| /* |
| * 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 org.apache.harmony.text.internal.nls.Messages; |
| |
| /** |
| * Provides the Unicode Bidirectional Algorithm. The algorithm is |
| * defined in the Unicode Standard Annex #9, version 13, also described in The |
| * Unicode Standard, Version 4.0 . |
| * |
| * 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. |
| * |
| * 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; |
| |
| /* |
| * Converts the constant from the value specified in the Java spec, to the |
| * value required by the ICU implementation. |
| */ |
| private final static int convertDirectionConstant(int javaConst) { |
| switch (javaConst) { |
| case DIRECTION_DEFAULT_LEFT_TO_RIGHT : return com.ibm.icu.text.Bidi.DIRECTION_DEFAULT_LEFT_TO_RIGHT; |
| case DIRECTION_DEFAULT_RIGHT_TO_LEFT : return com.ibm.icu.text.Bidi.DIRECTION_DEFAULT_RIGHT_TO_LEFT; |
| case DIRECTION_LEFT_TO_RIGHT : return com.ibm.icu.text.Bidi.DIRECTION_LEFT_TO_RIGHT; |
| case DIRECTION_RIGHT_TO_LEFT : return com.ibm.icu.text.Bidi.DIRECTION_RIGHT_TO_LEFT; |
| default : return com.ibm.icu.text.Bidi.DIRECTION_DEFAULT_LEFT_TO_RIGHT; |
| } |
| } |
| |
| /* |
| * Use an embedded ICU4J Bidi object to do all the work |
| */ |
| private com.ibm.icu.text.Bidi icuBidi; |
| |
| /** |
| * 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} is {@code 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) { |
| // text.14=paragraph is null |
| throw new IllegalArgumentException(Messages.getString("text.14")); //$NON-NLS-1$ |
| } |
| |
| icuBidi = new com.ibm.icu.text.Bidi(paragraph); |
| } |
| |
| /** |
| * 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) { |
| // text.0D=Negative textStart value {0} |
| throw new IllegalArgumentException(Messages.getString( |
| "text.0D", textStart)); //$NON-NLS-1$ |
| } |
| if (embStart < 0) { |
| // text.10=Negative embStart value {0} |
| throw new IllegalArgumentException(Messages.getString( |
| "text.10", embStart)); //$NON-NLS-1$ |
| } |
| if (paragraphLength < 0) { |
| // text.11=Negative paragraph length {0} |
| throw new IllegalArgumentException(Messages.getString( |
| "text.11", paragraphLength)); //$NON-NLS-1$ |
| } |
| |
| icuBidi = new com.ibm.icu.text.Bidi(text, textStart, embeddings, |
| embStart, paragraphLength, convertDirectionConstant(flags)); |
| } |
| |
| /** |
| * 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); |
| } |
| |
| /* private constructor used by createLineBidi() */ |
| private Bidi() { |
| super(); |
| } |
| |
| /** |
| * 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 icuBidi.baseIsLeftToRight(); |
| } |
| |
| /** |
| * 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) { |
| int length = icuBidi.getLength(); |
| if (lineStart < 0 || lineLimit < 0 || lineLimit > length |
| || lineStart > lineLimit) { |
| // text.12=Invalid ranges (start={0}, limit={1}, length={2}) |
| throw new IllegalArgumentException(Messages.getString( |
| "text.12", new Object[] { lineStart, lineLimit, length })); //$NON-NLS-1$ |
| } |
| |
| Bidi bidi = new Bidi(); |
| bidi.icuBidi = icuBidi.createLineBidi(lineStart, lineLimit); |
| return bidi; |
| } |
| |
| /** |
| * Returns the base level. |
| * |
| * @return the base level. |
| */ |
| public int getBaseLevel() { |
| return icuBidi.getBaseLevel(); |
| } |
| |
| /** |
| * Returns the length of the text in the {@code Bidi} object. |
| * |
| * @return the length. |
| */ |
| public int getLength() { |
| return icuBidi.getLength(); |
| } |
| |
| /** |
| * Returns the level of a specified character. |
| * |
| * @param offset |
| * the offset of the character. |
| * @return the level. |
| */ |
| public int getLevelAt(int offset) { |
| try { |
| return icuBidi.getLevelAt(offset); |
| } catch (RuntimeException e) { |
| return icuBidi.getBaseLevel(); |
| } |
| } |
| |
| /** |
| * Returns the number of runs in the bidirectional text. |
| * |
| * @return the number of runs, at least 1. |
| */ |
| public int getRunCount() { |
| int runCount = icuBidi.getRunCount(); |
| return (runCount < 1) ? 1 : runCount; |
| } |
| |
| /** |
| * 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) { |
| if (icuBidi.getRunCount() == 0) { |
| return icuBidi.getBaseLevel(); |
| } else { |
| return icuBidi.getRunLevel(run); |
| } |
| } |
| |
| /** |
| * 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) { |
| if (icuBidi.getRunCount() == 0) { |
| return icuBidi.getLength(); |
| } else { |
| return icuBidi.getRunLimit(run); |
| } |
| } |
| |
| /** |
| * 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) { |
| if (icuBidi.getRunCount() == 0) { |
| return 0; |
| } else { |
| return icuBidi.getRunStart(run); |
| } |
| } |
| |
| /** |
| * 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 icuBidi.isLeftToRight(); |
| } |
| |
| /** |
| * Indicates whether the text direction is mixed. |
| * |
| * @return {@code true} if the text direction is mixed; {@code false} |
| * otherwise. |
| */ |
| public boolean isMixed() { |
| return icuBidi.isMixed(); |
| } |
| |
| /** |
| * 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 icuBidi.isRightToLeft(); |
| } |
| |
| /** |
| * 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) { |
| // text.13=Invalid ranges (levels={0}, levelStart={1}, objects={2}, |
| // objectStart={3}, count={4}) |
| throw new IllegalArgumentException(Messages.getString("text.13", //$NON-NLS-1$ |
| new Object[] { levels.length, levelStart, objects.length, |
| objectStart, count })); |
| } |
| |
| com.ibm.icu.text.Bidi.reorderVisually(levels, levelStart, 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) { |
| //int length = text.length; |
| if (limit < 0 || start < 0 || start > limit || limit > text.length) { |
| throw new IllegalArgumentException(); |
| } |
| |
| return com.ibm.icu.text.Bidi.requiresBidi(text, start, limit); |
| } |
| |
| /** |
| * Returns the internal message of the {@code Bidi} object, used in |
| * debugging. |
| * |
| * @return a string containing the internal message. |
| */ |
| @Override |
| public String toString() { |
| return icuBidi.toString(); |
| } |
| } |
