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 /*

 ******************************************************************************

 *

 *   Copyright (C) 1999-2013, International Business Machines

 *   Corporation and others.  All Rights Reserved.

 *

 ******************************************************************************

 *   file name:  ubidiln.c

 *   encoding:   US-ASCII

 *   tab size:   8 (not used)

 *   indentation:4

 *

 *   created on: 1999aug06

 *   created by: Markus W. Scherer, updated by Matitiahu Allouche

 */

 #include "cmemory.h"

 #include "unicode/utypes.h"

 #include "unicode/ustring.h"

 #include "unicode/uchar.h"

 #include "unicode/ubidi.h"

 #include "ubidiimp.h"

 #include "uassert.h"

 #ifndef U_COMMON_IMPLEMENTATION

 #error U_COMMON_IMPLEMENTATION not set - must be set for all ICU source files in common/ - see http://userguide.icu-project.org/howtouseicu

 #endif

 /*

  * 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 6.3 BiDi algorithm as defined in

  * http://www.unicode.org/unicode/reports/tr9/ , version 28,

  * also described in The Unicode Standard, Version 6.3.0 .

  *

  * This means that there is a UBiDi 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 ubidi_getLogical/VisualIndex() functions 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 functions 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 UBiDi object to use the same levels array as

  * its paragraph parent object.

  *

  * When a UBiDi 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 function is called only from ubidi_setLine(), so pBiDi->paraLevel is

  * set correctly for the line even when contextual multiple paragraphs.

  */

 static void

 setTrailingWSStart(UBiDi *pBiDi) {

     /* pBiDi->direction!=UBIDI_MIXED */

     const DirProp *dirProps=pBiDi->dirProps;

     UBiDiLevel *levels=pBiDi->levels;

     int32_t start=pBiDi->length;

     UBiDiLevel paraLevel=pBiDi->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 ubidi_getLevels when

        orderParagraphsLTR==TRUE.

      */

     if(dirProps[start-1]==B) {

         pBiDi->trailingWSStart=start;   /* currently == pBiDi->length */

         return;

     }

     /* go backwards across all WS, BN, explicit codes */

     while(start>0 && DIRPROP_FLAG(PURE_DIRPROP(dirProps[start-1]))&MASK_WS) {

         --start;

     }

     /* if the WS run can be merged with the previous run then do so here */

     while(start>0 && levels[start-1]==paraLevel) {

         --start;

     }

     pBiDi->trailingWSStart=start;

 }

 /* ubidi_setLine ------------------------------------------------------------ */

 U_CAPI void U_EXPORT2

 ubidi_setLine(const UBiDi *pParaBiDi,

               int32_t start, int32_t limit,

               UBiDi *pLineBiDi,

               UErrorCode *pErrorCode) {

     int32_t length;

     /* check the argument values */

     RETURN_VOID_IF_NULL_OR_FAILING_ERRCODE(pErrorCode);

     RETURN_VOID_IF_NOT_VALID_PARA(pParaBiDi, *pErrorCode);

     RETURN_VOID_IF_BAD_RANGE(start, 0, limit, *pErrorCode);

     RETURN_VOID_IF_BAD_RANGE(limit, 0, pParaBiDi->length+1, *pErrorCode);

     if(pLineBiDi==NULL) {

         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;

         return;

     }

     if(ubidi_getParagraph(pParaBiDi, start, NULL, NULL, NULL, pErrorCode) !=

        ubidi_getParagraph(pParaBiDi, limit-1, NULL, NULL, NULL, pErrorCode)) {

         /* the line crosses a paragraph boundary */

         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;

         return;

     }

     /* set the values in pLineBiDi from its pParaBiDi parent */

     pLineBiDi->pParaBiDi=NULL;          /* mark unfinished setLine */

     pLineBiDi->text=pParaBiDi->text+start;

     length=pLineBiDi->length=limit-start;

     pLineBiDi->resultLength=pLineBiDi->originalLength=length;

     pLineBiDi->paraLevel=GET_PARALEVEL(pParaBiDi, start);

     pLineBiDi->paraCount=pParaBiDi->paraCount;

     pLineBiDi->runs=NULL;

     pLineBiDi->flags=0;

     pLineBiDi->reorderingMode=pParaBiDi->reorderingMode;

     pLineBiDi->reorderingOptions=pParaBiDi->reorderingOptions;

     pLineBiDi->controlCount=0;

     if(pParaBiDi->controlCount>0) {

         int32_t j;

         for(j=start; j<limit; j++) {

             if(IS_BIDI_CONTROL_CHAR(pParaBiDi->text[j])) {

                 pLineBiDi->controlCount++;

             }

         }

         pLineBiDi->resultLength-=pLineBiDi->controlCount;

     }

     pLineBiDi->dirProps=pParaBiDi->dirProps+start;

     pLineBiDi->levels=pParaBiDi->levels+start;

     pLineBiDi->runCount=-1;

     if(pParaBiDi->direction!=UBIDI_MIXED) {

         /* the parent is already trivial */

         pLineBiDi->direction=pParaBiDi->direction;

         /*

          * The parent's levels are all either

          * implicitly or explicitly ==paraLevel;

          * do the same here.

