Check in the pristine copy of ICU 4.6...

icu46/source/common/ubidi.c

+/*
+******************************************************************************
+*
+*   Copyright (C) 1999-2010, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+******************************************************************************
+*   file name:  ubidi.c
+*   encoding:   US-ASCII
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 1999jul27
+*   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 "ubidi_props.h"
+#include "ubidiimp.h"
+#include "uassert.h"
+
+/*
+ * General implementation notes:
+ *
+ * Throughout the implementation, there are comments like (W2) that refer to
+ * rules of the BiDi algorithm in its version 5, in this example to the second
+ * rule of the resolution of weak types.
+ *
+ * For handling surrogate pairs, where two UChar's form one "abstract" (or UTF-32)
+ * character according to UTF-16, the second UChar gets the directional property of
+ * the entire character assigned, while the first one gets a BN, a boundary
+ * neutral, type, which is ignored by most of the algorithm according to
+ * rule (X9) and the implementation suggestions of the BiDi algorithm.
+ *
+ * Later, adjustWSLevels() will set the level for each BN to that of the
+ * following character (UChar), which results in surrogate pairs getting the
+ * same level on each of their surrogates.
+ *
+ * In a UTF-8 implementation, the same thing could be done: the last byte of
+ * a multi-byte sequence would get the "real" property, while all previous
+ * bytes of that sequence would get BN.
+ *
+ * It is not possible to assign all those parts of a character the same real
+ * property because this would fail in the resolution of weak types with rules
+ * that look at immediately surrounding types.
+ *
+ * As a related topic, this implementation does not remove Boundary Neutral
+ * types from the input, but ignores them wherever this is relevant.
+ * For example, the loop for the resolution of the weak types reads
+ * types until it finds a non-BN.
+ * Also, explicit embedding codes are neither changed into BN nor removed.
+ * They are only treated the same way real BNs are.
+ * As stated before, adjustWSLevels() takes care of them at the end.
+ * For the purpose of conformance, the levels of all these codes
+ * do not matter.
+ *
+ * Note that this implementation never modifies the dirProps
+ * after the initial setup.
+ *
+ *
+ * In this implementation, the resolution of weak types (Wn),
+ * neutrals (Nn), and the assignment of the resolved level (In)
+ * are all done in one single loop, in resolveImplicitLevels().
+ * Changes of dirProp values are done on the fly, without writing
+ * them back to the dirProps array.
+ *
+ *
+ * This implementation contains code that allows to bypass steps of the
+ * algorithm that are not needed on the specific paragraph
+ * in order to speed up the most common cases considerably,
+ * like text that is entirely LTR, or RTL text without numbers.
+ *
+ * Most of this is done by setting a bit for each directional property
+ * in a flags variable and later checking for whether there are
+ * any LTR characters or any RTL characters, or both, whether
+ * there are any explicit embedding codes, etc.
+ *
+ * If the (Xn) steps are performed, then the flags are re-evaluated,
+ * because they will then not contain the embedding codes any more
+ * and will be adjusted for override codes, so that subsequently
+ * more bypassing may be possible than what the initial flags suggested.
+ *
+ * If the text is not mixed-directional, then the
+ * algorithm steps for the weak type resolution are not performed,
+ * and all levels are set to the paragraph level.
+ *
+ * If there are no explicit embedding codes, then the (Xn) steps
+ * are not performed.
+ *
+ * If embedding levels are supplied as a parameter, then all
+ * explicit embedding codes are ignored, and the (Xn) steps
+ * are not performed.
+ *
+ * White Space types could get the level of the run they belong to,
+ * and are checked with a test of (flags&MASK_EMBEDDING) to
+ * consider if the paragraph direction should be considered in
+ * the flags variable.
+ *
+ * If there are no White Space types in the paragraph, then
+ * (L1) is not necessary in adjustWSLevels().
+ */
+
+/* to avoid some conditional statements, use tiny constant arrays */
+static const Flags flagLR[2]={ DIRPROP_FLAG(L), DIRPROP_FLAG(R) };
+static const Flags flagE[2]={ DIRPROP_FLAG(LRE), DIRPROP_FLAG(RLE) };
+static const Flags flagO[2]={ DIRPROP_FLAG(LRO), DIRPROP_FLAG(RLO) };
+
+#define DIRPROP_FLAG_LR(level) flagLR[(level)&1]
+#define DIRPROP_FLAG_E(level) flagE[(level)&1]
+#define DIRPROP_FLAG_O(level) flagO[(level)&1]
+
+/* UBiDi object management -------------------------------------------------- */
+
+U_CAPI UBiDi * U_EXPORT2
+ubidi_open(void)
+{
+    UErrorCode errorCode=U_ZERO_ERROR;
+    return ubidi_openSized(0, 0, &errorCode);
+}
+
+U_CAPI UBiDi * U_EXPORT2
+ubidi_openSized(int32_t maxLength, int32_t maxRunCount, UErrorCode *pErrorCode) {
+    UBiDi *pBiDi;
+
+    /* check the argument values */
+    if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) {
+        return NULL;
+    } else if(maxLength<0 || maxRunCount<0) {
+        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
+        return NULL;    /* invalid arguments */
+    }
+
+    /* allocate memory for the object */
+    pBiDi=(UBiDi *)uprv_malloc(sizeof(UBiDi));
+    if(pBiDi==NULL) {
+        *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
+        return NULL;
+    }
+
+    /* reset the object, all pointers NULL, all flags FALSE, all sizes 0 */
+    uprv_memset(pBiDi, 0, sizeof(UBiDi));
+
+    /* get BiDi properties */
+    pBiDi->bdp=ubidi_getSingleton();
+
+    /* allocate memory for arrays as requested */
+    if(maxLength>0) {
+        if( !getInitialDirPropsMemory(pBiDi, maxLength) ||
+            !getInitialLevelsMemory(pBiDi, maxLength)
+        ) {
+            *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
+        }
+    } else {
+        pBiDi->mayAllocateText=TRUE;
+    }
+
+    if(maxRunCount>0) {
+        if(maxRunCount==1) {
+            /* use simpleRuns[] */
+            pBiDi->runsSize=sizeof(Run);
+        } else if(!getInitialRunsMemory(pBiDi, maxRunCount)) {
+            *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
+        }
+    } else {
+        pBiDi->mayAllocateRuns=TRUE;
+    }
+
+    if(U_SUCCESS(*pErrorCode)) {
+        return pBiDi;
+    } else {
+        ubidi_close(pBiDi);
+        return NULL;
+    }
+}
+
+/*
+ * We are allowed to allocate memory if memory==NULL or
+ * mayAllocate==TRUE for each array that we need.
+ * We also try to grow memory as needed if we
+ * allocate it.
+ *
+ * Assume sizeNeeded>0.
+ * If *pMemory!=NULL, then assume *pSize>0.
+ *
+ * ### this realloc() may unnecessarily copy the old data,
+ * which we know we don't need any more;
+ * is this the best way to do this??
+ */
+U_CFUNC UBool
+ubidi_getMemory(BidiMemoryForAllocation *bidiMem, int32_t *pSize, UBool mayAllocate, int32_t sizeNeeded) {
+    void **pMemory = (void **)bidiMem;
+    /* check for existing memory */
+    if(*pMemory==NULL) {
+        /* we need to allocate memory */
+        if(mayAllocate && (*pMemory=uprv_malloc(sizeNeeded))!=NULL) {
+            *pSize=sizeNeeded;
+            return TRUE;
+        } else {
+            return FALSE;
+        }
+    } else {
+        if(sizeNeeded<=*pSize) {
+            /* there is already enough memory */
+            return TRUE;
+        }
+        else if(!mayAllocate) {
+            /* not enough memory, and we must not allocate */
+            return FALSE;
+        } else {
+            /* we try to grow */
+            void *memory;
+            /* in most cases, we do not need the copy-old-data part of
+             * realloc, but it is needed when adding runs using getRunsMemory()
+             * in setParaRunsOnly()
+             */
+            if((memory=uprv_realloc(*pMemory, sizeNeeded))!=NULL) {
+                *pMemory=memory;
+                *pSize=sizeNeeded;
+                return TRUE;
+            } else {
+                /* we failed to grow */
+                return FALSE;
+            }
+        }
+    }
+}
+
+U_CAPI void U_EXPORT2
+ubidi_close(UBiDi *pBiDi) {
+    if(pBiDi!=NULL) {
+        pBiDi->pParaBiDi=NULL;          /* in case one tries to reuse this block */
+        if(pBiDi->dirPropsMemory!=NULL) {
+            uprv_free(pBiDi->dirPropsMemory);
+        }
+        if(pBiDi->levelsMemory!=NULL) {
+            uprv_free(pBiDi->levelsMemory);
+        }
+        if(pBiDi->runsMemory!=NULL) {
+            uprv_free(pBiDi->runsMemory);
+        }
+        if(pBiDi->parasMemory!=NULL) {
+            uprv_free(pBiDi->parasMemory);
+        }
+        if(pBiDi->insertPoints.points!=NULL) {
+            uprv_free(pBiDi->insertPoints.points);
+        }
+
+        uprv_free(pBiDi);
+    }
+}
+
+/* set to approximate "inverse BiDi" ---------------------------------------- */
+
+U_CAPI void U_EXPORT2
+ubidi_setInverse(UBiDi *pBiDi, UBool isInverse) {
+    if(pBiDi!=NULL) {
+        pBiDi->isInverse=isInverse;
+        pBiDi->reorderingMode = isInverse ? UBIDI_REORDER_INVERSE_NUMBERS_AS_L
+                                          : UBIDI_REORDER_DEFAULT;
+    }
+}
+
+U_CAPI UBool U_EXPORT2
+ubidi_isInverse(UBiDi *pBiDi) {
+    if(pBiDi!=NULL) {
+        return pBiDi->isInverse;
+    } else {
+        return FALSE;
+    }
+}
+
+/* FOOD FOR THOUGHT: currently the reordering modes are a mixture of
+ * algorithm for direct BiDi, algorithm for inverse BiDi and the bizarre
+ * concept of RUNS_ONLY which is a double operation.
+ * It could be advantageous to divide this into 3 concepts:
+ * a) Operation: direct / inverse / RUNS_ONLY
+ * b) Direct algorithm: default / NUMBERS_SPECIAL / GROUP_NUMBERS_WITH_R
+ * c) Inverse algorithm: default / INVERSE_LIKE_DIRECT / NUMBERS_SPECIAL
+ * This would allow combinations not possible today like RUNS_ONLY with
+ * NUMBERS_SPECIAL.
+ * Also allow to set INSERT_MARKS for the direct step of RUNS_ONLY and
+ * REMOVE_CONTROLS for the inverse step.
+ * Not all combinations would be supported, and probably not all do make sense.
+ * This would need to document which ones are supported and what are the
+ * fallbacks for unsupported combinations.
+ */
+U_CAPI void U_EXPORT2
+ubidi_setReorderingMode(UBiDi *pBiDi, UBiDiReorderingMode reorderingMode) {
+    if ((pBiDi!=NULL) && (reorderingMode >= UBIDI_REORDER_DEFAULT)
+                        && (reorderingMode < UBIDI_REORDER_COUNT)) {
+        pBiDi->reorderingMode = reorderingMode;
+        pBiDi->isInverse = (UBool)(reorderingMode == UBIDI_REORDER_INVERSE_NUMBERS_AS_L);
+    }
+}
+
+U_CAPI UBiDiReorderingMode U_EXPORT2
+ubidi_getReorderingMode(UBiDi *pBiDi) {
+    if (pBiDi!=NULL) {
+        return pBiDi->reorderingMode;
+    } else {
+        return UBIDI_REORDER_DEFAULT;
+    }
+}
+
+U_CAPI void U_EXPORT2
+ubidi_setReorderingOptions(UBiDi *pBiDi, uint32_t reorderingOptions) {
+    if (reorderingOptions & UBIDI_OPTION_REMOVE_CONTROLS) {
+        reorderingOptions&=~UBIDI_OPTION_INSERT_MARKS;
+    }
+    if (pBiDi!=NULL) {
+        pBiDi->reorderingOptions=reorderingOptions;
+    }
+}
+
+U_CAPI uint32_t U_EXPORT2
+ubidi_getReorderingOptions(UBiDi *pBiDi) {
+    if (pBiDi!=NULL) {
+        return pBiDi->reorderingOptions;
+    } else {
+        return 0;
+    }
+}
+
+U_CAPI UBiDiDirection U_EXPORT2
+ubidi_getBaseDirection(const UChar *text,
+int32_t length){
+
+    int32_t i;
+    UChar32 uchar;
+    UCharDirection dir;
+    
+    if( text==NULL || length<-1 ){
+        return UBIDI_NEUTRAL;
+    }
+
+    if(length==-1) {
+        length=u_strlen(text);
+    }
+
+    for( i = 0 ; i < length; ) {
+        /* i is incremented by U16_NEXT */
+        U16_NEXT(text, i, length, uchar);
+        dir = u_charDirection(uchar);
+        if( dir == U_LEFT_TO_RIGHT )
+                return UBIDI_LTR;
+        if( dir == U_RIGHT_TO_LEFT || dir ==U_RIGHT_TO_LEFT_ARABIC )
+                return UBIDI_RTL;
+    }
+    return UBIDI_NEUTRAL;
+}
+
+/* perform (P2)..(P3) ------------------------------------------------------- */
+
+/*
+ * Get the directional properties for the text,
+ * calculate the flags bit-set, and
+ * determine the paragraph level if necessary.
