/*
* @(#)Bidi.java 1.16 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
/*
* (C) Copyright IBM Corp. 1999-2003 - All Rights Reserved
*
* The original version of this source code and documentation is
* copyrighted and owned by IBM. These materials are provided
* under terms of a License Agreement between IBM and Sun.
* This technology is protected by multiple US and International
* patents. This notice and attribution to IBM may not be removed.
*/
package java.text;
import java.awt.Toolkit;
import java.awt.font.TextAttribute;
import java.awt.font.NumericShaper;
import sun.text.CodePointIterator;
/**
* This class implements the Unicode Bidirectional Algorithm.
* <p>
* A Bidi object provides information on the bidirectional reordering of the text
* used to create it. This is required, for example, to properly display Arabic
* or Hebrew text. These languages are inherently mixed directional, as they order
* numbers from left-to-right while ordering most other text from right-to-left.
* <p>
* Once created, a Bidi object can be queried to see if the text it represents is
* all left-to-right or all right-to-left. Such objects are very lightweight and
* this text is relatively easy to process.
* <p>
* If there are multiple runs of text, information about the runs can be accessed
* by indexing to get the start, limit, and level of a run. The level represents
* both the direction and the 'nesting level' of a directional run. Odd levels
* are right-to-left, while even levels are left-to-right. So for example level
* 0 represents left-to-right text, while level 1 represents right-to-left text, and
* level 2 represents left-to-right text embedded in a right-to-left run.
*
* @since 1.4
*/
public final class Bidi {
byte dir;
byte baselevel;
int length;
int[] runs;
int[] cws;
static {
java.security.AccessController.doPrivileged(
new sun.security.action.LoadLibraryAction("awt"));
java.security.AccessController.doPrivileged(
new sun.security.action.LoadLibraryAction("fontmanager"));
}
/** Constant indicating base direction is left-to-right. */
public static final int DIRECTION_LEFT_TO_RIGHT = 0;
/** Constant indicating base direction is right-to-left. */
public static final int DIRECTION_RIGHT_TO_LEFT = 1;
/**
* Constant indicating that the base direction depends on the first strong
* directional character in the text according to the Unicode
* Bidirectional Algorithm. If no strong directional character is present,
* the base direction is left-to-right.
*/
public static final int DIRECTION_DEFAULT_LEFT_TO_RIGHT = -2;
/**
* Constant indicating that the base direction depends on the first strong
* directional character in the text according to the Unicode
* Bidirectional Algorithm. If no strong directional character is present,
* the base direction is right-to-left.
*/
public static final int DIRECTION_DEFAULT_RIGHT_TO_LEFT = -1;
private static final int DIR_MIXED = 2;
/**
* Create Bidi from the given paragraph of text and base direction.
* @param paragraph a paragraph of text
* @param flags a collection of flags that control the algorithm. The
* algorithm understands the flags DIRECTION_LEFT_TO_RIGHT, DIRECTION_RIGHT_TO_LEFT,
* DIRECTION_DEFAULT_LEFT_TO_RIGHT, and DIRECTION_DEFAULT_RIGHT_TO_LEFT.
* Other values are reserved.
*/
public Bidi(String paragraph, int flags) {
if (paragraph == null) {
throw new IllegalArgumentException("paragraph is null");
}
nativeBidiChars(this, paragraph.toCharArray(), 0, null, 0, paragraph.length(), flags);
}
/**
* Create Bidi from the given paragraph of text.
* <p>
* The RUN_DIRECTION attribute in the text, if present, determines the base
* direction (left-to-right or right-to-left). If not present, the base
* direction is computes using the Unicode Bidirectional Algorithm, defaulting to left-to-right
* if there are no strong directional characters in the text. This attribute, if
* present, must be applied to all the text in the paragraph.
* <p>
* The BIDI_EMBEDDING attribute in the text, if present, represents embedding level
* information. Negative values from -1 to -62 indicate overrides at the absolute value
* of the level. Positive values from 1 to 62 indicate embeddings. Where values are
* zero or not defined, the base embedding level as determined by the base direction
* is assumed.
