icuSources/common/ubiditransform.cpp

   1 /*
   2 ******************************************************************************
   3 *
   4 * © 2016 and later: Unicode, Inc. and others.
   5 * License & terms of use: http://www.unicode.org/copyright.html
   6 *
   7 ******************************************************************************
   8 *   file name:  ubiditransform.c
   9 *   encoding:   UTF-8
  10 *   tab size:   8 (not used)
  11 *   indentation:4
  12 *
  13 *   created on: 2016jul24
  14 *   created by: Lina Kemmel
  15 *
  16 */
  17
  18 #include "cmemory.h"
  19 #include "unicode/ubidi.h"
  20 #include "unicode/ustring.h"
  21 #include "unicode/ushape.h"
  22 #include "unicode/utf16.h"
  23 #include "ustr_imp.h"
  24 #include "unicode/ubiditransform.h"
  25
  26 /* Some convenience defines */
  27 #define LTR                     UBIDI_LTR
  28 #define RTL                     UBIDI_RTL
  29 #define LOGICAL                 UBIDI_LOGICAL
  30 #define VISUAL                  UBIDI_VISUAL
  31 #define SHAPE_LOGICAL           U_SHAPE_TEXT_DIRECTION_LOGICAL
  32 #define SHAPE_VISUAL            U_SHAPE_TEXT_DIRECTION_VISUAL_LTR
  33
  34 #define CHECK_LEN(STR, LEN, ERROR) { \
  35         if (LEN == 0) return 0; \
  36         if (LEN < -1) { *(ERROR) = U_ILLEGAL_ARGUMENT_ERROR; return 0; } \
  37         if (LEN == -1) LEN = u_strlen(STR); \
  38     }
  39
  40 #define MAX_ACTIONS     7
  41
  42 /**
  43  * Typedef for a pointer to a function, which performs some operation (such as
  44  * reordering, setting "inverse" mode, character mirroring, etc.). Return value
  45  * indicates whether the text was changed in the course of this operation or
  46  * not.
  47  */
  48 typedef UBool (*UBiDiAction)(UBiDiTransform *, UErrorCode *);
  49
  50 /**
  51  * Structure that holds a predefined reordering scheme, including the following
  52  * information:
  53  * <ul>
  54  * <li>an input base direction,</li>
  55  * <li>an input order,</li>
  56  * <li>an output base direction,</li>
  57  * <li>an output order,</li>
  58  * <li>a digit shaping direction,</li>
  59  * <li>a letter shaping direction,</li>
  60  * <li>a base direction that should be applied when the reordering engine is
  61  *     invoked (which can not always be derived from the caller-defined
  62  *     options),</li>
  63  * <li>an array of pointers to functions that accomplish the bidi layout
  64  *     transformation.</li>
  65  * </ul>
  66  */
  67 typedef struct {
  68     UBiDiLevel        inLevel;               /* input level */
  69     UBiDiOrder        inOrder;               /* input order */
  70     UBiDiLevel        outLevel;              /* output level */
  71     UBiDiOrder        outOrder;              /* output order */
  72     uint32_t          digitsDir;             /* digit shaping direction */
  73     uint32_t          lettersDir;            /* letter shaping direction */
  74     UBiDiLevel        baseLevel;             /* paragraph level to be used with setPara */
  75     const UBiDiAction actions[MAX_ACTIONS];  /* array of pointers to functions carrying out the transformation */
  76 } ReorderingScheme;
  77
  78 struct UBiDiTransform {
  79     UBiDi                   *pBidi;             /* pointer to a UBiDi object */
  80     const ReorderingScheme  *pActiveScheme;     /* effective reordering scheme */
  81     UChar                   *src;               /* input text */
  82     UChar                   *dest;              /* output text */
  83     uint32_t                srcLength;          /* input text length - not really needed as we are zero-terminated and can u_strlen */
  84     uint32_t                srcSize;            /* input text capacity excluding the trailing zero */
  85     uint32_t                destSize;           /* output text capacity */
  86     uint32_t                *pDestLength;       /* number of UChars written to dest */
