Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 530 insertions, 0 deletions

diff --git a/intl/icu/source/common/ubiditransform.cpp b/intl/icu/source/common/ubiditransform.cpp
new file mode 100644
index 0000000000..01f5901a2c
--- /dev/null
+++ b/intl/icu/source/common/ubiditransform.cpp
@@ -0,0 +1,530 @@
+/*
+******************************************************************************
+*
+* © 2016 and later: Unicode, Inc. and others.
+* License & terms of use: http://www.unicode.org/copyright.html
+*
+******************************************************************************
+*   file name:  ubiditransform.c
+*   encoding:   UTF-8
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2016jul24
+*   created by: Lina Kemmel
+*
+*/
+
+#include "cmemory.h"
+#include "unicode/ubidi.h"
+#include "unicode/ustring.h"
+#include "unicode/ushape.h"
+#include "unicode/utf16.h"
+#include "ustr_imp.h"
+#include "unicode/ubiditransform.h"
+
+/* Some convenience defines */
+#define LTR                     UBIDI_LTR
+#define RTL                     UBIDI_RTL
+#define LOGICAL                 UBIDI_LOGICAL
+#define VISUAL                  UBIDI_VISUAL
+#define SHAPE_LOGICAL           U_SHAPE_TEXT_DIRECTION_LOGICAL
+#define SHAPE_VISUAL            U_SHAPE_TEXT_DIRECTION_VISUAL_LTR
+
+#define CHECK_LEN(STR, LEN, ERROR) UPRV_BLOCK_MACRO_BEGIN { \
+    if (LEN == 0) return 0; \
+    if (LEN < -1) { *(ERROR) = U_ILLEGAL_ARGUMENT_ERROR; return 0; } \
+    if (LEN == -1) LEN = u_strlen(STR); \
+} UPRV_BLOCK_MACRO_END
+
+#define MAX_ACTIONS     7
+
+/**
+ * Typedef for a pointer to a function, which performs some operation (such as
+ * reordering, setting "inverse" mode, character mirroring, etc.). Return value
+ * indicates whether the text was changed in the course of this operation or
+ * not.
+ */
+typedef UBool (*UBiDiAction)(UBiDiTransform *, UErrorCode *);
+
+/**
+ * Structure that holds a predefined reordering scheme, including the following
+ * information:
+ * <ul>
+ * <li>an input base direction,</li>
+ * <li>an input order,</li>
+ * <li>an output base direction,</li>
+ * <li>an output order,</li>
+ * <li>a digit shaping direction,</li>
+ * <li>a letter shaping direction,</li>
+ * <li>a base direction that should be applied when the reordering engine is
+ *     invoked (which can not always be derived from the caller-defined
+ *     options),</li>
+ * <li>an array of pointers to functions that accomplish the bidi layout
+ *     transformation.</li>
+ * </ul>
+ */
+typedef struct {
+    UBiDiLevel        inLevel;               /* input level */
+    UBiDiOrder        inOrder;               /* input order */
+    UBiDiLevel        outLevel;              /* output level */
+    UBiDiOrder        outOrder;              /* output order */
+    uint32_t          digitsDir;             /* digit shaping direction */
+    uint32_t          lettersDir;            /* letter shaping direction */
+    UBiDiLevel        baseLevel;             /* paragraph level to be used with setPara */
+    const UBiDiAction actions[MAX_ACTIONS];  /* array of pointers to functions carrying out the transformation */
+} ReorderingScheme;
+
+struct UBiDiTransform {
+    UBiDi                   *pBidi;             /* pointer to a UBiDi object */
+    const ReorderingScheme  *pActiveScheme;     /* effective reordering scheme */
+    char16_t                *src;               /* input text */
+    char16_t                *dest;              /* output text */
+    uint32_t                srcLength;          /* input text length - not really needed as we are zero-terminated and can u_strlen */
+    uint32_t                srcSize;            /* input text capacity excluding the trailing zero */
+    uint32_t                destSize;           /* output text capacity */
+    uint32_t                *pDestLength;       /* number of UChars written to dest */
+    uint32_t                reorderingOptions;  /* reordering options - currently only suppot DO_MIRRORING */
+    uint32_t                digits;             /* digit option for ArabicShaping */
+    uint32_t                letters;            /* letter option for ArabicShaping */
+};
+
+U_CAPI UBiDiTransform* U_EXPORT2
+ubiditransform_open(UErrorCode *pErrorCode)
+{
+    UBiDiTransform *pBiDiTransform = nullptr;
+    if (U_SUCCESS(*pErrorCode)) {
+        pBiDiTransform = (UBiDiTransform*) uprv_calloc(1, sizeof(UBiDiTransform));
+        if (pBiDiTransform == nullptr) {
+            *pErrorCode = U_MEMORY_ALLOCATION_ERROR;
+        }
+    }
+    return pBiDiTransform;
+}
+
+U_CAPI void U_EXPORT2
+ubiditransform_close(UBiDiTransform *pBiDiTransform)
+{
+    if (pBiDiTransform != nullptr) {
+        if (pBiDiTransform->pBidi != nullptr) {
+            ubidi_close(pBiDiTransform->pBidi);
+        }
+        if (pBiDiTransform->src != nullptr) {
+            uprv_free(pBiDiTransform->src);
+        }
+        uprv_free(pBiDiTransform);
+    }
+}
+
+/**
+ * Performs Bidi resolution of text.