+ */
+static void
+getDirProps(UBiDi *pBiDi) {
+    const UChar *text=pBiDi->text;
+    DirProp *dirProps=pBiDi->dirPropsMemory;    /* pBiDi->dirProps is const */
+
+    int32_t i=0, i1, length=pBiDi->originalLength;
+    Flags flags=0;      /* collect all directionalities in the text */
+    UChar32 uchar;
+    DirProp dirProp=0, paraDirDefault=0;/* initialize to avoid compiler warnings */
+    UBool isDefaultLevel=IS_DEFAULT_LEVEL(pBiDi->paraLevel);
+    /* for inverse BiDi, the default para level is set to RTL if there is a
+       strong R or AL character at either end of the text                           */
+    UBool isDefaultLevelInverse=isDefaultLevel && (UBool)
+            (pBiDi->reorderingMode==UBIDI_REORDER_INVERSE_LIKE_DIRECT ||
+             pBiDi->reorderingMode==UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL);
+    int32_t lastArabicPos=-1;
+    int32_t controlCount=0;
+    UBool removeBiDiControls = (UBool)(pBiDi->reorderingOptions &
+                                       UBIDI_OPTION_REMOVE_CONTROLS);
+
+    typedef enum {
+         NOT_CONTEXTUAL,                /* 0: not contextual paraLevel */
+         LOOKING_FOR_STRONG,            /* 1: looking for first strong char */
+         FOUND_STRONG_CHAR              /* 2: found first strong char       */
+    } State;
+    State state;
+    int32_t paraStart=0;                /* index of first char in paragraph */
+    DirProp paraDir;                    /* == CONTEXT_RTL within paragraphs
+                                           starting with strong R char      */
+    DirProp lastStrongDir=0;            /* for default level & inverse BiDi */
+    int32_t lastStrongLTR=0;            /* for STREAMING option             */
+
+    if(pBiDi->reorderingOptions & UBIDI_OPTION_STREAMING) {
+        pBiDi->length=0;
+        lastStrongLTR=0;
+    }
+    if(isDefaultLevel) {
+        paraDirDefault=pBiDi->paraLevel&1 ? CONTEXT_RTL : 0;
+        paraDir=paraDirDefault;
+        lastStrongDir=paraDirDefault;
+        state=LOOKING_FOR_STRONG;
+    } else {
+        state=NOT_CONTEXTUAL;
+        paraDir=0;
+    }
+    /* count paragraphs and determine the paragraph level (P2..P3) */
+    /*
+     * see comment in ubidi.h:
+     * the DEFAULT_XXX values are designed so that
+     * their bit 0 alone yields the intended default
+     */
+    for( /* i=0 above */ ; i<length; ) {
+        /* i is incremented by U16_NEXT */
+        U16_NEXT(text, i, length, uchar);
+        flags|=DIRPROP_FLAG(dirProp=(DirProp)ubidi_getCustomizedClass(pBiDi, uchar));
+        dirProps[i-1]=dirProp|paraDir;
+        if(uchar>0xffff) {  /* set the lead surrogate's property to BN */
+            flags|=DIRPROP_FLAG(BN);
+            dirProps[i-2]=(DirProp)(BN|paraDir);
+        }
+        if(state==LOOKING_FOR_STRONG) {
+            if(dirProp==L) {
+                state=FOUND_STRONG_CHAR;
+                if(paraDir) {
+                    paraDir=0;
+                    for(i1=paraStart; i1<i; i1++) {
+                        dirProps[i1]&=~CONTEXT_RTL;
+                    }
+                }
+                continue;
+            }
+            if(dirProp==R || dirProp==AL) {
+                state=FOUND_STRONG_CHAR;
+                if(paraDir==0) {
+                    paraDir=CONTEXT_RTL;
+                    for(i1=paraStart; i1<i; i1++) {
+                        dirProps[i1]|=CONTEXT_RTL;
+                    }
+                }
+                continue;
+            }
+        }
+        if(dirProp==L) {
+            lastStrongDir=0;
+            lastStrongLTR=i;            /* i is index to next character */
+        }
+        else if(dirProp==R) {
+            lastStrongDir=CONTEXT_RTL;
+        }
+        else if(dirProp==AL) {
+            lastStrongDir=CONTEXT_RTL;
+            lastArabicPos=i-1;
+        }
+        else if(dirProp==B) {
+            if(pBiDi->reorderingOptions & UBIDI_OPTION_STREAMING) {
+                pBiDi->length=i;        /* i is index to next character */
+            }
+            if(isDefaultLevelInverse && (lastStrongDir==CONTEXT_RTL) &&(paraDir!=lastStrongDir)) {
+                for( ; paraStart<i; paraStart++) {
+                    dirProps[paraStart]|=CONTEXT_RTL;
+                }
+            }
+            if(i<length) {              /* B not last char in text */
+                if(!((uchar==CR) && (text[i]==LF))) {
+                    pBiDi->paraCount++;
+                }
+                if(isDefaultLevel) {
+                    state=LOOKING_FOR_STRONG;
+                    paraStart=i;        /* i is index to next character */
+                    paraDir=paraDirDefault;
+                    lastStrongDir=paraDirDefault;
+                }
+            }
+        }
+        if(removeBiDiControls && IS_BIDI_CONTROL_CHAR(uchar)) {
+            controlCount++;
+        }
+    }
+    if(isDefaultLevelInverse && (lastStrongDir==CONTEXT_RTL) &&(paraDir!=lastStrongDir)) {
+        for(i1=paraStart; i1<length; i1++) {
+            dirProps[i1]|=CONTEXT_RTL;
+        }
+    }
+    if(isDefaultLevel) {
+        pBiDi->paraLevel=GET_PARALEVEL(pBiDi, 0);
+    }
+    if(pBiDi->reorderingOptions & UBIDI_OPTION_STREAMING) {
+        if((lastStrongLTR>pBiDi->length) &&
+           (GET_PARALEVEL(pBiDi, lastStrongLTR)==0)) {
+            pBiDi->length = lastStrongLTR;
+        }
+        if(pBiDi->length<pBiDi->originalLength) {
+            pBiDi->paraCount--;
+        }
+    }
+    /* The following line does nothing new for contextual paraLevel, but is
+       needed for absolute paraLevel.                               */
+    flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel);
+
+    if(pBiDi->orderParagraphsLTR && (flags&DIRPROP_FLAG(B))) {
+        flags|=DIRPROP_FLAG(L);
+    }
+
+    pBiDi->controlCount = controlCount;
+    pBiDi->flags=flags;
+    pBiDi->lastArabicPos=lastArabicPos;
+}
+
+/* perform (X1)..(X9) ------------------------------------------------------- */
+
+/* determine if the text is mixed-directional or single-directional */
+static UBiDiDirection
+directionFromFlags(UBiDi *pBiDi) {
+    Flags flags=pBiDi->flags;
+    /* if the text contains AN and neutrals, then some neutrals may become RTL */
+    if(!(flags&MASK_RTL || ((flags&DIRPROP_FLAG(AN)) && (flags&MASK_POSSIBLE_N)))) {
+        return UBIDI_LTR;
+    } else if(!(flags&MASK_LTR)) {
+        return UBIDI_RTL;
+    } else {
+        return UBIDI_MIXED;
+    }
+}
+
+/*
+ * Resolve the explicit levels as specified by explicit embedding codes.
+ * Recalculate the flags to have them reflect the real properties
+ * after taking the explicit embeddings into account.
+ *
+ * The BiDi algorithm is designed to result in the same behavior whether embedding
+ * levels are externally specified (from "styled text", supposedly the preferred
+ * method) or set by explicit embedding codes (LRx, RLx, PDF) in the plain text.
+ * That is why (X9) instructs to remove all explicit codes (and BN).
+ * However, in a real implementation, this removal of these codes and their index
+ * positions in the plain text is undesirable since it would result in
+ * reallocated, reindexed text.
+ * Instead, this implementation leaves the codes in there and just ignores them
+ * in the subsequent processing.
+ * In order to get the same reordering behavior, positions with a BN or an
+ * explicit embedding code just get the same level assigned as the last "real"
+ * character.
+ *
+ * Some implementations, not this one, then overwrite some of these
+ * directionality properties at "real" same-level-run boundaries by
+ * L or R codes so that the resolution of weak types can be performed on the
+ * entire paragraph at once instead of having to parse it once more and
+ * perform that resolution on same-level-runs.
+ * This limits the scope of the implicit rules in effectively
+ * the same way as the run limits.
+ *
+ * Instead, this implementation does not modify these codes.
+ * On one hand, the paragraph has to be scanned for same-level-runs, but
+ * on the other hand, this saves another loop to reset these codes,
+ * or saves making and modifying a copy of dirProps[].
+ *
+ *
+ * Note that (Pn) and (Xn) changed significantly from version 4 of the BiDi algorithm.
+ *
+ *
+ * Handling the stack of explicit levels (Xn):
+ *
+ * With the BiDi stack of explicit levels,
+ * as pushed with each LRE, RLE, LRO, and RLO and popped with each PDF,
+ * the explicit level must never exceed UBIDI_MAX_EXPLICIT_LEVEL==61.
+ *
+ * In order to have a correct push-pop semantics even in the case of overflows,
+ * there are two overflow counters:
+ * - countOver60 is incremented with each LRx at level 60
+ * - from level 60, one RLx increases the level to 61
+ * - countOver61 is incremented with each LRx and RLx at level 61
+ *
+ * Popping levels with PDF must work in the opposite order so that level 61
+ * is correct at the correct point. Underflows (too many PDFs) must be checked.
+ *
+ * This implementation assumes that UBIDI_MAX_EXPLICIT_LEVEL is odd.
+ */
+static UBiDiDirection
+resolveExplicitLevels(UBiDi *pBiDi) {
+    const DirProp *dirProps=pBiDi->dirProps;
+    UBiDiLevel *levels=pBiDi->levels;
+    const UChar *text=pBiDi->text;
+
+    int32_t i=0, length=pBiDi->length;
+    Flags flags=pBiDi->flags;       /* collect all directionalities in the text */
+    DirProp dirProp;
+    UBiDiLevel level=GET_PARALEVEL(pBiDi, 0);
+
+    UBiDiDirection direction;
+    int32_t paraIndex=0;
+
+    /* determine if the text is mixed-directional or single-directional */
+    direction=directionFromFlags(pBiDi);
+
+    /* we may not need to resolve any explicit levels, but for multiple
+       paragraphs we want to loop on all chars to set the para boundaries */
+    if((direction!=UBIDI_MIXED) && (pBiDi->paraCount==1)) {
+        /* not mixed directionality: levels don't matter - trailingWSStart will be 0 */
+    } else if((pBiDi->paraCount==1) &&
+              (!(flags&MASK_EXPLICIT) ||
+               (pBiDi->reorderingMode > UBIDI_REORDER_LAST_LOGICAL_TO_VISUAL))) {
+        /* mixed, but all characters are at the same embedding level */
+        /* or we are in "inverse BiDi" */
+        /* and we don't have contextual multiple paragraphs with some B char */
+        /* set all levels to the paragraph level */
+        for(i=0; i<length; ++i) {
+            levels[i]=level;
+        }
+    } else {
+        /* continue to perform (Xn) */
+
+        /* (X1) level is set for all codes, embeddingLevel keeps track of the push/pop operations */
+        /* both variables may carry the UBIDI_LEVEL_OVERRIDE flag to indicate the override status */
+        UBiDiLevel embeddingLevel=level, newLevel, stackTop=0;
+
+        UBiDiLevel stack[UBIDI_MAX_EXPLICIT_LEVEL];        /* we never push anything >=UBIDI_MAX_EXPLICIT_LEVEL */
+        uint32_t countOver60=0, countOver61=0;  /* count overflows of explicit levels */
+
+        /* recalculate the flags */
+        flags=0;
+
+        for(i=0; i<length; ++i) {
+            dirProp=NO_CONTEXT_RTL(dirProps[i]);
+            switch(dirProp) {
+            case LRE:
+            case LRO:
+                /* (X3, X5) */
+                newLevel=(UBiDiLevel)((embeddingLevel+2)&~(UBIDI_LEVEL_OVERRIDE|1)); /* least greater even level */
+                if(newLevel<=UBIDI_MAX_EXPLICIT_LEVEL) {
+                    stack[stackTop]=embeddingLevel;
+                    ++stackTop;
+                    embeddingLevel=newLevel;
+                    if(dirProp==LRO) {
+                        embeddingLevel|=UBIDI_LEVEL_OVERRIDE;
+                    }
+                    /* we don't need to set UBIDI_LEVEL_OVERRIDE off for LRE
+                       since this has already been done for newLevel which is
+                       the source for embeddingLevel.
