| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package java.text; |
| |
| import java.awt.font.NumericShaper; |
| import java.awt.font.TextAttribute; |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| |
| /** |
| * Implements the <a href="http://unicode.org/reports/tr9/">Unicode Bidirectional Algorithm</a>. |
| * |
| * <p>Use a {@code Bidi} object to get the information on the position reordering of a |
| * bidirectional text, such as Arabic or Hebrew. The natural display ordering of |
| * horizontal text in these languages is from right to left, while they order |
| * numbers from left to right. |
| * |
| * <p>If the text contains multiple runs, the information of each run can be |
| * obtained from the run index. The level of any particular run indicates the |
| * direction of the text as well as the nesting level. Left-to-right runs have |
| * even levels while right-to-left runs have odd levels. |
| */ |
| public final class Bidi { |
| /** |
| * Constant that indicates the default base level. If there is no strong |
| * character, then set the paragraph level to 0 (left-to-right). |
| */ |
| public static final int DIRECTION_DEFAULT_LEFT_TO_RIGHT = -2; |
| |
| /** |
| * Constant that indicates the default base level. If there is no strong |
| * character, then set the paragraph level to 1 (right-to-left). |
| */ |
| public static final int DIRECTION_DEFAULT_RIGHT_TO_LEFT = -1; |
| |
| /** |
| * Constant that specifies the default base level as 0 (left-to-right). |
| */ |
| public static final int DIRECTION_LEFT_TO_RIGHT = 0; |
| |
| /** |
| * Constant that specifies the default base level as 1 (right-to-left). |
| */ |
| public static final int DIRECTION_RIGHT_TO_LEFT = 1; |
| |
| /** |
| * TODO: if we care about performance, we might just want to use an int[] instead of a Run[]. |
| */ |
| static class Run { |
| private final int start; |
| private final int limit; |
| private final int level; |
| |
| public Run(int start, int limit, int level) { |
| this.start = start; |
| this.limit = limit; |
| this.level = level; |
| } |
| |
| public int getLevel() { |
| return level; |
| } |
| |
| public int getLimit() { |
| return limit; |
| } |
| |
| public int getStart() { |
| return start; |
| } |
| } |
| |
| /** |
| * Creates a {@code Bidi} object from the {@code |
| * AttributedCharacterIterator} of a paragraph text. The RUN_DIRECTION |
| * attribute determines the base direction of the bidirectional text. If it |
| * is not specified explicitly, the algorithm uses |
| * DIRECTION_DEFAULT_LEFT_TO_RIGHT by default. The BIDI_EMBEDDING attribute |
| * specifies the level of embedding for each character. Values between -1 |
| * and -62 denote overrides at the level's absolute value, values from 1 to |
| * 62 indicate embeddings, and the 0 value indicates the level is calculated |
| * by the algorithm automatically. For the character with no BIDI_EMBEDDING |
| * attribute or with a improper attribute value, such as a {@code null} |
| * value, the algorithm treats its embedding level as 0. The NUMERIC_SHAPING |
| * attribute specifies the instance of NumericShaper used to convert |
| * European digits to other decimal digits before performing the bidi |
| * algorithm. |
| * |
| * @param paragraph |
| * the String containing the paragraph text to perform the |
| * algorithm. |
| * @throws IllegalArgumentException if {@code paragraph == null} |
| * @see java.awt.font.TextAttribute#BIDI_EMBEDDING |
| * @see java.awt.font.TextAttribute#NUMERIC_SHAPING |
| * @see java.awt.font.TextAttribute#RUN_DIRECTION |
| */ |
| public Bidi(AttributedCharacterIterator paragraph) { |
| if (paragraph == null) { |
| throw new IllegalArgumentException("paragraph is null"); |
| } |
| |
| int begin = paragraph.getBeginIndex(); |
| int end = paragraph.getEndIndex(); |
| int length = end - begin; |
| char[] text = new char[length + 1]; // One more char for AttributedCharacterIterator.DONE |
| |
| if (length != 0) { |
| text[0] = paragraph.first(); |
| } else { |