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param pErrorCode Pointer to the error code value.
+ *
+ * @return Whether or not this function modifies the text. Besides the return
+ * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
+ */
+static UBool
+action_resolve(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
+{
+    ubidi_setPara(pTransform->pBidi, pTransform->src, pTransform->srcLength,
+            pTransform->pActiveScheme->baseLevel, nullptr, pErrorCode);
+    return false;
+}
+
+/**
+ * Performs basic reordering of text (Logical -> Visual LTR).
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param pErrorCode Pointer to the error code value.
+ *
+ * @return Whether or not this function modifies the text. Besides the return
+ * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
+ */
+static UBool
+action_reorder(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
+{
+    ubidi_writeReordered(pTransform->pBidi, pTransform->dest, pTransform->destSize,
+            static_cast<uint16_t>(pTransform->reorderingOptions), pErrorCode);
+
+    *pTransform->pDestLength = pTransform->srcLength;
+    pTransform->reorderingOptions = UBIDI_REORDER_DEFAULT;
+    return true;
+}
+
+/**
+ * Sets "inverse" mode on the <code>UBiDi</code> object.
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param pErrorCode Pointer to the error code value.
+ *
+ * @return Whether or not this function modifies the text. Besides the return
+ * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
+ */
+static UBool
+action_setInverse(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
+{
+    (void)pErrorCode;
+    ubidi_setInverse(pTransform->pBidi, true);
+    ubidi_setReorderingMode(pTransform->pBidi, UBIDI_REORDER_INVERSE_LIKE_DIRECT);
+    return false;
+}
+
+/**
+ * Sets "runs only" reordering mode indicating a Logical LTR <-> Logical RTL
+ * transformation.
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param pErrorCode Pointer to the error code value.
+ *
+ * @return Whether or not this function modifies the text. Besides the return
+ * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
+ */
+static UBool
+action_setRunsOnly(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
+{
+    (void)pErrorCode;
+    ubidi_setReorderingMode(pTransform->pBidi, UBIDI_REORDER_RUNS_ONLY);
+    return false;
+}
+
+/**
+ * Performs string reverse.
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param pErrorCode Pointer to the error code value.
+ *
+ * @return Whether or not this function modifies the text. Besides the return
+ * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
+ */
+static UBool
+action_reverse(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
+{
+    ubidi_writeReverse(pTransform->src, pTransform->srcLength,
+            pTransform->dest, pTransform->destSize,
+            UBIDI_REORDER_DEFAULT, pErrorCode);
+    *pTransform->pDestLength = pTransform->srcLength;
+    return true;
+}
+
+/**
+ * Applies a new value to the text that serves as input at the current
+ * processing step. This value is identical to the original one when we begin
+ * the processing, but usually changes as the transformation progresses.
+ * 
+ * @param pTransform A pointer to the <code>UBiDiTransform</code> structure.
+ * @param newSrc A pointer whose value is to be used as input text.
+ * @param newLength A length of the new text in <code>char16_t</code>s.
+ * @param newSize A new source capacity in <code>char16_t</code>s.
+ * @param pErrorCode Pointer to the error code value.
