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comparison: layout/base/nsBidi.cpp
layout/base/nsBidi.cpp
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| -1:000000000000 | 0:20da94894058 |
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| 1 /* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- | |
| 2 * | |
| 3 * This Source Code Form is subject to the terms of the Mozilla Public | |
| 4 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 6 | |
| 7 #include "nsBidi.h" | |
| 8 #include "nsUnicodeProperties.h" | |
| 9 #include "nsCRTGlue.h" | |
| 10 | |
| 11 using namespace mozilla::unicode; | |
| 12 | |
| 13 // These are #defined in <sys/regset.h> under Solaris 10 x86 | |
| 14 #undef CS | |
| 15 #undef ES | |
| 16 | |
| 17 /* Comparing the description of the Bidi algorithm with this implementation | |
| 18 is easier with the same names for the Bidi types in the code as there. | |
| 19 */ | |
| 20 enum { | |
| 21 L = eCharType_LeftToRight, | |
| 22 R = eCharType_RightToLeft, | |
| 23 EN = eCharType_EuropeanNumber, | |
| 24 ES = eCharType_EuropeanNumberSeparator, | |
| 25 ET = eCharType_EuropeanNumberTerminator, | |
| 26 AN = eCharType_ArabicNumber, | |
| 27 CS = eCharType_CommonNumberSeparator, | |
| 28 B = eCharType_BlockSeparator, | |
| 29 S = eCharType_SegmentSeparator, | |
| 30 WS = eCharType_WhiteSpaceNeutral, | |
| 31 O_N = eCharType_OtherNeutral, | |
| 32 LRE = eCharType_LeftToRightEmbedding, | |
| 33 LRO = eCharType_LeftToRightOverride, | |
| 34 AL = eCharType_RightToLeftArabic, | |
| 35 RLE = eCharType_RightToLeftEmbedding, | |
| 36 RLO = eCharType_RightToLeftOverride, | |
| 37 PDF = eCharType_PopDirectionalFormat, | |
| 38 NSM = eCharType_DirNonSpacingMark, | |
| 39 BN = eCharType_BoundaryNeutral, | |
| 40 dirPropCount | |
| 41 }; | |
| 42 | |
| 43 /* to avoid some conditional statements, use tiny constant arrays */ | |
| 44 static Flags flagLR[2]={ DIRPROP_FLAG(L), DIRPROP_FLAG(R) }; | |
| 45 static Flags flagE[2]={ DIRPROP_FLAG(LRE), DIRPROP_FLAG(RLE) }; | |
| 46 static Flags flagO[2]={ DIRPROP_FLAG(LRO), DIRPROP_FLAG(RLO) }; | |
| 47 | |
| 48 #define DIRPROP_FLAG_LR(level) flagLR[(level)&1] | |
| 49 #define DIRPROP_FLAG_E(level) flagE[(level)&1] | |
| 50 #define DIRPROP_FLAG_O(level) flagO[(level)&1] | |
| 51 | |
| 52 /* | |
| 53 * General implementation notes: | |
| 54 * | |
| 55 * Throughout the implementation, there are comments like (W2) that refer to | |
| 56 * rules of the Bidi algorithm in its version 5, in this example to the second | |
| 57 * rule of the resolution of weak types. | |
| 58 * | |
| 59 * For handling surrogate pairs, where two UChar's form one "abstract" (or UTF-32) | |
| 60 * character according to UTF-16, the second UChar gets the directional property of | |
| 61 * the entire character assigned, while the first one gets a BN, a boundary | |
| 62 * neutral, type, which is ignored by most of the algorithm according to | |
| 63 * rule (X9) and the implementation suggestions of the Bidi algorithm. | |
| 64 * | |
| 65 * Later, AdjustWSLevels() will set the level for each BN to that of the | |
| 66 * following character (UChar), which results in surrogate pairs getting the | |
| 67 * same level on each of their surrogates. | |
| 68 * | |
| 69 * In a UTF-8 implementation, the same thing could be done: the last byte of | |
| 70 * a multi-byte sequence would get the "real" property, while all previous | |
| 71 * bytes of that sequence would get BN. | |
| 72 * | |
| 73 * It is not possible to assign all those parts of a character the same real | |
| 74 * property because this would fail in the resolution of weak types with rules | |
| 75 * that look at immediately surrounding types. | |
| 76 * | |
| 77 * As a related topic, this implementation does not remove Boundary Neutral | |
| 78 * types from the input, but ignores them whenever this is relevant. | |
| 79 * For example, the loop for the resolution of the weak types reads | |
| 80 * types until it finds a non-BN. | |
| 81 * Also, explicit embedding codes are neither changed into BN nor removed. | |
| 82 * They are only treated the same way real BNs are. | |
| 83 * As stated before, AdjustWSLevels() takes care of them at the end. | |
| 84 * For the purpose of conformance, the levels of all these codes | |
| 85 * do not matter. | |
| 86 * | |
| 87 * Note that this implementation never modifies the dirProps | |
| 88 * after the initial setup. | |
| 89 * | |
| 90 * | |
| 91 * In this implementation, the resolution of weak types (Wn), | |
| 92 * neutrals (Nn), and the assignment of the resolved level (In) | |
| 93 * are all done in one single loop, in ResolveImplicitLevels(). | |
| 94 * Changes of dirProp values are done on the fly, without writing | |
| 95 * them back to the dirProps array. | |
| 96 * | |
| 97 * | |
| 98 * This implementation contains code that allows to bypass steps of the | |
| 99 * algorithm that are not needed on the specific paragraph | |
| 100 * in order to speed up the most common cases considerably, | |
