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/*
* Copyright (c) 2009, Oracle and/or its affiliates. All rights reserved.
* 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.
*
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/*
*******************************************************************************
* (C) Copyright IBM Corp. and others, 1996-2009 - 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 *
* to removed. *
*******************************************************************************
*/
/* Written by Simon Montagu, Matitiahu Allouche
* (ported from C code written by Markus W. Scherer)
*/
package sun.text.bidi;
import java.text.Bidi;
import java.util.Arrays;
public final class BidiLine {
/*
* General remarks about the functions in this file:
*
* These functions deal with the aspects of potentially mixed-directional
* text in a single paragraph or in a line of a single paragraph
* which has already been processed according to
* the Unicode 3.0 Bidi algorithm as defined in
* http://www.unicode.org/unicode/reports/tr9/ , version 13,
* also described in The Unicode Standard, Version 4.0.1 .
*
* This means that there is a Bidi object with a levels
* and a dirProps array.
* paraLevel and direction are also set.
* Only if the length of the text is zero, then levels==dirProps==NULL.
*
* The overall directionality of the paragraph
* or line is used to bypass the reordering steps if possible.
* Even purely RTL text does not need reordering there because
* the getLogical/VisualIndex() methods can compute the
* index on the fly in such a case.
*
* The implementation of the access to same-level-runs and of the reordering
* do attempt to provide better performance and less memory usage compared to
* a direct implementation of especially rule (L2) with an array of
* one (32-bit) integer per text character.
*
* Here, the levels array is scanned as soon as necessary, and a vector of
* same-level-runs is created. Reordering then is done on this vector.
* For each run of text positions that were resolved to the same level,
* only 8 bytes are stored: the first text position of the run and the visual
* position behind the run after reordering.
* One sign bit is used to hold the directionality of the run.
* This is inefficient if there are many very short runs. If the average run
* length is <2, then this uses more memory.
*
* In a further attempt to save memory, the levels array is never changed
* after all the resolution rules (Xn, Wn, Nn, In).
* Many methods have to consider the field trailingWSStart:
* if it is less than length, then there is an implicit trailing run
* at the paraLevel,
* which is not reflected in the levels array.
* This allows a line Bidi object to use the same levels array as
* its paragraph parent object.
*
* When a Bidi object is created for a line of a paragraph, then the
* paragraph's levels and dirProps arrays are reused by way of setting
* a pointer into them, not by copying. This again saves memory and forbids to
* change the now shared levels for (L1).
*/
/* handle trailing WS (L1) -------------------------------------------------- */
/*
* setTrailingWSStart() sets the start index for a trailing
* run of WS in the line. This is necessary because we do not modify
* the paragraph's levels array that we just point into.
* Using trailingWSStart is another form of performing (L1).
*
* To make subsequent operations easier, we also include the run
* before the WS if it is at the paraLevel - we merge the two here.
*
* This method is called only from setLine(), so paraLevel is
* set correctly for the line even when contextual multiple paragraphs.
*/
static void setTrailingWSStart(BidiBase bidiBase)
{
byte[] dirProps = bidiBase.dirProps;
byte[] levels = bidiBase.levels;
int start = bidiBase.length;
byte paraLevel = bidiBase.paraLevel;
/* If the line is terminated by a block separator, all preceding WS etc...
are already set to paragraph level.