+ */
+static void
+updateSrc(UBiDiTransform *pTransform, const char16_t *newSrc, uint32_t newLength,
+        uint32_t newSize, UErrorCode *pErrorCode)
+{
+    if (newSize < newLength) {
+        *pErrorCode = U_BUFFER_OVERFLOW_ERROR;
+        return;
+    }
+    if (newSize > pTransform->srcSize) {
+        newSize += 50; // allocate slightly more than needed right now
+        if (pTransform->src != nullptr) {
+            uprv_free(pTransform->src);
+            pTransform->src = nullptr;
+        }
+        pTransform->src = (char16_t *)uprv_malloc(newSize * sizeof(char16_t));
+        if (pTransform->src == nullptr) {
+            *pErrorCode = U_MEMORY_ALLOCATION_ERROR;
+            //pTransform->srcLength = pTransform->srcSize = 0;
+            return;
+        }
+        pTransform->srcSize = newSize;
+    }
+    u_strncpy(pTransform->src, newSrc, newLength);
+    pTransform->srcLength = u_terminateUChars(pTransform->src,
+    		pTransform->srcSize, newLength, pErrorCode);
+}
+
+/**
+ * Calls a lower level shaping function.
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param options Shaping options.
+ * @param pErrorCode Pointer to the error code value.
+ */
+static void
+doShape(UBiDiTransform *pTransform, uint32_t options, UErrorCode *pErrorCode)
+{
+    *pTransform->pDestLength = u_shapeArabic(pTransform->src,
+            pTransform->srcLength, pTransform->dest, pTransform->destSize,
+            options, pErrorCode);
+}
+
+/**
+ * Performs digit and letter shaping.
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param pErrorCode Pointer to the error code value.
+ *
+ * @return Whether or not this function modifies the text. Besides the return
+ * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
+ */
+static UBool
+action_shapeArabic(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
+{
+    if ((pTransform->letters | pTransform->digits) == 0) {
+        return false;
+    }
+    if (pTransform->pActiveScheme->lettersDir == pTransform->pActiveScheme->digitsDir) {
+        doShape(pTransform, pTransform->letters | pTransform->digits | pTransform->pActiveScheme->lettersDir,
+                pErrorCode);
+    } else {
+        doShape(pTransform, pTransform->digits | pTransform->pActiveScheme->digitsDir, pErrorCode);
+        if (U_SUCCESS(*pErrorCode)) {
+            updateSrc(pTransform, pTransform->dest, *pTransform->pDestLength,
+                    *pTransform->pDestLength, pErrorCode);
+            doShape(pTransform, pTransform->letters | pTransform->pActiveScheme->lettersDir,
+                    pErrorCode);
+        }
+    }
+    return true;
+}
+
+/**
+ * Performs character mirroring.
+ * 
+ * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
+ * @param pErrorCode Pointer to the error code value.
+ *
+ * @return Whether or not this function modifies the text. Besides the return
+ * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
+ */
+static UBool
+action_mirror(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
+{
+    UChar32 c;
+    uint32_t i = 0, j = 0;
+    if (0 == (pTransform->reorderingOptions & UBIDI_DO_MIRRORING)) {
+        return false;
+    }
+    if (pTransform->destSize < pTransform->srcLength) {
+        *pErrorCode = U_BUFFER_OVERFLOW_ERROR;
+        return false;
+    }
+    do {
+        UBool isOdd = ubidi_getLevelAt(pTransform->pBidi, i) & 1;
+        U16_NEXT(pTransform->src, i, pTransform->srcLength, c); 
+        U16_APPEND_UNSAFE(pTransform->dest, j, isOdd ? u_charMirror(c) : c);
+    } while (i < pTransform->srcLength);
+    
+    *pTransform->pDestLength = pTransform->srcLength;
+    pTransform->reorderingOptions = UBIDI_REORDER_DEFAULT;
+    return true;
+}
+
+/**
+ * All possible reordering schemes.