| 101 * like text that is entirely LTR, or RTL text without numbers. | |
| 102 * | |
| 103 * Most of this is done by setting a bit for each directional property | |
| 104 * in a flags variable and later checking for whether there are | |
| 105 * any LTR characters or any RTL characters, or both, whether | |
| 106 * there are any explicit embedding codes, etc. | |
| 107 * | |
| 108 * If the (Xn) steps are performed, then the flags are re-evaluated, | |
| 109 * because they will then not contain the embedding codes any more | |
| 110 * and will be adjusted for override codes, so that subsequently | |
| 111 * more bypassing may be possible than what the initial flags suggested. | |
| 112 * | |
| 113 * If the text is not mixed-directional, then the | |
| 114 * algorithm steps for the weak type resolution are not performed, | |
| 115 * and all levels are set to the paragraph level. | |
| 116 * | |
| 117 * If there are no explicit embedding codes, then the (Xn) steps | |
| 118 * are not performed. | |
| 119 * | |
| 120 * If embedding levels are supplied as a parameter, then all | |
| 121 * explicit embedding codes are ignored, and the (Xn) steps | |
| 122 * are not performed. | |
| 123 * | |
| 124 * White Space types could get the level of the run they belong to, | |
| 125 * and are checked with a test of (flags&MASK_EMBEDDING) to | |
| 126 * consider if the paragraph direction should be considered in | |
| 127 * the flags variable. | |
| 128 * | |
| 129 * If there are no White Space types in the paragraph, then | |
| 130 * (L1) is not necessary in AdjustWSLevels(). | |
| 131 */ | |
| 132 nsBidi::nsBidi() | |
| 133 { | |
| 134 Init(); | |
| 135 | |
| 136 mMayAllocateText=true; | |
| 137 mMayAllocateRuns=true; | |
| 138 } | |
| 139 | |
| 140 nsBidi::~nsBidi() | |
| 141 { | |
| 142 Free(); | |
| 143 } | |
| 144 | |
| 145 void nsBidi::Init() | |
| 146 { | |
| 147 /* reset the object, all pointers nullptr, all flags false, all sizes 0 */ | |
| 148 mLength = 0; | |
| 149 mParaLevel = 0; | |
| 150 mFlags = 0; | |
| 151 mDirection = NSBIDI_LTR; | |
| 152 mTrailingWSStart = 0; | |
| 153 | |
| 154 mDirPropsSize = 0; | |
| 155 mLevelsSize = 0; | |
| 156 mRunsSize = 0; | |
| 157 mRunCount = -1; | |
| 158 | |
| 159 mDirProps=nullptr; | |
| 160 mLevels=nullptr; | |
| 161 mRuns=nullptr; | |
| 162 | |
| 163 mDirPropsMemory=nullptr; | |
| 164 mLevelsMemory=nullptr; | |
| 165 mRunsMemory=nullptr; | |
| 166 | |
| 167 mMayAllocateText=false; | |
| 168 mMayAllocateRuns=false; | |
| 169 | |
| 170 } | |
| 171 | |
| 172 /* | |
| 173 * We are allowed to allocate memory if aMemory==nullptr or | |
| 174 * aMayAllocate==true for each array that we need. | |
| 175 * We also try to grow and shrink memory as needed if we | |
| 176 * allocate it. | |
| 177 * | |
| 178 * Assume aSizeNeeded>0. | |
| 179 * If *aMemory!=nullptr, then assume *aSize>0. | |
| 180 * | |
| 181 * ### this realloc() may unnecessarily copy the old data, | |
| 182 * which we know we don't need any more; | |
| 183 * is this the best way to do this?? | |
| 184 */ | |
| 185 bool nsBidi::GetMemory(void **aMemory, size_t *aSize, bool aMayAllocate, size_t aSizeNeeded) | |
| 186 { | |
| 187 /* check for existing memory */ | |
| 188 if(*aMemory==nullptr) { | |
| 189 /* we need to allocate memory */ | |
| 190 if(!aMayAllocate) { | |
| 191 return false; | |
| 192 } else { | |
| 193 *aMemory=moz_malloc(aSizeNeeded); | |
| 194 if (*aMemory!=nullptr) { | |
| 195 *aSize=aSizeNeeded; | |
| 196 return true; | |
| 197 } else { | |
| 198 *aSize=0; | |
| 199 return false; | |
| 200 } | |
| 201 } | |
| 202 } else { | |
| 203 /* there is some memory, is it enough or too much? */ | |
| 204 if(aSizeNeeded>*aSize && !aMayAllocate) { | |
| 205 /* not enough memory, and we must not allocate */ | |
| 206 return false; | |
| 207 } else if(aSizeNeeded!=*aSize && aMayAllocate) { | |
| 208 /* we may try to grow or shrink */ | |
| 209 void *memory=moz_realloc(*aMemory, aSizeNeeded); | |
| 210 | |
| 211 if(memory!=nullptr) { | |
| 212 *aMemory=memory; | |
| 213 *aSize=aSizeNeeded; | |
| 214 return true; | |
| 215 } else { | |
| 216 /* we failed to grow */ | |
| 217 return false; | |
| 218 } | |
| 219 } else { | |
| 220 /* we have at least enough memory and must not allocate */ | |
| 221 return true; | |
| 222 } | |
| 223 } | |
| 224 } | |
| 225 | |
| 226 void nsBidi::Free() | |
| 227 { | |
| 228 moz_free(mDirPropsMemory); | |
| 229 mDirPropsMemory = nullptr; | |
| 230 moz_free(mLevelsMemory); | |
| 231 mLevelsMemory = nullptr; | |
| 232 moz_free(mRunsMemory); | |
| 233 mRunsMemory = nullptr; | |
| 234 } | |
| 235 | |
| 236 /* SetPara ------------------------------------------------------------ */ | |
| 237 | |
| 238 nsresult nsBidi::SetPara(const char16_t *aText, int32_t aLength, | |
| 239 nsBidiLevel aParaLevel, nsBidiLevel *aEmbeddingLevels) | |
| 240 { | |
| 241 nsBidiDirection direction; | |
| 242 | |
| 243 /* check the argument values */ | |
| 244 if(aText==nullptr || | |
| 245 ((NSBIDI_MAX_EXPLICIT_LEVEL<aParaLevel) && !IS_DEFAULT_LEVEL(aParaLevel)) || | |