  87     uint32_t                reorderingOptions;  /* reordering options - currently only suppot DO_MIRRORING */
  88     uint32_t                digits;             /* digit option for ArabicShaping */
  89     uint32_t                letters;            /* letter option for ArabicShaping */
  90 };
  91
  92 U_DRAFT UBiDiTransform* U_EXPORT2
  93 ubiditransform_open(UErrorCode *pErrorCode)
  94 {
  95     UBiDiTransform *pBiDiTransform = NULL;
  96     if (U_SUCCESS(*pErrorCode)) {
  97         pBiDiTransform = (UBiDiTransform*) uprv_calloc(1, sizeof(UBiDiTransform));
  98         if (pBiDiTransform == NULL) {
  99             *pErrorCode = U_MEMORY_ALLOCATION_ERROR;
 100         }
 101     }
 102     return pBiDiTransform;
 103 }
 104
 105 U_DRAFT void U_EXPORT2
 106 ubiditransform_close(UBiDiTransform *pBiDiTransform)
 107 {
 108     if (pBiDiTransform != NULL) {
 109         if (pBiDiTransform->pBidi != NULL) {
 110             ubidi_close(pBiDiTransform->pBidi);
 111         }
 112         if (pBiDiTransform->src != NULL) {
 113             uprv_free(pBiDiTransform->src);
 114         }
 115         uprv_free(pBiDiTransform);
 116     }
 117 }
 118
 119 /**
 120  * Performs Bidi resolution of text.
 121  *
 122  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 123  * @param pErrorCode Pointer to the error code value.
 124  *
 125  * @return Whether or not this function modifies the text. Besides the return
 126  * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
 127  */
 128 static UBool
 129 action_resolve(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
 130 {
 131     ubidi_setPara(pTransform->pBidi, pTransform->src, pTransform->srcLength,
 132             pTransform->pActiveScheme->baseLevel, NULL, pErrorCode);
 133     return FALSE;
 134 }
 135
 136 /**
 137  * Performs basic reordering of text (Logical -> Visual LTR).
 138  *
 139  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 140  * @param pErrorCode Pointer to the error code value.
 141  *
 142  * @return Whether or not this function modifies the text. Besides the return
 143  * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
 144  */
 145 static UBool
 146 action_reorder(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
 147 {
 148     ubidi_writeReordered(pTransform->pBidi, pTransform->dest, pTransform->destSize,
 149             pTransform->reorderingOptions, pErrorCode);
 150
 151     *pTransform->pDestLength = pTransform->srcLength;
 152     pTransform->reorderingOptions = UBIDI_REORDER_DEFAULT;
 153     return TRUE;
 154 }
 155
 156 /**
 157  * Sets "inverse" mode on the <code>UBiDi</code> object.
 158  *
 159  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 160  * @param pErrorCode Pointer to the error code value.
 161  *
 162  * @return Whether or not this function modifies the text. Besides the return
 163  * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
 164  */
 165 static UBool
 166 action_setInverse(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
 167 {
 168     (void)pErrorCode;
 169     ubidi_setInverse(pTransform->pBidi, TRUE);
 170     ubidi_setReorderingMode(pTransform->pBidi, UBIDI_REORDER_INVERSE_LIKE_DIRECT);
 171     return FALSE;
 172 }
 173
 174 /**
 175  * Sets "runs only" reordering mode indicating a Logical LTR <-> Logical RTL
 176  * transformation.
 177  *
 178  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 179  * @param pErrorCode Pointer to the error code value.
 180  *
 181  * @return Whether or not this function modifies the text. Besides the return
 182  * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
 183  */
 184 static UBool
 185 action_setRunsOnly(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
 186 {
 187     (void)pErrorCode;
 188     ubidi_setReorderingMode(pTransform->pBidi, UBIDI_REORDER_RUNS_ONLY);
 189     return FALSE;
 190 }
 191
 192 /**
 193  * Performs string reverse.
 194  *
 195  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 196  * @param pErrorCode Pointer to the error code value.