+ *
+ */
+static const ReorderingScheme Schemes[] =
+{
+    /* 0: Logical LTR => Visual LTR */
+    {LTR, LOGICAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
+            {action_shapeArabic, action_resolve, action_reorder, nullptr}},
+    /* 1: Logical RTL => Visual LTR */
+    {RTL, LOGICAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
+            {action_resolve, action_reorder, action_shapeArabic, nullptr}},
+    /* 2: Logical LTR => Visual RTL */
+    {LTR, LOGICAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
+            {action_shapeArabic, action_resolve, action_reorder, action_reverse, nullptr}},
+    /* 3: Logical RTL => Visual RTL */
+    {RTL, LOGICAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
+            {action_resolve, action_reorder, action_shapeArabic, action_reverse, nullptr}},
+    /* 4: Visual LTR => Logical RTL */
+    {LTR, VISUAL, RTL, LOGICAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
+            {action_shapeArabic, action_setInverse, action_resolve, action_reorder, nullptr}},
+    /* 5: Visual RTL => Logical RTL */
+    {RTL, VISUAL, RTL, LOGICAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
+            {action_reverse, action_shapeArabic, action_setInverse, action_resolve, action_reorder, nullptr}},
+    /* 6: Visual LTR => Logical LTR */
+    {LTR, VISUAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
+            {action_setInverse, action_resolve, action_reorder, action_shapeArabic, nullptr}},
+    /* 7: Visual RTL => Logical LTR */
+    {RTL, VISUAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
+            {action_reverse, action_setInverse, action_resolve, action_reorder, action_shapeArabic, nullptr}},
+    /* 8: Logical LTR => Logical RTL */
+    {LTR, LOGICAL, RTL, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
+            {action_shapeArabic, action_resolve, action_mirror, action_setRunsOnly, action_resolve, action_reorder, nullptr}},
+    /* 9: Logical RTL => Logical LTR */
+    {RTL, LOGICAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, RTL,
+            {action_resolve, action_mirror, action_setRunsOnly, action_resolve, action_reorder, action_shapeArabic, nullptr}},
+    /* 10: Visual LTR => Visual RTL */
+    {LTR, VISUAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
+            {action_shapeArabic, action_setInverse, action_resolve, action_mirror, action_reverse, nullptr}},
+    /* 11: Visual RTL => Visual LTR */
+    {RTL, VISUAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
+            {action_reverse, action_shapeArabic, action_setInverse, action_resolve, action_mirror, nullptr}},
+    /* 12: Logical LTR => Logical LTR */
+    {LTR, LOGICAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
+            {action_resolve, action_mirror, action_shapeArabic, nullptr}},
+    /* 13: Logical RTL => Logical RTL */
+    {RTL, LOGICAL, RTL, LOGICAL, SHAPE_VISUAL, SHAPE_LOGICAL, RTL,
+            {action_resolve, action_mirror, action_shapeArabic, nullptr}},
+    /* 14: Visual LTR => Visual LTR */
+    {LTR, VISUAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
+            {action_resolve, action_mirror, action_shapeArabic, nullptr}},
+    /* 15: Visual RTL => Visual RTL */
+    {RTL, VISUAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
+            {action_reverse, action_resolve, action_mirror, action_shapeArabic, action_reverse, nullptr}}
+};
+
+static const uint32_t nSchemes = sizeof(Schemes) / sizeof(*Schemes);
+
+/**
+ * When the direction option is <code>UBIDI_DEFAULT_LTR</code> or
+ * <code>UBIDI_DEFAULT_RTL</code>, resolve the base direction according to that
+ * of the first strong bidi character.
+ */
+static void
+resolveBaseDirection(const char16_t *text, uint32_t length,
+        UBiDiLevel *pInLevel, UBiDiLevel *pOutLevel)
+{
+    switch (*pInLevel) {
+        case UBIDI_DEFAULT_LTR:
+        case UBIDI_DEFAULT_RTL: {
+            UBiDiLevel level = static_cast<UBiDiLevel>(ubidi_getBaseDirection(text, length));
+            *pInLevel = static_cast<UBiDiLevel>(level != UBIDI_NEUTRAL) ? level
+                    : *pInLevel == UBIDI_DEFAULT_RTL ? static_cast<UBiDiLevel>(RTL) : static_cast<UBiDiLevel>(LTR);
+            break;
+        }
+        default:
+            *pInLevel &= 1;
+            break;
+    }
+    switch (*pOutLevel) {
+        case UBIDI_DEFAULT_LTR:
+        case UBIDI_DEFAULT_RTL:
+            *pOutLevel = *pInLevel;
+            break;
+        default:
+            *pOutLevel &= 1;
+            break;
+    }
+}
+
+/**
+ * Finds a valid <code>ReorderingScheme</code> matching the
+ * caller-defined scheme.