          */

         if(pParaBiDi->trailingWSStart<=start) {

             pLineBiDi->trailingWSStart=0;

         } else if(pParaBiDi->trailingWSStart<limit) {

             pLineBiDi->trailingWSStart=pParaBiDi->trailingWSStart-start;

         } else {

             pLineBiDi->trailingWSStart=length;

         }

     } else {

         const UBiDiLevel *levels=pLineBiDi->levels;

         int32_t i, trailingWSStart;

         UBiDiLevel level;

         setTrailingWSStart(pLineBiDi);

         trailingWSStart=pLineBiDi->trailingWSStart;

         /* recalculate pLineBiDi->direction */

         if(trailingWSStart==0) {

             /* all levels are at paraLevel */

             pLineBiDi->direction=(UBiDiDirection)(pLineBiDi->paraLevel&1);

         } else {

             /* get the level of the first character */

             level=(UBiDiLevel)(levels[0]&1);

             /* if there is anything of a different level, then the line is mixed */

             if(trailingWSStart<length && (pLineBiDi->paraLevel&1)!=level) {

                 /* the trailing WS is at paraLevel, which differs from levels[0] */

                 pLineBiDi->direction=UBIDI_MIXED;

             } else {

                 /* see if levels[1..trailingWSStart-1] have the same direction as levels[0] and paraLevel */

                 i=1;

                 for(;;) {

                     if(i==trailingWSStart) {

                         /* the direction values match those in level */

                         pLineBiDi->direction=(UBiDiDirection)level;

                         break;

                     } else if((levels[i]&1)!=level) {

                         pLineBiDi->direction=UBIDI_MIXED;

                         break;

                     }

                     ++i;

                 }

             }

         }

         switch(pLineBiDi->direction) {

         case UBIDI_LTR:

             /* make sure paraLevel is even */

             pLineBiDi->paraLevel=(UBiDiLevel)((pLineBiDi->paraLevel+1)&~1);

             /* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */

             pLineBiDi->trailingWSStart=0;

             break;

         case UBIDI_RTL:

             /* make sure paraLevel is odd */

             pLineBiDi->paraLevel|=1;

             /* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */

             pLineBiDi->trailingWSStart=0;

             break;

         default:

             break;

         }

     }

     pLineBiDi->pParaBiDi=pParaBiDi;     /* mark successful setLine */

     return;

 }

 U_CAPI UBiDiLevel U_EXPORT2

 ubidi_getLevelAt(const UBiDi *pBiDi, int32_t charIndex) {

     /* return paraLevel if in the trailing WS run, otherwise the real level */

     if(!IS_VALID_PARA_OR_LINE(pBiDi) || charIndex<0 || pBiDi->length<=charIndex) {

         return 0;

     } else if(pBiDi->direction!=UBIDI_MIXED || charIndex>=pBiDi->trailingWSStart) {

         return GET_PARALEVEL(pBiDi, charIndex);

     } else {

         return pBiDi->levels[charIndex];

     }

 }

 U_CAPI const UBiDiLevel * U_EXPORT2

 ubidi_getLevels(UBiDi *pBiDi, UErrorCode *pErrorCode) {

     int32_t start, length;

     RETURN_IF_NULL_OR_FAILING_ERRCODE(pErrorCode, NULL);

     RETURN_IF_NOT_VALID_PARA_OR_LINE(pBiDi, *pErrorCode, NULL);

     if((length=pBiDi->length)<=0) {

         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;

         return NULL;

     }

     if((start=pBiDi->trailingWSStart)==length) {

         /* the current levels array reflects the WS run */

         return pBiDi->levels;

     }

     /*

      * 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 UBiDi object for a line, and

      * we need to create a new levels array.

      */

     if(getLevelsMemory(pBiDi, length)) {

         UBiDiLevel *levels=pBiDi->levelsMemory;

         if(start>0 && levels!=pBiDi->levels) {

             uprv_memcpy(levels, pBiDi->levels, start);

         }

         /* pBiDi->paraLevel is ok even if contextual multiple paragraphs,

            since pBidi is a line object                                     */

         uprv_memset(levels+start, pBiDi->paraLevel, length-start);

         /* this new levels array is set for the line and reflects the WS run */

         pBiDi->trailingWSStart=length;

         return pBiDi->levels=levels;

     } else {

         /* out of memory */

         *pErrorCode=U_MEMORY_ALLOCATION_ERROR;

         return NULL;

     }

 }

 U_CAPI void U_EXPORT2

 ubidi_getLogicalRun(const UBiDi *pBiDi, int32_t logicalPosition,

                     int32_t *pLogicalLimit, UBiDiLevel *pLevel) {

     UErrorCode errorCode;

     int32_t runCount, visualStart, logicalLimit, logicalFirst, i;

     Run iRun;

     errorCode=U_ZERO_ERROR;

     RETURN_VOID_IF_BAD_RANGE(logicalPosition, 0, pBiDi->length, errorCode);

     /* ubidi_countRuns will check VALID_PARA_OR_LINE */

     runCount=ubidi_countRuns((UBiDi *)pBiDi, &errorCode);

     if(U_FAILURE(errorCode)) {

         return;