+                     */
+                } else if((embeddingLevel&~UBIDI_LEVEL_OVERRIDE)==UBIDI_MAX_EXPLICIT_LEVEL) {
+                    ++countOver61;
+                } else /* (embeddingLevel&~UBIDI_LEVEL_OVERRIDE)==UBIDI_MAX_EXPLICIT_LEVEL-1 */ {
+                    ++countOver60;
+                }
+                flags|=DIRPROP_FLAG(BN);
+                break;
+            case RLE:
+            case RLO:
+                /* (X2, X4) */
+                newLevel=(UBiDiLevel)(((embeddingLevel&~UBIDI_LEVEL_OVERRIDE)+1)|1); /* least greater odd level */
+                if(newLevel<=UBIDI_MAX_EXPLICIT_LEVEL) {
+                    stack[stackTop]=embeddingLevel;
+                    ++stackTop;
+                    embeddingLevel=newLevel;
+                    if(dirProp==RLO) {
+                        embeddingLevel|=UBIDI_LEVEL_OVERRIDE;
+                    }
+                    /* we don't need to set UBIDI_LEVEL_OVERRIDE off for RLE
+                       since this has already been done for newLevel which is
+                       the source for embeddingLevel.
+                     */
+                } else {
+                    ++countOver61;
+                }
+                flags|=DIRPROP_FLAG(BN);
+                break;
+            case PDF:
+                /* (X7) */
+                /* handle all the overflow cases first */
+                if(countOver61>0) {
+                    --countOver61;
+                } else if(countOver60>0 && (embeddingLevel&~UBIDI_LEVEL_OVERRIDE)!=UBIDI_MAX_EXPLICIT_LEVEL) {
+                    /* handle LRx overflows from level 60 */
+                    --countOver60;
+                } else if(stackTop>0) {
+                    /* this is the pop operation; it also pops level 61 while countOver60>0 */
+                    --stackTop;
+                    embeddingLevel=stack[stackTop];
+                /* } else { (underflow) */
+                }
+                flags|=DIRPROP_FLAG(BN);
+                break;
+            case B:
+                stackTop=0;
+                countOver60=countOver61=0;
+                level=GET_PARALEVEL(pBiDi, i);
+                if((i+1)<length) {
+                    embeddingLevel=GET_PARALEVEL(pBiDi, i+1);
+                    if(!((text[i]==CR) && (text[i+1]==LF))) {
+                        pBiDi->paras[paraIndex++]=i+1;
+                    }
+                }
+                flags|=DIRPROP_FLAG(B);
+                break;
+            case BN:
+                /* BN, LRE, RLE, and PDF are supposed to be removed (X9) */
+                /* they will get their levels set correctly in adjustWSLevels() */
+                flags|=DIRPROP_FLAG(BN);
+                break;
+            default:
+                /* all other types get the "real" level */
+                if(level!=embeddingLevel) {
+                    level=embeddingLevel;
+                    if(level&UBIDI_LEVEL_OVERRIDE) {
+                        flags|=DIRPROP_FLAG_O(level)|DIRPROP_FLAG_MULTI_RUNS;
+                    } else {
+                        flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG_MULTI_RUNS;
+                    }
+                }
+                if(!(level&UBIDI_LEVEL_OVERRIDE)) {
+                    flags|=DIRPROP_FLAG(dirProp);
+                }
+                break;
+            }
+
+            /*
+             * We need to set reasonable levels even on BN codes and
+             * explicit codes because we will later look at same-level runs (X10).
+             */
+            levels[i]=level;
+        }
+        if(flags&MASK_EMBEDDING) {
+            flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel);
+        }
+        if(pBiDi->orderParagraphsLTR && (flags&DIRPROP_FLAG(B))) {
+            flags|=DIRPROP_FLAG(L);
+        }
+
+        /* subsequently, ignore the explicit codes and BN (X9) */
+
+        /* again, determine if the text is mixed-directional or single-directional */
+        pBiDi->flags=flags;
+        direction=directionFromFlags(pBiDi);
+    }
+
+    return direction;
+}
+
+/*
+ * Use a pre-specified embedding levels array:
+ *
+ * Adjust the directional properties for overrides (->LEVEL_OVERRIDE),
+ * ignore all explicit codes (X9),
+ * and check all the preset levels.
+ *
+ * Recalculate the flags to have them reflect the real properties
+ * after taking the explicit embeddings into account.
+ */
+static UBiDiDirection
+checkExplicitLevels(UBiDi *pBiDi, UErrorCode *pErrorCode) {
+    const DirProp *dirProps=pBiDi->dirProps;
+    DirProp dirProp;
+    UBiDiLevel *levels=pBiDi->levels;
+    const UChar *text=pBiDi->text;
+
+    int32_t i, length=pBiDi->length;
+    Flags flags=0;  /* collect all directionalities in the text */
+    UBiDiLevel level;
+    uint32_t paraIndex=0;
+
+    for(i=0; i<length; ++i) {
+        level=levels[i];
+        dirProp=NO_CONTEXT_RTL(dirProps[i]);
+        if(level&UBIDI_LEVEL_OVERRIDE) {
+            /* keep the override flag in levels[i] but adjust the flags */
+            level&=~UBIDI_LEVEL_OVERRIDE;     /* make the range check below simpler */
+            flags|=DIRPROP_FLAG_O(level);
+        } else {
+            /* set the flags */
+            flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG(dirProp);
+        }
+        if((level<GET_PARALEVEL(pBiDi, i) &&
+            !((0==level)&&(dirProp==B))) ||
+           (UBIDI_MAX_EXPLICIT_LEVEL<level)) {
+            /* level out of bounds */
+            *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
+            return UBIDI_LTR;
+        }
+        if((dirProp==B) && ((i+1)<length)) {
+            if(!((text[i]==CR) && (text[i+1]==LF))) {
+                pBiDi->paras[paraIndex++]=i+1;
+            }
+        }
+    }
+    if(flags&MASK_EMBEDDING) {
+        flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel);
+    }
+
+    /* determine if the text is mixed-directional or single-directional */
+    pBiDi->flags=flags;
+    return directionFromFlags(pBiDi);
+}
+
+/******************************************************************
+ The Properties state machine table
+*******************************************************************
+
+ All table cells are 8 bits:
+      bits 0..4:  next state
+      bits 5..7:  action to perform (if > 0)
+
+ Cells may be of format "n" where n represents the next state
+ (except for the rightmost column).
+ Cells may also be of format "s(x,y)" where x represents an action
+ to perform and y represents the next state.
+
+*******************************************************************
+ Definitions and type for properties state table
+*******************************************************************
+*/
+#define IMPTABPROPS_COLUMNS 14
+#define IMPTABPROPS_RES (IMPTABPROPS_COLUMNS - 1)
+#define GET_STATEPROPS(cell) ((cell)&0x1f)
+#define GET_ACTIONPROPS(cell) ((cell)>>5)
+#define s(action, newState) ((uint8_t)(newState+(action<<5)))
+
+static const uint8_t groupProp[] =          /* dirProp regrouped */
+{
+/*  L   R   EN  ES  ET  AN  CS  B   S   WS  ON  LRE LRO AL  RLE RLO PDF NSM BN  */
+    0,  1,  2,  7,  8,  3,  9,  6,  5,  4,  4,  10, 10, 12, 10, 10, 10, 11, 10
+};
+enum { DirProp_L=0, DirProp_R=1, DirProp_EN=2, DirProp_AN=3, DirProp_ON=4, DirProp_S=5, DirProp_B=6 }; /* reduced dirProp */
+
+/******************************************************************
+
+      PROPERTIES  STATE  TABLE
+
+ In table impTabProps,
+      - the ON column regroups ON and WS
+      - the BN column regroups BN, LRE, RLE, LRO, RLO, PDF
+      - the Res column is the reduced property assigned to a run
+
+ Action 1: process current run1, init new run1
+        2: init new run2
+        3: process run1, process run2, init new run1
+        4: process run1, set run1=run2, init new run2
+
+ Notes:
+  1) This table is used in resolveImplicitLevels().
+  2) This table triggers actions when there is a change in the Bidi
+     property of incoming characters (action 1).
+  3) Most such property sequences are processed immediately (in
+     fact, passed to processPropertySeq().
+  4) However, numbers are assembled as one sequence. This means
+     that undefined situations (like CS following digits, until
+     it is known if the next char will be a digit) are held until
+     following chars define them.
+     Example: digits followed by CS, then comes another CS or ON;
+              the digits will be processed, then the CS assigned
+              as the start of an ON sequence (action 3).
+  5) There are cases where more than one sequence must be
+     processed, for instance digits followed by CS followed by L:
+     the digits must be processed as one sequence, and the CS
+     must be processed as an ON sequence, all this before starting
+     assembling chars for the opening L sequence.
+
+
+*/
+static const uint8_t impTabProps[][IMPTABPROPS_COLUMNS] =
+{
+/*                        L ,     R ,    EN ,    AN ,    ON ,     S ,     B ,    ES ,    ET ,    CS ,    BN ,   NSM ,    AL ,  Res */
+/* 0 Init        */ {     1 ,     2 ,     4 ,     5 ,     7 ,    15 ,    17 ,     7 ,     9 ,     7 ,     0 ,     7 ,     3 ,  DirProp_ON },
+/* 1 L           */ {     1 , s(1,2), s(1,4), s(1,5), s(1,7),s(1,15),s(1,17), s(1,7), s(1,9), s(1,7),     1 ,     1 , s(1,3),   DirProp_L },
+/* 2 R           */ { s(1,1),     2 , s(1,4), s(1,5), s(1,7),s(1,15),s(1,17), s(1,7), s(1,9), s(1,7),     2 ,     2 , s(1,3),   DirProp_R },
+/* 3 AL          */ { s(1,1), s(1,2), s(1,6), s(1,6), s(1,8),s(1,16),s(1,17), s(1,8), s(1,8), s(1,8),     3 ,     3 ,     3 ,   DirProp_R },
+/* 4 EN          */ { s(1,1), s(1,2),     4 , s(1,5), s(1,7),s(1,15),s(1,17),s(2,10),    11 ,s(2,10),     4 ,     4 , s(1,3),  DirProp_EN },
+/* 5 AN          */ { s(1,1), s(1,2), s(1,4),     5 , s(1,7),s(1,15),s(1,17), s(1,7), s(1,9),s(2,12),     5 ,     5 , s(1,3),  DirProp_AN },
+/* 6 AL:EN/AN    */ { s(1,1), s(1,2),     6 ,     6 , s(1,8),s(1,16),s(1,17), s(1,8), s(1,8),s(2,13),     6 ,     6 , s(1,3),  DirProp_AN },
+/* 7 ON          */ { s(1,1), s(1,2), s(1,4), s(1,5),     7 ,s(1,15),s(1,17),     7 ,s(2,14),     7 ,     7 ,     7 , s(1,3),  DirProp_ON },
+/* 8 AL:ON       */ { s(1,1), s(1,2), s(1,6), s(1,6),     8 ,s(1,16),s(1,17),     8 ,     8 ,     8 ,     8 ,     8 , s(1,3),  DirProp_ON },
+/* 9 ET          */ { s(1,1), s(1,2),     4 , s(1,5),     7 ,s(1,15),s(1,17),     7 ,     9 ,     7 ,     9 ,     9 , s(1,3),  DirProp_ON },
+/*10 EN+ES/CS    */ { s(3,1), s(3,2),     4 , s(3,5), s(4,7),s(3,15),s(3,17), s(4,7),s(4,14), s(4,7),    10 , s(4,7), s(3,3),  DirProp_EN },
+/*11 EN+ET       */ { s(1,1), s(1,2),     4 , s(1,5), s(1,7),s(1,15),s(1,17), s(1,7),    11 , s(1,7),    11 ,    11 , s(1,3),  DirProp_EN },
+/*12 AN+CS       */ { s(3,1), s(3,2), s(3,4),     5 , s(4,7),s(3,15),s(3,17), s(4,7),s(4,14), s(4,7),    12 , s(4,7), s(3,3),  DirProp_AN },
+/*13 AL:EN/AN+CS */ { s(3,1), s(3,2),     6 ,     6 , s(4,8),s(3,16),s(3,17), s(4,8), s(4,8), s(4,8),    13 , s(4,8), s(3,3),  DirProp_AN },
+/*14 ON+ET       */ { s(1,1), s(1,2), s(4,4), s(1,5),     7 ,s(1,15),s(1,17),     7 ,    14 ,     7 ,    14 ,    14 , s(1,3),  DirProp_ON },
+/*15 S           */ { s(1,1), s(1,2), s(1,4), s(1,5), s(1,7),    15 ,s(1,17), s(1,7), s(1,9), s(1,7),    15 , s(1,7), s(1,3),   DirProp_S },
+/*16 AL:S        */ { s(1,1), s(1,2), s(1,6), s(1,6), s(1,8),    16 ,s(1,17), s(1,8), s(1,8), s(1,8),    16 , s(1,8), s(1,3),   DirProp_S },
+/*17 B           */ { s(1,1), s(1,2), s(1,4), s(1,5), s(1,7),s(1,15),    17 , s(1,7), s(1,9), s(1,7),    17 , s(1,7), s(1,3),   DirProp_B }
+};
+
+/*  we must undef macro s because the levels table have a different
+ *  structure (4 bits for action and 4 bits for next state.