| 246 aLength<-1 | |
| 247 ) { | |
| 248 return NS_ERROR_INVALID_ARG; | |
| 249 } | |
| 250 | |
| 251 if(aLength==-1) { | |
| 252 aLength = NS_strlen(aText); | |
| 253 } | |
| 254 | |
| 255 /* initialize member data */ | |
| 256 mLength=aLength; | |
| 257 mParaLevel=aParaLevel; | |
| 258 mDirection=NSBIDI_LTR; | |
| 259 mTrailingWSStart=aLength; /* the levels[] will reflect the WS run */ | |
| 260 | |
| 261 mDirProps=nullptr; | |
| 262 mLevels=nullptr; | |
| 263 mRuns=nullptr; | |
| 264 | |
| 265 if(aLength==0) { | |
| 266 /* | |
| 267 * For an empty paragraph, create an nsBidi object with the aParaLevel and | |
| 268 * the flags and the direction set but without allocating zero-length arrays. | |
| 269 * There is nothing more to do. | |
| 270 */ | |
| 271 if(IS_DEFAULT_LEVEL(aParaLevel)) { | |
| 272 mParaLevel&=1; | |
| 273 } | |
| 274 if(aParaLevel&1) { | |
| 275 mFlags=DIRPROP_FLAG(R); | |
| 276 mDirection=NSBIDI_RTL; | |
| 277 } else { | |
| 278 mFlags=DIRPROP_FLAG(L); | |
| 279 mDirection=NSBIDI_LTR; | |
| 280 } | |
| 281 | |
| 282 mRunCount=0; | |
| 283 return NS_OK; | |
| 284 } | |
| 285 | |
| 286 mRunCount=-1; | |
| 287 | |
| 288 /* | |
| 289 * Get the directional properties, | |
| 290 * the flags bit-set, and | |
| 291 * determine the partagraph level if necessary. | |
| 292 */ | |
| 293 if(GETDIRPROPSMEMORY(aLength)) { | |
| 294 mDirProps=mDirPropsMemory; | |
| 295 GetDirProps(aText); | |
| 296 } else { | |
| 297 return NS_ERROR_OUT_OF_MEMORY; | |
| 298 } | |
| 299 | |
| 300 /* are explicit levels specified? */ | |
| 301 if(aEmbeddingLevels==nullptr) { | |
| 302 /* no: determine explicit levels according to the (Xn) rules */\ | |
| 303 if(GETLEVELSMEMORY(aLength)) { | |
| 304 mLevels=mLevelsMemory; | |
| 305 direction=ResolveExplicitLevels(); | |
| 306 } else { | |
| 307 return NS_ERROR_OUT_OF_MEMORY; | |
| 308 } | |
| 309 } else { | |
| 310 /* set BN for all explicit codes, check that all levels are aParaLevel..NSBIDI_MAX_EXPLICIT_LEVEL */ | |
| 311 mLevels=aEmbeddingLevels; | |
| 312 nsresult rv = CheckExplicitLevels(&direction); | |
| 313 if(NS_FAILED(rv)) { | |
| 314 return rv; | |
| 315 } | |
| 316 } | |
| 317 | |
| 318 /* | |
| 319 * The steps after (X9) in the Bidi algorithm are performed only if | |
| 320 * the paragraph text has mixed directionality! | |
| 321 */ | |
| 322 switch(direction) { | |
| 323 case NSBIDI_LTR: | |
| 324 /* make sure paraLevel is even */ | |
| 325 mParaLevel=(mParaLevel+1)&~1; | |
| 326 | |
| 327 /* all levels are implicitly at paraLevel (important for GetLevels()) */ | |
| 328 mTrailingWSStart=0; | |
| 329 break; | |
| 330 case NSBIDI_RTL: | |
| 331 /* make sure paraLevel is odd */ | |
| 332 mParaLevel|=1; | |
| 333 | |
| 334 /* all levels are implicitly at paraLevel (important for GetLevels()) */ | |
| 335 mTrailingWSStart=0; | |
| 336 break; | |
| 337 default: | |
| 338 /* | |
| 339 * If there are no external levels specified and there | |
| 340 * are no significant explicit level codes in the text, | |
| 341 * then we can treat the entire paragraph as one run. | |
| 342 * Otherwise, we need to perform the following rules on runs of | |
| 343 * the text with the same embedding levels. (X10) | |
| 344 * "Significant" explicit level codes are ones that actually | |
| 345 * affect non-BN characters. | |
| 346 * Examples for "insignificant" ones are empty embeddings | |
| 347 * LRE-PDF, LRE-RLE-PDF-PDF, etc. | |
| 348 */ | |
| 349 if(aEmbeddingLevels==nullptr && !(mFlags&DIRPROP_FLAG_MULTI_RUNS)) { | |
| 350 ResolveImplicitLevels(0, aLength, | |
| 351 GET_LR_FROM_LEVEL(mParaLevel), | |
| 352 GET_LR_FROM_LEVEL(mParaLevel)); | |
| 353 } else { | |
| 354 /* sor, eor: start and end types of same-level-run */ | |
| 355 nsBidiLevel *levels=mLevels; | |
| 356 int32_t start, limit=0; | |
| 357 nsBidiLevel level, nextLevel; | |
| 358 DirProp sor, eor; | |
| 359 | |
| 360 /* determine the first sor and set eor to it because of the loop body (sor=eor there) */ | |
| 361 level=mParaLevel; | |
| 362 nextLevel=levels[0]; | |
| 363 if(level<nextLevel) { | |
| 364 eor=GET_LR_FROM_LEVEL(nextLevel); | |
| 365 } else { | |
| 366 eor=GET_LR_FROM_LEVEL(level); | |
| 367 } | |
| 368 | |
| 369 do { | |
| 370 /* determine start and limit of the run (end points just behind the run) */ | |
| 371 | |
| 372 /* the values for this run's start are the same as for the previous run's end */ | |
| 373 sor=eor; | |
| 374 start=limit; | |
| 375 level=nextLevel; | |
| 376 | |
| 377 /* search for the limit of this run */ | |
| 378 while(++limit<aLength && levels[limit]==level) {} | |
| 379 | |
| 380 /* get the correct level of the next run */ | |
| 381 if(limit<aLength) { | |
| 382 nextLevel=levels[limit]; | |
| 383 } else { | |
| 384 nextLevel=mParaLevel; | |
| 385 } | |
| 386 | |
| 387 /* determine eor from max(level, nextLevel); sor is last run's eor */ | |
| 388 if((level&~NSBIDI_LEVEL_OVERRIDE)<(nextLevel&~NSBIDI_LEVEL_OVERRIDE)) { | |
| 389 eor=GET_LR_FROM_LEVEL(nextLevel); | |
| 390 } else { | |
| 391 eor=GET_LR_FROM_LEVEL(level); | |
| 392 } | |