     }

     /* this is done based on runs rather than on levels since levels have

        a special interpretation when UBIDI_REORDER_RUNS_ONLY

      */

     visualStart=logicalLimit=0;

     iRun=pBiDi->runs[0];

     for(i=0; i<runCount; i++) {

         iRun = pBiDi->runs[i];

         logicalFirst=GET_INDEX(iRun.logicalStart);

         logicalLimit=logicalFirst+iRun.visualLimit-visualStart;

         if((logicalPosition>=logicalFirst) &&

            (logicalPosition<logicalLimit)) {

             break;

         }

         visualStart = iRun.visualLimit;

     }

     if(pLogicalLimit) {

         *pLogicalLimit=logicalLimit;

     }

     if(pLevel) {

         if(pBiDi->reorderingMode==UBIDI_REORDER_RUNS_ONLY) {

             *pLevel=(UBiDiLevel)GET_ODD_BIT(iRun.logicalStart);

         }

         else if(pBiDi->direction!=UBIDI_MIXED || logicalPosition>=pBiDi->trailingWSStart) {

             *pLevel=GET_PARALEVEL(pBiDi, logicalPosition);

         } else {

         *pLevel=pBiDi->levels[logicalPosition];

         }

     }

 }

 /* runs API functions ------------------------------------------------------- */

 U_CAPI int32_t U_EXPORT2

 ubidi_countRuns(UBiDi *pBiDi, UErrorCode *pErrorCode) {

     RETURN_IF_NULL_OR_FAILING_ERRCODE(pErrorCode, -1);

     RETURN_IF_NOT_VALID_PARA_OR_LINE(pBiDi, *pErrorCode, -1);

     ubidi_getRuns(pBiDi, pErrorCode);

     if(U_FAILURE(*pErrorCode)) {

         return -1;

     }

     return pBiDi->runCount;

 }

 U_CAPI UBiDiDirection U_EXPORT2

 ubidi_getVisualRun(UBiDi *pBiDi, int32_t runIndex,

                    int32_t *pLogicalStart, int32_t *pLength)

 {

     int32_t start;

     UErrorCode errorCode = U_ZERO_ERROR;

     RETURN_IF_NOT_VALID_PARA_OR_LINE(pBiDi, errorCode, UBIDI_LTR);

     ubidi_getRuns(pBiDi, &errorCode);

     if(U_FAILURE(errorCode)) {

         return UBIDI_LTR;

     }

     RETURN_IF_BAD_RANGE(runIndex, 0, pBiDi->runCount, errorCode, UBIDI_LTR);

     start=pBiDi->runs[runIndex].logicalStart;

     if(pLogicalStart!=NULL) {

         *pLogicalStart=GET_INDEX(start);

     }

     if(pLength!=NULL) {

         if(runIndex>0) {

             *pLength=pBiDi->runs[runIndex].visualLimit-

                      pBiDi->runs[runIndex-1].visualLimit;

         } else {

             *pLength=pBiDi->runs[0].visualLimit;

         }

     }

     return (UBiDiDirection)GET_ODD_BIT(start);

 }

 /* in trivial cases there is only one trivial run; called by ubidi_getRuns() */

 static void

 getSingleRun(UBiDi *pBiDi, UBiDiLevel level) {

     /* simple, single-run case */

     pBiDi->runs=pBiDi->simpleRuns;

     pBiDi->runCount=1;

     /* fill and reorder the single run */

     pBiDi->runs[0].logicalStart=MAKE_INDEX_ODD_PAIR(0, level);

     pBiDi->runs[0].visualLimit=pBiDi->length;

     pBiDi->runs[0].insertRemove=0;

 }

 /* 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.

  */

 static void

 reorderLine(UBiDi *pBiDi, UBiDiLevel minLevel, UBiDiLevel maxLevel) {

     Run *runs, tempRun;

     UBiDiLevel *levels;

     int32_t firstRun, endRun, limitRun, runCount;

     /* nothing to do? */

     if(maxLevel<=(minLevel|1)) {

         return;

     }

     /*

      * 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=pBiDi->runs;

     levels=pBiDi->levels;

     runCount=pBiDi->runCount;

     /* do not include the WS run at paraLevel<=old minLevel except in the simple loop */

     if(pBiDi->trailingWSStart<pBiDi->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].logicalStart]<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].logicalStart]>=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)) {

         firstRun=0;

         /* include the trailing WS run in this complete reordering */

         if(pBiDi->trailingWSStart==pBiDi->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 int32_t getRunFromLogicalIndex(UBiDi *pBiDi, int32_t logicalIndex, UErrorCode *pErrorCode) {

     Run *runs=pBiDi->runs;

     int32_t runCount=pBiDi->runCount, visualStart=0, i, length, logicalStart;

     for(i=0; i<runCount; i++) {

         length=runs[i].visualLimit-visualStart;

         logicalStart=GET_INDEX(runs[i].logicalStart);

         if((logicalIndex>=logicalStart) && (logicalIndex<(logicalStart+length))) {

             return i;

         }

         visualStart+=length;

     }

     /* we should never get here */

     U_ASSERT(FALSE);

     *pErrorCode = U_INVALID_STATE_ERROR;

     return 0;

 }

 /*

  * Compute the runs array from the levels array.