+ */
+#undef s
+
+/******************************************************************
+ The levels state machine tables
+*******************************************************************
+
+ All table cells are 8 bits:
+      bits 0..3:  next state
+      bits 4..7:  action to perform (if > 0)
+
+ Cells may be of format "n" where n represents the next state
+ (except for the rightmost column).
+ Cells may also be of format "s(x,y)" where x represents an action
+ to perform and y represents the next state.
+
+ This format limits each table to 16 states each and to 15 actions.
+
+*******************************************************************
+ Definitions and type for levels state tables
+*******************************************************************
+*/
+#define IMPTABLEVELS_COLUMNS (DirProp_B + 2)
+#define IMPTABLEVELS_RES (IMPTABLEVELS_COLUMNS - 1)
+#define GET_STATE(cell) ((cell)&0x0f)
+#define GET_ACTION(cell) ((cell)>>4)
+#define s(action, newState) ((uint8_t)(newState+(action<<4)))
+
+typedef uint8_t ImpTab[][IMPTABLEVELS_COLUMNS];
+typedef uint8_t ImpAct[];
+
+/* FOOD FOR THOUGHT: each ImpTab should have its associated ImpAct,
+ * instead of having a pair of ImpTab and a pair of ImpAct.
+ */
+typedef struct ImpTabPair {
+    const void * pImpTab[2];
+    const void * pImpAct[2];
+} ImpTabPair;
+
+/******************************************************************
+
+      LEVELS  STATE  TABLES
+
+ In all levels state tables,
+      - state 0 is the initial state
+      - the Res column is the increment to add to the text level
+        for this property sequence.
+
+ The impAct arrays for each table of a pair map the local action
+ numbers of the table to the total list of actions. For instance,
+ action 2 in a given table corresponds to the action number which
+ appears in entry [2] of the impAct array for that table.
+ The first entry of all impAct arrays must be 0.
+
+ Action 1: init conditional sequence
+        2: prepend conditional sequence to current sequence
+        3: set ON sequence to new level - 1
+        4: init EN/AN/ON sequence
+        5: fix EN/AN/ON sequence followed by R
+        6: set previous level sequence to level 2
+
+ Notes:
+  1) These tables are used in processPropertySeq(). The input
+     is property sequences as determined by resolveImplicitLevels.
+  2) Most such property sequences are processed immediately
+     (levels are assigned).
+  3) However, some sequences cannot be assigned a final level till
+     one or more following sequences are received. For instance,
+     ON following an R sequence within an even-level paragraph.
+     If the following sequence is R, the ON sequence will be
+     assigned basic run level+1, and so will the R sequence.
+  4) S is generally handled like ON, since its level will be fixed
+     to paragraph level in adjustWSLevels().
+
+*/
+
+static const ImpTab impTabL_DEFAULT =   /* Even paragraph level */
+/*  In this table, conditional sequences receive the higher possible level
+    until proven otherwise.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     0 ,     1 ,     0 ,     2 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : R          */ {     0 ,     1 ,     3 ,     3 , s(1,4), s(1,4),     0 ,  1 },
+/* 2 : AN         */ {     0 ,     1 ,     0 ,     2 , s(1,5), s(1,5),     0 ,  2 },
+/* 3 : R+EN/AN    */ {     0 ,     1 ,     3 ,     3 , s(1,4), s(1,4),     0 ,  2 },
+/* 4 : R+ON       */ { s(2,0),     1 ,     3 ,     3 ,     4 ,     4 , s(2,0),  1 },
+/* 5 : AN+ON      */ { s(2,0),     1 , s(2,0),     2 ,     5 ,     5 , s(2,0),  1 }
+};
+static const ImpTab impTabR_DEFAULT =   /* Odd  paragraph level */
+/*  In this table, conditional sequences receive the lower possible level
+    until proven otherwise.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     1 ,     0 ,     2 ,     2 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : L          */ {     1 ,     0 ,     1 ,     3 , s(1,4), s(1,4),     0 ,  1 },
+/* 2 : EN/AN      */ {     1 ,     0 ,     2 ,     2 ,     0 ,     0 ,     0 ,  1 },
+/* 3 : L+AN       */ {     1 ,     0 ,     1 ,     3 ,     5 ,     5 ,     0 ,  1 },
+/* 4 : L+ON       */ { s(2,1),     0 , s(2,1),     3 ,     4 ,     4 ,     0 ,  0 },
+/* 5 : L+AN+ON    */ {     1 ,     0 ,     1 ,     3 ,     5 ,     5 ,     0 ,  0 }
+};
+static const ImpAct impAct0 = {0,1,2,3,4,5,6};
+static const ImpTabPair impTab_DEFAULT = {{&impTabL_DEFAULT,
+                                           &impTabR_DEFAULT},
+                                          {&impAct0, &impAct0}};
+
+static const ImpTab impTabL_NUMBERS_SPECIAL =   /* Even paragraph level */
+/*  In this table, conditional sequences receive the higher possible level
+    until proven otherwise.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     0 ,     2 ,    1 ,      1 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : L+EN/AN    */ {     0 ,     2 ,    1 ,      1 ,     0 ,     0 ,     0 ,  2 },
+/* 2 : R          */ {     0 ,     2 ,    4 ,      4 , s(1,3),     0 ,     0 ,  1 },
+/* 3 : R+ON       */ { s(2,0),     2 ,    4 ,      4 ,     3 ,     3 , s(2,0),  1 },
+/* 4 : R+EN/AN    */ {     0 ,     2 ,    4 ,      4 , s(1,3), s(1,3),     0 ,  2 }
+  };
+static const ImpTabPair impTab_NUMBERS_SPECIAL = {{&impTabL_NUMBERS_SPECIAL,
+                                                   &impTabR_DEFAULT},
+                                                  {&impAct0, &impAct0}};
+
+static const ImpTab impTabL_GROUP_NUMBERS_WITH_R =
+/*  In this table, EN/AN+ON sequences receive levels as if associated with R
+    until proven that there is L or sor/eor on both sides. AN is handled like EN.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 init         */ {     0 ,     3 , s(1,1), s(1,1),     0 ,     0 ,     0 ,  0 },
+/* 1 EN/AN        */ { s(2,0),     3 ,     1 ,     1 ,     2 , s(2,0), s(2,0),  2 },
+/* 2 EN/AN+ON     */ { s(2,0),     3 ,     1 ,     1 ,     2 , s(2,0), s(2,0),  1 },
+/* 3 R            */ {     0 ,     3 ,     5 ,     5 , s(1,4),     0 ,     0 ,  1 },
+/* 4 R+ON         */ { s(2,0),     3 ,     5 ,     5 ,     4 , s(2,0), s(2,0),  1 },
+/* 5 R+EN/AN      */ {     0 ,     3 ,     5 ,     5 , s(1,4),     0 ,     0 ,  2 }
+};
+static const ImpTab impTabR_GROUP_NUMBERS_WITH_R =
+/*  In this table, EN/AN+ON sequences receive levels as if associated with R
+    until proven that there is L on both sides. AN is handled like EN.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 init         */ {     2 ,     0 ,     1 ,     1 ,     0 ,     0 ,     0 ,  0 },
+/* 1 EN/AN        */ {     2 ,     0 ,     1 ,     1 ,     0 ,     0 ,     0 ,  1 },
+/* 2 L            */ {     2 ,     0 , s(1,4), s(1,4), s(1,3),     0 ,     0 ,  1 },
+/* 3 L+ON         */ { s(2,2),     0 ,     4 ,     4 ,     3 ,     0 ,     0 ,  0 },
+/* 4 L+EN/AN      */ { s(2,2),     0 ,     4 ,     4 ,     3 ,     0 ,     0 ,  1 }
+};
+static const ImpTabPair impTab_GROUP_NUMBERS_WITH_R = {
+                        {&impTabL_GROUP_NUMBERS_WITH_R,
+                         &impTabR_GROUP_NUMBERS_WITH_R},
+                        {&impAct0, &impAct0}};
+
+
+static const ImpTab impTabL_INVERSE_NUMBERS_AS_L =
+/*  This table is identical to the Default LTR table except that EN and AN are
+    handled like L.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     0 ,     1 ,     0 ,     0 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : R          */ {     0 ,     1 ,     0 ,     0 , s(1,4), s(1,4),     0 ,  1 },
+/* 2 : AN         */ {     0 ,     1 ,     0 ,     0 , s(1,5), s(1,5),     0 ,  2 },
+/* 3 : R+EN/AN    */ {     0 ,     1 ,     0 ,     0 , s(1,4), s(1,4),     0 ,  2 },
+/* 4 : R+ON       */ { s(2,0),     1 , s(2,0), s(2,0),     4 ,     4 , s(2,0),  1 },
+/* 5 : AN+ON      */ { s(2,0),     1 , s(2,0), s(2,0),     5 ,     5 , s(2,0),  1 }
+};
+static const ImpTab impTabR_INVERSE_NUMBERS_AS_L =
+/*  This table is identical to the Default RTL table except that EN and AN are
+    handled like L.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     1 ,     0 ,     1 ,     1 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : L          */ {     1 ,     0 ,     1 ,     1 , s(1,4), s(1,4),     0 ,  1 },
+/* 2 : EN/AN      */ {     1 ,     0 ,     1 ,     1 ,     0 ,     0 ,     0 ,  1 },
+/* 3 : L+AN       */ {     1 ,     0 ,     1 ,     1 ,     5 ,     5 ,     0 ,  1 },
+/* 4 : L+ON       */ { s(2,1),     0 , s(2,1), s(2,1),     4 ,     4 ,     0 ,  0 },
+/* 5 : L+AN+ON    */ {     1 ,     0 ,     1 ,     1 ,     5 ,     5 ,     0 ,  0 }
+};
+static const ImpTabPair impTab_INVERSE_NUMBERS_AS_L = {
+                        {&impTabL_INVERSE_NUMBERS_AS_L,
+                         &impTabR_INVERSE_NUMBERS_AS_L},
+                        {&impAct0, &impAct0}};
+
+static const ImpTab impTabR_INVERSE_LIKE_DIRECT =   /* Odd  paragraph level */
+/*  In this table, conditional sequences receive the lower possible level
+    until proven otherwise.