* <p>
* The NUMERIC_SHAPING attribute in the text, if present, converts European digits to
* other decimal digits before running the bidi algorithm. This attribute, if present,
* must be applied to all the text in the paragraph.
*
* @param paragraph a paragraph of text with optional character and paragraph attribute information
*
* @see TextAttribute#BIDI_EMBEDDING
* @see TextAttribute#NUMERIC_SHAPING
* @see TextAttribute#RUN_DIRECTION
*/
public Bidi(AttributedCharacterIterator paragraph) {
if (paragraph == null) {
throw new IllegalArgumentException("paragraph is null");
}
int flags = DIRECTION_DEFAULT_LEFT_TO_RIGHT;
byte[] embeddings = null;
int start = paragraph.getBeginIndex();
int limit = paragraph.getEndIndex();
int length = limit - start;
int n = 0;
char[] text = new char[length];
for (char c = paragraph.first(); c != paragraph.DONE; c = paragraph.next()) {
text[n++] = c;
}
paragraph.first();
try {
Boolean runDirection = (Boolean)paragraph.getAttribute(TextAttribute.RUN_DIRECTION);
if (runDirection != null) {
if (TextAttribute.RUN_DIRECTION_LTR.equals(runDirection)) {
flags = DIRECTION_LEFT_TO_RIGHT; // clears default setting
} else {
flags = DIRECTION_RIGHT_TO_LEFT;
}
}
}
catch (ClassCastException e) {
}
try {
NumericShaper shaper = (NumericShaper)paragraph.getAttribute(TextAttribute.NUMERIC_SHAPING);
if (shaper != null) {
shaper.shape(text, 0, text.length);
}
}
catch (ClassCastException e) {
}
int pos = start;
do {
paragraph.setIndex(pos);
Object embeddingLevel = paragraph.getAttribute(TextAttribute.BIDI_EMBEDDING);
int newpos = paragraph.getRunLimit(TextAttribute.BIDI_EMBEDDING);
if (embeddingLevel != null) {
try {
int intLevel = ((Integer)embeddingLevel).intValue();
if (intLevel >= -61 && intLevel < 61) {
byte level = (byte)(intLevel < 0 ? (-intLevel | 0x80) : intLevel);
if (embeddings == null) {
embeddings = new byte[length];
}
for (int i = pos - start; i < newpos - start; ++i) {
embeddings[i] = level;
}
}
}
catch (ClassCastException e) {
}
}
pos = newpos;
} while (pos < limit);
nativeBidiChars(this, text, 0, embeddings, 0, text.length, flags);
}
/**
* Create Bidi from the given text, embedding, and direction information.
* The embeddings array may be null. If present, the values represent embedding level
* information. Negative values from -1 to -61 indicate overrides at the absolute value
* of the level. Positive values from 1 to 61 indicate embeddings. Where values are
* zero, the base embedding level as determined by the base direction is assumed.
* @param text an array containing the paragraph of text to process.
* @param textStart the index into the text array of the start of the paragraph.
* @param embeddings an array containing embedding values for each character in the paragraph.
* This can be null, in which case it is assumed that there is no external embedding information.
* @param embStart the index into the embedding array of the start of the paragraph.
* @param paragraphLength the length of the paragraph in the text and embeddings arrays.
* @param flags a collection of flags that control the algorithm. The
* algorithm understands the flags DIRECTION_LEFT_TO_RIGHT, DIRECTION_RIGHT_TO_LEFT,
* DIRECTION_DEFAULT_LEFT_TO_RIGHT, and DIRECTION_DEFAULT_RIGHT_TO_LEFT.
* Other values are reserved.
