Back to index...

	/*
	* 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) 1999-2003, International Business Machines
	* Corporation and others. All Rights Reserved.
	*
	*******************************************************************************
	*/

	package sun.font;

	/**
	* <code>ScriptRun</code> is used to find runs of characters in
	* the same script, as defined in the <code>Script</code> class.
	* It implements a simple iterator over an array of characters.
	* The iterator will assign <code>COMMON</code> and <code>INHERITED</code>
	* characters to the same script as the preceding characters. If the
	* COMMON and INHERITED characters are first, they will be assigned to
	* the same script as the following characters.
	*
	* The iterator will try to match paired punctuation. If it sees an
	* opening punctuation character, it will remember the script that
	* was assigned to that character, and assign the same script to the
	* matching closing punctuation.
	*
	* No attempt is made to combine related scripts into a single run. In
	* particular, Hiragana, Katakana, and Han characters will appear in seperate
	* runs.

	* Here is an example of how to iterate over script runs:
	* <pre>
	* void printScriptRuns(char[] text)
	* {
	* ScriptRun scriptRun = new ScriptRun(text, 0, text.length);
	*
	* while (scriptRun.next()) {
	* int start = scriptRun.getScriptStart();
	* int limit = scriptRun.getScriptLimit();
	* int script = scriptRun.getScriptCode();
	*
	* System.out.println("Script \"" + Script.getName(script) + "\" from " +
	* start + " to " + limit + ".");
	* }
	* }
	* </pre>
	*
	*/
	public final class ScriptRun
	{
	private char[] text; // fixed once set by constructor
	private int textStart;
	private int textLimit;

	private int scriptStart; // change during iteration
	private int scriptLimit;
	private int scriptCode;

	private int stack[]; // stack used to handle paired punctuation if encountered
	private int parenSP;

	public ScriptRun() {
	// must call init later or we die.
	}

	/**
	* Construct a <code>ScriptRun</code> object which iterates over a subrange
	* of the given characetrs.
	*
	* @param chars the array of characters over which to iterate.
	* @param start the index of the first character over which to iterate
	* @param count the number of characters over which to iterate
	*/
	public ScriptRun(char[] chars, int start, int count)
	{
	init(chars, start, count);
	}

	public void init(char[] chars, int start, int count)
	{
	if (chars == null \|\| start < 0 \|\| count < 0 \|\| count > chars.length - start) {
	throw new IllegalArgumentException();
	}

	text = chars;
	textStart = start;
	textLimit = start + count;

	scriptStart = textStart;
	scriptLimit = textStart;
	scriptCode = Script.INVALID_CODE;
	parenSP = 0;
	}

	/**
	* Get the starting index of the current script run.
	*
	* @return the index of the first character in the current script run.
	*/
	public final int getScriptStart() {
	return scriptStart;
	}

	/**
	* Get the index of the first character after the current script run.
	*
	* @return the index of the first character after the current script run.
	*/
	public final int getScriptLimit() {
	return scriptLimit;
	}

	/**
	* Get the script code for the script of the current script run.
	*
	* @return the script code for the script of the current script run.
	* @see #Script
	*/
	public final int getScriptCode() {
	return scriptCode;
	}

	/**
	* Find the next script run. Returns <code>false</code> if there
	* isn't another run, returns <code>true</code> if there is.
	*
	* @return <code>false</code> if there isn't another run, <code>true</code> if there is.
	*/
	public final boolean next() {
	int startSP = parenSP; // used to find the first new open character

	// if we've fallen off the end of the text, we're done
	if (scriptLimit >= textLimit) {
	return false;
	}

	scriptCode = Script.COMMON;
	scriptStart = scriptLimit;

	int ch;

	while ((ch = nextCodePoint()) != DONE) {
	int sc = ScriptRunData.getScript(ch);
	int pairIndex = sc == Script.COMMON ? getPairIndex(ch) : -1;

	// Paired character handling:
	//
	// if it's an open character, push it onto the stack.
	// if it's a close character, find the matching open on the
	// stack, and use that script code. Any non-matching open
	// characters above it on the stack will be popped.
	if (pairIndex >= 0) {
	if ((pairIndex & 1) == 0) {
	if (stack == null) {
	stack = new int[32];
	} else if (parenSP == stack.length) {
	int[] newstack = new int[stack.length + 32];
	System.arraycopy(stack, 0, newstack, 0, stack.length);
	stack = newstack;
	}

	stack[parenSP++] = pairIndex;
	stack[parenSP++] = scriptCode;
	} else if (parenSP > 0) {
	int pi = pairIndex & ~1;

	while ((parenSP -= 2) >= 0 && stack[parenSP] != pi);

	if (parenSP >= 0) {
	sc = stack[parenSP+1];
	} else {
	parenSP = 0;
	}
	if (parenSP < startSP) {
	startSP = parenSP;
	}
	}
	}

	if (sameScript(scriptCode, sc)) {
	if (scriptCode <= Script.INHERITED && sc > Script.INHERITED) {
	scriptCode = sc;

