Back to index...

	/*
	* Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/
	/*
	*******************************************************************************
	* Copyright (C) 1996-2011, International Business Machines Corporation and *
	* others. All Rights Reserved. *
	*******************************************************************************
	*/

	package sun.text.normalizer;

	import java.io.IOException;
	import java.util.Locale;

	final class Utility {

	/**
	* Convert characters outside the range U+0020 to U+007F to
	* Unicode escapes, and convert backslash to a double backslash.
	*/
	public static final String escape(String s) {
	StringBuilder buf = new StringBuilder();
	for (int i=0; i<s.length(); ) {
	int c = Character.codePointAt(s, i);
	i += UTF16.getCharCount(c);
	if (c >= ' ' && c <= 0x007F) {
	if (c == '\\') {
	buf.append("\\\\"); // That is, "\\"
	} else {
	buf.append((char)c);
	}
	} else {
	boolean four = c <= 0xFFFF;
	buf.append(four ? "\\u" : "\\U");
	buf.append(hex(c, four ? 4 : 8));
	}
	}
	return buf.toString();
	}

	/* This map must be in ASCENDING ORDER OF THE ESCAPE CODE */
	private static final char[] UNESCAPE_MAP = {
	/" 0x22, 0x22 /
	/' 0x27, 0x27 /
	/? 0x3F, 0x3F /
	/\ 0x5C, 0x5C /
	/a/ 0x61, 0x07,
	/b/ 0x62, 0x08,
	/e/ 0x65, 0x1b,
	/f/ 0x66, 0x0c,
	/n/ 0x6E, 0x0a,
	/r/ 0x72, 0x0d,
	/t/ 0x74, 0x09,
	/v/ 0x76, 0x0b
	};

	/**
	* Convert an escape to a 32-bit code point value. We attempt
	* to parallel the icu4c unescapeAt() function.
	* @param offset16 an array containing offset to the character
	* <em>after</em> the backslash. Upon return offset16[0] will
	* be updated to point after the escape sequence.
	* @return character value from 0 to 10FFFF, or -1 on error.
	*/
	public static int unescapeAt(String s, int[] offset16) {
	int c;
	int result = 0;
	int n = 0;
	int minDig = 0;
	int maxDig = 0;
	int bitsPerDigit = 4;
	int dig;
	int i;
	boolean braces = false;

	/* Check that offset is in range */
	int offset = offset16[0];
	int length = s.length();
	if (offset < 0 \|\| offset >= length) {
	return -1;
	}

	/* Fetch first UChar after '\\' */
	c = Character.codePointAt(s, offset);
	offset += UTF16.getCharCount(c);

	/* Convert hexadecimal and octal escapes */
	switch (c) {
	case 'u':
	minDig = maxDig = 4;
	break;
	case 'U':
	minDig = maxDig = 8;
	break;
	case 'x':
	minDig = 1;
	if (offset < length && UTF16.charAt(s, offset) == 0x7B /{/) {
	++offset;
	braces = true;
	maxDig = 8;
	} else {
	maxDig = 2;
	}
	break;
	default:
	dig = UCharacter.digit(c, 8);
	if (dig >= 0) {
	minDig = 1;
	maxDig = 3;
	n = 1; /* Already have first octal digit */
	bitsPerDigit = 3;
	result = dig;
	}
	break;
	}
	if (minDig != 0) {
	while (offset < length && n < maxDig) {
	c = UTF16.charAt(s, offset);
	dig = UCharacter.digit(c, (bitsPerDigit == 3) ? 8 : 16);
	if (dig < 0) {
	break;
	}
	result = (result << bitsPerDigit) \| dig;
	offset += UTF16.getCharCount(c);
	++n;
	}
	if (n < minDig) {
	return -1;
	}
	if (braces) {
	if (c != 0x7D /}/) {
	return -1;
	}
	++offset;
	}
	if (result < 0 \|\| result >= 0x110000) {
	return -1;
	}
	// If an escape sequence specifies a lead surrogate, see
	// if there is a trail surrogate after it, either as an
	// escape or as a literal. If so, join them up into a
	// supplementary.
	if (offset < length &&
	UTF16.isLeadSurrogate((char) result)) {
	int ahead = offset+1;
	c = s.charAt(offset); // [sic] get 16-bit code unit
	if (c == '\\' && ahead < length) {
	int o[] = new int[] { ahead };
	c = unescapeAt(s, o);
	ahead = o[0];
	}
	if (UTF16.isTrailSurrogate((char) c)) {
	offset = ahead;
	result = UCharacterProperty.getRawSupplementary(
	(char) result, (char) c);
	}
	}
	offset16[0] = offset;
	return result;
	}

	/* Convert C-style escapes in table */
	for (i=0; i<UNESCAPE_MAP.length; i+=2) {
	if (c == UNESCAPE_MAP[i]) {
	offset16[0] = offset;
	return UNESCAPE_MAP[i+1];
	} else if (c < UNESCAPE_MAP[i]) {
	break;
	}
	}

	/* Map \cX to control-X: X & 0x1F */
	if (c == 'c' && offset < length) {
	c = UTF16.charAt(s, offset);
	offset16[0] = offset + UTF16.getCharCount(c);
	return 0x1F & c;
	}

	/* If no special forms are recognized, then consider
	* the backslash to generically escape the next character. */
	offset16[0] = offset;
	return c;
	}

	/**
	* Supplies a zero-padded hex representation of an integer (without 0x)
	*/
	public static String hex(long i, int places) {
	if (i == Long.MIN_VALUE) return "-8000000000000000";
	boolean negative = i < 0;
	if (negative) {
	i = -i;
	}
	String result = Long.toString(i, 16).toUpperCase(Locale.ENGLISH);
	if (result.length() < places) {
	result = "0000000000000000".substring(result.length(),places) + result;
	}
	if (negative) {
	return '-' + result;
	}
	return result;
	}

	static final char DIGITS[] = {
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
	'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
	'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
	'U', 'V', 'W', 'X', 'Y', 'Z'
	};

	/**
	* Return true if the character is NOT printable ASCII. The tab,
	* newline and linefeed characters are considered unprintable.
	*/
	public static boolean isUnprintable(int c) {
	//0x20 = 32 and 0x7E = 126
	return !(c >= 0x20 && c <= 0x7E);
	}

	/**
	* Escape unprintable characters using <backslash>uxxxx notation
	* for U+0000 to U+FFFF and <backslash>Uxxxxxxxx for U+10000 and
	* above. If the character is printable ASCII, then do nothing
	* and return FALSE. Otherwise, append the escaped notation and
	* return TRUE.
	*/
	public static <T extends Appendable> boolean escapeUnprintable(T result, int c) {
	try {
	if (isUnprintable(c)) {
	result.append('\\');
	if ((c & ~0xFFFF) != 0) {
	result.append('U');
	result.append(DIGITS[0xF&(c>>28)]);
	result.append(DIGITS[0xF&(c>>24)]);
	result.append(DIGITS[0xF&(c>>20)]);
	result.append(DIGITS[0xF&(c>>16)]);
	} else {
	result.append('u');
	}
	result.append(DIGITS[0xF&(c>>12)]);
	result.append(DIGITS[0xF&(c>>8)]);
	result.append(DIGITS[0xF&(c>>4)]);
	result.append(DIGITS[0xF&c]);
	return true;
	}
	return false;
	} catch (IOException e) {
	throw new IllegalArgumentException(e);
	}
	}
	}

Back to index...