| 393 | |
| 394 /* if the run consists of overridden directional types, then there | |
| 395 are no implicit types to be resolved */ | |
| 396 if(!(level&NSBIDI_LEVEL_OVERRIDE)) { | |
| 397 ResolveImplicitLevels(start, limit, sor, eor); | |
| 398 } | |
| 399 } while(limit<aLength); | |
| 400 } | |
| 401 | |
| 402 /* reset the embedding levels for some non-graphic characters (L1), (X9) */ | |
| 403 AdjustWSLevels(); | |
| 404 break; | |
| 405 } | |
| 406 | |
| 407 mDirection=direction; | |
| 408 return NS_OK; | |
| 409 } | |
| 410 | |
| 411 /* perform (P2)..(P3) ------------------------------------------------------- */ | |
| 412 | |
| 413 /* | |
| 414 * Get the directional properties for the text, | |
| 415 * calculate the flags bit-set, and | |
| 416 * determine the partagraph level if necessary. | |
| 417 */ | |
| 418 void nsBidi::GetDirProps(const char16_t *aText) | |
| 419 { | |
| 420 DirProp *dirProps=mDirPropsMemory; /* mDirProps is const */ | |
| 421 | |
| 422 int32_t i=0, length=mLength; | |
| 423 Flags flags=0; /* collect all directionalities in the text */ | |
| 424 char16_t uchar; | |
| 425 DirProp dirProp; | |
| 426 | |
| 427 if(IS_DEFAULT_LEVEL(mParaLevel)) { | |
| 428 /* determine the paragraph level (P2..P3) */ | |
| 429 for(;;) { | |
| 430 uchar=aText[i]; | |
| 431 if(!IS_FIRST_SURROGATE(uchar) || i+1==length || !IS_SECOND_SURROGATE(aText[i+1])) { | |
| 432 /* not a surrogate pair */ | |
| 433 flags|=DIRPROP_FLAG(dirProps[i]=dirProp=GetBidiCat((uint32_t)uchar)); | |
| 434 } else { | |
| 435 /* a surrogate pair */ | |
| 436 dirProps[i++]=BN; /* first surrogate in the pair gets the BN type */ | |
| 437 flags|=DIRPROP_FLAG(dirProps[i]=dirProp=GetBidiCat(GET_UTF_32(uchar, aText[i])))|DIRPROP_FLAG(BN); | |
| 438 } | |
| 439 ++i; | |
| 440 if(dirProp==L) { | |
| 441 mParaLevel=0; | |
| 442 break; | |
| 443 } else if(dirProp==R || dirProp==AL) { | |
| 444 mParaLevel=1; | |
| 445 break; | |
| 446 } else if(i==length) { | |
| 447 /* | |
| 448 * see comment in nsIBidi.h: | |
| 449 * the DEFAULT_XXX values are designed so that | |
| 450 * their bit 0 alone yields the intended default | |
| 451 */ | |
| 452 mParaLevel&=1; | |
| 453 break; | |
| 454 } | |
| 455 } | |
| 456 } | |
| 457 | |
| 458 /* get the rest of the directional properties and the flags bits */ | |
| 459 while(i<length) { | |
| 460 uchar=aText[i]; | |
| 461 if(!IS_FIRST_SURROGATE(uchar) || i+1==length || !IS_SECOND_SURROGATE(aText[i+1])) { | |
| 462 /* not a surrogate pair */ | |
| 463 flags|=DIRPROP_FLAG(dirProps[i]=GetBidiCat((uint32_t)uchar)); | |
| 464 } else { | |
| 465 /* a surrogate pair */ | |
| 466 dirProps[i++]=BN; /* second surrogate in the pair gets the BN type */ | |
| 467 flags|=DIRPROP_FLAG(dirProps[i]=GetBidiCat(GET_UTF_32(uchar, aText[i])))|DIRPROP_FLAG(BN); | |
| 468 } | |
| 469 ++i; | |
| 470 } | |
| 471 if(flags&MASK_EMBEDDING) { | |
| 472 flags|=DIRPROP_FLAG_LR(mParaLevel); | |
| 473 } | |
| 474 mFlags=flags; | |
| 475 } | |
| 476 | |
| 477 /* perform (X1)..(X9) ------------------------------------------------------- */ | |
| 478 | |
| 479 /* | |
| 480 * Resolve the explicit levels as specified by explicit embedding codes. | |
| 481 * Recalculate the flags to have them reflect the real properties | |
| 482 * after taking the explicit embeddings into account. | |
| 483 * | |
| 484 * The Bidi algorithm is designed to result in the same behavior whether embedding | |
| 485 * levels are externally specified (from "styled text", supposedly the preferred | |
| 486 * method) or set by explicit embedding codes (LRx, RLx, PDF) in the plain text. | |
| 487 * That is why (X9) instructs to remove all explicit codes (and BN). | |
| 488 * However, in a real implementation, this removal of these codes and their index | |
| 489 * positions in the plain text is undesirable since it would result in | |
| 490 * reallocated, reindexed text. | |
| 491 * Instead, this implementation leaves the codes in there and just ignores them | |
| 492 * in the subsequent processing. | |
| 493 * In order to get the same reordering behavior, positions with a BN or an | |
| 494 * explicit embedding code just get the same level assigned as the last "real" | |
| 495 * character. | |
| 496 * | |
| 497 * Some implementations, not this one, then overwrite some of these | |
| 498 * directionality properties at "real" same-level-run boundaries by | |
| 499 * L or R codes so that the resolution of weak types can be performed on the | |
| 500 * entire paragraph at once instead of having to parse it once more and | |
| 501 * perform that resolution on same-level-runs. | |
| 502 * This limits the scope of the implicit rules in effectively | |
| 503 * the same way as the run limits. | |
| 504 * | |
| 505 * Instead, this implementation does not modify these codes. | |
| 506 * On one hand, the paragraph has to be scanned for same-level-runs, but | |
| 507 * on the other hand, this saves another loop to reset these codes, | |
| 508 * or saves making and modifying a copy of dirProps[]. | |
| 509 * | |