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     1 ,     0 ,     2 ,     2 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : L          */ {     1 ,     0 ,     1 ,     2 , s(1,3), s(1,3),     0 ,  1 },
+/* 2 : EN/AN      */ {     1 ,     0 ,     2 ,     2 ,     0 ,     0 ,     0 ,  1 },
+/* 3 : L+ON       */ { s(2,1), s(3,0),     6 ,     4 ,     3 ,     3 , s(3,0),  0 },
+/* 4 : L+ON+AN    */ { s(2,1), s(3,0),     6 ,     4 ,     5 ,     5 , s(3,0),  3 },
+/* 5 : L+AN+ON    */ { s(2,1), s(3,0),     6 ,     4 ,     5 ,     5 , s(3,0),  2 },
+/* 6 : L+ON+EN    */ { s(2,1), s(3,0),     6 ,     4 ,     3 ,     3 , s(3,0),  1 }
+};
+static const ImpAct impAct1 = {0,1,11,12};
+/* FOOD FOR THOUGHT: in LTR table below, check case "JKL 123abc"
+ */
+static const ImpTabPair impTab_INVERSE_LIKE_DIRECT = {
+                        {&impTabL_DEFAULT,
+                         &impTabR_INVERSE_LIKE_DIRECT},
+                        {&impAct0, &impAct1}};
+
+static const ImpTab impTabL_INVERSE_LIKE_DIRECT_WITH_MARKS =
+/*  The case handled in this table is (visually):  R EN L
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     0 , s(6,3),     0 ,     1 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : L+AN       */ {     0 , s(6,3),     0 ,     1 , s(1,2), s(3,0),     0 ,  4 },
+/* 2 : L+AN+ON    */ { s(2,0), s(6,3), s(2,0),     1 ,     2 , s(3,0), s(2,0),  3 },
+/* 3 : R          */ {     0 , s(6,3), s(5,5), s(5,6), s(1,4), s(3,0),     0 ,  3 },
+/* 4 : R+ON       */ { s(3,0), s(4,3), s(5,5), s(5,6),     4 , s(3,0), s(3,0),  3 },
+/* 5 : R+EN       */ { s(3,0), s(4,3),     5 , s(5,6), s(1,4), s(3,0), s(3,0),  4 },
+/* 6 : R+AN       */ { s(3,0), s(4,3), s(5,5),     6 , s(1,4), s(3,0), s(3,0),  4 }
+};
+static const ImpTab impTabR_INVERSE_LIKE_DIRECT_WITH_MARKS =
+/*  The cases handled in this table are (visually):  R EN L
+                                                     R L AN L
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ { s(1,3),     0 ,     1 ,     1 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : R+EN/AN    */ { s(2,3),     0 ,     1 ,     1 ,     2 , s(4,0),     0 ,  1 },
+/* 2 : R+EN/AN+ON */ { s(2,3),     0 ,     1 ,     1 ,     2 , s(4,0),     0 ,  0 },
+/* 3 : L          */ {     3 ,     0 ,     3 , s(3,6), s(1,4), s(4,0),     0 ,  1 },
+/* 4 : L+ON       */ { s(5,3), s(4,0),     5 , s(3,6),     4 , s(4,0), s(4,0),  0 },
+/* 5 : L+ON+EN    */ { s(5,3), s(4,0),     5 , s(3,6),     4 , s(4,0), s(4,0),  1 },
+/* 6 : L+AN       */ { s(5,3), s(4,0),     6 ,     6 ,     4 , s(4,0), s(4,0),  3 }
+};
+static const ImpAct impAct2 = {0,1,7,8,9,10};
+static const ImpTabPair impTab_INVERSE_LIKE_DIRECT_WITH_MARKS = {
+                        {&impTabL_INVERSE_LIKE_DIRECT_WITH_MARKS,
+                         &impTabR_INVERSE_LIKE_DIRECT_WITH_MARKS},
+                        {&impAct0, &impAct2}};
+
+static const ImpTabPair impTab_INVERSE_FOR_NUMBERS_SPECIAL = {
+                        {&impTabL_NUMBERS_SPECIAL,
+                         &impTabR_INVERSE_LIKE_DIRECT},
+                        {&impAct0, &impAct1}};
+
+static const ImpTab impTabL_INVERSE_FOR_NUMBERS_SPECIAL_WITH_MARKS =
+/*  The case handled in this table is (visually):  R EN L
+*/
+{
+/*                         L ,     R ,    EN ,    AN ,    ON ,     S ,     B , Res */
+/* 0 : init       */ {     0 , s(6,2),     1 ,     1 ,     0 ,     0 ,     0 ,  0 },
+/* 1 : L+EN/AN    */ {     0 , s(6,2),     1 ,     1 ,     0 , s(3,0),     0 ,  4 },
+/* 2 : R          */ {     0 , s(6,2), s(5,4), s(5,4), s(1,3), s(3,0),     0 ,  3 },
+/* 3 : R+ON       */ { s(3,0), s(4,2), s(5,4), s(5,4),     3 , s(3,0), s(3,0),  3 },
+/* 4 : R+EN/AN    */ { s(3,0), s(4,2),     4 ,     4 , s(1,3), s(3,0), s(3,0),  4 }
+};
+static const ImpTabPair impTab_INVERSE_FOR_NUMBERS_SPECIAL_WITH_MARKS = {
+                        {&impTabL_INVERSE_FOR_NUMBERS_SPECIAL_WITH_MARKS,
+                         &impTabR_INVERSE_LIKE_DIRECT_WITH_MARKS},
+                        {&impAct0, &impAct2}};
+
+#undef s
+
+typedef struct {
+    const ImpTab * pImpTab;             /* level table pointer          */
+    const ImpAct * pImpAct;             /* action map array             */
+    int32_t startON;                    /* start of ON sequence         */
+    int32_t startL2EN;                  /* start of level 2 sequence    */
+    int32_t lastStrongRTL;              /* index of last found R or AL  */
+    int32_t state;                      /* current state                */
+    UBiDiLevel runLevel;                /* run level before implicit solving */
+} LevState;
+
+/*------------------------------------------------------------------------*/
+
+static void
+addPoint(UBiDi *pBiDi, int32_t pos, int32_t flag)
+  /* param pos:     position where to insert
+     param flag:    one of LRM_BEFORE, LRM_AFTER, RLM_BEFORE, RLM_AFTER
+  */
+{
+#define FIRSTALLOC  10
+    Point point;
+    InsertPoints * pInsertPoints=&(pBiDi->insertPoints);
+
+    if (pInsertPoints->capacity == 0)
+    {
+        pInsertPoints->points=uprv_malloc(sizeof(Point)*FIRSTALLOC);
+        if (pInsertPoints->points == NULL)
+        {
+            pInsertPoints->errorCode=U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+        pInsertPoints->capacity=FIRSTALLOC;
+    }
+    if (pInsertPoints->size >= pInsertPoints->capacity) /* no room for new point */
+    {
+        void * savePoints=pInsertPoints->points;
+        pInsertPoints->points=uprv_realloc(pInsertPoints->points,
+                                           pInsertPoints->capacity*2*sizeof(Point));
+        if (pInsertPoints->points == NULL)
+        {
+            pInsertPoints->points=savePoints;
+            pInsertPoints->errorCode=U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+        else  pInsertPoints->capacity*=2;
+    }
+    point.pos=pos;
+    point.flag=flag;
+    pInsertPoints->points[pInsertPoints->size]=point;
+    pInsertPoints->size++;
+#undef FIRSTALLOC
+}
+
+/* perform rules (Wn), (Nn), and (In) on a run of the text ------------------ */
+
+/*
+ * This implementation of the (Wn) rules applies all rules in one pass.
+ * In order to do so, it needs a look-ahead of typically 1 character
+ * (except for W5: sequences of ET) and keeps track of changes
+ * in a rule Wp that affect a later Wq (p<q).
+ *
+ * The (Nn) and (In) rules are also performed in that same single loop,
+ * but effectively one iteration behind for white space.
+ *
+ * Since all implicit rules are performed in one step, it is not necessary
+ * to actually store the intermediate directional properties in dirProps[].
+ */
+
+static void
+processPropertySeq(UBiDi *pBiDi, LevState *pLevState, uint8_t _prop,
+                   int32_t start, int32_t limit) {
+    uint8_t cell, oldStateSeq, actionSeq;
+    const ImpTab * pImpTab=pLevState->pImpTab;
+    const ImpAct * pImpAct=pLevState->pImpAct;
+    UBiDiLevel * levels=pBiDi->levels;
+    UBiDiLevel level, addLevel;
+    InsertPoints * pInsertPoints;
+    int32_t start0, k;
+
+    start0=start;                           /* save original start position */
+    oldStateSeq=(uint8_t)pLevState->state;
+    cell=(*pImpTab)[oldStateSeq][_prop];
+    pLevState->state=GET_STATE(cell);       /* isolate the new state */
+    actionSeq=(*pImpAct)[GET_ACTION(cell)]; /* isolate the action */
+    addLevel=(*pImpTab)[pLevState->state][IMPTABLEVELS_RES];
+
+    if(actionSeq) {
+        switch(actionSeq) {
+        case 1:                         /* init ON seq */
+            pLevState->startON=start0;
+            break;
+
+        case 2:                         /* prepend ON seq to current seq */
+            start=pLevState->startON;
+            break;
+
+        case 3:                         /* L or S after possible relevant EN/AN */
+            /* check if we had EN after R/AL */
+            if (pLevState->startL2EN >= 0) {
+                addPoint(pBiDi, pLevState->startL2EN, LRM_BEFORE);
+            }
+            pLevState->startL2EN=-1;  /* not within previous if since could also be -2 */
+            /* check if we had any relevant EN/AN after R/AL */
+            pInsertPoints=&(pBiDi->insertPoints);
+            if ((pInsertPoints->capacity == 0) ||
+                (pInsertPoints->size <= pInsertPoints->confirmed))
+            {
+                /* nothing, just clean up */
+                pLevState->lastStrongRTL=-1;
+                /* check if we have a pending conditional segment */
+                level=(*pImpTab)[oldStateSeq][IMPTABLEVELS_RES];
+                if ((level & 1) && (pLevState->startON > 0)) {  /* after ON */
+                    start=pLevState->startON;   /* reset to basic run level */
+                }
+                if (_prop == DirProp_S)                /* add LRM before S */
+                {
+                    addPoint(pBiDi, start0, LRM_BEFORE);
+                    pInsertPoints->confirmed=pInsertPoints->size;
+                }
+                break;
+            }
+            /* reset previous RTL cont to level for LTR text */
+            for (k=pLevState->lastStrongRTL+1; k<start0; k++)
+            {
+                /* reset odd level, leave runLevel+2 as is */
+                levels[k]=(levels[k] - 2) & ~1;
+            }
+            /* mark insert points as confirmed */
+            pInsertPoints->confirmed=pInsertPoints->size;
+            pLevState->lastStrongRTL=-1;
+            if (_prop == DirProp_S)            /* add LRM before S */
+            {
+                addPoint(pBiDi, start0, LRM_BEFORE);
+                pInsertPoints->confirmed=pInsertPoints->size;
+            }
+            break;
+
+        case 4:                         /* R/AL after possible relevant EN/AN */
+            /* just clean up */
+            pInsertPoints=&(pBiDi->insertPoints);
+            if (pInsertPoints->capacity > 0)
+                /* remove all non confirmed insert points */
+                pInsertPoints->size=pInsertPoints->confirmed;
+            pLevState->startON=-1;
+            pLevState->startL2EN=-1;
+            pLevState->lastStrongRTL=limit - 1;
+            break;
+
+        case 5:                         /* EN/AN after R/AL + possible cont */
+            /* check for real AN */
+            if ((_prop == DirProp_AN) && (NO_CONTEXT_RTL(pBiDi->dirProps[start0]) == AN) &&
+                (pBiDi->reorderingMode!=UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL))
+            {
+                /* real AN */
+                if (pLevState->startL2EN == -1) /* if no relevant EN already found */
+                {
+                    /* just note the righmost digit as a strong RTL */
+                    pLevState->lastStrongRTL=limit - 1;
+                    break;
+                }
+                if (pLevState->startL2EN >= 0)  /* after EN, no AN */
+                {
+                    addPoint(pBiDi, pLevState->startL2EN, LRM_BEFORE);
+                    pLevState->startL2EN=-2;
+                }
+                /* note AN */
+                addPoint(pBiDi, start0, LRM_BEFORE);
+                break;
+            }
+            /* if first EN/AN after R/AL */
+            if (pLevState->startL2EN == -1) {
+                pLevState->startL2EN=start0;
+            }
+            break;
+
+        case 6:                         /* note location of latest R/AL */
+            pLevState->lastStrongRTL=limit - 1;
+            pLevState->startON=-1;
+            break;
+
+        case 7:                         /* L after R+ON/EN/AN */
+            /* include possible adjacent number on the left */
+            for (k=start0-1; k>=0 && !(levels[k]&1); k--);
+            if(k>=0) {
+                addPoint(pBiDi, k, RLM_BEFORE);             /* add RLM before */
+                pInsertPoints=&(pBiDi->insertPoints);
+                pInsertPoints->confirmed=pInsertPoints->size;   /* confirm it */
+            }
+            pLevState->startON=start0;
+            break;
+
+        case 8:                         /* AN after L */
+            /* AN numbers between L text on both sides may be trouble. */
+            /* tentatively bracket with LRMs; will be confirmed if followed by L */
+            addPoint(pBiDi, start0, LRM_BEFORE);    /* add LRM before */
+            addPoint(pBiDi, start0, LRM_AFTER);     /* add LRM after  */
+            break;
+
+        case 9:                         /* R after L+ON/EN/AN */
+            /* false alert, infirm LRMs around previous AN */
+            pInsertPoints=&(pBiDi->insertPoints);
+            pInsertPoints->size=pInsertPoints->confirmed;
+            if (_prop == DirProp_S)            /* add RLM before S */
+            {
+                addPoint(pBiDi, start0, RLM_BEFORE);
+                pInsertPoints->confirmed=pInsertPoints->size;
+            }
+            break;
+
+        case 10:                        /* L after L+ON/AN */
+            level=pLevState->runLevel + addLevel;
+            for(k=pLevState->startON; k<start0; k++) {
+                if (levels[k]<level)
+                    levels[k]=level;
+            }
+            pInsertPoints=&(pBiDi->insertPoints);
+            pInsertPoints->confirmed=pInsertPoints->size;   /* confirm inserts */
+            pLevState->startON=start0;
+            break;
+
+        case 11:                        /* L after L+ON+EN/AN/ON */
+            level=pLevState->runLevel;
+            for(k=start0-1; k>=pLevState->startON; k--) {
+                if(levels[k]==level+3) {
+                    while(levels[k]==level+3) {
+                        levels[k--]-=2;
+                    }
+                    while(levels[k]==level) {
+                        k--;
+                    }
+                }
+                if(levels[k]==level+2) {
+                    levels[k]=level;
+                    continue;
+                }
+                levels[k]=level+1;
+            }
+            break;
+
+        case 12:                        /* R after L+ON+EN/AN/ON */
+            level=pLevState->runLevel+1;
+            for(k=start0-1; k>=pLevState->startON; k--) {
+                if(levels[k]>level) {
+                    levels[k]-=2;
+                }
+            }
+            break;
+
+        default:                        /* we should never get here */
+            U_ASSERT(FALSE);
+            break;
+        }
+    }
+    if((addLevel) || (start < start0)) {
+        level=pLevState->runLevel + addLevel;
+        for(k=start; k<limit; k++) {
+            levels[k]=level;
+        }
+    }
+}
+
+static void
+resolveImplicitLevels(UBiDi *pBiDi,
+                      int32_t start, int32_t limit,
+                      DirProp sor, DirProp eor) {
+    const DirProp *dirProps=pBiDi->dirProps;
+
+    LevState levState;
+    int32_t i, start1, start2;
+    uint8_t oldStateImp, stateImp, actionImp;
+    uint8_t gprop, resProp, cell;
+    UBool inverseRTL;
+    DirProp nextStrongProp=R;
+    int32_t nextStrongPos=-1;
+
+    levState.startON = -1;  /* silence gcc flow analysis */
+
+    /* check for RTL inverse BiDi mode */
+    /* FOOD FOR THOUGHT: in case of RTL inverse BiDi, it would make sense to
+     * loop on the text characters from end to start.