*/
public Bidi(char[] text, int textStart, byte[] embeddings, int embStart, int paragraphLength, int flags) {
if (text == null) {
throw new IllegalArgumentException("text is null");
}
if (paragraphLength < 0) {
throw new IllegalArgumentException("bad length: " + paragraphLength);
}
if (textStart < 0 || paragraphLength > text.length - textStart) {
throw new IllegalArgumentException("bad range: " + textStart +
" length: " + paragraphLength +
" for text of length: " + text.length);
}
if (embeddings != null && (embStart < 0 || paragraphLength > embeddings.length - embStart)) {
throw new IllegalArgumentException("bad range: " + embStart +
" length: " + paragraphLength +
" for embeddings of length: " + text.length);
}
if (embeddings != null) {
// native uses high bit to indicate override, not negative value, sigh
for (int i = embStart, embLimit = embStart + paragraphLength; i < embLimit; ++i) {
if (embeddings[i] < 0) {
byte[] temp = new byte[paragraphLength];
System.arraycopy(embeddings, embStart, temp, 0, paragraphLength);
for (i -= embStart; i < paragraphLength; ++i) {
if (temp[i] < 0) {
temp[i] = (byte)(-temp[i] | 0x80);
}
}
embeddings = temp;
embStart = 0;
break;
}
}
}
nativeBidiChars(this, text, textStart, embeddings, embStart, paragraphLength, flags);
}
/**
* Private constructor used by line bidi.
*/
private Bidi(int dir, int baseLevel, int length, int[] data, int[] cws) {
reset(dir, baseLevel, length, data, cws);
}
/**
* Private mutator used by native code.
*/
private void reset(int dir, int baselevel, int length, int[] data, int[] cws) {
this.dir = (byte)dir;
this.baselevel = (byte)baselevel;
this.length = length;
this.runs = data;
this.cws = cws;
}
/**
* Create a Bidi object representing the bidi information on a line of text within
* the paragraph represented by the current Bidi. This call is not required if the
* entire paragraph fits on one line.
* @param lineStart the offset from the start of the paragraph to the start of the line.
* @param lineLimit the offset from the start of the paragraph to the limit of the line.
*/
public Bidi createLineBidi(int lineStart, int lineLimit) {
if (lineStart == 0 && lineLimit == length) {
return this;
}
int lineLength = lineLimit - lineStart;
if (lineStart < 0 ||
lineLimit < lineStart ||
lineLimit > length) {
throw new IllegalArgumentException("range " + lineStart +
" to " + lineLimit +
" is invalid for paragraph of length " + length);
}
if (runs == null) {
return new Bidi(dir, baselevel, lineLength, null, null);
} else {
int cwspos = -1;
int[] ncws = null;
if (cws != null) {
int cwss = 0;
int cwsl = cws.length;
while (cwss < cwsl) {
if (cws[cwss] >= lineStart) {
cwsl = cwss;
while (cwsl < cws.length && cws[cwsl] < lineLimit) {
cwsl++;
}
int ll = lineLimit-1;
while (cwsl > cwss && cws[cwsl-1] == ll) {
cwspos = ll; // record start of counter-directional whitespace
--cwsl;
--ll;
}
if (cwspos == lineStart) { // entire line is cws, so ignore
return new Bidi(dir, baselevel, lineLength, null, null);
}
int ncwslen = cwsl - cwss;
if (ncwslen > 0) {
ncws = new int[ncwslen];
for (int i = 0; i < ncwslen; ++i) {
ncws[i] = cws[cwss+i] - lineStart;
}
}
break;
}
++cwss;
}
}
int[] nruns = null;
int nlevel = baselevel;
int limit = cwspos == -1 ? lineLimit : cwspos;
int rs = 0;
int rl = runs.length;
int ndir = dir;
for (; rs < runs.length; rs += 2) {
if (runs[rs] > lineStart) {
rl = rs;
while (rl < runs.length && runs[rl] < limit) {
rl += 2;
}
if ((rl > rs) || (runs[rs+1] != baselevel)) {
rl += 2;
if (cwspos != -1 && rl > rs && runs[rl-1] != baselevel) { // add level for cws
nruns = new int[rl - rs + 2];
nruns[rl - rs] = lineLength;
nruns[rl - rs + 1] = baselevel;
} else {
limit = lineLimit;
nruns = new int[rl - rs];
}
int n = 0;
for (int i = rs; i < rl; i += 2) {
nruns[n++] = runs[i] - lineStart;
nruns[n++] = runs[i+1];
}
nruns[n-2] = limit - lineStart;
} else {
ndir = (runs[rs+1] & 0x1) == 0 ? DIRECTION_LEFT_TO_RIGHT : DIRECTION_RIGHT_TO_LEFT;
}
break;
}
}
return new Bidi(ndir, baselevel, lineLength, nruns, ncws);
}
}
/**
* Return true if the line is not left-to-right or right-to-left. This means it either has mixed runs of left-to-right
* and right-to-left text, or the base direction differs from the direction of the only run of text.
