEFT PARENTHESIS) appears as '(' in
   * left-to-right text, but ')' in right-to-left text.
   *
   * @param ch the character to look up
   * @return true if the character is mirrored
   * @since 1.4
   */
  public static boolean isMirrored(char ch)
  {
    return (readChar(ch) & MIRROR_MASK) != 0;
  }

  /**
   * Compares another Character to this Character, numerically.
   *
   * @param anotherCharacter Character to compare with this Character
   * @return a negative integer if this Character is less than
   *         anotherCharacter, zero if this Character is equal, and
   *         a positive integer if this Character is greater
   * @throws NullPointerException if anotherCharacter is null
   * @since 1.2
   */
  public int compareTo(Character anotherCharacter)
  {
    return value - anotherCharacter.value;
  }

  /**
   * Compares an object to this Character.  Assuming the object is a
   * Character object, this method performs the same comparison as
   * compareTo(Character).
   *
   * @param o object to compare
   * @return the comparison value
   * @throws ClassCastException if o is not a Character object
   * @throws NullPointerException if o is null
   * @see #compareTo(Character)
   * @since 1.2
   */
  public int compareTo(Object o)
  {
    return compareTo((Character) o);
  }

  /**
   * Returns an <code>Character</code> object wrapping the value.
   * In contrast to the <code>Character</code> constructor, this method
   * will cache some values.  It is used by boxing conversion.
   *
   * @param val the value to wrap
   * @return the <code>Character</code>
   * 
   * @since 1.5
   */
  public static Character valueOf(char val)
  {
    if (val > MAX_CACHE)
      return new Character(val);
    synchronized (charCache)
      {
    if (charCache[val - MIN_VALUE] == null)
      charCache[val - MIN_VALUE] = new Character(val);
    return charCache[val - MIN_VALUE];
      }
  }

  /**
   * Reverse the bytes in val.
   * @since 1.5
   */
  public static char reverseBytes(char val)
  {
    return (char) (((val >> 8) & 0xff) | ((val << 8) & 0xff00));
  }

  /**
   * Converts a unicode code point to a UTF-16 representation of that
   * code point.
   * 
   * @param codePoint the unicode code point