Setting trailingWSStart to pBidi->length will avoid changing the
level of B chars from 0 to paraLevel in getLevels when
orderParagraphsLTR==TRUE
*/
if (BidiBase.NoContextRTL(dirProps[start - 1]) == BidiBase.B) {
bidiBase.trailingWSStart = start; /* currently == bidiBase.length */
return;
}
/* go backwards across all WS, BN, explicit codes */
while (start > 0 &&
(BidiBase.DirPropFlagNC(dirProps[start - 1]) & BidiBase.MASK_WS) != 0) {
--start;
}
/* if the WS run can be merged with the previous run then do so here */
while (start > 0 && levels[start - 1] == paraLevel) {
--start;
}
bidiBase.trailingWSStart=start;
}
public static Bidi setLine(Bidi bidi, BidiBase paraBidi,
Bidi newBidi, BidiBase newBidiBase,
int start, int limit) {
int length;
BidiBase lineBidi = newBidiBase;
/* set the values in lineBidi from its paraBidi parent */
/* class members are already initialized to 0 */
// lineBidi.paraBidi = null; /* mark unfinished setLine */
// lineBidi.flags = 0;
// lineBidi.controlCount = 0;
length = lineBidi.length = lineBidi.originalLength =
lineBidi.resultLength = limit - start;
lineBidi.text = new char[length];
System.arraycopy(paraBidi.text, start, lineBidi.text, 0, length);
lineBidi.paraLevel = paraBidi.GetParaLevelAt(start);
lineBidi.paraCount = paraBidi.paraCount;
lineBidi.runs = new BidiRun[0];
if (paraBidi.controlCount > 0) {
int j;
for (j = start; j < limit; j++) {
if (BidiBase.IsBidiControlChar(paraBidi.text[j])) {
lineBidi.controlCount++;
}
}
lineBidi.resultLength -= lineBidi.controlCount;
}
/* copy proper subset of DirProps */
lineBidi.getDirPropsMemory(length);
lineBidi.dirProps = lineBidi.dirPropsMemory;
System.arraycopy(paraBidi.dirProps, start, lineBidi.dirProps, 0,
length);
/* copy proper subset of Levels */
lineBidi.getLevelsMemory(length);
lineBidi.levels = lineBidi.levelsMemory;
System.arraycopy(paraBidi.levels, start, lineBidi.levels, 0,
length);
lineBidi.runCount = -1;
if (paraBidi.direction != BidiBase.MIXED) {
/* the parent is already trivial */
lineBidi.direction = paraBidi.direction;
/*
* The parent's levels are all either
* implicitly or explicitly ==paraLevel;
* do the same here.
*/
if (paraBidi.trailingWSStart <= start) {
lineBidi.trailingWSStart = 0;
} else if (paraBidi.trailingWSStart < limit) {
lineBidi.trailingWSStart = paraBidi.trailingWSStart - start;
} else {
lineBidi.trailingWSStart = length;
}
} else {
byte[] levels = lineBidi.levels;
int i, trailingWSStart;
byte level;
setTrailingWSStart(lineBidi);
trailingWSStart = lineBidi.trailingWSStart;
/* recalculate lineBidi.direction */
if (trailingWSStart == 0) {
/* all levels are at paraLevel */
lineBidi.direction = (byte)(lineBidi.paraLevel & 1);
} else {
/* get the level of the first character */
level = (byte)(levels[0] & 1);
/* if there is anything of a different level, then the line
is mixed */
if (trailingWSStart < length &&
(lineBidi.paraLevel & 1) != level) {
/* the trailing WS is at paraLevel, which differs from
levels[0] */
lineBidi.direction = BidiBase.MIXED;
} else {
/* see if levels[1..trailingWSStart-1] have the same
direction as levels[0] and paraLevel */
for (i = 1; ; i++) {
if (i == trailingWSStart) {
/* the direction values match those in level */
lineBidi.direction = level;
break;
} else if ((levels[i] & 1) != level) {
lineBidi.direction = BidiBase.MIXED;
break;
}
}
}
}
switch(lineBidi.direction) {
case Bidi.DIRECTION_LEFT_TO_RIGHT:
/* make sure paraLevel is even */
lineBidi.paraLevel = (byte)
((lineBidi.paraLevel + 1) & ~1);
/* all levels are implicitly at paraLevel (important for
getLevels()) */
lineBidi.trailingWSStart = 0;
break;
case Bidi.DIRECTION_RIGHT_TO_LEFT:
/* make sure paraLevel is odd */
lineBidi.paraLevel |= 1;
/* all levels are implicitly at paraLevel (important for
getLevels()) */
lineBidi.trailingWSStart = 0;
break;
default:
break;
}
}
newBidiBase.paraBidi = paraBidi; /* mark successful setLine */
return newBidi;
}
static byte getLevelAt(BidiBase bidiBase, int charIndex)
{
/* return paraLevel if in the trailing WS run, otherwise the real level */
if (bidiBase.direction != BidiBase.MIXED || charIndex >= bidiBase.trailingWSStart) {
return bidiBase.GetParaLevelAt(charIndex);
} else {
return bidiBase.levels[charIndex];
}
}
static byte[] getLevels(BidiBase bidiBase)
{
int start = bidiBase.trailingWSStart;
int length = bidiBase.length;
if (start != length) {
/* the current levels array does not reflect the WS run */
/*
* After the previous if(), we know that the levels array
* has an implicit trailing WS run and therefore does not fully
* reflect itself all the levels.