+     * This would need a different properties state table (at least different
+     * actions) and different levels state tables (maybe very similar to the
+     * LTR corresponding ones.
+     */
+    inverseRTL=(UBool)
+        ((start<pBiDi->lastArabicPos) && (GET_PARALEVEL(pBiDi, start) & 1) &&
+         (pBiDi->reorderingMode==UBIDI_REORDER_INVERSE_LIKE_DIRECT  ||
+          pBiDi->reorderingMode==UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL));
+    /* initialize for levels state table */
+    levState.startL2EN=-1;              /* used for INVERSE_LIKE_DIRECT_WITH_MARKS */
+    levState.lastStrongRTL=-1;          /* used for INVERSE_LIKE_DIRECT_WITH_MARKS */
+    levState.state=0;
+    levState.runLevel=pBiDi->levels[start];
+    levState.pImpTab=(const ImpTab*)((pBiDi->pImpTabPair)->pImpTab)[levState.runLevel&1];
+    levState.pImpAct=(const ImpAct*)((pBiDi->pImpTabPair)->pImpAct)[levState.runLevel&1];
+    processPropertySeq(pBiDi, &levState, sor, start, start);
+    /* initialize for property state table */
+    if(NO_CONTEXT_RTL(dirProps[start])==NSM) {
+        stateImp = 1 + sor;
+    } else {
+        stateImp=0;
+    }
+    start1=start;
+    start2=start;
+
+    for(i=start; i<=limit; i++) {
+        if(i>=limit) {
+            gprop=eor;
+        } else {
+            DirProp prop, prop1;
+            prop=NO_CONTEXT_RTL(dirProps[i]);
+            if(inverseRTL) {
+                if(prop==AL) {
+                    /* AL before EN does not make it AN */
+                    prop=R;
+                } else if(prop==EN) {
+                    if(nextStrongPos<=i) {
+                        /* look for next strong char (L/R/AL) */
+                        int32_t j;
+                        nextStrongProp=R;   /* set default */
+                        nextStrongPos=limit;
+                        for(j=i+1; j<limit; j++) {
+                            prop1=NO_CONTEXT_RTL(dirProps[j]);
+                            if(prop1==L || prop1==R || prop1==AL) {
+                                nextStrongProp=prop1;
+                                nextStrongPos=j;
+                                break;
+                            }
+                        }
+                    }
+                    if(nextStrongProp==AL) {
+                        prop=AN;
+                    }
+                }
+            }
+            gprop=groupProp[prop];
+        }
+        oldStateImp=stateImp;
+        cell=impTabProps[oldStateImp][gprop];
+        stateImp=GET_STATEPROPS(cell);      /* isolate the new state */
+        actionImp=GET_ACTIONPROPS(cell);    /* isolate the action */
+        if((i==limit) && (actionImp==0)) {
+            /* there is an unprocessed sequence if its property == eor   */
+            actionImp=1;                    /* process the last sequence */
+        }
+        if(actionImp) {
+            resProp=impTabProps[oldStateImp][IMPTABPROPS_RES];
+            switch(actionImp) {
+            case 1:             /* process current seq1, init new seq1 */
+                processPropertySeq(pBiDi, &levState, resProp, start1, i);
+                start1=i;
+                break;
+            case 2:             /* init new seq2 */
+                start2=i;
+                break;
+            case 3:             /* process seq1, process seq2, init new seq1 */
+                processPropertySeq(pBiDi, &levState, resProp, start1, start2);
+                processPropertySeq(pBiDi, &levState, DirProp_ON, start2, i);
+                start1=i;
+                break;
+            case 4:             /* process seq1, set seq1=seq2, init new seq2 */
+                processPropertySeq(pBiDi, &levState, resProp, start1, start2);
+                start1=start2;
+                start2=i;
+                break;
+            default:            /* we should never get here */
+                U_ASSERT(FALSE);
+                break;
+            }
+        }
+    }
+    /* flush possible pending sequence, e.g. ON */
+    processPropertySeq(pBiDi, &levState, eor, limit, limit);
+}
+
+/* perform (L1) and (X9) ---------------------------------------------------- */
+
+/*
+ * Reset the embedding levels for some non-graphic characters (L1).
+ * This function also sets appropriate levels for BN, and
+ * explicit embedding types that are supposed to have been removed
+ * from the paragraph in (X9).
+ */
+static void
+adjustWSLevels(UBiDi *pBiDi) {
+    const DirProp *dirProps=pBiDi->dirProps;
+    UBiDiLevel *levels=pBiDi->levels;
+    int32_t i;
+
+    if(pBiDi->flags&MASK_WS) {
+        UBool orderParagraphsLTR=pBiDi->orderParagraphsLTR;
+        Flags flag;
+
+        i=pBiDi->trailingWSStart;
+        while(i>0) {
+            /* reset a sequence of WS/BN before eop and B/S to the paragraph paraLevel */
+            while(i>0 && (flag=DIRPROP_FLAG_NC(dirProps[--i]))&MASK_WS) {
+                if(orderParagraphsLTR&&(flag&DIRPROP_FLAG(B))) {
+                    levels[i]=0;
+                } else {
+                    levels[i]=GET_PARALEVEL(pBiDi, i);
+                }
+            }
+
+            /* reset BN to the next character's paraLevel until B/S, which restarts above loop */
+            /* here, i+1 is guaranteed to be <length */
+            while(i>0) {
+                flag=DIRPROP_FLAG_NC(dirProps[--i]);
+                if(flag&MASK_BN_EXPLICIT) {
+                    levels[i]=levels[i+1];
+                } else if(orderParagraphsLTR&&(flag&DIRPROP_FLAG(B))) {
+                    levels[i]=0;
+                    break;
+                } else if(flag&MASK_B_S) {
+                    levels[i]=GET_PARALEVEL(pBiDi, i);
+                    break;
+                }
+            }
+        }
+    }
+}
+
+#define BIDI_MIN(x, y)   ((x)<(y) ? (x) : (y))
+#define BIDI_ABS(x)      ((x)>=0  ? (x) : (-(x)))
+static void
+setParaRunsOnly(UBiDi *pBiDi, const UChar *text, int32_t length,
+                UBiDiLevel paraLevel, UErrorCode *pErrorCode) {
+    void *runsOnlyMemory;
+    int32_t *visualMap;
+    UChar *visualText;
+    int32_t saveLength, saveTrailingWSStart;
+    const UBiDiLevel *levels;
+    UBiDiLevel *saveLevels;
+    UBiDiDirection saveDirection;
+    UBool saveMayAllocateText;
+    Run *runs;
+    int32_t visualLength, i, j, visualStart, logicalStart,
+            runCount, runLength, addedRuns, insertRemove,
+            start, limit, step, indexOddBit, logicalPos,
+            index0, index1;
+    uint32_t saveOptions;
+
+    pBiDi->reorderingMode=UBIDI_REORDER_DEFAULT;
+    if(length==0) {
+        ubidi_setPara(pBiDi, text, length, paraLevel, NULL, pErrorCode);
+        goto cleanup3;
+    }
+    /* obtain memory for mapping table and visual text */
+    runsOnlyMemory=uprv_malloc(length*(sizeof(int32_t)+sizeof(UChar)+sizeof(UBiDiLevel)));
+    if(runsOnlyMemory==NULL) {
+        *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
+        goto cleanup3;
+    }
+    visualMap=runsOnlyMemory;
+    visualText=(UChar *)&visualMap[length];
+    saveLevels=(UBiDiLevel *)&visualText[length];
+    saveOptions=pBiDi->reorderingOptions;
+    if(saveOptions & UBIDI_OPTION_INSERT_MARKS) {
+        pBiDi->reorderingOptions&=~UBIDI_OPTION_INSERT_MARKS;
+        pBiDi->reorderingOptions|=UBIDI_OPTION_REMOVE_CONTROLS;
+    }
+    paraLevel&=1;                       /* accept only 0 or 1 */
+    ubidi_setPara(pBiDi, text, length, paraLevel, NULL, pErrorCode);
+    if(U_FAILURE(*pErrorCode)) {
+        goto cleanup3;
+    }
+    /* we cannot access directly pBiDi->levels since it is not yet set if
+     * direction is not MIXED
+     */
+    levels=ubidi_getLevels(pBiDi, pErrorCode);
+    uprv_memcpy(saveLevels, levels, pBiDi->length*sizeof(UBiDiLevel));
+    saveTrailingWSStart=pBiDi->trailingWSStart;
+    saveLength=pBiDi->length;
+    saveDirection=pBiDi->direction;
+
+    /* FOOD FOR THOUGHT: instead of writing the visual text, we could use
+     * the visual map and the dirProps array to drive the second call
+     * to ubidi_setPara (but must make provision for possible removal of
+     * BiDi controls.  Alternatively, only use the dirProps array via
+     * customized classifier callback.