* @return true if the line is not left-to-right or right-to-left.
*/
public boolean isMixed() {
return dir == DIR_MIXED;
}
/**
* Return true if the line is all left-to-right text and the base direction is left-to-right.
* @return true if the line is all left-to-right text and the base direction is left-to-right
*/
public boolean isLeftToRight() {
return dir == DIRECTION_LEFT_TO_RIGHT;
}
/**
* Return true if the line is all right-to-left text, and the base direction is right-to-left.
* @return true if the line is all right-to-left text, and the base direction is right-to-left
*/
public boolean isRightToLeft() {
return dir == DIRECTION_RIGHT_TO_LEFT;
}
/**
* Return the length of text in the line.
* @return the length of text in the line
*/
public int getLength() {
return length;
}
/**
* Return true if the base direction is left-to-right.
* @return true if the base direction is left-to-right
*/
public boolean baseIsLeftToRight() {
return (baselevel & 0x1) == 0;
}
/**
* Return the base level (0 if left-to-right, 1 if right-to-left).
* @return the base level
*/
public int getBaseLevel() {
return baselevel;
}
/**
* Return the resolved level of the character at offset. If offset is <0 or >=
* the length of the line, return the base direction level.
* @param offset the index of the character for which to return the level
* @return the resolved level of the character at offset
*/
public int getLevelAt(int offset) {
if (runs == null || offset < 0 || offset >= length) {
return baselevel;
} else {
int i = 0;
do {
if (offset < runs[i]) {
return runs[i+1];
}
i += 2;
} while (true);
}
}
/**
* Return the number of level runs.
* @return the number of level runs
*/
public int getRunCount() {
return runs == null ? 1 : runs.length / 2;
}
/**
* Return the level of the nth logical run in this line.
* @param run the index of the run, between 0 and <code>getRunCount()</code>
* @return the level of the run
*/
public int getRunLevel(int run) {
return runs == null ? baselevel : runs[run * 2 + 1];
}
/**
* Return the index of the character at the start of the nth logical run in this line, as
* an offset from the start of the line.
* @param run the index of the run, between 0 and <code>getRunCount()</code>
* @return the start of the run
*/
public int getRunStart(int run) {
return (runs == null || run == 0) ? 0 : runs[run * 2 - 2];
}
/**
* Return the index of the character past the end of the nth logical run in this line, as
* an offset from the start of the line. For example, this will return the length
* of the line for the last run on the line.
* @param run the index of the run, between 0 and <code>getRunCount()</code>
* @return limit the limit of the run
*/
public int getRunLimit(int run) {
return runs == null ? length : runs[run * 2];
}
/**
* Return true if the specified text requires bidi analysis. If this returns false,
* the text will display left-to-right. Clients can then avoid constructing a Bidi object.
* Text in the Arabic Presentation Forms area of Unicode is presumed to already be shaped
* and ordered for display, and so will not cause this function to return true.
*
* @param text the text containing the characters to test
* @param start the start of the range of characters to test
* @param limit the limit of the range of characters to test
* @return true if the range of characters requires bidi analysis
*/
public static boolean requiresBidi(char[] text, int start, int limit) {
CodePointIterator cpi = CodePointIterator.create(text, start, limit);
for (int cp = cpi.next(); cp != CodePointIterator.DONE; cp = cpi.next()) {
if (cp > 0x0590) {
int dc = nativeGetDirectionCode(cp);
if ((RMASK & (1 << dc)) != 0) {
return true;
}
}
}
return false;
}
/**
* Reorder the objects in the array into visual order based on their levels.