  * After ubidi_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 UBIDI_OPTION_INSERT_MARKS is set, insertRemove will contain the

  * sum of appropriate LRM/RLM_BEFORE/AFTER flags.

  * If option UBIDI_OPTION_REMOVE_CONTROLS is set, insertRemove will contain the

  * negative number of BiDi control characters within this run.

  */

 U_CFUNC UBool

 ubidi_getRuns(UBiDi *pBiDi, UErrorCode *pErrorCode) {

     /*

      * This method returns immediately if the runs are already set. This

      * includes the case of length==0 (handled in setPara)..

      */

     if (pBiDi->runCount>=0) {

         return TRUE;

     }

     if(pBiDi->direction!=UBIDI_MIXED) {

         /* simple, single-run case - this covers length==0 */

         /* pBiDi->paraLevel is ok even for contextual multiple paragraphs */

         getSingleRun(pBiDi, pBiDi->paraLevel);

     } else /* UBIDI_MIXED, length>0 */ {

         /* mixed directionality */

         int32_t length=pBiDi->length, limit;

         UBiDiLevel *levels=pBiDi->levels;

         int32_t i, runCount;

         UBiDiLevel level=UBIDI_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 UBiDi 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=pBiDi->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(pBiDi, levels[0]);

         } else /* runCount>1 || limit<length */ {

             /* allocate and set the runs */

             Run *runs;

             int32_t runIndex, start;

             UBiDiLevel minLevel=UBIDI_MAX_EXPLICIT_LEVEL+1, maxLevel=0;

             /* now, count a (non-mergeable) WS run */

             if(limit<length) {

                 ++runCount;

             }

             /* runCount>1 */

             if(getRunsMemory(pBiDi, runCount)) {

                 runs=pBiDi->runsMemory;

             } else {

                 return FALSE;

             }

             /* 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].logicalStart=start;

                 runs[runIndex].visualLimit=i-start;

                 runs[runIndex].insertRemove=0;

                 ++runIndex;

             } while(i<limit);

             if(limit<length) {

                 /* there is a separate WS run */

                 runs[runIndex].logicalStart=limit;

                 runs[runIndex].visualLimit=length-limit;

                 /* For the trailing WS run, pBiDi->paraLevel is ok even

                    if contextual multiple paragraphs.                   */

                 if(pBiDi->paraLevel<minLevel) {

                     minLevel=pBiDi->paraLevel;

                 }

             }

             /* set the object fields */

             pBiDi->runs=runs;

             pBiDi->runCount=runCount;

             reorderLine(pBiDi, 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) {

                 ADD_ODD_BIT_FROM_LEVEL(runs[i].logicalStart, levels[runs[i].logicalStart]);

                 limit+=runs[i].visualLimit;

                 runs[i].visualLimit=limit;

             }

             /* Set the "odd" bit for the trailing WS run. */

             /* For a RTL paragraph, it will be the *first* run in visual order. */

             /* For the trailing WS run, pBiDi->paraLevel is ok even if

                contextual multiple paragraphs.                          */

             if(runIndex<runCount) {

                 int32_t trailingRun = ((pBiDi->paraLevel & 1) != 0)? 0 : runIndex;

                 ADD_ODD_BIT_FROM_LEVEL(runs[trailingRun].logicalStart, pBiDi->paraLevel);

             }

         }

     }

     /* handle insert LRM/RLM BEFORE/AFTER run */

     if(pBiDi->insertPoints.size>0) {

         Point *point, *start=pBiDi->insertPoints.points,

                       *limit=start+pBiDi->insertPoints.size;

         int32_t runIndex;

         for(point=start; point<limit; point++) {

             runIndex=getRunFromLogicalIndex(pBiDi, point->pos, pErrorCode);

             pBiDi->runs[runIndex].insertRemove|=point->flag;

         }

     }

     /* handle remove BiDi control characters */

     if(pBiDi->controlCount>0) {

         int32_t runIndex;

         const UChar *start=pBiDi->text, *limit=start+pBiDi->length, *pu;

         for(pu=start; pu<limit; pu++) {

             if(IS_BIDI_CONTROL_CHAR(*pu)) {

                 runIndex=getRunFromLogicalIndex(pBiDi, (int32_t)(pu-start), pErrorCode);

                 pBiDi->runs[runIndex].insertRemove--;

             }

         }

     }

     return TRUE;

 }

 static UBool

 prepareReorder(const UBiDiLevel *levels, int32_t length,

                int32_t *indexMap,

                UBiDiLevel *pMinLevel, UBiDiLevel *pMaxLevel) {

     int32_t start;

     UBiDiLevel level, minLevel, maxLevel;

     if(levels==NULL || length<=0) {

         return FALSE;

     }

     /* determine minLevel and maxLevel */

     minLevel=UBIDI_MAX_EXPLICIT_LEVEL+1;

     maxLevel=0;

     for(start=length; start>0;) {

         level=levels[--start];

         if(level>UBIDI_MAX_EXPLICIT_LEVEL+1) {

             return FALSE;

         }

         if(level<minLevel) {

             minLevel=level;

