/* * 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; /** * ScriptRun is used to find runs of characters in * the same script, as defined in the Script class. * It implements a simple iterator over an array of characters. * The iterator will assign COMMON and INHERITED * 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: *
 * 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 + ".");
 *     }
 *  }
 * 
* */ 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 ScriptRun 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 false if there * isn't another run, returns true if there is. * * @return false if there isn't another run, true 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 true 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; }