| paragraph.first(); |
| } |
| |
| // First check the RUN_DIRECTION attribute. |
| int flags = DIRECTION_DEFAULT_LEFT_TO_RIGHT; |
| Object direction = paragraph.getAttribute(TextAttribute.RUN_DIRECTION); |
| if (direction != null && direction instanceof Boolean) { |
| if (direction.equals(TextAttribute.RUN_DIRECTION_LTR)) { |
| flags = DIRECTION_LEFT_TO_RIGHT; |
| } else { |
| flags = DIRECTION_RIGHT_TO_LEFT; |
| } |
| } |
| |
| // Retrieve the text and gather BIDI_EMBEDDINGS |
| byte[] embeddings = null; |
| for (int textLimit = 1, i = 1; i < length; textLimit = paragraph |
| .getRunLimit(TextAttribute.BIDI_EMBEDDING) |
| - begin + 1) { |
| Object embedding = paragraph.getAttribute(TextAttribute.BIDI_EMBEDDING); |
| if (embedding != null && embedding instanceof Integer) { |
| int embLevel = ((Integer) embedding).intValue(); |
| |
| if (embeddings == null) { |
| embeddings = new byte[length]; |
| } |
| |
| for (; i < textLimit; i++) { |
| text[i] = paragraph.next(); |
| embeddings[i - 1] = (byte) embLevel; |
| } |
| } else { |
| for (; i < textLimit; i++) { |
| text[i] = paragraph.next(); |
| } |
| } |
| } |
| |
| // Apply NumericShaper to the text |
| Object numericShaper = paragraph.getAttribute(TextAttribute.NUMERIC_SHAPING); |
| if (numericShaper != null && numericShaper instanceof NumericShaper) { |
| ((NumericShaper) numericShaper).shape(text, 0, length); |
| } |
| |
| long bidi = 0; |
| try { |
| bidi = createUBiDi(text, 0, embeddings, 0, length, flags); |
| readBidiInfo(bidi); |
| } finally { |
| ubidi_close(bidi); |
| } |
| } |
| |
| /** |
| * Creates a {@code Bidi} object. |
| * |
| * @param text |
| * the char array of the paragraph text that is processed. |
| * @param textStart |
| * the index in {@code text} of the start of the paragraph. |
| * @param embeddings |
| * the embedding level array of the paragraph text, specifying |
| * the embedding level information for each character. Values |
| * between -1 and -61 denote overrides at the level's absolute |
| * value, values from 1 to 61 indicate embeddings, and the 0 |
| * value indicates the level is calculated by the algorithm |
| * automatically. |
| * @param embStart |
| * the index in {@code embeddings} of the start of the paragraph. |
| * @param paragraphLength |
| * the length of the text to perform the algorithm. |
| * @param flags |
| * indicates the base direction of the bidirectional text. It is |
| * expected that this will be one of the direction constant |
| * values defined in this class. An unknown value is treated as |
| * DIRECTION_DEFAULT_LEFT_TO_RIGHT. |
| * @throws IllegalArgumentException |
| * if {@code textStart}, {@code embStart}, or {@code |
| * paragraphLength} is negative; if |
| * {@code text.length < textStart + paragraphLength} or |
| * {@code embeddings.length < embStart + paragraphLength}. |
| * @see #DIRECTION_LEFT_TO_RIGHT |
| * @see #DIRECTION_RIGHT_TO_LEFT |
| * @see #DIRECTION_DEFAULT_RIGHT_TO_LEFT |
| * @see #DIRECTION_DEFAULT_LEFT_TO_RIGHT |
| */ |
| public Bidi(char[] text, int textStart, byte[] embeddings, int embStart, |
| int paragraphLength, int flags) { |
| |
| if (text == null || text.length - textStart < paragraphLength) { |
| throw new IllegalArgumentException(); |
| } |
| |
| if (embeddings != null) { |
| if (embeddings.length - embStart < paragraphLength) { |
| throw new IllegalArgumentException(); |
| } |
| } |
| |
| if (textStart < 0) { |
| throw new IllegalArgumentException("Negative textStart value " + textStart); |
| } |
| if (embStart < 0) { |
| throw new IllegalArgumentException("Negative embStart value " + embStart); |
| } |
| if (paragraphLength < 0) { |
| throw new IllegalArgumentException("Negative paragraph length " + paragraphLength); |
| } |
| |
| long bidi = 0; |
| try { |
| bidi = createUBiDi(text, textStart, embeddings, embStart, paragraphLength, flags); |
| readBidiInfo(bidi); |
| } finally { |
| ubidi_close(bidi); |
| } |
| } |
| |
| /** |
| * Creates a {@code Bidi} object. |
| * |
| * @param paragraph |
