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	/*
	* Copyright (c) 2005, 2009, 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.
	*/
	/*
	*******************************************************************************
	* (C) Copyright IBM Corp. and others, 1996-2009 - All Rights Reserved *
	* *
	* The original version of this source code and documentation is copyrighted *
	* and owned by IBM, These materials are provided under terms of a License *
	* Agreement between IBM and Sun. This technology is protected by multiple *
	* US and International patents. This notice and attribution to IBM may not *
	* to removed. *
	*******************************************************************************
	*/

	package sun.text.normalizer;

	public final class Utility {

	/**
	* Convenience utility to compare two Object[]s
	* Ought to be in System.
	* @param len the length to compare.
	* The start indices and start+len must be valid.
	*/
	public final static boolean arrayRegionMatches(char[] source, int sourceStart,
	char[] target, int targetStart,
	int len)
	{
	int sourceEnd = sourceStart + len;
	int delta = targetStart - sourceStart;
	for (int i = sourceStart; i < sourceEnd; i++) {
	if (source[i]!=target[i + delta])
	return false;
	}
	return true;
	}

	/**
	* 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) {
	StringBuffer buf = new StringBuffer();
	for (int i=0; i<s.length(); ) {
	int c = UTF16.charAt(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");
	hex(c, four ? 4 : 8, buf);
	}
	}
	return buf.toString();
	}

	/* This map must be in ASCENDING ORDER OF THE ESCAPE CODE */
	static private 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 = UTF16.charAt(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;
	}

	/**
	* Convert a integer to size width hex uppercase digits.
	* E.g., hex('a', 4, str) => "0041".
	* Append the output to the given StringBuffer.
	* If width is too small to fit, nothing will be appended to output.
	*/
	public static StringBuffer hex(int ch, int width, StringBuffer output) {
	return appendNumber(output, ch, 16, width);
	}

	/**
	* Convert a integer to size width (minimum) hex uppercase digits.
	* E.g., hex('a', 4, str) => "0041". If the integer requires more
	* than width digits, more will be used.
	*/
	public static String hex(int ch, int width) {
	StringBuffer buf = new StringBuffer();
	return appendNumber(buf, ch, 16, width).toString();
	}

	/**
	* Skip over a sequence of zero or more white space characters
	* at pos. Return the index of the first non-white-space character
	* at or after pos, or str.length(), if there is none.
	*/
	public static int skipWhitespace(String str, int pos) {
	while (pos < str.length()) {
	int c = UTF16.charAt(str, pos);
	if (!UCharacterProperty.isRuleWhiteSpace(c)) {
	break;
	}
	pos += UTF16.getCharCount(c);
	}
	return pos;
	}

	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'
	};

	/**
	* Append the digits of a positive integer to the given
	* <code>StringBuffer</code> in the given radix. This is
	* done recursively since it is easiest to generate the low-
	* order digit first, but it must be appended last.
	*
	* @param result is the <code>StringBuffer</code> to append to
	* @param n is the positive integer
	* @param radix is the radix, from 2 to 36 inclusive
	* @param minDigits is the minimum number of digits to append.
	*/
	private static void recursiveAppendNumber(StringBuffer result, int n,
	int radix, int minDigits)
	{
	int digit = n % radix;

	if (n >= radix \|\| minDigits > 1) {
	recursiveAppendNumber(result, n / radix, radix, minDigits - 1);
	}

	result.append(DIGITS[digit]);
	}

	/**
	* Append a number to the given StringBuffer in the given radix.
	* Standard digits '0'-'9' are used and letters 'A'-'Z' for
	* radices 11 through 36.
	* @param result the digits of the number are appended here
	* @param n the number to be converted to digits; may be negative.
	* If negative, a '-' is prepended to the digits.
	* @param radix a radix from 2 to 36 inclusive.
	* @param minDigits the minimum number of digits, not including
	* any '-', to produce. Values less than 2 have no effect. One
	* digit is always emitted regardless of this parameter.
	* @return a reference to result
	*/
	public static StringBuffer appendNumber(StringBuffer result, int n,
	int radix, int minDigits)
	throws IllegalArgumentException
	{
	if (radix < 2 \|\| radix > 36) {
	throw new IllegalArgumentException("Illegal radix " + radix);
	}


	int abs = n;

	if (n < 0) {
	abs = -n;
	result.append("-");
	}

	recursiveAppendNumber(result, abs, radix, minDigits);

	return result;
	}

	/**
	* Return true if the character is NOT printable ASCII. The tab,
	* newline and linefeed characters are considered unprintable.
	*/
	public static boolean isUnprintable(int c) {
	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 boolean escapeUnprintable(StringBuffer result, int c) {
	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;
	}

	/**
	* Similar to StringBuffer.getChars, version 1.3.
	* Since JDK 1.2 implements StringBuffer.getChars differently, this method
	* is here to provide consistent results.
	* To be removed after JDK 1.2 ceased to be the reference platform.
	* @param src source string buffer
	* @param srcBegin offset to the start of the src to retrieve from
	* @param srcEnd offset to the end of the src to retrieve from
	* @param dst char array to store the retrieved chars
	* @param dstBegin offset to the start of the destination char array to
	* store the retrieved chars
	*/
	public static void getChars(StringBuffer src, int srcBegin, int srcEnd,
	char dst[], int dstBegin)
	{
	if (srcBegin == srcEnd) {
	return;
	}
	src.getChars(srcBegin, srcEnd, dst, dstBegin);
	}

	}

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