+     */
+    visualLength=ubidi_writeReordered(pBiDi, visualText, length,
+                                      UBIDI_DO_MIRRORING, pErrorCode);
+    ubidi_getVisualMap(pBiDi, visualMap, pErrorCode);
+    if(U_FAILURE(*pErrorCode)) {
+        goto cleanup2;
+    }
+    pBiDi->reorderingOptions=saveOptions;
+
+    pBiDi->reorderingMode=UBIDI_REORDER_INVERSE_LIKE_DIRECT;
+    paraLevel^=1;
+    /* Because what we did with reorderingOptions, visualText may be shorter
+     * than the original text. But we don't want the levels memory to be
+     * reallocated shorter than the original length, since we need to restore
+     * the levels as after the first call to ubidi_setpara() before returning.
+     * We will force mayAllocateText to FALSE before the second call to
+     * ubidi_setpara(), and will restore it afterwards.
+     */
+    saveMayAllocateText=pBiDi->mayAllocateText;
+    pBiDi->mayAllocateText=FALSE;
+    ubidi_setPara(pBiDi, visualText, visualLength, paraLevel, NULL, pErrorCode);
+    pBiDi->mayAllocateText=saveMayAllocateText;
+    ubidi_getRuns(pBiDi, pErrorCode);
+    if(U_FAILURE(*pErrorCode)) {
+        goto cleanup1;
+    }
+    /* check if some runs must be split, count how many splits */
+    addedRuns=0;
+    runCount=pBiDi->runCount;
+    runs=pBiDi->runs;
+    visualStart=0;
+    for(i=0; i<runCount; i++, visualStart+=runLength) {
+        runLength=runs[i].visualLimit-visualStart;
+        if(runLength<2) {
+            continue;
+        }
+        logicalStart=GET_INDEX(runs[i].logicalStart);
+        for(j=logicalStart+1; j<logicalStart+runLength; j++) {
+            index0=visualMap[j];
+            index1=visualMap[j-1];
+            if((BIDI_ABS(index0-index1)!=1) || (saveLevels[index0]!=saveLevels[index1])) {
+                addedRuns++;
+            }
+        }
+    }
+    if(addedRuns) {
+        if(getRunsMemory(pBiDi, runCount+addedRuns)) {
+            if(runCount==1) {
+                /* because we switch from UBiDi.simpleRuns to UBiDi.runs */
+                pBiDi->runsMemory[0]=runs[0];
+            }
+            runs=pBiDi->runs=pBiDi->runsMemory;
+            pBiDi->runCount+=addedRuns;
+        } else {
+            goto cleanup1;
+        }
+    }
+    /* split runs which are not consecutive in source text */
+    for(i=runCount-1; i>=0; i--) {
+        runLength= i==0 ? runs[0].visualLimit :
+                          runs[i].visualLimit-runs[i-1].visualLimit;
+        logicalStart=runs[i].logicalStart;
+        indexOddBit=GET_ODD_BIT(logicalStart);
+        logicalStart=GET_INDEX(logicalStart);
+        if(runLength<2) {
+            if(addedRuns) {
+                runs[i+addedRuns]=runs[i];
+            }
+            logicalPos=visualMap[logicalStart];
+            runs[i+addedRuns].logicalStart=MAKE_INDEX_ODD_PAIR(logicalPos,
+                                            saveLevels[logicalPos]^indexOddBit);
+            continue;
+        }
+        if(indexOddBit) {
+            start=logicalStart;
+            limit=logicalStart+runLength-1;
+            step=1;
+        } else {
+            start=logicalStart+runLength-1;
+            limit=logicalStart;
+            step=-1;
+        }
+        for(j=start; j!=limit; j+=step) {
+            index0=visualMap[j];
+            index1=visualMap[j+step];
+            if((BIDI_ABS(index0-index1)!=1) || (saveLevels[index0]!=saveLevels[index1])) {
+                logicalPos=BIDI_MIN(visualMap[start], index0);
+                runs[i+addedRuns].logicalStart=MAKE_INDEX_ODD_PAIR(logicalPos,
+                                            saveLevels[logicalPos]^indexOddBit);
+                runs[i+addedRuns].visualLimit=runs[i].visualLimit;
+                runs[i].visualLimit-=BIDI_ABS(j-start)+1;
+                insertRemove=runs[i].insertRemove&(LRM_AFTER|RLM_AFTER);
+                runs[i+addedRuns].insertRemove=insertRemove;
+                runs[i].insertRemove&=~insertRemove;
+                start=j+step;
+                addedRuns--;
+            }
+        }
+        if(addedRuns) {
+            runs[i+addedRuns]=runs[i];
+        }
+        logicalPos=BIDI_MIN(visualMap[start], visualMap[limit]);
+        runs[i+addedRuns].logicalStart=MAKE_INDEX_ODD_PAIR(logicalPos,
+                                            saveLevels[logicalPos]^indexOddBit);
+    }
+
+  cleanup1:
+    /* restore initial paraLevel */
+    pBiDi->paraLevel^=1;
+  cleanup2:
+    /* restore real text */
+    pBiDi->text=text;
+    pBiDi->length=saveLength;
+    pBiDi->originalLength=length;
+    pBiDi->direction=saveDirection;
+    /* the saved levels should never excess levelsSize, but we check anyway */
+    if(saveLength>pBiDi->levelsSize) {
+        saveLength=pBiDi->levelsSize;
+    }
+    uprv_memcpy(pBiDi->levels, saveLevels, saveLength*sizeof(UBiDiLevel));
+    pBiDi->trailingWSStart=saveTrailingWSStart;
+    /* free memory for mapping table and visual text */
+    uprv_free(runsOnlyMemory);
+    if(pBiDi->runCount>1) {
+        pBiDi->direction=UBIDI_MIXED;
+    }
+  cleanup3:
+    pBiDi->reorderingMode=UBIDI_REORDER_RUNS_ONLY;
+}
+
+/* ubidi_setPara ------------------------------------------------------------ */
+
+U_CAPI void U_EXPORT2
+ubidi_setPara(UBiDi *pBiDi, const UChar *text, int32_t length,
+              UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels,
+              UErrorCode *pErrorCode) {
+    UBiDiDirection direction;
+
+    /* check the argument values */
+    RETURN_VOID_IF_NULL_OR_FAILING_ERRCODE(pErrorCode);
+    if(pBiDi==NULL || text==NULL || length<-1 ||
+       (paraLevel>UBIDI_MAX_EXPLICIT_LEVEL && paraLevel<UBIDI_DEFAULT_LTR)) {
+        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
+        return;
+    }
+
+    if(length==-1) {
+        length=u_strlen(text);
+    }
+
+    /* special treatment for RUNS_ONLY mode */
+    if(pBiDi->reorderingMode==UBIDI_REORDER_RUNS_ONLY) {
+        setParaRunsOnly(pBiDi, text, length, paraLevel, pErrorCode);
+        return;
+    }
+
+    /* initialize the UBiDi structure */
+    pBiDi->pParaBiDi=NULL;          /* mark unfinished setPara */
+    pBiDi->text=text;
+    pBiDi->length=pBiDi->originalLength=pBiDi->resultLength=length;
+    pBiDi->paraLevel=paraLevel;
+    pBiDi->direction=UBIDI_LTR;
+    pBiDi->paraCount=1;
+
+    pBiDi->dirProps=NULL;
+    pBiDi->levels=NULL;
+    pBiDi->runs=NULL;
+    pBiDi->insertPoints.size=0;         /* clean up from last call */
+    pBiDi->insertPoints.confirmed=0;    /* clean up from last call */
+
+    /*
+     * Save the original paraLevel if contextual; otherwise, set to 0.
+     */
+    if(IS_DEFAULT_LEVEL(paraLevel)) {
+        pBiDi->defaultParaLevel=paraLevel;
+    } else {
+        pBiDi->defaultParaLevel=0;
+    }
+
+    if(length==0) {
+        /*
+         * For an empty paragraph, create a UBiDi object with the paraLevel and
+         * the flags and the direction set but without allocating zero-length arrays.
+         * There is nothing more to do.
+         */
+        if(IS_DEFAULT_LEVEL(paraLevel)) {
+            pBiDi->paraLevel&=1;
+            pBiDi->defaultParaLevel=0;
+        }
+        if(paraLevel&1) {
+            pBiDi->flags=DIRPROP_FLAG(R);
+            pBiDi->direction=UBIDI_RTL;
+        } else {
+            pBiDi->flags=DIRPROP_FLAG(L);
+            pBiDi->direction=UBIDI_LTR;
+        }
+
+        pBiDi->runCount=0;
+        pBiDi->paraCount=0;
+        pBiDi->pParaBiDi=pBiDi;         /* mark successful setPara */
+        return;
+    }
+
+    pBiDi->runCount=-1;
+
+    /*
+     * Get the directional properties,
+     * the flags bit-set, and
+     * determine the paragraph level if necessary.
+     */
+    if(getDirPropsMemory(pBiDi, length)) {
+        pBiDi->dirProps=pBiDi->dirPropsMemory;
+        getDirProps(pBiDi);
+    } else {
+        *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
+        return;
+    }
+    /* the processed length may have changed if UBIDI_OPTION_STREAMING */
+    length= pBiDi->length;
+    pBiDi->trailingWSStart=length;  /* the levels[] will reflect the WS run */
+    /* allocate paras memory */
+    if(pBiDi->paraCount>1) {
+        if(getInitialParasMemory(pBiDi, pBiDi->paraCount)) {
+            pBiDi->paras=pBiDi->parasMemory;
+            pBiDi->paras[pBiDi->paraCount-1]=length;
+        } else {
+            *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+    } else {
+        /* initialize paras for single paragraph */
+        pBiDi->paras=pBiDi->simpleParas;
+        pBiDi->simpleParas[0]=length;
+    }
+
+    /* are explicit levels specified? */
+    if(embeddingLevels==NULL) {
+        /* no: determine explicit levels according to the (Xn) rules */\
+        if(getLevelsMemory(pBiDi, length)) {
+            pBiDi->levels=pBiDi->levelsMemory;
+            direction=resolveExplicitLevels(pBiDi);
+        } else {
+            *pErrorCode=U_MEMORY_ALLOCATION_ERROR;
+            return;
+        }
+    } else {
+        /* set BN for all explicit codes, check that all levels are 0 or paraLevel..UBIDI_MAX_EXPLICIT_LEVEL */
+        pBiDi->levels=embeddingLevels;
+        direction=checkExplicitLevels(pBiDi, pErrorCode);
+        if(U_FAILURE(*pErrorCode)) {
+            return;
+        }
+    }
+
+    /*
+     * The steps after (X9) in the UBiDi algorithm are performed only if
+     * the paragraph text has mixed directionality!
+     */
+    pBiDi->direction=direction;
+    switch(direction) {
+    case UBIDI_LTR:
+        /* make sure paraLevel is even */
+        pBiDi->paraLevel=(UBiDiLevel)((pBiDi->paraLevel+1)&~1);
+
+        /* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */
+        pBiDi->trailingWSStart=0;
+        break;
+    case UBIDI_RTL:
+        /* make sure paraLevel is odd */
+        pBiDi->paraLevel|=1;
+
+        /* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */
+        pBiDi->trailingWSStart=0;
+        break;
+    default:
+        /*
+         *  Choose the right implicit state table
+         */
+        switch(pBiDi->reorderingMode) {
+        case UBIDI_REORDER_DEFAULT:
+            pBiDi->pImpTabPair=&impTab_DEFAULT;
+            break;
+        case UBIDI_REORDER_NUMBERS_SPECIAL:
+            pBiDi->pImpTabPair=&impTab_NUMBERS_SPECIAL;
+            break;
+        case UBIDI_REORDER_GROUP_NUMBERS_WITH_R:
+            pBiDi->pImpTabPair=&impTab_GROUP_NUMBERS_WITH_R;
+            break;
+        case UBIDI_REORDER_INVERSE_NUMBERS_AS_L:
+            pBiDi->pImpTabPair=&impTab_INVERSE_NUMBERS_AS_L;
+            break;
+        case UBIDI_REORDER_INVERSE_LIKE_DIRECT:
+            if (pBiDi->reorderingOptions & UBIDI_OPTION_INSERT_MARKS) {
+                pBiDi->pImpTabPair=&impTab_INVERSE_LIKE_DIRECT_WITH_MARKS;
+            } else {
+                pBiDi->pImpTabPair=&impTab_INVERSE_LIKE_DIRECT;
+            }
+            break;
+        case UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL:
+            if (pBiDi->reorderingOptions & UBIDI_OPTION_INSERT_MARKS) {
+                pBiDi->pImpTabPair=&impTab_INVERSE_FOR_NUMBERS_SPECIAL_WITH_MARKS;
+            } else {
+                pBiDi->pImpTabPair=&impTab_INVERSE_FOR_NUMBERS_SPECIAL;
+            }
+            break;
+        default:
+            /* we should never get here */
+            U_ASSERT(FALSE);
+            break;
+        }
+        /*
+         * If there are no external levels specified and there
+         * are no significant explicit level codes in the text,
+         * then we can treat the entire paragraph as one run.
