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/*
 * Copyright 2008 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package java.lang;

import java.io.Serializable;

/**
 * Wraps a native char as an object.
 *
 * TODO(jat): many of the classification methods implemented here are not
 * correct in that they only handle ASCII characters, and many other methods
 * are not currently implemented.  I think the proper approach is to introduce * a deferred binding parameter which substitutes an implementation using
 * a fully-correct Unicode character database, at the expense of additional
 * data being downloaded.  That way developers that need the functionality
 * can get it without those who don't need it paying for it.
 *
 * 
 * The following methods are still not implemented -- most would require Unicode
 * character db to be useful:
 *  - digit / is* / to*(int codePoint)
 *  - isDefined(char)
 *  - isIdentifierIgnorable(char)
 *  - isJavaIdentifierPart(char)
 *  - isJavaIdentifierStart(char)
 *  - isJavaLetter(char) -- deprecated, so probably not
 *  - isJavaLetterOrDigit(char) -- deprecated, so probably not
 *  - isISOControl(char)
 *  - isMirrored(char)
 *  - isSpaceChar(char)
 *  - isTitleCase(char)
 *  - isUnicodeIdentifierPart(char)
 *  - isUnicodeIdentifierStart(char)
 *  - isWhitespace(char)
 *  - getDirectionality(*)
 *  - getNumericValue(*)
 *  - getType(*)
 *  - reverseBytes(char) -- any use for this at all in the browser?
 *  - toTitleCase(*)
 *  - all the category constants for classification
 *
 * The following do not properly handle characters outside of ASCII:
 *  - digit(char c, int radix)
 *  - isDigit(char c)
 *  - isLetter(char c)
 *  - isLetterOrDigit(char c)
 *  - isLowerCase(char c)
 *  - isUpperCase(char c)
 * 
*/ public final class Character implements Comparable, Serializable { /** * Helper class to share code between implementations, by making a char * array look like a CharSequence. */ static class CharSequenceAdapter implements CharSequence { private char[] charArray; private int start; private int end; public CharSequenceAdapter(char[] charArray) { this(charArray, 0, charArray.length); } public CharSequenceAdapter(char[] charArray, int start, int end) { this.charArray = charArray; this.start = start; this.end = end; } public char charAt(int index) { return charArray[index + start]; } public int length() { return end - start; } public java.lang.CharSequence subSequence(int start, int end) { return new CharSequenceAdapter(charArray, this.start + start, this.start + end); } } /** * Use nested class to avoid clinit on outer. */ private static class BoxedValues { // Box values according to JLS - from \u0000 to \u007f private static Character[] boxedValues = new Character[128]; } public static final Class TYPE = Character.class; public static final int MIN_RADIX = 2; public static final int MAX_RADIX = 36; public static final char MIN_VALUE = '\u0000'; public static final char MAX_VALUE = '\uFFFF'; public static final char MIN_SURROGATE = '\uD800'; public static final char MAX_SURROGATE = '\uDFFF'; public static final char MIN_LOW_SURROGATE = '\uDC00'; public static final char MAX_LOW_SURROGATE = '\uDFFF'; public static final char MIN_HIGH_SURROGATE = '\uD800'; public static final char MAX_HIGH_SURROGATE = '\uDBFF'; public static final int MIN_SUPPLEMENTARY_CODE_POINT = 0x10000; public static final int MIN_CODE_POINT = 0x0000; public static final int MAX_CODE_POINT = 0x10FFFF; public static final int SIZE = 16; public static int charCount(int codePoint) { return codePoint >= MIN_SUPPLEMENTARY_CODE_POINT ? 