| * the string containing the paragraph text to perform the |
| * algorithm on. |
| * @param flags |
| * indicates the base direction of the bidirectional text. It is |
| * expected that this will be one of the direction constant |
| * values defined in this class. An unknown value is treated as |
| * DIRECTION_DEFAULT_LEFT_TO_RIGHT. |
| * @see #DIRECTION_LEFT_TO_RIGHT |
| * @see #DIRECTION_RIGHT_TO_LEFT |
| * @see #DIRECTION_DEFAULT_RIGHT_TO_LEFT |
| * @see #DIRECTION_DEFAULT_LEFT_TO_RIGHT |
| */ |
| public Bidi(String paragraph, int flags) { |
| this((paragraph == null ? null : paragraph.toCharArray()), 0, null, 0, |
| (paragraph == null ? 0 : paragraph.length()), flags); |
| } |
| |
| // create the native UBiDi struct, need to be closed with ubidi_close(). |
| private static long createUBiDi(char[] text, int textStart, |
| byte[] embeddings, int embStart, int paragraphLength, int flags) { |
| char[] realText = null; |
| |
| byte[] realEmbeddings = null; |
| |
| if (text == null || text.length - textStart < paragraphLength) { |
| throw new IllegalArgumentException(); |
| } |
| realText = new char[paragraphLength]; |
| System.arraycopy(text, textStart, realText, 0, paragraphLength); |
| |
| if (embeddings != null) { |
| if (embeddings.length - embStart < paragraphLength) { |
| throw new IllegalArgumentException(); |
| } |
| if (paragraphLength > 0) { |
| Bidi temp = new Bidi(text, textStart, null, 0, paragraphLength, flags); |
| realEmbeddings = new byte[paragraphLength]; |
| System.arraycopy(temp.offsetLevel, 0, realEmbeddings, 0, paragraphLength); |
| for (int i = 0; i < paragraphLength; i++) { |
| byte e = embeddings[i]; |
| if (e < 0) { |
| realEmbeddings[i] = (byte) (UBIDI_LEVEL_OVERRIDE - e); |
| } else if (e > 0) { |
| realEmbeddings[i] = e; |
| } else { |
| realEmbeddings[i] |= (byte) UBIDI_LEVEL_OVERRIDE; |
| } |
| } |
| } |
| } |
| |
| if (flags > 1 || flags < -2) { |
| flags = 0; |
| } |
| |
| long bidi = 0; |
| boolean needsDeletion = true; |
| try { |
| bidi = ubidi_open(); |
| ubidi_setPara(bidi, realText, paragraphLength, flags, realEmbeddings); |
| needsDeletion = false; |
| } finally { |
| if (needsDeletion) { |
| ubidi_close(bidi); |
| } |
| } |
| return bidi; |
| } |
| |
| /* private constructor used by createLineBidi() */ |
| private Bidi(long pBidi) { |
| readBidiInfo(pBidi); |
| } |
| |
| // read info from the native UBiDi struct |
| private void readBidiInfo(long pBidi) { |
| length = ubidi_getLength(pBidi); |
| |
| offsetLevel = (length == 0) ? null : ubidi_getLevels(pBidi); |
| |
| baseLevel = ubidi_getParaLevel(pBidi); |
| |
| int runCount = ubidi_countRuns(pBidi); |
| if (runCount == 0) { |
| unidirectional = true; |
| runs = null; |
| } else if (runCount < 0) { |
| runs = null; |
| } else { |
| runs = ubidi_getRuns(pBidi); |
| |
| // Simplified case for one run which has the base level |
| if (runCount == 1 && runs[0].getLevel() == baseLevel) { |
| unidirectional = true; |
| runs = null; |
| } |
| } |
| |
| direction = ubidi_getDirection(pBidi); |
| } |
| |
| private int baseLevel; |
| |
| private int length; |
| |
| private byte[] offsetLevel; |
| |
| private Run[] runs; |
| |
| private int direction; |
| |
| private boolean unidirectional; |
| |
| /** |
| * Returns whether the base level is from left to right. |
| * |
| * @return true if the base level is from left to right. |
| */ |
| public boolean baseIsLeftToRight() { |
| return baseLevel % 2 == 0 ? true : false; |
| } |
| |
| /** |
| * Creates a new {@code Bidi} object containing the information of one line |
| * from this object. |
| * |
| * @param lineStart |
| * the start offset of the line. |
| * @param lineLimit |
| * the limit of the line. |
| * @return the new line Bidi object. In this new object, the indices will |
| * range from 0 to (limit - start - 1). |
| * @throws IllegalArgumentException |
| * if {@code lineStart < 0}, {@code lineLimit < 0}, {@code |
| * lineStart > lineLimit} or if {@code lineStart} is greater |