| 510 * | |
| 511 * Note that (Pn) and (Xn) changed significantly from version 4 of the Bidi algorithm. | |
| 512 * | |
| 513 * | |
| 514 * Handling the stack of explicit levels (Xn): | |
| 515 * | |
| 516 * With the Bidi stack of explicit levels, | |
| 517 * as pushed with each LRE, RLE, LRO, and RLO and popped with each PDF, | |
| 518 * the explicit level must never exceed NSBIDI_MAX_EXPLICIT_LEVEL==61. | |
| 519 * | |
| 520 * In order to have a correct push-pop semantics even in the case of overflows, | |
| 521 * there are two overflow counters: | |
| 522 * - countOver60 is incremented with each LRx at level 60 | |
| 523 * - from level 60, one RLx increases the level to 61 | |
| 524 * - countOver61 is incremented with each LRx and RLx at level 61 | |
| 525 * | |
| 526 * Popping levels with PDF must work in the opposite order so that level 61 | |
| 527 * is correct at the correct point. Underflows (too many PDFs) must be checked. | |
| 528 * | |
| 529 * This implementation assumes that NSBIDI_MAX_EXPLICIT_LEVEL is odd. | |
| 530 */ | |
| 531 | |
| 532 nsBidiDirection nsBidi::ResolveExplicitLevels() | |
| 533 { | |
| 534 const DirProp *dirProps=mDirProps; | |
| 535 nsBidiLevel *levels=mLevels; | |
| 536 | |
| 537 int32_t i=0, length=mLength; | |
| 538 Flags flags=mFlags; /* collect all directionalities in the text */ | |
| 539 DirProp dirProp; | |
| 540 nsBidiLevel level=mParaLevel; | |
| 541 | |
| 542 nsBidiDirection direction; | |
| 543 | |
| 544 /* determine if the text is mixed-directional or single-directional */ | |
| 545 direction=DirectionFromFlags(flags); | |
| 546 | |
| 547 /* we may not need to resolve any explicit levels */ | |
| 548 if(direction!=NSBIDI_MIXED) { | |
| 549 /* not mixed directionality: levels don't matter - trailingWSStart will be 0 */ | |
| 550 } else if(!(flags&MASK_EXPLICIT)) { | |
| 551 /* mixed, but all characters are at the same embedding level */ | |
| 552 /* set all levels to the paragraph level */ | |
| 553 for(i=0; i<length; ++i) { | |
| 554 levels[i]=level; | |
| 555 } | |
| 556 } else { | |
| 557 /* continue to perform (Xn) */ | |
| 558 | |
| 559 /* (X1) level is set for all codes, embeddingLevel keeps track of the push/pop operations */ | |
| 560 /* both variables may carry the NSBIDI_LEVEL_OVERRIDE flag to indicate the override status */ | |
| 561 nsBidiLevel embeddingLevel=level, newLevel, stackTop=0; | |
| 562 | |
| 563 nsBidiLevel stack[NSBIDI_MAX_EXPLICIT_LEVEL]; /* we never push anything >=NSBIDI_MAX_EXPLICIT_LEVEL */ | |
| 564 uint32_t countOver60=0, countOver61=0; /* count overflows of explicit levels */ | |
| 565 | |
| 566 /* recalculate the flags */ | |
| 567 flags=0; | |
| 568 | |
| 569 /* since we assume that this is a single paragraph, we ignore (X8) */ | |
| 570 for(i=0; i<length; ++i) { | |
| 571 dirProp=dirProps[i]; | |
| 572 switch(dirProp) { | |
| 573 case LRE: | |
| 574 case LRO: | |
| 575 /* (X3, X5) */ | |
| 576 newLevel=(embeddingLevel+2)&~(NSBIDI_LEVEL_OVERRIDE|1); /* least greater even level */ | |
| 577 if(newLevel<=NSBIDI_MAX_EXPLICIT_LEVEL) { | |
| 578 stack[stackTop]=embeddingLevel; | |
| 579 ++stackTop; | |
| 580 embeddingLevel=newLevel; | |
| 581 if(dirProp==LRO) { | |
| 582 embeddingLevel|=NSBIDI_LEVEL_OVERRIDE; | |
| 583 } else { | |
| 584 embeddingLevel&=~NSBIDI_LEVEL_OVERRIDE; | |
| 585 } | |
| 586 } else if((embeddingLevel&~NSBIDI_LEVEL_OVERRIDE)==NSBIDI_MAX_EXPLICIT_LEVEL) { | |
| 587 ++countOver61; | |
| 588 } else /* (embeddingLevel&~NSBIDI_LEVEL_OVERRIDE)==NSBIDI_MAX_EXPLICIT_LEVEL-1 */ { | |
| 589 ++countOver60; | |
| 590 } | |
| 591 flags|=DIRPROP_FLAG(BN); | |
| 592 break; | |
| 593 case RLE: | |
| 594 case RLO: | |
| 595 /* (X2, X4) */ | |
| 596 newLevel=((embeddingLevel&~NSBIDI_LEVEL_OVERRIDE)+1)|1; /* least greater odd level */ | |
| 597 if(newLevel<=NSBIDI_MAX_EXPLICIT_LEVEL) { | |
| 598 stack[stackTop]=embeddingLevel; | |
| 599 ++stackTop; | |
| 600 embeddingLevel=newLevel; | |
| 601 if(dirProp==RLO) { | |
| 602 embeddingLevel|=NSBIDI_LEVEL_OVERRIDE; | |
| 603 } else { | |
| 604 embeddingLevel&=~NSBIDI_LEVEL_OVERRIDE; | |
| 605 } | |
| 606 } else { | |
| 607 ++countOver61; | |
| 608 } | |
| 609 flags|=DIRPROP_FLAG(BN); | |
| 610 break; | |
| 611 case PDF: | |
| 612 /* (X7) */ | |
| 613 /* handle all the overflow cases first */ | |
| 614 if(countOver61>0) { | |
| 615 --countOver61; | |
| 616 } else if(countOver60>0 && (embeddingLevel&~NSBIDI_LEVEL_OVERRIDE)!=NSBIDI_MAX_EXPLICIT_LEVEL) { | |
| 617 /* handle LRx overflows from level 60 */ | |
| 618 --countOver60; | |
| 619 } else if(stackTop>0) { | |
| 620 /* this is the pop operation; it also pops level 61 while countOver60>0 */ | |
| 621 --stackTop; | |
| 622 embeddingLevel=stack[stackTop]; | |
| 623 /* } else { (underflow) */ | |
| 624 } | |
| 625 flags|=DIRPROP_FLAG(BN); | |
| 626 break; | |
| 627 case B: | |
| 628 /* | |
| 629 * We do not really expect to see a paragraph separator (B), | |
| 630 * but we should do something reasonable with it, | |
| 631 * especially at the end of the text. | |
| 632 */ | |