         }

         if(level>maxLevel) {

             maxLevel=level;

         }

     }

     *pMinLevel=minLevel;

     *pMaxLevel=maxLevel;

     /* initialize the index map */

     for(start=length; start>0;) {

         --start;

         indexMap[start]=start;

     }

     return TRUE;

 }

 /* reorder a line based on a levels array (L2) ------------------------------ */

 U_CAPI void U_EXPORT2

 ubidi_reorderLogical(const UBiDiLevel *levels, int32_t length, int32_t *indexMap) {

     int32_t start, limit, sumOfSosEos;

     UBiDiLevel minLevel = 0, maxLevel = 0;

     if(indexMap==NULL || !prepareReorder(levels, length, indexMap, &minLevel, &maxLevel)) {

         return;

     }

     /* nothing to do? */

     if(minLevel==maxLevel && (minLevel&1)==0) {

         return;

     }

     /* 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<length && levels[start]<maxLevel) {

                 ++start;

             }

             if(start>=length) {

                 break;  /* no more such sequences */

             }

             /* look for the limit of such a sequence (the index behind it) */

             for(limit=start; ++limit<length && levels[limit]>=maxLevel;) {}

             /*

              * sos=start of sequence, eos=end of sequence

              *

              * The closed (inclusive) interval from sos to eos includes all the logical

              * and visual indexes within this sequence. They are logically and

              * visually contiguous and in the same range.

              *

              * For each run, the new visual index=sos+eos-old visual index;

              * we pre-add sos+eos into sumOfSosEos ->

              * new visual index=sumOfSosEos-old visual index;

              */

             sumOfSosEos=start+limit-1;

             /* reorder each index in the sequence */

             do {

                 indexMap[start]=sumOfSosEos-indexMap[start];

             } while(++start<limit);

             /* start==limit */

             if(limit==length) {

                 break;  /* no more such sequences */

             } else {

                 start=limit+1;

             }

         }

     } while(--maxLevel>=minLevel);

 }

 U_CAPI void U_EXPORT2

 ubidi_reorderVisual(const UBiDiLevel *levels, int32_t length, int32_t *indexMap) {

     int32_t start, end, limit, temp;

     UBiDiLevel minLevel = 0, maxLevel = 0;

     if(indexMap==NULL || !prepareReorder(levels, length, indexMap, &minLevel, &maxLevel)) {

         return;

     }

     /* nothing to do? */

     if(minLevel==maxLevel && (minLevel&1)==0) {

         return;

     }

     /* 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<length && levels[start]<maxLevel) {

                 ++start;

             }

             if(start>=length) {

                 break;  /* no more such runs */

             }

             /* look for the limit of such a sequence (the index behind it) */

             for(limit=start; ++limit<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==length) {

                 break;  /* no more such sequences */

             } else {

                 start=limit+1;

             }

         }

     } while(--maxLevel>=minLevel);

 }

 /* API functions for logical<->visual mapping ------------------------------- */

 U_CAPI int32_t U_EXPORT2

 ubidi_getVisualIndex(UBiDi *pBiDi, int32_t logicalIndex, UErrorCode *pErrorCode) {

     int32_t visualIndex=UBIDI_MAP_NOWHERE;

     RETURN_IF_NULL_OR_FAILING_ERRCODE(pErrorCode, -1);

     RETURN_IF_NOT_VALID_PARA_OR_LINE(pBiDi, *pErrorCode, -1);

     RETURN_IF_BAD_RANGE(logicalIndex, 0, pBiDi->length, *pErrorCode, -1);

     /* we can do the trivial cases without the runs array */

     switch(pBiDi->direction) {

     case UBIDI_LTR:

         visualIndex=logicalIndex;

         break;

     case UBIDI_RTL:

         visualIndex=pBiDi->length-logicalIndex-1;

         break;

     default:

         if(!ubidi_getRuns(pBiDi, pErrorCode)) {

             *pErrorCode=U_MEMORY_ALLOCATION_ERROR;

             return -1;

         } else {

             Run *runs=pBiDi->runs;

             int32_t i, visualStart=0, offset, length;

             /* linear search for the run, search on the visual runs */

             for(i=0; i<pBiDi->runCount; ++i) {

                 length=runs[i].visualLimit-visualStart;

                 offset=logicalIndex-GET_INDEX(runs[i].logicalStart);

                 if(offset>=0 && offset<length) {

                     if(IS_EVEN_RUN(runs[i].logicalStart)) {

                         /* LTR */

                         visualIndex=visualStart+offset;

                     } else {

                         /* RTL */

                         visualIndex=visualStart+length-offset-1;

                     }

                     break;          /* exit for loop */

                 }

                 visualStart+=length;

             }

             if(i>=pBiDi->runCount) {

                 return UBIDI_MAP_NOWHERE;

             }

         }

     }

     if(pBiDi->insertPoints.size>0) {

         /* add the number of added marks until the calculated visual index */

         Run *runs=pBiDi->runs;

         int32_t i, length, insertRemove;

         int32_t visualStart=0, markFound=0;

         for(i=0; ; i++, visualStart+=length) {

             length=runs[i].visualLimit-visualStart;

             insertRemove=runs[i].insertRemove;

             if(insertRemove & (LRM_BEFORE|RLM_BEFORE)) {

                 markFound++;