| * than the length of this object's paragraph text. |
| */ |
| public Bidi createLineBidi(int lineStart, int lineLimit) { |
| if (lineStart < 0 || lineLimit < 0 || lineLimit > length || lineStart > lineLimit) { |
| throw new IllegalArgumentException("Invalid ranges (start=" + lineStart + ", " + |
| "limit=" + lineLimit + ", length=" + length + ")"); |
| } |
| |
| char[] text = new char[this.length]; |
| Arrays.fill(text, 'a'); |
| byte[] embeddings = new byte[this.length]; |
| for (int i = 0; i < embeddings.length; i++) { |
| embeddings[i] = (byte) -this.offsetLevel[i]; |
| } |
| |
| int dir = this.baseIsLeftToRight() |
| ? Bidi.DIRECTION_LEFT_TO_RIGHT |
| : Bidi.DIRECTION_RIGHT_TO_LEFT; |
| long parent = 0; |
| try { |
| parent = createUBiDi(text, 0, embeddings, 0, this.length, dir); |
| if (lineStart == lineLimit) { |
| return createEmptyLineBidi(parent); |
| } |
| return new Bidi(ubidi_setLine(parent, lineStart, lineLimit)); |
| } finally { |
| ubidi_close(parent); |
| } |
| } |
| |
| private Bidi createEmptyLineBidi(long parent) { |
| // ICU4C doesn't allow this case, but the RI does. |
| Bidi result = new Bidi(parent); |
| result.length = 0; |
| result.offsetLevel = null; |
| result.runs = null; |
| result.unidirectional = true; |
| return result; |
| } |
| |
| /** |
| * Returns the base level. |
| * |
| * @return the base level. |
| */ |
| public int getBaseLevel() { |
| return baseLevel; |
| } |
| |
| /** |
| * Returns the length of the text in the {@code Bidi} object. |
| * |
| * @return the length. |
| */ |
| public int getLength() { |
| return length; |
| } |
| |
| /** |
| * Returns the level of a specified character. |
| * |
| * @param offset |
| * the offset of the character. |
| * @return the level. |
| */ |
| public int getLevelAt(int offset) { |
| try { |
| return offsetLevel[offset] & ~UBIDI_LEVEL_OVERRIDE; |
| } catch (RuntimeException e) { |
| return baseLevel; |
| } |
| } |
| |
| /** |
| * Returns the number of runs in the bidirectional text. |
| * |
| * @return the number of runs, at least 1. |
| */ |
| public int getRunCount() { |
| return unidirectional ? 1 : runs.length; |
| } |
| |
| /** |
| * Returns the level of the specified run. |
| * |
| * @param run |
| * the index of the run. |
| * @return the level of the run. |
| */ |
| public int getRunLevel(int run) { |
| return unidirectional ? baseLevel : runs[run].getLevel(); |
| } |
| |
| /** |
| * Returns the limit offset of the specified run. |
| * |
| * @param run |
| * the index of the run. |
| * @return the limit offset of the run. |
| */ |
| public int getRunLimit(int run) { |
| return unidirectional ? length : runs[run].getLimit(); |
| } |
| |
| /** |
| * Returns the start offset of the specified run. |
| * |
| * @param run |
| * the index of the run. |
| * @return the start offset of the run. |
| */ |
| public int getRunStart(int run) { |
| return unidirectional ? 0 : runs[run].getStart(); |
| } |
| |
| /** |
| * Indicates whether the text is from left to right, that is, both the base |
| * direction and the text direction is from left to right. |
| * |
| * @return {@code true} if the text is from left to right; {@code false} |
| * otherwise. |
| */ |
| public boolean isLeftToRight() { |
| return direction == UBiDiDirection_UBIDI_LTR; |
| } |
| |
| /** |
| * Indicates whether the text direction is mixed. |
| * |
| * @return {@code true} if the text direction is mixed; {@code false} |
| * otherwise. |
| */ |
| public boolean isMixed() { |
| return direction == UBiDiDirection_UBIDI_MIXED; |
| } |
| |
| /** |
| * Indicates whether the text is from right to left, that is, both the base |
| * direction and the text direction is from right to left. |
| * |
| * @return {@code true} if the text is from right to left; {@code false} |
| * otherwise. |
| */ |
| public boolean isRightToLeft() { |
| return direction == UBiDiDirection_UBIDI_RTL; |
| } |
| |
| /** |
| * Reorders a range of objects according to their specified levels. This is |
| * a convenience function that does not use a {@code Bidi} object. The range |