| 633 stackTop=0; | |
| 634 countOver60=countOver61=0; | |
| 635 embeddingLevel=level=mParaLevel; | |
| 636 flags|=DIRPROP_FLAG(B); | |
| 637 break; | |
| 638 case BN: | |
| 639 /* BN, LRE, RLE, and PDF are supposed to be removed (X9) */ | |
| 640 /* they will get their levels set correctly in AdjustWSLevels() */ | |
| 641 flags|=DIRPROP_FLAG(BN); | |
| 642 break; | |
| 643 default: | |
| 644 /* all other types get the "real" level */ | |
| 645 if(level!=embeddingLevel) { | |
| 646 level=embeddingLevel; | |
| 647 if(level&NSBIDI_LEVEL_OVERRIDE) { | |
| 648 flags|=DIRPROP_FLAG_O(level)|DIRPROP_FLAG_MULTI_RUNS; | |
| 649 } else { | |
| 650 flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG_MULTI_RUNS; | |
| 651 } | |
| 652 } | |
| 653 if(!(level&NSBIDI_LEVEL_OVERRIDE)) { | |
| 654 flags|=DIRPROP_FLAG(dirProp); | |
| 655 } | |
| 656 break; | |
| 657 } | |
| 658 | |
| 659 /* | |
| 660 * We need to set reasonable levels even on BN codes and | |
| 661 * explicit codes because we will later look at same-level runs (X10). | |
| 662 */ | |
| 663 levels[i]=level; | |
| 664 } | |
| 665 if(flags&MASK_EMBEDDING) { | |
| 666 flags|=DIRPROP_FLAG_LR(mParaLevel); | |
| 667 } | |
| 668 | |
| 669 /* subsequently, ignore the explicit codes and BN (X9) */ | |
| 670 | |
| 671 /* again, determine if the text is mixed-directional or single-directional */ | |
| 672 mFlags=flags; | |
| 673 direction=DirectionFromFlags(flags); | |
| 674 } | |
| 675 return direction; | |
| 676 } | |
| 677 | |
| 678 /* | |
| 679 * Use a pre-specified embedding levels array: | |
| 680 * | |
| 681 * Adjust the directional properties for overrides (->LEVEL_OVERRIDE), | |
| 682 * ignore all explicit codes (X9), | |
| 683 * and check all the preset levels. | |
| 684 * | |
| 685 * Recalculate the flags to have them reflect the real properties | |
| 686 * after taking the explicit embeddings into account. | |
| 687 */ | |
| 688 nsresult nsBidi::CheckExplicitLevels(nsBidiDirection *aDirection) | |
| 689 { | |
| 690 const DirProp *dirProps=mDirProps; | |
| 691 nsBidiLevel *levels=mLevels; | |
| 692 | |
| 693 int32_t i, length=mLength; | |
| 694 Flags flags=0; /* collect all directionalities in the text */ | |
| 695 nsBidiLevel level, paraLevel=mParaLevel; | |
| 696 | |
| 697 for(i=0; i<length; ++i) { | |
| 698 level=levels[i]; | |
| 699 if(level&NSBIDI_LEVEL_OVERRIDE) { | |
| 700 /* keep the override flag in levels[i] but adjust the flags */ | |
| 701 level&=~NSBIDI_LEVEL_OVERRIDE; /* make the range check below simpler */ | |
| 702 flags|=DIRPROP_FLAG_O(level); | |
| 703 } else { | |
| 704 /* set the flags */ | |
| 705 flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG(dirProps[i]); | |
| 706 } | |
| 707 if(level<paraLevel || NSBIDI_MAX_EXPLICIT_LEVEL<level) { | |
| 708 /* level out of bounds */ | |
| 709 *aDirection = NSBIDI_LTR; | |
| 710 return NS_ERROR_INVALID_ARG; | |
| 711 } | |
| 712 } | |
| 713 if(flags&MASK_EMBEDDING) { | |
| 714 flags|=DIRPROP_FLAG_LR(mParaLevel); | |
| 715 } | |
| 716 | |
| 717 /* determine if the text is mixed-directional or single-directional */ | |
| 718 mFlags=flags; | |
| 719 *aDirection = DirectionFromFlags(flags); | |
| 720 return NS_OK; | |
| 721 } | |
| 722 | |
| 723 /* determine if the text is mixed-directional or single-directional */ | |
| 724 nsBidiDirection nsBidi::DirectionFromFlags(Flags aFlags) | |
| 725 { | |
| 726 /* if the text contains AN and neutrals, then some neutrals may become RTL */ | |
| 727 if(!(aFlags&MASK_RTL || (aFlags&DIRPROP_FLAG(AN) && aFlags&MASK_POSSIBLE_N))) { | |
| 728 return NSBIDI_LTR; | |
| 729 } else if(!(aFlags&MASK_LTR)) { | |
| 730 return NSBIDI_RTL; | |
| 731 } else { | |
| 732 return NSBIDI_MIXED; | |
| 733 } | |
| 734 } | |
| 735 | |
| 736 /* perform rules (Wn), (Nn), and (In) on a run of the text ------------------ */ | |
| 737 | |
| 738 /* | |
| 739 * This implementation of the (Wn) rules applies all rules in one pass. | |
| 740 * In order to do so, it needs a look-ahead of typically 1 character | |
| 741 * (except for W5: sequences of ET) and keeps track of changes | |
| 742 * in a rule Wp that affect a later Wq (p<q). | |
| 743 * | |
| 744 * historyOfEN is a variable-saver: it contains 4 boolean states; | |
| 745 * a bit in it set to 1 means: | |
| 746 * bit 0: the current code is an EN after W2 | |
| 747 * bit 1: the current code is an EN after W4 | |
| 748 * bit 2: the previous code was an EN after W2 | |
| 749 * bit 3: the previous code was an EN after W4 | |
| 750 * In other words, b0..1 have transitions of EN in the current iteration, | |
| 751 * while b2..3 have the transitions of EN in the previous iteration. | |
| 752 * A simple historyOfEN<<=2 suffices for the propagation. | |
| 753 * | |
| 754 * The (Nn) and (In) rules are also performed in that same single loop, | |
| 755 * but effectively one iteration behind for white space. | |
| 756 * | |
| 757 * Since all implicit rules are performed in one step, it is not necessary | |
| 758 * to actually store the intermediate directional properties in dirProps[]. | |