             }

             /* is it the run containing the visual index? */

             if(visualIndex<runs[i].visualLimit) {

                 return visualIndex+markFound;

             }

             if(insertRemove & (LRM_AFTER|RLM_AFTER)) {

                 markFound++;

             }

         }

     }

     else if(pBiDi->controlCount>0) {

         /* subtract the number of controls until the calculated visual index */

         Run *runs=pBiDi->runs;

         int32_t i, j, start, limit, length, insertRemove;

         int32_t visualStart=0, controlFound=0;

         UChar uchar=pBiDi->text[logicalIndex];

         /* is the logical index pointing to a control ? */

         if(IS_BIDI_CONTROL_CHAR(uchar)) {

             return UBIDI_MAP_NOWHERE;

         }

         /* loop on runs */

         for(i=0; ; i++, visualStart+=length) {

             length=runs[i].visualLimit-visualStart;

             insertRemove=runs[i].insertRemove;

             /* calculated visual index is beyond this run? */

             if(visualIndex>=runs[i].visualLimit) {

                 controlFound-=insertRemove;

                 continue;

             }

             /* calculated visual index must be within current run */

             if(insertRemove==0) {

                 return visualIndex-controlFound;

             }

             if(IS_EVEN_RUN(runs[i].logicalStart)) {

                 /* LTR: check from run start to logical index */

                 start=runs[i].logicalStart;

                 limit=logicalIndex;

             } else {

                 /* RTL: check from logical index to run end */

                 start=logicalIndex+1;

                 limit=GET_INDEX(runs[i].logicalStart)+length;

             }

             for(j=start; j<limit; j++) {

                 uchar=pBiDi->text[j];

                 if(IS_BIDI_CONTROL_CHAR(uchar)) {

                     controlFound++;

                 }

             }

             return visualIndex-controlFound;

         }

     }

     return visualIndex;

 }

 U_CAPI int32_t U_EXPORT2

 ubidi_getLogicalIndex(UBiDi *pBiDi, int32_t visualIndex, UErrorCode *pErrorCode) {

     Run *runs;

     int32_t i, runCount, start;

     RETURN_IF_NULL_OR_FAILING_ERRCODE(pErrorCode, -1);

     RETURN_IF_NOT_VALID_PARA_OR_LINE(pBiDi, *pErrorCode, -1);

     RETURN_IF_BAD_RANGE(visualIndex, 0, pBiDi->resultLength, *pErrorCode, -1);

     /* we can do the trivial cases without the runs array */

     if(pBiDi->insertPoints.size==0 && pBiDi->controlCount==0) {

         if(pBiDi->direction==UBIDI_LTR) {

             return visualIndex;

         }

         else if(pBiDi->direction==UBIDI_RTL) {

             return pBiDi->length-visualIndex-1;

         }

     }

     if(!ubidi_getRuns(pBiDi, pErrorCode)) {

         *pErrorCode=U_MEMORY_ALLOCATION_ERROR;

         return -1;

     }

     runs=pBiDi->runs;

     runCount=pBiDi->runCount;

     if(pBiDi->insertPoints.size>0) {

         /* handle inserted LRM/RLM */

         int32_t markFound=0, insertRemove;

         int32_t visualStart=0, length;

         runs=pBiDi->runs;

         /* subtract number of marks until visual index */

         for(i=0; ; i++, visualStart+=length) {

             length=runs[i].visualLimit-visualStart;

             insertRemove=runs[i].insertRemove;

             if(insertRemove&(LRM_BEFORE|RLM_BEFORE)) {

                 if(visualIndex<=(visualStart+markFound)) {

                     return UBIDI_MAP_NOWHERE;

                 }

                 markFound++;

             }

             /* is adjusted visual index within this run? */

             if(visualIndex<(runs[i].visualLimit+markFound)) {

                 visualIndex-=markFound;

                 break;

             }

             if(insertRemove&(LRM_AFTER|RLM_AFTER)) {

                 if(visualIndex==(visualStart+length+markFound)) {

                     return UBIDI_MAP_NOWHERE;

                 }

                 markFound++;

             }

         }

     }

     else if(pBiDi->controlCount>0) {

         /* handle removed BiDi control characters */

         int32_t controlFound=0, insertRemove, length;

         int32_t logicalStart, logicalEnd, visualStart=0, j, k;

         UChar uchar;

         UBool evenRun;

         /* add number of controls until visual index */

         for(i=0; ; i++, visualStart+=length) {

             length=runs[i].visualLimit-visualStart;

             insertRemove=runs[i].insertRemove;

             /* is adjusted visual index beyond current run? */

             if(visualIndex>=(runs[i].visualLimit-controlFound+insertRemove)) {

                 controlFound-=insertRemove;

                 continue;

             }

             /* adjusted visual index is within current run */

             if(insertRemove==0) {

                 visualIndex+=controlFound;

                 break;

             }

             /* count non-control chars until visualIndex */

             logicalStart=runs[i].logicalStart;

             evenRun=IS_EVEN_RUN(logicalStart);