* This must be a Bidi object for a line, and
* we need to create a new levels array.
*/
/* bidiBase.paraLevel is ok even if contextual multiple paragraphs,
since bidiBase is a line object */
Arrays.fill(bidiBase.levels, start, length, bidiBase.paraLevel);
/* this new levels array is set for the line and reflects the WS run */
bidiBase.trailingWSStart = length;
}
if (length < bidiBase.levels.length) {
byte[] levels = new byte[length];
System.arraycopy(bidiBase.levels, 0, levels, 0, length);
return levels;
}
return bidiBase.levels;
}
static BidiRun getLogicalRun(BidiBase bidiBase, int logicalPosition)
{
/* this is done based on runs rather than on levels since levels have
a special interpretation when REORDER_RUNS_ONLY
*/
BidiRun newRun = new BidiRun(), iRun;
getRuns(bidiBase);
int runCount = bidiBase.runCount;
int visualStart = 0, logicalLimit = 0;
iRun = bidiBase.runs[0];
for (int i = 0; i < runCount; i++) {
iRun = bidiBase.runs[i];
logicalLimit = iRun.start + iRun.limit - visualStart;
if ((logicalPosition >= iRun.start) &&
(logicalPosition < logicalLimit)) {
break;
}
visualStart = iRun.limit;
}
newRun.start = iRun.start;
newRun.limit = logicalLimit;
newRun.level = iRun.level;
return newRun;
}
/* in trivial cases there is only one trivial run; called by getRuns() */
private static void getSingleRun(BidiBase bidiBase, byte level) {
/* simple, single-run case */
bidiBase.runs = bidiBase.simpleRuns;
bidiBase.runCount = 1;
/* fill and reorder the single run */
bidiBase.runs[0] = new BidiRun(0, bidiBase.length, level);
}
/* reorder the runs array (L2) ---------------------------------------------- */
/*
* Reorder the same-level runs in the runs array.
* Here, runCount>1 and maxLevel>=minLevel>=paraLevel.
* All the visualStart fields=logical start before reordering.
* The "odd" bits are not set yet.
*
* Reordering with this data structure lends itself to some handy shortcuts:
*
* Since each run is moved but not modified, and since at the initial maxLevel
* each sequence of same-level runs consists of only one run each, we
* don't need to do anything there and can predecrement maxLevel.
* In many simple cases, the reordering is thus done entirely in the
* index mapping.
* Also, reordering occurs only down to the lowest odd level that occurs,
* which is minLevel|1. However, if the lowest level itself is odd, then
* in the last reordering the sequence of the runs at this level or higher
* will be all runs, and we don't need the elaborate loop to search for them.
* This is covered by ++minLevel instead of minLevel|=1 followed
* by an extra reorder-all after the reorder-some loop.
* About a trailing WS run:
* Such a run would need special treatment because its level is not
* reflected in levels[] if this is not a paragraph object.
* Instead, all characters from trailingWSStart on are implicitly at
* paraLevel.
* However, for all maxLevel>paraLevel, this run will never be reordered
* and does not need to be taken into account. maxLevel==paraLevel is only reordered
* if minLevel==paraLevel is odd, which is done in the extra segment.
