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/* * 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 preceeding 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; }