             REMOVE_ODD_BIT(logicalStart);

             logicalEnd=logicalStart+length-1;

             for(j=0; j<length; j++) {

                 k= evenRun ? logicalStart+j : logicalEnd-j;

                 uchar=pBiDi->text[k];

                 if(IS_BIDI_CONTROL_CHAR(uchar)) {

                     controlFound++;

                 }

                 if((visualIndex+controlFound)==(visualStart+j)) {

                     break;

                 }

             }

             visualIndex+=controlFound;

             break;

         }

     }

     /* handle all cases */

     if(runCount<=10) {

         /* linear search for the run */

         for(i=0; visualIndex>=runs[i].visualLimit; ++i) {}

     } else {

         /* binary search for the run */

         int32_t begin=0, limit=runCount;

         /* the middle if() is guaranteed to find the run, we don't need a loop limit */

         for(;;) {

             i=(begin+limit)/2;

             if(visualIndex>=runs[i].visualLimit) {

                 begin=i+1;

             } else if(i==0 || visualIndex>=runs[i-1].visualLimit) {

                 break;

             } else {

                 limit=i;

             }

         }

     }

     start=runs[i].logicalStart;

     if(IS_EVEN_RUN(start)) {

         /* LTR */

         /* the offset in runs[i] is visualIndex-runs[i-1].visualLimit */

         if(i>0) {

             visualIndex-=runs[i-1].visualLimit;

         }

         return start+visualIndex;

     } else {

         /* RTL */

         return GET_INDEX(start)+runs[i].visualLimit-visualIndex-1;

     }

 }

 U_CAPI void U_EXPORT2

 ubidi_getLogicalMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode) {

     RETURN_VOID_IF_NULL_OR_FAILING_ERRCODE(pErrorCode);

     /* ubidi_countRuns() checks for VALID_PARA_OR_LINE */

     ubidi_countRuns(pBiDi, pErrorCode);

     if(U_FAILURE(*pErrorCode)) {

         /* no op */

     } else if(indexMap==NULL) {

         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;

     } else {

         /* fill a logical-to-visual index map using the runs[] */

         int32_t visualStart, visualLimit, i, j, k;

         int32_t logicalStart, logicalLimit;

         Run *runs=pBiDi->runs;

         if (pBiDi->length<=0) {

             return;

         }

         if (pBiDi->length>pBiDi->resultLength) {

             uprv_memset(indexMap, 0xFF, pBiDi->length*sizeof(int32_t));

         }

         visualStart=0;

         for(j=0; j<pBiDi->runCount; ++j) {

             logicalStart=GET_INDEX(runs[j].logicalStart);

             visualLimit=runs[j].visualLimit;

             if(IS_EVEN_RUN(runs[j].logicalStart)) {

                 do { /* LTR */

                     indexMap[logicalStart++]=visualStart++;

                 } while(visualStart<visualLimit);

             } else {

                 logicalStart+=visualLimit-visualStart;  /* logicalLimit */

                 do { /* RTL */

                     indexMap[--logicalStart]=visualStart++;

                 } while(visualStart<visualLimit);

             }

             /* visualStart==visualLimit; */

         }

         if(pBiDi->insertPoints.size>0) {

             int32_t markFound=0, runCount=pBiDi->runCount;

             int32_t length, insertRemove;

             visualStart=0;

             /* add number of marks found until each index */

             for(i=0; i<runCount; i++, visualStart+=length) {

                 length=runs[i].visualLimit-visualStart;

                 insertRemove=runs[i].insertRemove;

                 if(insertRemove&(LRM_BEFORE|RLM_BEFORE)) {

                     markFound++;

                 }

                 if(markFound>0) {

                     logicalStart=GET_INDEX(runs[i].logicalStart);

                     logicalLimit=logicalStart+length;

                     for(j=logicalStart; j<logicalLimit; j++) {

                         indexMap[j]+=markFound;

                     }

                 }

                 if(insertRemove&(LRM_AFTER|RLM_AFTER)) {

                     markFound++;

                 }

             }

         }

         else if(pBiDi->controlCount>0) {

             int32_t controlFound=0, runCount=pBiDi->runCount;

             int32_t length, insertRemove;

             UBool evenRun;

             UChar uchar;

             visualStart=0;

             /* subtract number of controls found until each index */

             for(i=0; i<runCount; i++, visualStart+=length) {

                 length=runs[i].visualLimit-visualStart;

                 insertRemove=runs[i].insertRemove;

                 /* no control found within previous runs nor within this run */

                 if((controlFound-insertRemove)==0) {

                     continue;

                 }

                 logicalStart=runs[i].logicalStart;

                 evenRun=IS_EVEN_RUN(logicalStart);

                 REMOVE_ODD_BIT(logicalStart);

                 logicalLimit=logicalStart+length;

                 /* if no control within this run */

                 if(insertRemove==0) {

                     for(j=logicalStart; j<logicalLimit; j++) {

                         indexMap[j]-=controlFound;

                     }

                     continue;

                 }

                 for(j=0; j<length; j++) {

                     k= evenRun ? logicalStart+j : logicalLimit-j-1;

                     uchar=pBiDi->text[k];

                     if(IS_BIDI_CONTROL_CHAR(uchar)) {

                         controlFound++;