| 759 */ | |
| 760 | |
| 761 #define EN_SHIFT 2 | |
| 762 #define EN_AFTER_W2 1 | |
| 763 #define EN_AFTER_W4 2 | |
| 764 #define EN_ALL 3 | |
| 765 #define PREV_EN_AFTER_W2 4 | |
| 766 #define PREV_EN_AFTER_W4 8 | |
| 767 | |
| 768 void nsBidi::ResolveImplicitLevels(int32_t aStart, int32_t aLimit, | |
| 769 DirProp aSOR, DirProp aEOR) | |
| 770 { | |
| 771 const DirProp *dirProps=mDirProps; | |
| 772 nsBidiLevel *levels=mLevels; | |
| 773 | |
| 774 int32_t i, next, neutralStart=-1; | |
| 775 DirProp prevDirProp, dirProp, nextDirProp, lastStrong, beforeNeutral; | |
| 776 uint8_t historyOfEN; | |
| 777 | |
| 778 /* initialize: current at aSOR, next at aStart (it is aStart<aLimit) */ | |
| 779 next=aStart; | |
| 780 beforeNeutral=dirProp=lastStrong=aSOR; | |
| 781 nextDirProp=dirProps[next]; | |
| 782 historyOfEN=0; | |
| 783 | |
| 784 /* | |
| 785 * In all steps of this implementation, BN and explicit embedding codes | |
| 786 * must be treated as if they didn't exist (X9). | |
| 787 * They will get levels set before a non-neutral character, and remain | |
| 788 * undefined before a neutral one, but AdjustWSLevels() will take care | |
| 789 * of all of them. | |
| 790 */ | |
| 791 while(DIRPROP_FLAG(nextDirProp)&MASK_BN_EXPLICIT) { | |
| 792 if(++next<aLimit) { | |
| 793 nextDirProp=dirProps[next]; | |
| 794 } else { | |
| 795 nextDirProp=aEOR; | |
| 796 break; | |
| 797 } | |
| 798 } | |
| 799 | |
| 800 /* loop for entire run */ | |
| 801 while(next<aLimit) { | |
| 802 /* advance */ | |
| 803 prevDirProp=dirProp; | |
| 804 dirProp=nextDirProp; | |
| 805 i=next; | |
| 806 do { | |
| 807 if(++next<aLimit) { | |
| 808 nextDirProp=dirProps[next]; | |
| 809 } else { | |
| 810 nextDirProp=aEOR; | |
| 811 break; | |
| 812 } | |
| 813 } while(DIRPROP_FLAG(nextDirProp)&MASK_BN_EXPLICIT); | |
| 814 historyOfEN<<=EN_SHIFT; | |
| 815 | |
| 816 /* (W1..W7) */ | |
| 817 switch(dirProp) { | |
| 818 case L: | |
| 819 lastStrong=L; | |
| 820 break; | |
| 821 case R: | |
| 822 lastStrong=R; | |
| 823 break; | |
| 824 case AL: | |
| 825 /* (W3) */ | |
| 826 lastStrong=AL; | |
| 827 dirProp=R; | |
| 828 break; | |
| 829 case EN: | |
| 830 /* we have to set historyOfEN correctly */ | |
| 831 if(lastStrong==AL) { | |
| 832 /* (W2) */ | |
| 833 dirProp=AN; | |
| 834 } else { | |
| 835 if(lastStrong==L) { | |
| 836 /* (W7) */ | |
| 837 dirProp=L; | |
| 838 } | |
| 839 /* this EN stays after (W2) and (W4) - at least before (W7) */ | |
| 840 historyOfEN|=EN_ALL; | |
| 841 } | |
| 842 break; | |
| 843 case ES: | |
| 844 if( historyOfEN&PREV_EN_AFTER_W2 && /* previous was EN before (W4) */ | |
| 845 nextDirProp==EN && lastStrong!=AL /* next is EN and (W2) won't make it AN */ | |
| 846 ) { | |
| 847 /* (W4) */ | |
| 848 if(lastStrong!=L) { | |
| 849 dirProp=EN; | |
| 850 } else { | |
| 851 /* (W7) */ | |
| 852 dirProp=L; | |
| 853 } | |
| 854 historyOfEN|=EN_AFTER_W4; | |
| 855 } else { | |
| 856 /* (W6) */ | |
| 857 dirProp=O_N; | |
| 858 } | |
| 859 break; | |
| 860 case CS: | |
| 861 if( historyOfEN&PREV_EN_AFTER_W2 && /* previous was EN before (W4) */ | |
| 862 nextDirProp==EN && lastStrong!=AL /* next is EN and (W2) won't make it AN */ | |
| 863 ) { | |
| 864 /* (W4) */ | |
| 865 if(lastStrong!=L) { | |
| 866 dirProp=EN; | |
| 867 } else { | |
| 868 /* (W7) */ | |
| 869 dirProp=L; | |
| 870 } | |
| 871 historyOfEN|=EN_AFTER_W4; | |
| 872 } else if(prevDirProp==AN && /* previous was AN */ | |
| 873 (nextDirProp==AN || /* next is AN */ | |
| 874 (nextDirProp==EN && lastStrong==AL)) /* or (W2) will make it one */ | |
| 875 ) { | |
| 876 /* (W4) */ | |
| 877 dirProp=AN; | |
| 878 } else { | |
| 879 /* (W6) */ | |
| 880 dirProp=O_N; | |
| 881 } | |
| 882 break; | |
| 883 case ET: | |
| 884 /* get sequence of ET; advance only next, not current, previous or historyOfEN */ | |
| 885 while(next<aLimit && DIRPROP_FLAG(nextDirProp)&MASK_ET_NSM_BN /* (W1), (X9) */) { | |
| 886 if(++next<aLimit) { | |
| 887 nextDirProp=dirProps[next]; | |
| 888 } else { | |
| 889 nextDirProp=aEOR; | |
| 890 break; | |
| 891 } | |
| 892 } | |
| 893 | |
| 894 if( historyOfEN&PREV_EN_AFTER_W4 || /* previous was EN before (W5) */ | |
| 895 (nextDirProp==EN && lastStrong!=AL) /* next is EN and (W2) won't make it AN */ | |
| 896 ) { | |
| 897 /* (W5) */ | |
| 898 if(lastStrong!=L) { | |
| 899 dirProp=EN; | |
| 900 } else { | |
| 901 /* (W7) */ | |
| 902 dirProp=L; | |
| 903 } | |
| 904 } else { | |
| 905 /* (W6) */ | |
| 906 dirProp=O_N; | |
| 907 } | |
| 908 | |
| 909 /* apply the result of (W1), (W5)..(W7) to the entire sequence of ET */ | |
| 910 break; | |
| 911 case NSM: | |
| 912 /* (W1) */ | |
| 913 dirProp=prevDirProp; | |
| 914 /* set historyOfEN back to prevDirProp's historyOfEN */ | |
| 915 historyOfEN>>=EN_SHIFT; | |
| 916 /* | |
| 917 * Technically, this should be done before the switch() in the form | |
| 918 * if(nextDirProp==NSM) { | |
| 919 * dirProps[next]=nextDirProp=dirProp; | |
| 920 * } | |
| 921 * | |
| 922 * - effectively one iteration ahead. | |