 197  *
 198  * @return Whether or not this function modifies the text. Besides the return
 199  * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
 200  */
 201 static UBool
 202 action_reverse(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
 203 {
 204     ubidi_writeReverse(pTransform->src, pTransform->srcLength,
 205             pTransform->dest, pTransform->destSize,
 206             UBIDI_REORDER_DEFAULT, pErrorCode);
 207     *pTransform->pDestLength = pTransform->srcLength;
 208     return TRUE;
 209 }
 210
 211 /**
 212  * Applies a new value to the text that serves as input at the current
 213  * processing step. This value is identical to the original one when we begin
 214  * the processing, but usually changes as the transformation progresses.
 215  *
 216  * @param pTransform A pointer to the <code>UBiDiTransform</code> structure.
 217  * @param newSrc A pointer whose value is to be used as input text.
 218  * @param newLength A length of the new text in <code>UChar</code>s.
 219  * @param newSize A new source capacity in <code>UChar</code>s.
 220  * @param pErrorCode Pointer to the error code value.
 221  */
 222 static void
 223 updateSrc(UBiDiTransform *pTransform, const UChar *newSrc, uint32_t newLength,
 224         uint32_t newSize, UErrorCode *pErrorCode)
 225 {
 226     if (newSize < newLength) {
 227         *pErrorCode = U_BUFFER_OVERFLOW_ERROR;
 228         return;
 229     }
 230     if (newSize > pTransform->srcSize) {
 231         newSize += 50; // allocate slightly more than needed right now
 232         if (pTransform->src != NULL) {
 233             uprv_free(pTransform->src);
 234             pTransform->src = NULL;
 235         }
 236         pTransform->src = (UChar *)uprv_malloc(newSize * sizeof(UChar));
 237         if (pTransform->src == NULL) {
 238             *pErrorCode = U_MEMORY_ALLOCATION_ERROR;
 239             //pTransform->srcLength = pTransform->srcSize = 0;
 240             return;
 241         }
 242         pTransform->srcSize = newSize;
 243     }
 244     u_strncpy(pTransform->src, newSrc, newLength);
 245     pTransform->srcLength = u_terminateUChars(pTransform->src,
 246                 pTransform->srcSize, newLength, pErrorCode);
 247 }
 248
 249 /**
 250  * Calls a lower level shaping function.
 251  *
 252  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 253  * @param options Shaping options.
 254  * @param pErrorCode Pointer to the error code value.
 255  */
 256 static void
 257 doShape(UBiDiTransform *pTransform, uint32_t options, UErrorCode *pErrorCode)
 258 {
 259     *pTransform->pDestLength = u_shapeArabic(pTransform->src,
 260             pTransform->srcLength, pTransform->dest, pTransform->destSize,
 261             options, pErrorCode);
 262 }
 263
 264 /**
 265  * Performs digit and letter shaping.
 266  *
 267  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 268  * @param pErrorCode Pointer to the error code value.
 269  *
 270  * @return Whether or not this function modifies the text. Besides the return
 271  * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
 272  */
 273 static UBool
 274 action_shapeArabic(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
 275 {
 276     if ((pTransform->letters | pTransform->digits) == 0) {
 277         return FALSE;
 278     }
 279     if (pTransform->pActiveScheme->lettersDir == pTransform->pActiveScheme->digitsDir) {
 280         doShape(pTransform, pTransform->letters | pTransform->digits | pTransform->pActiveScheme->lettersDir,
 281                 pErrorCode);
 282     } else {
 283         doShape(pTransform, pTransform->digits | pTransform->pActiveScheme->digitsDir, pErrorCode);
 284         if (U_SUCCESS(*pErrorCode)) {
 285             updateSrc(pTransform, pTransform->dest, *pTransform->pDestLength,
 286                     *pTransform->pDestLength, pErrorCode);
 287             doShape(pTransform, pTransform->letters | pTransform->pActiveScheme->lettersDir,
 288                     pErrorCode);
 289         }
 290     }
 291     return TRUE;
 292 }
 293
 294 /**
 295  * Performs character mirroring.