                         indexMap[k]=UBIDI_MAP_NOWHERE;

                         continue;

                     }

                     indexMap[k]-=controlFound;

                 }

             }

         }

     }

 }

 U_CAPI void U_EXPORT2

 ubidi_getVisualMap(UBiDi *pBiDi, int32_t *indexMap, UErrorCode *pErrorCode) {

     RETURN_VOID_IF_NULL_OR_FAILING_ERRCODE(pErrorCode);

     if(indexMap==NULL) {

         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;

         return;

     }

     /* ubidi_countRuns() checks for VALID_PARA_OR_LINE */

     ubidi_countRuns(pBiDi, pErrorCode);

     if(U_SUCCESS(*pErrorCode)) {

         /* fill a visual-to-logical index map using the runs[] */

         Run *runs=pBiDi->runs, *runsLimit=runs+pBiDi->runCount;

         int32_t logicalStart, visualStart, visualLimit, *pi=indexMap;

         if (pBiDi->resultLength<=0) {

             return;

         }

         visualStart=0;

         for(; runs<runsLimit; ++runs) {

             logicalStart=runs->logicalStart;

             visualLimit=runs->visualLimit;

             if(IS_EVEN_RUN(logicalStart)) {

                 do { /* LTR */

                     *pi++ = logicalStart++;

                 } while(++visualStart<visualLimit);

             } else {

                 REMOVE_ODD_BIT(logicalStart);

                 logicalStart+=visualLimit-visualStart;  /* logicalLimit */

                 do { /* RTL */

                     *pi++ = --logicalStart;

                 } while(++visualStart<visualLimit);

             }

             /* visualStart==visualLimit; */

         }

         if(pBiDi->insertPoints.size>0) {

             int32_t markFound=0, runCount=pBiDi->runCount;

             int32_t insertRemove, i, j, k;

             runs=pBiDi->runs;

             /* count all inserted marks */

             for(i=0; i<runCount; i++) {

                 insertRemove=runs[i].insertRemove;

                 if(insertRemove&(LRM_BEFORE|RLM_BEFORE)) {

                     markFound++;

                 }

                 if(insertRemove&(LRM_AFTER|RLM_AFTER)) {

                     markFound++;

                 }

             }

             /* move back indexes by number of preceding marks */

             k=pBiDi->resultLength;

             for(i=runCount-1; i>=0 && markFound>0; i--) {

                 insertRemove=runs[i].insertRemove;

                 if(insertRemove&(LRM_AFTER|RLM_AFTER)) {

                     indexMap[--k]= UBIDI_MAP_NOWHERE;

                     markFound--;

                 }

                 visualStart= i>0 ? runs[i-1].visualLimit : 0;

                 for(j=runs[i].visualLimit-1; j>=visualStart && markFound>0; j--) {

                     indexMap[--k]=indexMap[j];

                 }

                 if(insertRemove&(LRM_BEFORE|RLM_BEFORE)) {

                     indexMap[--k]= UBIDI_MAP_NOWHERE;

                     markFound--;

                 }

             }

         }

         else if(pBiDi->controlCount>0) {

             int32_t runCount=pBiDi->runCount, logicalEnd;

             int32_t insertRemove, length, i, j, k, m;

             UChar uchar;

             UBool evenRun;

             runs=pBiDi->runs;

             visualStart=0;

             /* move forward indexes by number of preceding controls */

             k=0;

             for(i=0; i<runCount; i++, visualStart+=length) {

                 length=runs[i].visualLimit-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].visualLimit;

                     for(j=visualStart; j<visualLimit; j++) {

                         indexMap[k++]=indexMap[j];

                     }

                     continue;

                 }

                 logicalStart=runs[i].logicalStart;

                 evenRun=IS_EVEN_RUN(logicalStart);

                 REMOVE_ODD_BIT(logicalStart);

                 logicalEnd=logicalStart+length-1;

                 for(j=0; j<length; j++) {

                     m= evenRun ? logicalStart+j : logicalEnd-j;

                     uchar=pBiDi->text[m];

                     if(!IS_BIDI_CONTROL_CHAR(uchar)) {

                         indexMap[k++]=m;

                     }

                 }

             }

         }

     }

 }

 U_CAPI void U_EXPORT2

 ubidi_invertMap(const int32_t *srcMap, int32_t *destMap, int32_t length) {

     if(srcMap!=NULL && destMap!=NULL && length>0) {

         const int32_t *pi;

         int32_t destLength=-1, count=0;

         /* find highest value and count positive indexes in srcMap */

         pi=srcMap+length;

         while(pi>srcMap) {

             if(*--pi>destLength) {

                 destLength=*pi;

             }

             if(*pi>=0) {

                 count++;

             }

         }

         destLength++;           /* add 1 for origin 0 */

         if(count<destLength) {

             /* we must fill unmatched destMap entries with -1 */

             uprv_memset(destMap, 0xFF, destLength*sizeof(int32_t));

         }

         pi=srcMap+length;

         while(length>0) {

             if(*--pi>=0) {

                 destMap[*pi]=--length;

             } else {

                 --length;

             }

         }

     }

 }