+         * Otherwise, we need to perform the following rules on runs of
+         * the text with the same embedding levels. (X10)
+         * "Significant" explicit level codes are ones that actually
+         * affect non-BN characters.
+         * Examples for "insignificant" ones are empty embeddings
+         * LRE-PDF, LRE-RLE-PDF-PDF, etc.
+         */
+        if(embeddingLevels==NULL && pBiDi->paraCount<=1 &&
+                                   !(pBiDi->flags&DIRPROP_FLAG_MULTI_RUNS)) {
+            resolveImplicitLevels(pBiDi, 0, length,
+                                    GET_LR_FROM_LEVEL(GET_PARALEVEL(pBiDi, 0)),
+                                    GET_LR_FROM_LEVEL(GET_PARALEVEL(pBiDi, length-1)));
+        } else {
+            /* sor, eor: start and end types of same-level-run */
+            UBiDiLevel *levels=pBiDi->levels;
+            int32_t start, limit=0;
+            UBiDiLevel level, nextLevel;
+            DirProp sor, eor;
+
+            /* determine the first sor and set eor to it because of the loop body (sor=eor there) */
+            level=GET_PARALEVEL(pBiDi, 0);
+            nextLevel=levels[0];
+            if(level<nextLevel) {
+                eor=GET_LR_FROM_LEVEL(nextLevel);
+            } else {
+                eor=GET_LR_FROM_LEVEL(level);
+            }
+
+            do {
+                /* determine start and limit of the run (end points just behind the run) */
+
+                /* the values for this run's start are the same as for the previous run's end */
+                start=limit;
+                level=nextLevel;
+                if((start>0) && (NO_CONTEXT_RTL(pBiDi->dirProps[start-1])==B)) {
+                    /* except if this is a new paragraph, then set sor = para level */
+                    sor=GET_LR_FROM_LEVEL(GET_PARALEVEL(pBiDi, start));
+                } else {
+                    sor=eor;
+                }
+
+                /* search for the limit of this run */
+                while(++limit<length && levels[limit]==level) {}
+
+                /* get the correct level of the next run */
+                if(limit<length) {
+                    nextLevel=levels[limit];
+                } else {
+                    nextLevel=GET_PARALEVEL(pBiDi, length-1);
+                }
+
+                /* determine eor from max(level, nextLevel); sor is last run's eor */
+                if((level&~UBIDI_LEVEL_OVERRIDE)<(nextLevel&~UBIDI_LEVEL_OVERRIDE)) {
+                    eor=GET_LR_FROM_LEVEL(nextLevel);
+                } else {
+                    eor=GET_LR_FROM_LEVEL(level);
+                }
+
+                /* if the run consists of overridden directional types, then there
+                   are no implicit types to be resolved */
+                if(!(level&UBIDI_LEVEL_OVERRIDE)) {
+                    resolveImplicitLevels(pBiDi, start, limit, sor, eor);
+                } else {
+                    /* remove the UBIDI_LEVEL_OVERRIDE flags */
+                    do {
+                        levels[start++]&=~UBIDI_LEVEL_OVERRIDE;
+                    } while(start<limit);
+                }
+            } while(limit<length);
+        }
+        /* check if we got any memory shortage while adding insert points */
+        if (U_FAILURE(pBiDi->insertPoints.errorCode))
+        {
+            *pErrorCode=pBiDi->insertPoints.errorCode;
+            return;
+        }
+        /* reset the embedding levels for some non-graphic characters (L1), (X9) */
+        adjustWSLevels(pBiDi);
+        break;
+    }
+    /* add RLM for inverse Bidi with contextual orientation resolving
+     * to RTL which would not round-trip otherwise
+     */
+    if((pBiDi->defaultParaLevel>0) &&
+       (pBiDi->reorderingOptions & UBIDI_OPTION_INSERT_MARKS) &&
+       ((pBiDi->reorderingMode==UBIDI_REORDER_INVERSE_LIKE_DIRECT) ||
+        (pBiDi->reorderingMode==UBIDI_REORDER_INVERSE_FOR_NUMBERS_SPECIAL))) {
+        int32_t i, j, start, last;
+        DirProp dirProp;
+        for(i=0; i<pBiDi->paraCount; i++) {
+            last=pBiDi->paras[i]-1;
+            if((pBiDi->dirProps[last] & CONTEXT_RTL)==0) {
+                continue;           /* LTR paragraph */
+            }
+            start= i==0 ? 0 : pBiDi->paras[i - 1];
+            for(j=last; j>=start; j--) {
+                dirProp=NO_CONTEXT_RTL(pBiDi->dirProps[j]);
+                if(dirProp==L) {
+                    if(j<last) {
+                        while(NO_CONTEXT_RTL(pBiDi->dirProps[last])==B) {
+                            last--;
+                        }
+                    }
+                    addPoint(pBiDi, last, RLM_BEFORE);
+                    break;
+                }
+                if(DIRPROP_FLAG(dirProp) & MASK_R_AL) {
+                    break;
+                }
+            }
+        }
+    }
+
+    if(pBiDi->reorderingOptions & UBIDI_OPTION_REMOVE_CONTROLS) {
+        pBiDi->resultLength -= pBiDi->controlCount;
+    } else {
+        pBiDi->resultLength += pBiDi->insertPoints.size;
+    }
+    pBiDi->pParaBiDi=pBiDi;             /* mark successful setPara */
+}
+
+U_CAPI void U_EXPORT2
+ubidi_orderParagraphsLTR(UBiDi *pBiDi, UBool orderParagraphsLTR) {
+    if(pBiDi!=NULL) {
+        pBiDi->orderParagraphsLTR=orderParagraphsLTR;
+    }
+}
+
+U_CAPI UBool U_EXPORT2
+ubidi_isOrderParagraphsLTR(UBiDi *pBiDi) {
+    if(pBiDi!=NULL) {
+        return pBiDi->orderParagraphsLTR;
+    } else {
+        return FALSE;
+    }
+}
+
+U_CAPI UBiDiDirection U_EXPORT2
+ubidi_getDirection(const UBiDi *pBiDi) {
+    if(IS_VALID_PARA_OR_LINE(pBiDi)) {
+        return pBiDi->direction;
+    } else {
+        return UBIDI_LTR;
+    }
+}
+
+U_CAPI const UChar * U_EXPORT2
+ubidi_getText(const UBiDi *pBiDi) {
+    if(IS_VALID_PARA_OR_LINE(pBiDi)) {
+        return pBiDi->text;
+    } else {
+        return NULL;
+    }
+}
+
+U_CAPI int32_t U_EXPORT2
+ubidi_getLength(const UBiDi *pBiDi) {
+    if(IS_VALID_PARA_OR_LINE(pBiDi)) {
+        return pBiDi->originalLength;
+    } else {
+        return 0;
+    }
+}
+
+U_CAPI int32_t U_EXPORT2
+ubidi_getProcessedLength(const UBiDi *pBiDi) {
+    if(IS_VALID_PARA_OR_LINE(pBiDi)) {
+        return pBiDi->length;
+    } else {
+        return 0;
+    }
+}
+
+U_CAPI int32_t U_EXPORT2
+ubidi_getResultLength(const UBiDi *pBiDi) {
+    if(IS_VALID_PARA_OR_LINE(pBiDi)) {
+        return pBiDi->resultLength;
+    } else {
+        return 0;
+    }
+}
+
+/* paragraphs API functions ------------------------------------------------- */
+
+U_CAPI UBiDiLevel U_EXPORT2
+ubidi_getParaLevel(const UBiDi *pBiDi) {
+    if(IS_VALID_PARA_OR_LINE(pBiDi)) {
+        return pBiDi->paraLevel;
+    } else {
+        return 0;
+    }
+}
+
+U_CAPI int32_t U_EXPORT2
+ubidi_countParagraphs(UBiDi *pBiDi) {
+    if(!IS_VALID_PARA_OR_LINE(pBiDi)) {
+        return 0;
+    } else {
+        return pBiDi->paraCount;
+    }
+}
+
+U_CAPI void U_EXPORT2
+ubidi_getParagraphByIndex(const UBiDi *pBiDi, int32_t paraIndex,
+                          int32_t *pParaStart, int32_t *pParaLimit,
+                          UBiDiLevel *pParaLevel, UErrorCode *pErrorCode) {
+    int32_t paraStart;
+
+    /* check the argument values */
+    RETURN_VOID_IF_NULL_OR_FAILING_ERRCODE(pErrorCode);
+    RETURN_VOID_IF_NOT_VALID_PARA_OR_LINE(pBiDi, *pErrorCode);
+    RETURN_VOID_IF_BAD_RANGE(paraIndex, 0, pBiDi->paraCount, *pErrorCode);
+
+    pBiDi=pBiDi->pParaBiDi;             /* get Para object if Line object */
+    if(paraIndex) {
+        paraStart=pBiDi->paras[paraIndex-1];
+    } else {
+        paraStart=0;
+    }
+    if(pParaStart!=NULL) {
+        *pParaStart=paraStart;
+    }
+    if(pParaLimit!=NULL) {
+        *pParaLimit=pBiDi->paras[paraIndex];
+    }
+    if(pParaLevel!=NULL) {
+        *pParaLevel=GET_PARALEVEL(pBiDi, paraStart);
+    }
+}
+
+U_CAPI int32_t U_EXPORT2
+ubidi_getParagraph(const UBiDi *pBiDi, int32_t charIndex,
+                          int32_t *pParaStart, int32_t *pParaLimit,
+                          UBiDiLevel *pParaLevel, UErrorCode *pErrorCode) {
+    uint32_t paraIndex;
+
+    /* check the argument values */
+    /* pErrorCode will be checked by the call to ubidi_getParagraphByIndex */
+    RETURN_IF_NULL_OR_FAILING_ERRCODE(pErrorCode, -1);
+    RETURN_IF_NOT_VALID_PARA_OR_LINE(pBiDi, *pErrorCode, -1);
+    pBiDi=pBiDi->pParaBiDi;             /* get Para object if Line object */
+    RETURN_IF_BAD_RANGE(charIndex, 0, pBiDi->length, *pErrorCode, -1);
+
+    for(paraIndex=0; charIndex>=pBiDi->paras[paraIndex]; paraIndex++);
+    ubidi_getParagraphByIndex(pBiDi, paraIndex, pParaStart, pParaLimit, pParaLevel, pErrorCode);
+    return paraIndex;
+}
+
+U_CAPI void U_EXPORT2
+ubidi_setClassCallback(UBiDi *pBiDi, UBiDiClassCallback *newFn,
+                       const void *newContext, UBiDiClassCallback **oldFn,
+                       const void **oldContext, UErrorCode *pErrorCode)
+{
+    RETURN_VOID_IF_NULL_OR_FAILING_ERRCODE(pErrorCode);
+    if(pBiDi==NULL) {
+        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
+        return;
+    }
+    if( oldFn )
+    {
+        *oldFn = pBiDi->fnClassCallback;
+    }
+    if( oldContext )
+    {
+        *oldContext = pBiDi->coClassCallback;
+    }
+    pBiDi->fnClassCallback = newFn;
+    pBiDi->coClassCallback = newContext;
+}
+
+U_CAPI void U_EXPORT2
+ubidi_getClassCallback(UBiDi *pBiDi, UBiDiClassCallback **fn, const void **context)
+{
+    if(pBiDi==NULL) {
+        return;
+    }
+    if( fn )
+    {
+        *fn = pBiDi->fnClassCallback;
+    }
+    if( context )
+    {
+        *context = pBiDi->coClassCallback;
+    }
+}
+
+U_CAPI UCharDirection U_EXPORT2
+ubidi_getCustomizedClass(UBiDi *pBiDi, UChar32 c)
+{
+    UCharDirection dir;
+
+    if( pBiDi->fnClassCallback == NULL ||
+        (dir = (*pBiDi->fnClassCallback)(pBiDi->coClassCallback, c)) == U_BIDI_CLASS_DEFAULT )
+    {
+        return ubidi_getClass(pBiDi->bdp, c);
+    } else {
+        return dir;
+    }
+}
+