 296  *
 297  * @param pTransform Pointer to the <code>UBiDiTransform</code> structure.
 298  * @param pErrorCode Pointer to the error code value.
 299  *
 300  * @return Whether or not this function modifies the text. Besides the return
 301  * value, the caller should also check <code>U_SUCCESS(*pErrorCode)</code>.
 302  */
 303 static UBool
 304 action_mirror(UBiDiTransform *pTransform, UErrorCode *pErrorCode)
 305 {
 306     UChar32 c;
 307     uint32_t i = 0, j = 0;
 308     if (0 == (pTransform->reorderingOptions & UBIDI_DO_MIRRORING)) {
 309         return FALSE;
 310     }
 311     if (pTransform->destSize < pTransform->srcLength) {
 312         *pErrorCode = U_BUFFER_OVERFLOW_ERROR;
 313         return FALSE;
 314     }
 315     do {
 316         UBool isOdd = ubidi_getLevelAt(pTransform->pBidi, i) & 1;
 317         U16_NEXT(pTransform->src, i, pTransform->srcLength, c);
 318         U16_APPEND_UNSAFE(pTransform->dest, j, isOdd ? u_charMirror(c) : c);
 319     } while (i < pTransform->srcLength);
 320
 321     *pTransform->pDestLength = pTransform->srcLength;
 322     pTransform->reorderingOptions = UBIDI_REORDER_DEFAULT;
 323     return TRUE;
 324 }
 325
 326 /**
 327  * All possible reordering schemes.
 328  *
 329  */
 330 static const ReorderingScheme Schemes[] =
 331 {
 332     /* 0: Logical LTR => Visual LTR */
 333     {LTR, LOGICAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
 334             {action_shapeArabic, action_resolve, action_reorder, NULL}},
 335     /* 1: Logical RTL => Visual LTR */
 336     {RTL, LOGICAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
 337             {action_resolve, action_reorder, action_shapeArabic, NULL}},
 338     /* 2: Logical LTR => Visual RTL */
 339     {LTR, LOGICAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
 340             {action_shapeArabic, action_resolve, action_reorder, action_reverse, NULL}},
 341     /* 3: Logical RTL => Visual RTL */
 342     {RTL, LOGICAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
 343             {action_resolve, action_reorder, action_shapeArabic, action_reverse, NULL}},
 344     /* 4: Visual LTR => Logical RTL */
 345     {LTR, VISUAL, RTL, LOGICAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
 346             {action_shapeArabic, action_setInverse, action_resolve, action_reorder, NULL}},
 347     /* 5: Visual RTL => Logical RTL */
 348     {RTL, VISUAL, RTL, LOGICAL, SHAPE_LOGICAL, SHAPE_VISUAL, RTL,
 349             {action_reverse, action_shapeArabic, action_setInverse, action_resolve, action_reorder, NULL}},
 350     /* 6: Visual LTR => Logical LTR */
 351     {LTR, VISUAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
 352             {action_setInverse, action_resolve, action_reorder, action_shapeArabic, NULL}},
 353     /* 7: Visual RTL => Logical LTR */
 354     {RTL, VISUAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
 355             {action_reverse, action_setInverse, action_resolve, action_reorder, action_shapeArabic, NULL}},
 356     /* 8: Logical LTR => Logical RTL */
 357     {LTR, LOGICAL, RTL, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
 358             {action_shapeArabic, action_resolve, action_mirror, action_setRunsOnly, action_resolve, action_reorder, NULL}},
 359     /* 9: Logical RTL => Logical LTR */
 360     {RTL, LOGICAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, RTL,
 361             {action_resolve, action_mirror, action_setRunsOnly, action_resolve, action_reorder, action_shapeArabic, NULL}},