* This means that for the main reordering loop we don't need to consider
* this run and can --runCount. If it is later part of the all-runs
* reordering, then runCount is adjusted accordingly.
*/
private static void reorderLine(BidiBase bidiBase, byte minLevel, byte maxLevel) {
/* nothing to do? */
if (maxLevel<=(minLevel|1)) {
return;
}
BidiRun[] runs;
BidiRun tempRun;
byte[] levels;
int firstRun, endRun, limitRun, runCount;
/*
* Reorder only down to the lowest odd level
* and reorder at an odd minLevel in a separate, simpler loop.
* See comments above for why minLevel is always incremented.
*/
++minLevel;
runs = bidiBase.runs;
levels = bidiBase.levels;
runCount = bidiBase.runCount;
/* do not include the WS run at paraLevel<=old minLevel except in the simple loop */
if (bidiBase.trailingWSStart < bidiBase.length) {
--runCount;
}
while (--maxLevel >= minLevel) {
firstRun = 0;
/* loop for all sequences of runs */
for ( ; ; ) {
/* look for a sequence of runs that are all at >=maxLevel */
/* look for the first run of such a sequence */
while (firstRun < runCount && levels[runs[firstRun].start] < maxLevel) {
++firstRun;
}
if (firstRun >= runCount) {
break; /* no more such runs */
}
/* look for the limit run of such a sequence (the run behind it) */
for (limitRun = firstRun; ++limitRun < runCount &&
levels[runs[limitRun].start]>=maxLevel; ) {}
/* Swap the entire sequence of runs from firstRun to limitRun-1. */
endRun = limitRun - 1;
while (firstRun < endRun) {
tempRun = runs[firstRun];
runs[firstRun] = runs[endRun];
runs[endRun] = tempRun;
++firstRun;
--endRun;
}
if (limitRun == runCount) {
break; /* no more such runs */
} else {
firstRun = limitRun + 1;
}
}
}
/* now do maxLevel==old minLevel (==odd!), see above */
if ((minLevel & 1) == 0) {
firstRun = 0;
/* include the trailing WS run in this complete reordering */
if (bidiBase.trailingWSStart == bidiBase.length) {
--runCount;
}
/* Swap the entire sequence of all runs. (endRun==runCount) */
while (firstRun < runCount) {
tempRun = runs[firstRun];
runs[firstRun] = runs[runCount];
runs[runCount] = tempRun;
++firstRun;
--runCount;
}
}
}
/* compute the runs array --------------------------------------------------- */
static int getRunFromLogicalIndex(BidiBase bidiBase, int logicalIndex) {
BidiRun[] runs = bidiBase.runs;
int runCount = bidiBase.runCount, visualStart = 0, i, length, logicalStart;
for (i = 0; i < runCount; i++) {
length = runs[i].limit - visualStart;
logicalStart = runs[i].start;
if ((logicalIndex >= logicalStart) && (logicalIndex < (logicalStart+length))) {
return i;
}
visualStart += length;
}
/* we should never get here */
throw new IllegalStateException("Internal ICU error in getRunFromLogicalIndex");
}
/*
* Compute the runs array from the levels array.
* After getRuns() returns true, runCount is guaranteed to be >0
* and the runs are reordered.
* Odd-level runs have visualStart on their visual right edge and
* they progress visually to the left.
* If option OPTION_INSERT_MARKS is set, insertRemove will contain the
* sum of appropriate LRM/RLM_BEFORE/AFTER flags.
* If option OPTION_REMOVE_CONTROLS is set, insertRemove will contain the
* negative number of BiDi control characters within this run.
*/
static void getRuns(BidiBase bidiBase) {
/*
* This method returns immediately if the runs are already set. This
* includes the case of length==0 (handled in setPara)..