	// now that we have a final script code, fix any open
	// characters we pushed before we knew the script code.
	while (startSP < parenSP) {
	stack[startSP+1] = scriptCode;
	startSP += 2;
	}
	}

	// if this character is a close paired character,
	// pop it from the stack
	if (pairIndex > 0 && (pairIndex & 1) != 0 && parenSP > 0) {
	parenSP -= 2;
	}
	} else {
	// We've just seen the first character of
	// the next run. Back over it so we'll see
	// it again the next time.
	pushback(ch);

	// we're outta here
	break;
	}
	}

	return true;
	}

	static final int SURROGATE_START = 0x10000;
	static final int LEAD_START = 0xd800;
	static final int LEAD_LIMIT = 0xdc00;
	static final int TAIL_START = 0xdc00;
	static final int TAIL_LIMIT = 0xe000;
	static final int LEAD_SURROGATE_SHIFT = 10;
	static final int SURROGATE_OFFSET = SURROGATE_START - (LEAD_START << LEAD_SURROGATE_SHIFT) - TAIL_START;

	static final int DONE = -1;

	private final int nextCodePoint() {
	if (scriptLimit >= textLimit) {
	return DONE;
	}
	int ch = text[scriptLimit++];
	if (ch >= LEAD_START && ch < LEAD_LIMIT && scriptLimit < textLimit) {
	int nch = text[scriptLimit];
	if (nch >= TAIL_START && nch < TAIL_LIMIT) {
	++scriptLimit;
	ch = (ch << LEAD_SURROGATE_SHIFT) + nch + SURROGATE_OFFSET;
	}
	}
	return ch;
	}

	private final void pushback(int ch) {
	if (ch >= 0) {
	if (ch >= 0x10000) {
	scriptLimit -= 2;
	} else {
	scriptLimit -= 1;
	}
	}
	}

	/**
	* Compare two script codes to see if they are in the same script. If one script is
	* a strong script, and the other is INHERITED or COMMON, it will compare equal.
	*
	* @param scriptOne one of the script codes.
	* @param scriptTwo the other script code.
	* @return <code>true</code> if the two scripts are the same.
	* @see com.ibm.icu.lang.Script
	*/
	private static boolean sameScript(int scriptOne, int scriptTwo) {
	return scriptOne == scriptTwo \|\| scriptOne <= Script.INHERITED \|\| scriptTwo <= Script.INHERITED;
	}

	/**
	* Find the highest bit that's set in a word. Uses a binary search through
	* the bits.
	*
	* @param n the word in which to find the highest bit that's set.
	* @return the bit number (counting from the low order bit) of the highest bit.
	*/
	private static final byte highBit(int n)
	{
	if (n <= 0) {
	return -32;
	}

	byte bit = 0;

	if (n >= 1 << 16) {
	n >>= 16;
	bit += 16;
	}

	if (n >= 1 << 8) {
	n >>= 8;
	bit += 8;
	}

	if (n >= 1 << 4) {
	n >>= 4;
	bit += 4;
	}

	if (n >= 1 << 2) {
	n >>= 2;
	bit += 2;
	}

	if (n >= 1 << 1) {
	n >>= 1;
	bit += 1;
	}

	return bit;
	}

	/**
	* Search the pairedChars array for the given character.
	*
	* @param ch the character for which to search.
	* @return the index of the character in the table, or -1 if it's not there.
	*/
	private static int getPairIndex(int ch)
	{
	int probe = pairedCharPower;
	int index = 0;

	if (ch >= pairedChars[pairedCharExtra]) {
	index = pairedCharExtra;
	}

	while (probe > (1 << 0)) {
	probe >>= 1;

	if (ch >= pairedChars[index + probe]) {
	index += probe;
	}
	}

	if (pairedChars[index] != ch) {
	index = -1;
	}

	return index;
	}

	// all common
	private static int pairedChars[] = {
	0x0028, 0x0029, // ascii paired punctuation // common
	0x003c, 0x003e, // common
	0x005b, 0x005d, // common
	0x007b, 0x007d, // common
	0x00ab, 0x00bb, // guillemets // common
	0x2018, 0x2019, // general punctuation // common
	0x201c, 0x201d, // common
	0x2039, 0x203a, // common
	0x3008, 0x3009, // chinese paired punctuation // common
	0x300a, 0x300b,
	0x300c, 0x300d,
	0x300e, 0x300f,
	0x3010, 0x3011,
	0x3014, 0x3015,
	0x3016, 0x3017,
	0x3018, 0x3019,
	0x301a, 0x301b
	};

	private static final int pairedCharPower = 1 << highBit(pairedChars.length);
	private static final int pairedCharExtra = pairedChars.length - pairedCharPower;

	}

Back to index...