 362     /* 10: Visual LTR => Visual RTL */
 363     {LTR, VISUAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
 364             {action_shapeArabic, action_setInverse, action_resolve, action_mirror, action_reverse, NULL}},
 365     /* 11: Visual RTL => Visual LTR */
 366     {RTL, VISUAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
 367             {action_reverse, action_shapeArabic, action_setInverse, action_resolve, action_mirror, NULL}},
 368     /* 12: Logical LTR => Logical LTR */
 369     {LTR, LOGICAL, LTR, LOGICAL, SHAPE_LOGICAL, SHAPE_LOGICAL, LTR,
 370             {action_resolve, action_mirror, action_shapeArabic, NULL}},
 371     /* 13: Logical RTL => Logical RTL */
 372     {RTL, LOGICAL, RTL, LOGICAL, SHAPE_VISUAL, SHAPE_LOGICAL, RTL,
 373             {action_resolve, action_mirror, action_shapeArabic, NULL}},
 374     /* 14: Visual LTR => Visual LTR */
 375     {LTR, VISUAL, LTR, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
 376             {action_resolve, action_mirror, action_shapeArabic, NULL}},
 377     /* 15: Visual RTL => Visual RTL */
 378     {RTL, VISUAL, RTL, VISUAL, SHAPE_LOGICAL, SHAPE_VISUAL, LTR,
 379             {action_reverse, action_resolve, action_mirror, action_shapeArabic, action_reverse, NULL}}
 380 };
 381
 382 static const uint32_t nSchemes = sizeof(Schemes) / sizeof(*Schemes);
 383
 384 /**
 385  * When the direction option is <code>UBIDI_DEFAULT_LTR</code> or
 386  * <code>UBIDI_DEFAULT_RTL</code>, resolve the base direction according to that
 387  * of the first strong bidi character.
 388  */
 389 static void
 390 resolveBaseDirection(const UChar *text, uint32_t length,
 391         UBiDiLevel *pInLevel, UBiDiLevel *pOutLevel)
 392 {
 393     switch (*pInLevel) {
 394         case UBIDI_DEFAULT_LTR:
 395         case UBIDI_DEFAULT_RTL: {
 396             UBiDiLevel level = ubidi_getBaseDirection(text, length);
 397             *pInLevel = level != UBIDI_NEUTRAL ? level
 398                     : *pInLevel == UBIDI_DEFAULT_RTL ? RTL : LTR;
 399             break;
 400         }
 401         default:
 402             *pInLevel &= 1;
 403             break;
 404     }
 405     switch (*pOutLevel) {
 406         case UBIDI_DEFAULT_LTR:
 407         case UBIDI_DEFAULT_RTL:
 408             *pOutLevel = *pInLevel;
 409             break;
 410         default:
 411             *pOutLevel &= 1;
 412             break;
 413     }
 414 }
 415
 416 /**
 417  * Finds a valid <code>ReorderingScheme</code> matching the
 418  * caller-defined scheme.
 419  *
 420  * @return A valid <code>ReorderingScheme</code> object or NULL
 421  */
 422 static const ReorderingScheme*
 423 findMatchingScheme(UBiDiLevel inLevel, UBiDiLevel outLevel,
 424         UBiDiOrder inOrder, UBiDiOrder outOrder)
 425 {
 426     uint32_t i;
 427     for (i = 0; i < nSchemes; i++) {
 428         const ReorderingScheme *pScheme = Schemes + i;
 429         if (inLevel == pScheme->inLevel && outLevel == pScheme->outLevel
 430                 && inOrder == pScheme->inOrder && outOrder == pScheme->outOrder) {
 431             return pScheme;
 432         }
 433     }
 434     return NULL;
 435 }
 436
 437 U_DRAFT uint32_t U_EXPORT2
 438 ubiditransform_transform(UBiDiTransform *pBiDiTransform,
 439             const UChar *src, int32_t srcLength,
 440             UChar *dest, int32_t destSize,
 441             UBiDiLevel inParaLevel, UBiDiOrder inOrder,
 442             UBiDiLevel outParaLevel, UBiDiOrder outOrder,
 443             UBiDiMirroring doMirroring, uint32_t shapingOptions,