*/
if (bidiBase.runCount >= 0) {
return;
}
if (bidiBase.direction != BidiBase.MIXED) {
/* simple, single-run case - this covers length==0 */
/* bidiBase.paraLevel is ok even for contextual multiple paragraphs */
getSingleRun(bidiBase, bidiBase.paraLevel);
} else /* BidiBase.MIXED, length>0 */ {
/* mixed directionality */
int length = bidiBase.length, limit;
byte[] levels = bidiBase.levels;
int i, runCount;
byte level = BidiBase.INTERNAL_LEVEL_DEFAULT_LTR; /* initialize with no valid level */
/*
* If there are WS characters at the end of the line
* and the run preceding them has a level different from
* paraLevel, then they will form their own run at paraLevel (L1).
* Count them separately.
* We need some special treatment for this in order to not
* modify the levels array which a line Bidi object shares
* with its paragraph parent and its other line siblings.
* In other words, for the trailing WS, it may be
* levels[]!=paraLevel but we have to treat it like it were so.
*/
limit = bidiBase.trailingWSStart;
/* count the runs, there is at least one non-WS run, and limit>0 */
runCount = 0;
for (i = 0; i < limit; ++i) {
/* increment runCount at the start of each run */
if (levels[i] != level) {
++runCount;
level = levels[i];
}
}
/*
* We don't need to see if the last run can be merged with a trailing
* WS run because setTrailingWSStart() would have done that.
*/
if (runCount == 1 && limit == length) {
/* There is only one non-WS run and no trailing WS-run. */
getSingleRun(bidiBase, levels[0]);
} else /* runCount>1 || limit<length */ {
/* allocate and set the runs */
BidiRun[] runs;
int runIndex, start;
byte minLevel = BidiBase.MAX_EXPLICIT_LEVEL + 1;
byte maxLevel=0;
/* now, count a (non-mergeable) WS run */
if (limit < length) {
++runCount;
}
/* runCount > 1 */
bidiBase.getRunsMemory(runCount);
runs = bidiBase.runsMemory;
/* set the runs */
/* FOOD FOR THOUGHT: this could be optimized, e.g.:
* 464->444, 484->444, 575->555, 595->555
* However, that would take longer. Check also how it would
* interact with BiDi control removal and inserting Marks.
*/
runIndex = 0;
/* search for the run limits and initialize visualLimit values with the run lengths */
i = 0;
do {
/* prepare this run */
start = i;
level = levels[i];
if (level < minLevel) {
minLevel = level;
}
if (level > maxLevel) {
maxLevel = level;
}
/* look for the run limit */
while (++i < limit && levels[i] == level) {}
/* i is another run limit */
runs[runIndex] = new BidiRun(start, i - start, level);
++runIndex;
} while (i < limit);
if (limit < length) {
/* there is a separate WS run */
runs[runIndex] = new BidiRun(limit, length - limit, bidiBase.paraLevel);
/* For the trailing WS run, bidiBase.paraLevel is ok even
if contextual multiple paragraphs. */
if (bidiBase.paraLevel < minLevel) {
minLevel = bidiBase.paraLevel;
}
}
/* set the object fields */
bidiBase.runs = runs;
bidiBase.runCount = runCount;
reorderLine(bidiBase, minLevel, maxLevel);
/* now add the direction flags and adjust the visualLimit's to be just that */
/* this loop will also handle the trailing WS run */
limit = 0;
for (i = 0; i < runCount; ++i) {
runs[i].level = levels[runs[i].start];
limit = (runs[i].limit += limit);
}
/* Set the embedding level for the trailing WS run. */
/* For a RTL paragraph, it will be the *first* run in visual order. */
/* For the trailing WS run, bidiBase.paraLevel is ok even if
contextual multiple paragraphs. */
if (runIndex < runCount) {
int trailingRun = ((bidiBase.paraLevel & 1) != 0)? 0 : runIndex;
runs[trailingRun].level = bidiBase.paraLevel;
