381 lines
12 KiB
Java
381 lines
12 KiB
Java
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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/*
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*******************************************************************************
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*
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* Copyright (C) 1999-2003, International Business Machines
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* Corporation and others. All Rights Reserved.
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*
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*******************************************************************************
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*/
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package sun.font;
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/**
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* <code>ScriptRun</code> is used to find runs of characters in
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* the same script, as defined in the <code>Script</code> class.
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* It implements a simple iterator over an array of characters.
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* The iterator will assign <code>COMMON</code> and <code>INHERITED</code>
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* characters to the same script as the preceding characters. If the
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* COMMON and INHERITED characters are first, they will be assigned to
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* the same script as the following characters.
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*
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* The iterator will try to match paired punctuation. If it sees an
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* opening punctuation character, it will remember the script that
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* was assigned to that character, and assign the same script to the
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* matching closing punctuation.
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*
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* No attempt is made to combine related scripts into a single run. In
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* particular, Hiragana, Katakana, and Han characters will appear in seperate
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* runs.
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* Here is an example of how to iterate over script runs:
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* <pre>
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* void printScriptRuns(char[] text)
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* {
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* ScriptRun scriptRun = new ScriptRun(text, 0, text.length);
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*
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* while (scriptRun.next()) {
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* int start = scriptRun.getScriptStart();
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* int limit = scriptRun.getScriptLimit();
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* int script = scriptRun.getScriptCode();
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*
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* System.out.println("Script \"" + Script.getName(script) + "\" from " +
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* start + " to " + limit + ".");
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* }
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* }
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* </pre>
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*
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*/
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public final class ScriptRun
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{
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private char[] text; // fixed once set by constructor
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private int textStart;
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private int textLimit;
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private int scriptStart; // change during iteration
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private int scriptLimit;
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private int scriptCode;
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private int stack[]; // stack used to handle paired punctuation if encountered
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private int parenSP;
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public ScriptRun() {
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// must call init later or we die.
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}
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/**
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* Construct a <code>ScriptRun</code> object which iterates over a subrange
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* of the given characetrs.
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*
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* @param chars the array of characters over which to iterate.
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* @param start the index of the first character over which to iterate
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* @param count the number of characters over which to iterate
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*/
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public ScriptRun(char[] chars, int start, int count)
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{
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init(chars, start, count);
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}
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public void init(char[] chars, int start, int count)
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{
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if (chars == null || start < 0 || count < 0 || count > chars.length - start) {
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throw new IllegalArgumentException();
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}
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text = chars;
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textStart = start;
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textLimit = start + count;
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scriptStart = textStart;
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scriptLimit = textStart;
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scriptCode = Script.INVALID_CODE;
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parenSP = 0;
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}
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/**
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* Get the starting index of the current script run.
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*
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* @return the index of the first character in the current script run.
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*/
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public final int getScriptStart() {
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return scriptStart;
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}
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/**
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* Get the index of the first character after the current script run.
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*
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* @return the index of the first character after the current script run.
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*/
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public final int getScriptLimit() {
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return scriptLimit;
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}
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/**
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* Get the script code for the script of the current script run.
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*
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* @return the script code for the script of the current script run.
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* @see #Script
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*/
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public final int getScriptCode() {
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return scriptCode;
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}
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/**
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* Find the next script run. Returns <code>false</code> if there
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* isn't another run, returns <code>true</code> if there is.
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*
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* @return <code>false</code> if there isn't another run, <code>true</code> if there is.
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*/
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public final boolean next() {
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int startSP = parenSP; // used to find the first new open character
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// if we've fallen off the end of the text, we're done
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if (scriptLimit >= textLimit) {
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return false;
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}
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scriptCode = Script.COMMON;
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scriptStart = scriptLimit;
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int ch;
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while ((ch = nextCodePoint()) != DONE) {
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int sc = ScriptRunData.getScript(ch);
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int pairIndex = sc == Script.COMMON ? getPairIndex(ch) : -1;
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// Paired character handling:
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//
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// if it's an open character, push it onto the stack.
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// if it's a close character, find the matching open on the
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// stack, and use that script code. Any non-matching open
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// characters above it on the stack will be popped.
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if (pairIndex >= 0) {
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if ((pairIndex & 1) == 0) {
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if (stack == null) {
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stack = new int[32];
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} else if (parenSP == stack.length) {
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int[] newstack = new int[stack.length + 32];
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System.arraycopy(stack, 0, newstack, 0, stack.length);
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stack = newstack;
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}
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stack[parenSP++] = pairIndex;
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stack[parenSP++] = scriptCode;
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} else if (parenSP > 0) {
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int pi = pairIndex & ~1;
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while ((parenSP -= 2) >= 0 && stack[parenSP] != pi);
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if (parenSP >= 0) {
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sc = stack[parenSP+1];
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} else {
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parenSP = 0;
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}
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if (parenSP < startSP) {
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startSP = parenSP;
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}
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}
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}
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if (sameScript(scriptCode, sc)) {
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if (scriptCode <= Script.INHERITED && sc > Script.INHERITED) {
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scriptCode = sc;
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// now that we have a final script code, fix any open
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// characters we pushed before we knew the script code.