 444             UErrorCode *pErrorCode)
 445 {
 446     uint32_t destLength = 0;
 447     UBool textChanged = FALSE;
 448     const UBiDiTransform *pOrigTransform = pBiDiTransform;
 449     const UBiDiAction *action = NULL;
 450
 451     if (U_FAILURE(*pErrorCode)) {
 452         return 0;
 453     }
 454     if (src == NULL || dest == NULL) {
 455         *pErrorCode = U_ILLEGAL_ARGUMENT_ERROR;
 456         return 0;
 457     }
 458     CHECK_LEN(src, srcLength, pErrorCode);
 459     CHECK_LEN(dest, destSize, pErrorCode);
 460
 461     if (pBiDiTransform == NULL) {
 462         pBiDiTransform = ubiditransform_open(pErrorCode);
 463         if (U_FAILURE(*pErrorCode)) {
 464             return 0;
 465         }
 466     }
 467     /* Current limitation: in multiple paragraphs will be resolved according
 468        to the 1st paragraph */
 469     resolveBaseDirection(src, srcLength, &inParaLevel, &outParaLevel);
 470
 471     pBiDiTransform->pActiveScheme = findMatchingScheme(inParaLevel, outParaLevel,
 472             inOrder, outOrder);
 473     if (pBiDiTransform->pActiveScheme == NULL) {
 474         goto cleanup;
 475     }
 476     pBiDiTransform->reorderingOptions = doMirroring ? UBIDI_DO_MIRRORING
 477             : UBIDI_REORDER_DEFAULT;
 478
 479     /* Ignore TEXT_DIRECTION_* flags, as we apply our own depending on the text
 480        scheme at the time shaping is invoked. */
 481     shapingOptions &= ~U_SHAPE_TEXT_DIRECTION_MASK;
 482     pBiDiTransform->digits = shapingOptions & ~U_SHAPE_LETTERS_MASK;
 483     pBiDiTransform->letters = shapingOptions & ~U_SHAPE_DIGITS_MASK;
 484
 485     updateSrc(pBiDiTransform, src, srcLength, destSize > srcLength ? destSize : srcLength, pErrorCode);
 486     if (U_FAILURE(*pErrorCode)) {
 487         goto cleanup;
 488     }
 489     if (pBiDiTransform->pBidi == NULL) {
 490         pBiDiTransform->pBidi = ubidi_openSized(0, 0, pErrorCode);
 491         if (U_FAILURE(*pErrorCode)) {
 492             goto cleanup;
 493         }
 494     }
 495     pBiDiTransform->dest = dest;
 496     pBiDiTransform->destSize = destSize;
 497     pBiDiTransform->pDestLength = &destLength;
 498
 499     /* Checking for U_SUCCESS() within the loop to bail out on first failure. */
 500     for (action = pBiDiTransform->pActiveScheme->actions; *action && U_SUCCESS(*pErrorCode); action++) {
 501         if ((*action)(pBiDiTransform, pErrorCode)) {
 502             if (action + 1) {
 503                 updateSrc(pBiDiTransform, pBiDiTransform->dest, *pBiDiTransform->pDestLength,
 504                         *pBiDiTransform->pDestLength, pErrorCode);
 505             }
 506             textChanged = TRUE;
 507         }
 508     }
 509     ubidi_setInverse(pBiDiTransform->pBidi, FALSE);
 510
 511     if (!textChanged && U_SUCCESS(*pErrorCode)) {
 512         /* Text was not changed - just copy src to dest */
 513         if (destSize < srcLength) {
 514             *pErrorCode = U_BUFFER_OVERFLOW_ERROR;
 515         } else {
 516             u_strncpy(dest, src, srcLength);
 517             destLength = srcLength;
 518         }
 519     }
 520 cleanup:
 521     if (pOrigTransform != pBiDiTransform) {
 522         ubiditransform_close(pBiDiTransform);
 523     } else {
 524         pBiDiTransform->dest = NULL;
 525         pBiDiTransform->pDestLength = NULL;
 526         pBiDiTransform->srcLength = 0;
 527         pBiDiTransform->destSize = 0;
 528     }
 529     return U_FAILURE(*pErrorCode) ? 0 : destLength;
 530 }