/*
 * Copyright (c) 2009, 2021, 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.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.
 */

/*
*******************************************************************************
*   Copyright (C) 2001-2014, International Business Machines
*   Corporation and others.  All Rights Reserved.
*******************************************************************************
*/
/* Written by Simon Montagu, Matitiahu Allouche
 * (ported from C code written by Markus W. Scherer)
 */

package jdk_internal.icu.text;

import java.util.Arrays;

import jdk_internal.bidi.Bidi;

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 <a
	 * href="http://www.unicode.org/reports/tr9/">Unicode Standard Annex #9: Unicode
	 * Bidirectional Algorithm</a>, 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 (dirProps[start - 1] == BidiBase.B) {
			bidiBase.trailingWSStart = start; /* currently == bidiBase.length */
			return;
		}
		/* go backwards across all WS, BN, explicit codes */
		while (start > 0 && (BidiBase.DirPropFlag(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;
	}

	static Bidi setLine(BidiBase paraBidi, Bidi newBidi, BidiBase lineBidi, int start, int limit) {
		int length;

		/* 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];
		lineBidi.reorderingMode = paraBidi.reorderingMode;
		lineBidi.reorderingOptions = paraBidi.reorderingOptions;
		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 lineBidiBase.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;
			}
		}

		lineBidi.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 getVisualRun(BidiBase bidiBase, int runIndex) {
		int start = bidiBase.runs[runIndex].start;
		int limit;
		byte level = bidiBase.runs[runIndex].level;

		if (runIndex > 0) {
			limit = start + bidiBase.runs[runIndex].limit - bidiBase.runs[runIndex - 1].limit;
		} else {
			limit = start + bidiBase.runs[0].limit;
		}
		return new BidiRun(start, limit, level);
	}

	/* 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 = -1; /* 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 < 0 || 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 */
				do { /* RTL */
					indexMap[idx++] = --logicalStart;
				} while (++visualStart < visualLimit);
			}
			/* visualStart==visualLimit; */
		}

		if (bidiBase.insertPoints.size > 0) {
			int markFound = 0, runCount = bidiBase.runCount;
			int insertRemove, i, j, k;
			runs = bidiBase.runs;
			/* count all inserted marks */
			for (i = 0; i < runCount; i++) {
				insertRemove = runs[i].insertRemove;
				if ((insertRemove & (BidiBase.LRM_BEFORE | BidiBase.RLM_BEFORE)) > 0) {
					markFound++;
				}
				if ((insertRemove & (BidiBase.LRM_AFTER | BidiBase.RLM_AFTER)) > 0) {
					markFound++;
				}
			}
			/* move back indexes by number of preceding marks */
			k = bidiBase.resultLength;
			for (i = runCount - 1; i >= 0 && markFound > 0; i--) {
				insertRemove = runs[i].insertRemove;
				if ((insertRemove & (BidiBase.LRM_AFTER | BidiBase.RLM_AFTER)) > 0) {
					indexMap[--k] = BidiBase.MAP_NOWHERE;
					markFound--;
				}
				visualStart = i > 0 ? runs[i - 1].limit : 0;
				for (j = runs[i].limit - 1; j >= visualStart && markFound > 0; j--) {
					indexMap[--k] = indexMap[j];
				}
				if ((insertRemove & (BidiBase.LRM_BEFORE | BidiBase.RLM_BEFORE)) > 0) {
					indexMap[--k] = BidiBase.MAP_NOWHERE;
					markFound--;
				}
			}
		} else if (bidiBase.controlCount > 0) {
			int runCount = bidiBase.runCount, logicalEnd;
			int insertRemove, length, i, j, k, m;
			char uchar;
			boolean evenRun;
			runs = bidiBase.runs;
			visualStart = 0;
			/* move forward indexes by number of preceding controls */
			k = 0;
			for (i = 0; i < runCount; i++, visualStart += length) {
				length = runs[i].limit - visualStart;
				insertRemove = runs[i].insertRemove;
				/* if no control found yet, nothing to do in this run */
				if ((insertRemove == 0) && (k == visualStart)) {
					k += length;
					continue;
				}
				/* if no control in this run */
				if (insertRemove == 0) {
					visualLimit = runs[i].limit;
					for (j = visualStart; j < visualLimit; j++) {
						indexMap[k++] = indexMap[j];
					}
					continue;
				}
				logicalStart = runs[i].start;
				evenRun = runs[i].isEvenRun();
				logicalEnd = logicalStart + length - 1;
				for (j = 0; j < length; j++) {
					m = evenRun ? logicalStart + j : logicalEnd - j;
					uchar = bidiBase.text[m];
					if (!BidiBase.IsBidiControlChar(uchar)) {
						indexMap[k++] = m;
					}
				}
			}
		}
		if (allocLength == bidiBase.resultLength) {
			return indexMap;
		}
		int[] newMap = new int[bidiBase.resultLength];
		System.arraycopy(indexMap, 0, newMap, 0, bidiBase.resultLength);
		return newMap;
	}

}