* This is a utility function to use when you have a collection of objects
* representing runs of text in logical order, each run containing text
* at a single level. The elements at <code>index</code> from
* <code>objectStart</code> up to <code>objectStart + count</code>
* in the objects array will be reordered into visual order assuming
* each run of text has the level indicated by the corresponding element
* in the levels array (at <code>index - objectStart + levelStart</code>).
*
* @param levels an array representing the bidi level of each object
* @param levelStart the start position in the levels array
* @param objects the array of objects to be reordered into visual order
* @param objectStart the start position in the objects array
* @param count the number of objects to reorder
*/
public static void reorderVisually(byte[] levels, int levelStart, Object[] objects, int objectStart, int count) {
if (count < 0) {
throw new IllegalArgumentException("count " + count + " must be >= 0");
}
if (levelStart < 0 || levelStart + count > levels.length) {
throw new IllegalArgumentException("levelStart " + levelStart + " and count " + count +
" out of range [0, " + levels.length + "]");
}
if (objectStart < 0 || objectStart + count > objects.length) {
throw new IllegalArgumentException("objectStart " + objectStart + " and count " + count +
" out of range [0, " + objects.length + "]");
}
byte lowestOddLevel = (byte)(NUMLEVELS + 1);
byte highestLevel = 0;
// initialize mapping and levels
int levelLimit = levelStart + count;
for (int i = levelStart; i < levelLimit; i++) {
byte level = levels[i];
if (level > highestLevel) {
highestLevel = level;
}
if ((level & 0x01) != 0 && level < lowestOddLevel) {
lowestOddLevel = level;
}
}
int delta = objectStart - levelStart;
while (highestLevel >= lowestOddLevel) {
int i = levelStart;
for (;;) {
while (i < levelLimit && levels[i] < highestLevel) {
i++;
}
int begin = i++;
if (begin == levelLimit) {
break; // no more runs at this level
}
while (i < levelLimit && levels[i] >= highestLevel) {
i++;
}
int end = i - 1;
begin += delta;
end += delta;
while (begin < end) {
Object temp = objects[begin];
objects[begin] = objects[end];
objects[end] = temp;
++begin;
--end;
}
}
--highestLevel;
}
}
private static final char NUMLEVELS = 62;
private static final int RMASK =
(1 << 1 /* U_RIGHT_TO_LEFT */) |
(1 << 5 /* U_ARABIC_NUMBER */) |
(1 << 13 /* U_RIGHT_TO_LEFT_ARABIC */) |
(1 << 14 /* U_RIGHT_TO_LEFT_EMBEDDING */) |
(1 << 15 /* U_RIGHT_TO_LEFT_OVERRIDE */);
/** Access native bidi implementation. */
private static native int nativeGetDirectionCode(int cp);
/** Access native bidi implementation. */
private static synchronized native void nativeBidiChars(Bidi bidi, char[] text, int textStart,
byte[] embeddings, int embeddingStart,
int length, int flags);
/**
* Display the bidi internal state, used in debugging.
*/
public String toString() {
StringBuffer buf = new StringBuffer(super.toString());
buf.append("[dir: " + dir);
buf.append(" baselevel: " + baselevel);
buf.append(" length: " + length);
if (runs == null) {
buf.append(" runs: null");
} else {
buf.append(" runs: [");
for (int i = 0; i < runs.length; i += 2) {
if (i != 0) {
buf.append(' ');
}
buf.append(runs[i]); // limit
buf.append('/');
buf.append(runs[i+1]); // level
}
buf.append(']');
}
if (cws == null) {
buf.append(" cws: null");
} else {
buf.append(" cws: [");
for (int i = 0; i < cws.length; ++i) {
if (i != 0) {
buf.append(' ');
}
buf.append(Integer.toHexString(cws[i]));
}
buf.append(']');
}
buf.append(']');
return buf.toString();
}
}
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