| * of objects at {@code index} from {@code objectStart} to {@code |
| * objectStart + count} will be reordered according to the range of levels |
| * at {@code index} from {@code levelStart} to {@code levelStart + count}. |
| * |
| * @param levels |
| * the level array, which is already determined. |
| * @param levelStart |
| * the start offset of the range of the levels. |
| * @param objects |
| * the object array to reorder. |
| * @param objectStart |
| * the start offset of the range of objects. |
| * @param count |
| * the count of the range of objects to reorder. |
| * @throws IllegalArgumentException |
| * if {@code count}, {@code levelStart} or {@code objectStart} |
| * is negative; if {@code count > levels.length - levelStart} or |
| * if {@code count > objects.length - objectStart}. |
| */ |
| public static void reorderVisually(byte[] levels, int levelStart, |
| Object[] objects, int objectStart, int count) { |
| if (count < 0 || levelStart < 0 || objectStart < 0 |
| || count > levels.length - levelStart |
| || count > objects.length - objectStart) { |
| throw new IllegalArgumentException("Invalid ranges (levels=" + levels.length + |
| ", levelStart=" + levelStart + ", objects=" + objects.length + |
| ", objectStart=" + objectStart + ", count=" + count + ")"); |
| } |
| |
| byte[] realLevels = new byte[count]; |
| System.arraycopy(levels, levelStart, realLevels, 0, count); |
| |
| int[] indices = ubidi_reorderVisual(realLevels, count); |
| |
| ArrayList<Object> result = new ArrayList<Object>(count); |
| for (int i = 0; i < count; i++) { |
| result.add(objects[objectStart + indices[i]]); |
| } |
| |
| System.arraycopy(result.toArray(), 0, objects, objectStart, count); |
| } |
| |
| /** |
| * Indicates whether a range of characters of a text requires a {@code Bidi} |
| * object to display properly. |
| * |
| * @param text |
| * the char array of the text. |
| * @param start |
| * the start offset of the range of characters. |
| * @param limit |
| * the limit offset of the range of characters. |
| * @return {@code true} if the range of characters requires a {@code Bidi} |
| * object; {@code false} otherwise. |
| * @throws IllegalArgumentException |
| * if {@code start} or {@code limit} is negative; {@code start > |
| * limit} or {@code limit} is greater than the length of this |
| * object's paragraph text. |
| */ |
| public static boolean requiresBidi(char[] text, int start, int limit) { |
| if (limit < 0 || start < 0 || start > limit || limit > text.length) { |
| throw new IllegalArgumentException(); |
| } |
| |
| Bidi bidi = new Bidi(text, start, null, 0, limit - start, 0); |
| return !bidi.isLeftToRight(); |
| } |
| |
| @Override |
| public String toString() { |
| return getClass().getName() |
| + "[direction: " + direction + " baseLevel: " + baseLevel |
| + " length: " + length + " runs: " + Arrays.toString(runs) + "]"; |
| } |
| |
| // ICU4C constants. |
| private static final int UBIDI_LEVEL_OVERRIDE = 0x80; |
| private static final int UBiDiDirection_UBIDI_LTR = 0; |
| private static final int UBiDiDirection_UBIDI_RTL = 1; |
| private static final int UBiDiDirection_UBIDI_MIXED = 2; |
| |
| // ICU4C functions. |
| private static native long ubidi_open(); |
| private static native void ubidi_close(long pBiDi); |
| private static native void ubidi_setPara(long pBiDi, char[] text, int length, int paraLevel, byte[] embeddingLevels); |
| private static native long ubidi_setLine(final long pParaBiDi, int start, int limit); |
| private static native int ubidi_getDirection(final long pBiDi); |
| private static native int ubidi_getLength(final long pBiDi); |
| private static native byte ubidi_getParaLevel(final long pBiDi); |
| private static native byte[] ubidi_getLevels(long pBiDi); |
| private static native int ubidi_countRuns(long pBiDi); |
| private static native Bidi.Run[] ubidi_getRuns(long pBidi); |
| private static native int[] ubidi_reorderVisual(byte[] levels, int length); |
| } |