+ * 
+ * @return A valid <code>ReorderingScheme</code> object or nullptr
+ */
+static const ReorderingScheme*
+findMatchingScheme(UBiDiLevel inLevel, UBiDiLevel outLevel,
+        UBiDiOrder inOrder, UBiDiOrder outOrder)
+{
+    uint32_t i;
+    for (i = 0; i < nSchemes; i++) {
+        const ReorderingScheme *pScheme = Schemes + i;
+        if (inLevel == pScheme->inLevel && outLevel == pScheme->outLevel
+                && inOrder == pScheme->inOrder && outOrder == pScheme->outOrder) {
+            return pScheme;
+        }
+    }
+    return nullptr;
+}
+
+U_CAPI uint32_t U_EXPORT2
+ubiditransform_transform(UBiDiTransform *pBiDiTransform,
+            const char16_t *src, int32_t srcLength,
+            char16_t *dest, int32_t destSize,
+            UBiDiLevel inParaLevel, UBiDiOrder inOrder,
+            UBiDiLevel outParaLevel, UBiDiOrder outOrder,
+            UBiDiMirroring doMirroring, uint32_t shapingOptions,
+            UErrorCode *pErrorCode)
+{
+    uint32_t destLength = 0;
+    UBool textChanged = false;
+    const UBiDiTransform *pOrigTransform = pBiDiTransform;
+    const UBiDiAction *action = nullptr;
+
+    if (U_FAILURE(*pErrorCode)) {
+        return 0;
+    }
+    if (src == nullptr || dest == nullptr) {
+        *pErrorCode = U_ILLEGAL_ARGUMENT_ERROR;
+        return 0;
+    }
+    CHECK_LEN(src, srcLength, pErrorCode);
+    CHECK_LEN(dest, destSize, pErrorCode);
+
+    if (pBiDiTransform == nullptr) {
+        pBiDiTransform = ubiditransform_open(pErrorCode);
+        if (U_FAILURE(*pErrorCode)) {
+            return 0;
+        }
+    }
+    /* Current limitation: in multiple paragraphs will be resolved according
+       to the 1st paragraph */
+    resolveBaseDirection(src, srcLength, &inParaLevel, &outParaLevel);
+
+    pBiDiTransform->pActiveScheme = findMatchingScheme(inParaLevel, outParaLevel,
+            inOrder, outOrder);
+    if (pBiDiTransform->pActiveScheme == nullptr) {
+        goto cleanup;
+    }
+    pBiDiTransform->reorderingOptions = doMirroring ? UBIDI_DO_MIRRORING
+            : UBIDI_REORDER_DEFAULT;
+
+    /* Ignore TEXT_DIRECTION_* flags, as we apply our own depending on the text
+       scheme at the time shaping is invoked. */
+    shapingOptions &= ~U_SHAPE_TEXT_DIRECTION_MASK;
+    pBiDiTransform->digits = shapingOptions & ~U_SHAPE_LETTERS_MASK;
+    pBiDiTransform->letters = shapingOptions & ~U_SHAPE_DIGITS_MASK;
+
+    updateSrc(pBiDiTransform, src, srcLength, destSize > srcLength ? destSize : srcLength, pErrorCode);
+    if (U_FAILURE(*pErrorCode)) {
+        goto cleanup;
+    }
+    if (pBiDiTransform->pBidi == nullptr) {
+        pBiDiTransform->pBidi = ubidi_openSized(0, 0, pErrorCode);
+        if (U_FAILURE(*pErrorCode)) {
+            goto cleanup;
+        }
+    }
+    pBiDiTransform->dest = dest;
+    pBiDiTransform->destSize = destSize;
+    pBiDiTransform->pDestLength = &destLength;
+
+    /* Checking for U_SUCCESS() within the loop to bail out on first failure. */
+    for (action = pBiDiTransform->pActiveScheme->actions; *action && U_SUCCESS(*pErrorCode); action++) {
+        if ((*action)(pBiDiTransform, pErrorCode)) {
+            if (action + 1) {
+                updateSrc(pBiDiTransform, pBiDiTransform->dest, *pBiDiTransform->pDestLength,
+                        *pBiDiTransform->pDestLength, pErrorCode);
+            }
+            textChanged = true;
+        }
+    }
+    ubidi_setInverse(pBiDiTransform->pBidi, false);
+
+    if (!textChanged && U_SUCCESS(*pErrorCode)) {
+        /* Text was not changed - just copy src to dest */
+        if (destSize < srcLength) {
+            *pErrorCode = U_BUFFER_OVERFLOW_ERROR;
+        } else {
+            u_strncpy(dest, src, srcLength);
+            destLength = srcLength;
+        }
+    }
+cleanup:
+    if (pOrigTransform != pBiDiTransform) {
+        ubiditransform_close(pBiDiTransform);
+    } else {
+        pBiDiTransform->dest = nullptr;
+        pBiDiTransform->pDestLength = nullptr;
+        pBiDiTransform->srcLength = 0;
+        pBiDiTransform->destSize = 0;
+    }
+    return U_FAILURE(*pErrorCode) ? 0 : destLength;
+}