2 : 1; } public static int codePointAt(char[] a, int index) { return codePointAt(new CharSequenceAdapter(a), index, a.length); } public static int codePointAt(char[] a, int index, int limit) { return codePointAt(new CharSequenceAdapter(a), index, limit); } public static int codePointAt(CharSequence seq, int index) { return codePointAt(seq, index, seq.length()); } public static int codePointBefore(char[] a, int index) { return codePointBefore(new CharSequenceAdapter(a), index, 0); } public static int codePointBefore(char[] a, int index, int start) { return codePointBefore(new CharSequenceAdapter(a), index, start); } public static int codePointBefore(CharSequence cs, int index) { return codePointBefore(cs, index, 0); } public static int codePointCount(char[] a, int offset, int count) { return codePointCount(new CharSequenceAdapter(a), offset, offset + count); } public static int codePointCount(CharSequence seq, int beginIndex, int endIndex) { int count = 0; for (int idx = beginIndex; idx < endIndex; ) { char ch = seq.charAt(idx++); if (isHighSurrogate(ch) && idx < endIndex && (isLowSurrogate(seq.charAt(idx)))) { // skip the second char of surrogate pairs ++idx; } ++count; } return count; } /* * TODO: correct Unicode handling. */ public static int digit(char c, int radix) { if (radix < MIN_RADIX || radix > MAX_RADIX) { return -1; } if (c >= '0' && c < '0' + Math.min(radix, 10)) { return c - '0'; } // The offset by 10 is to re-base the alpha values if (c >= 'a' && c < (radix + 'a' - 10)) { return c - 'a' + 10; } if (c >= 'A' && c < (radix + 'A' - 10)) { return c - 'A' + 10; } return -1; } public static char forDigit(int digit, int radix) { if (radix < MIN_RADIX || radix > MAX_RADIX) { return 0; } if (digit < 0 || digit >= radix) { return 0; } final int baseTenMax = 10; if (digit < baseTenMax) { return (char) ('0' + digit); } else { return (char) ('a' + digit - baseTenMax); } } /** * @skip * * public for shared implementation with Arrays.hashCode */ public static int hashCode(char c) { return c; } /* * TODO: correct Unicode handling. */ public static native boolean isDigit(char c) /*-{ return (null != String.fromCharCode(c).match(/\d/)); }-*/; public static boolean isHighSurrogate(char ch) { return ch >= MIN_HIGH_SURROGATE && ch <= MAX_HIGH_SURROGATE; } /* * TODO: correct Unicode handling. */ public static native boolean isLetter(char c) /*-{ return (null != String.fromCharCode(c).match(/[A-Z]/i)); }-*/; /* * TODO: correct Unicode handling. */ public static native boolean isLetterOrDigit(char c) /*-{ return (null != String.fromCharCode(c).match(/[A-Z\d]/i)); }-*/; /* * TODO: correct Unicode handling. */ public static boolean isLowerCase(char c) { return toLowerCase(c) == c && isLetter(c); } public static boolean isLowSurrogate(char ch) { return ch >= MIN_LOW_SURROGATE && ch <= MAX_LOW_SURROGATE; } /** * Deprecated - see isWhitespace(char). */ @Deprecated public static boolean isSpace(char c) { switch (c) { case ' ': return true; case '\n': return true; case '\t': return true; case '\f': return true; case '\r': return true; default: return false; } } public static boolean isSupplementaryCodePoint(int codePoint) { return codePoint >= MIN_SUPPLEMENTARY_CODE_POINT && codePoint <= MAX_CODE_POINT; } public static boolean isSurrogatePair(char highSurrogate, char lowSurrogate) { return isHighSurrogate(highSurrogate) && isLowSurrogate(lowSurrogate); } /* * TODO: correct Unicode handling. */ public static boolean isUpperCase(char c) { return toUpperCase(c) == c && isLetter(c); } public static boolean isValidCodePoint(int codePoint) { return codePoint >= MIN_CODE_POINT && codePoint <= MAX_CODE_POINT; } public static int offsetByCodePoints(char[] a, int start, int count, int index, int codePointOffset) { return offsetByCodePoints(new CharSequenceAdapter(a, start, count), index, codePointOffset); } public static int offsetByCodePoints(CharSequence seq, int index, int codePointOffset) { if (codePointOffset < 0) { // move backwards while (codePointOffset < 0) { --index; if (Character.isLowSurrogate(seq.charAt(index)) && Character.isHighSurrogate(seq.charAt(index - 1))) { --index; } ++codePointOffset; } } else { // move forwards while (codePointOffset > 0) { if (Character.isHighSurrogate(seq.charAt(index)) && Character.isLowSurrogate(seq.charAt(index + 1))) { ++index; } ++index; --codePointOffset; } } return index; } public static char[] toChars(int codePoint) { if (codePoint < 0 || codePoint > MAX_CODE_POINT) { throw new IllegalArgumentException(); } if (codePoint >= MIN_SUPPLEMENTARY_CODE_POINT) { return new char[] { getHighSurrogate(codePoint), getLowSurrogate(codePoint), }; } else { return new char[] { (char) codePoint, }; } } public static int toChars(int codePoint, char[] dst, int dstIndex) { if (codePoint < 0 || codePoint > MAX_CODE_POINT) { throw new IllegalArgumentException(); } if (codePoint >= MIN_SUPPLEMENTARY_CODE_POINT) { dst[dstIndex++] = getHighSurrogate(codePoint); dst[dstIndex] = getLowSurrogate(codePoint); return 2; } else { dst[dstIndex] = (char) codePoint; return 1; } } public static int toCodePoint(char highSurrogate, char lowSurrogate) { /* * High and low surrogate chars have the bottom 10 bits to store the value * above MIN_SUPPLEMENTARY_CODE_POINT, so grab those bits and add the * offset. */ return MIN_SUPPLEMENTARY_CODE_POINT + ((highSurrogate & 1023) << 10) + (lowSurrogate & 1023); } public static native char toLowerCase(char c) /*-{ return String.fromCharCode(c).toLowerCase().charCodeAt(0); }-*/; public static String toString(char x) { return String.valueOf(x); } public static native char toUpperCase(char c) /*-{ return String.fromCharCode(c).toUpperCase().charCodeAt(0); }-*/; public static Character valueOf(char c) { if (c < 128) { Character result = BoxedValues.boxedValues[c]; if (result == null) { result = BoxedValues.boxedValues[c] = new Character(c); } return result; } return new Character(c); } static int codePointAt(CharSequence cs, int index, int limit) { char hiSurrogate = cs.charAt(index++); char loSurrogate; if (Character.isHighSurrogate(hiSurrogate) && index < limit && Character.isLowSurrogate(loSurrogate = cs.charAt(index))) { return Character.toCodePoint(hiSurrogate, loSurrogate); } return hiSurrogate; } static int codePointBefore(CharSequence cs, int index, int start) { char loSurrogate = cs.charAt(--index); char highSurrogate; if (isLowSurrogate(loSurrogate) && index > start && isHighSurrogate(highSurrogate = cs.charAt(index - 1))) { return toCodePoint(highSurrogate, loSurrogate); } return loSurrogate; } /** * Computes the high surrogate character of the UTF16 representation of a * non-BMP code point. See {@link getLowSurrogate}. * * @param codePoint requested codePoint, required to be >= * MIN_SUPPLEMENTARY_CODE_POINT * @return high surrogate character */ static char getHighSurrogate(int codePoint) { return (char) (MIN_HIGH_SURROGATE + (((codePoint - MIN_SUPPLEMENTARY_CODE_POINT) >> 10) & 1023)); } /** * Computes the low surrogate character of the UTF16 representation of a * non-BMP code point. See {@link getHighSurrogate}. * * @param codePoint requested codePoint, required to be >= * MIN_SUPPLEMENTARY_CODE_POINT * @return low surrogate character */ static char getLowSurrogate(int codePoint) { return (char) (MIN_LOW_SURROGATE + ((codePoint - MIN_SUPPLEMENTARY_CODE_POINT) & 1023)); } private final transient char value; public Character(char value) { this.value = value; } public char charValue() { return value; } public int compareTo(Character c) { // JLS specifies that the chars are promoted to int before subtraction. return value - c.value; } @Override public boolean equals(Object o) { return (o instanceof Character) && (((Character) o).value == value); } @Override public int hashCode() { return hashCode(value); } @Override public String toString() { return String.valueOf(value); } }




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