}
}
}
/* handle insert LRM/RLM BEFORE/AFTER run */
if (bidiBase.insertPoints.size > 0) {
BidiBase.Point point;
int runIndex, ip;
for (ip = 0; ip < bidiBase.insertPoints.size; ip++) {
point = bidiBase.insertPoints.points[ip];
runIndex = getRunFromLogicalIndex(bidiBase, point.pos);
bidiBase.runs[runIndex].insertRemove |= point.flag;
}
}
/* handle remove BiDi control characters */
if (bidiBase.controlCount > 0) {
int runIndex, ic;
char c;
for (ic = 0; ic < bidiBase.length; ic++) {
c = bidiBase.text[ic];
if (BidiBase.IsBidiControlChar(c)) {
runIndex = getRunFromLogicalIndex(bidiBase, ic);
bidiBase.runs[runIndex].insertRemove--;
}
}
}
}
static int[] prepareReorder(byte[] levels, byte[] pMinLevel, byte[] pMaxLevel)
{
int start;
byte level, minLevel, maxLevel;
if (levels == null || levels.length <= 0) {
return null;
}
/* determine minLevel and maxLevel */
minLevel = BidiBase.MAX_EXPLICIT_LEVEL + 1;
maxLevel = 0;
for (start = levels.length; start>0; ) {
level = levels[--start];
if (level > BidiBase.MAX_EXPLICIT_LEVEL + 1) {
return null;
}
if (level < minLevel) {
minLevel = level;
}
if (level > maxLevel) {
maxLevel = level;
}
}
pMinLevel[0] = minLevel;
pMaxLevel[0] = maxLevel;
/* initialize the index map */
int[] indexMap = new int[levels.length];
for (start = levels.length; start > 0; ) {
--start;
indexMap[start] = start;
}
return indexMap;
}
static int[] reorderVisual(byte[] levels)
{
byte[] aMinLevel = new byte[1];
byte[] aMaxLevel = new byte[1];
int start, end, limit, temp;
byte minLevel, maxLevel;
int[] indexMap = prepareReorder(levels, aMinLevel, aMaxLevel);
if (indexMap == null) {
return null;
}
minLevel = aMinLevel[0];
maxLevel = aMaxLevel[0];
/* nothing to do? */
if (minLevel == maxLevel && (minLevel & 1) == 0) {
return indexMap;
}
/* reorder only down to the lowest odd level */
minLevel |= 1;
/* loop maxLevel..minLevel */
do {
start = 0;
/* loop for all sequences of levels to reorder at the current maxLevel */
for ( ; ; ) {
/* look for a sequence of levels that are all at >=maxLevel */
/* look for the first index of such a sequence */
while (start < levels.length && levels[start] < maxLevel) {
++start;
}
if (start >= levels.length) {
break; /* no more such runs */
}
/* look for the limit of such a sequence (the index behind it) */
for (limit = start; ++limit < levels.length && levels[limit] >= maxLevel; ) {}
/*
* Swap the entire interval of indexes from start to limit-1.
* We don't need to swap the levels for the purpose of this
* algorithm: the sequence of levels that we look at does not
* move anyway.
*/
end = limit - 1;
while (start < end) {
temp = indexMap[start];
indexMap[start] = indexMap[end];
indexMap[end] = temp;
++start;
--end;
}
if (limit == levels.length) {
break; /* no more such sequences */
} else {
start = limit + 1;
}
}
} while (--maxLevel >= minLevel);
return indexMap;
}
static int[] getVisualMap(BidiBase bidiBase)
{
/* fill a visual-to-logical index map using the runs[] */
BidiRun[] runs = bidiBase.runs;
int logicalStart, visualStart, visualLimit;
int allocLength = bidiBase.length > bidiBase.resultLength ? bidiBase.length
: bidiBase.resultLength;
int[] indexMap = new int[allocLength];
visualStart = 0;
int idx = 0;
for (int j = 0; j < bidiBase.runCount; ++j) {
logicalStart = runs[j].start;
visualLimit = runs[j].limit;
if (runs[j].isEvenRun()) {
do { /* LTR */
indexMap[idx++] = logicalStart++;
} while (++visualStart < visualLimit);
} else {
logicalStart += visualLimit - visualStart; /* logicalLimit */
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