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while (startSP < parenSP) {
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stack[startSP+1] = scriptCode;
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startSP += 2;
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}
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}
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// if this character is a close paired character,
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// pop it from the stack
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if (pairIndex > 0 && (pairIndex & 1) != 0 && parenSP > 0) {
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parenSP -= 2;
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}
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} else {
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// We've just seen the first character of
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// the next run. Back over it so we'll see
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// it again the next time.
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pushback(ch);
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// we're outta here
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break;
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}
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}
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return true;
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}
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static final int SURROGATE_START = 0x10000;
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static final int LEAD_START = 0xd800;
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static final int LEAD_LIMIT = 0xdc00;
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static final int TAIL_START = 0xdc00;
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static final int TAIL_LIMIT = 0xe000;
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static final int LEAD_SURROGATE_SHIFT = 10;
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static final int SURROGATE_OFFSET = SURROGATE_START - (LEAD_START << LEAD_SURROGATE_SHIFT) - TAIL_START;
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static final int DONE = -1;
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private final int nextCodePoint() {
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if (scriptLimit >= textLimit) {
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return DONE;
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}
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int ch = text[scriptLimit++];
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if (ch >= LEAD_START && ch < LEAD_LIMIT && scriptLimit < textLimit) {
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int nch = text[scriptLimit];
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if (nch >= TAIL_START && nch < TAIL_LIMIT) {
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++scriptLimit;
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ch = (ch << LEAD_SURROGATE_SHIFT) + nch + SURROGATE_OFFSET;
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}
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}
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return ch;
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}
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private final void pushback(int ch) {
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if (ch >= 0) {
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if (ch >= 0x10000) {
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scriptLimit -= 2;
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} else {
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scriptLimit -= 1;
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}
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}
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}
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/**
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* Compare two script codes to see if they are in the same script. If one script is
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* a strong script, and the other is INHERITED or COMMON, it will compare equal.
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*
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* @param scriptOne one of the script codes.
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* @param scriptTwo the other script code.
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* @return <code>true</code> if the two scripts are the same.
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* @see com.ibm.icu.lang.Script
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*/
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private static boolean sameScript(int scriptOne, int scriptTwo) {
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return scriptOne == scriptTwo || scriptOne <= Script.INHERITED || scriptTwo <= Script.INHERITED;
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}
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/**
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* Find the highest bit that's set in a word. Uses a binary search through
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* the bits.
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*
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* @param n the word in which to find the highest bit that's set.
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* @return the bit number (counting from the low order bit) of the highest bit.
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*/
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private static final byte highBit(int n)
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{
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if (n <= 0) {
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return -32;
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}
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byte bit = 0;
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if (n >= 1 << 16) {
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n >>= 16;
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bit += 16;
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}
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if (n >= 1 << 8) {
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n >>= 8;
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bit += 8;
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}
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if (n >= 1 << 4) {
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n >>= 4;
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bit += 4;
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}
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if (n >= 1 << 2) {
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n >>= 2;
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bit += 2;
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}
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if (n >= 1 << 1) {
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n >>= 1;
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bit += 1;
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}
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return bit;
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}
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/**
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* Search the pairedChars array for the given character.
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*
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* @param ch the character for which to search.
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* @return the index of the character in the table, or -1 if it's not there.
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*/
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private static int getPairIndex(int ch)
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{
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int probe = pairedCharPower;
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int index = 0;
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if (ch >= pairedChars[pairedCharExtra]) {
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index = pairedCharExtra;
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}
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while (probe > (1 << 0)) {
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probe >>= 1;
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if (ch >= pairedChars[index + probe]) {
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index += probe;
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}
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}
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if (pairedChars[index] != ch) {
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index = -1;
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}
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return index;
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}
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// all common
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private static int pairedChars[] = {
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0x0028, 0x0029, // ascii paired punctuation // common
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0x003c, 0x003e, // common
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0x005b, 0x005d, // common
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0x007b, 0x007d, // common
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0x00ab, 0x00bb, // guillemets // common
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0x2018, 0x2019, // general punctuation // common
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0x201c, 0x201d, // common
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0x2039, 0x203a, // common
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0x3008, 0x3009, // chinese paired punctuation // common
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0x300a, 0x300b,
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0x300c, 0x300d,
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0x300e, 0x300f,
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0x3010, 0x3011,
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0x3014, 0x3015,
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0x3016, 0x3017,
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0x3018, 0x3019,
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0x301a, 0x301b
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};
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private static final int pairedCharPower = 1 << highBit(pairedChars.length);
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private static final int pairedCharExtra = pairedChars.length - pairedCharPower;
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}
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