| 923 * However, whether the next dirProp is NSM or is equal to the current dirProp | |
| 924 * does not change the outcome of any condition in (W2)..(W7). | |
| 925 */ | |
| 926 break; | |
| 927 default: | |
| 928 break; | |
| 929 } | |
| 930 | |
| 931 /* here, it is always [prev,this,next]dirProp!=BN; it may be next>i+1 */ | |
| 932 | |
| 933 /* perform (Nn) - here, only L, R, EN, AN, and neutrals are left */ | |
| 934 /* this is one iteration late for the neutrals */ | |
| 935 if(DIRPROP_FLAG(dirProp)&MASK_N) { | |
| 936 if(neutralStart<0) { | |
| 937 /* start of a sequence of neutrals */ | |
| 938 neutralStart=i; | |
| 939 beforeNeutral=prevDirProp; | |
| 940 } | |
| 941 } else /* not a neutral, can be only one of { L, R, EN, AN } */ { | |
| 942 /* | |
| 943 * Note that all levels[] values are still the same at this | |
| 944 * point because this function is called for an entire | |
| 945 * same-level run. | |
| 946 * Therefore, we need to read only one actual level. | |
| 947 */ | |
| 948 nsBidiLevel level=levels[i]; | |
| 949 | |
| 950 if(neutralStart>=0) { | |
| 951 nsBidiLevel final; | |
| 952 /* end of a sequence of neutrals (dirProp is "afterNeutral") */ | |
| 953 if(beforeNeutral==L) { | |
| 954 if(dirProp==L) { | |
| 955 final=0; /* make all neutrals L (N1) */ | |
| 956 } else { | |
| 957 final=level; /* make all neutrals "e" (N2) */ | |
| 958 } | |
| 959 } else /* beforeNeutral is one of { R, EN, AN } */ { | |
| 960 if(dirProp==L) { | |
| 961 final=level; /* make all neutrals "e" (N2) */ | |
| 962 } else { | |
| 963 final=1; /* make all neutrals R (N1) */ | |
| 964 } | |
| 965 } | |
| 966 /* perform (In) on the sequence of neutrals */ | |
| 967 if((level^final)&1) { | |
| 968 /* do something only if we need to _change_ the level */ | |
| 969 do { | |
| 970 ++levels[neutralStart]; | |
| 971 } while(++neutralStart<i); | |
| 972 } | |
| 973 neutralStart=-1; | |
| 974 } | |
| 975 | |
| 976 /* perform (In) on the non-neutral character */ | |
| 977 /* | |
| 978 * in the cases of (W5), processing a sequence of ET, | |
| 979 * and of (X9), skipping BN, | |
| 980 * there may be multiple characters from i to <next | |
| 981 * that all get (virtually) the same dirProp and (really) the same level | |
| 982 */ | |
| 983 if(dirProp==L) { | |
| 984 if(level&1) { | |
| 985 ++level; | |
| 986 } else { | |
| 987 i=next; /* we keep the levels */ | |
| 988 } | |
| 989 } else if(dirProp==R) { | |
| 990 if(!(level&1)) { | |
| 991 ++level; | |
| 992 } else { | |
| 993 i=next; /* we keep the levels */ | |
| 994 } | |
| 995 } else /* EN or AN */ { | |
| 996 level=(level+2)&~1; /* least greater even level */ | |
| 997 } | |
| 998 | |
| 999 /* apply the new level to the sequence, if necessary */ | |
| 1000 while(i<next) { | |
| 1001 levels[i++]=level; | |
| 1002 } | |
| 1003 } | |
| 1004 } | |
| 1005 | |
| 1006 /* perform (Nn) - here, | |
| 1007 the character after the neutrals is aEOR, which is either L or R */ | |
| 1008 /* this is one iteration late for the neutrals */ | |
| 1009 if(neutralStart>=0) { | |
| 1010 /* | |
| 1011 * Note that all levels[] values are still the same at this | |
| 1012 * point because this function is called for an entire | |
| 1013 * same-level run. | |
| 1014 * Therefore, we need to read only one actual level. | |
| 1015 */ | |
| 1016 nsBidiLevel level=levels[neutralStart], final; | |
| 1017 | |
| 1018 /* end of a sequence of neutrals (aEOR is "afterNeutral") */ | |
| 1019 if(beforeNeutral==L) { | |
| 1020 if(aEOR==L) { | |
| 1021 final=0; /* make all neutrals L (N1) */ | |
| 1022 } else { | |
| 1023 final=level; /* make all neutrals "e" (N2) */ | |
| 1024 } | |
| 1025 } else /* beforeNeutral is one of { R, EN, AN } */ { | |
| 1026 if(aEOR==L) { | |
| 1027 final=level; /* make all neutrals "e" (N2) */ | |
| 1028 } else { | |
| 1029 final=1; /* make all neutrals R (N1) */ | |
| 1030 } | |
| 1031 } | |
| 1032 /* perform (In) on the sequence of neutrals */ | |
| 1033 if((level^final)&1) { | |
| 1034 /* do something only if we need to _change_ the level */ | |
| 1035 do { | |
| 1036 ++levels[neutralStart]; | |
| 1037 } while(++neutralStart<aLimit); | |
| 1038 } | |
| 1039 } | |
| 1040 } | |
| 1041 | |
| 1042 /* perform (L1) and (X9) ---------------------------------------------------- */ | |
| 1043 | |
| 1044 /* | |
| 1045 * Reset the embedding levels for some non-graphic characters (L1). | |
| 1046 * This function also sets appropriate levels for BN, and | |
| 1047 * explicit embedding types that are supposed to have been removed | |
| 1048 * from the paragraph in (X9). | |
| 1049 */ | |
| 1050 void nsBidi::AdjustWSLevels() | |
| 1051 { | |
| 1052 const DirProp *dirProps=mDirProps; | |
| 1053 nsBidiLevel *levels=mLevels; | |
| 1054 int32_t i; | |
| 1055 | |
| 1056 if(mFlags&MASK_WS) { | |
| 1057 nsBidiLevel paraLevel=mParaLevel; | |
| 1058 Flags flag; | |
| 1059 | |
| 1060 i=mTrailingWSStart; | |
| 1061 while(i>0) { | |
| 1062 /* reset a sequence of WS/BN before eop and B/S to the paragraph paraLevel */ | |
| 1063 while(i>0 && DIRPROP_FLAG(dirProps[--i])&MASK_WS) { | |
| 1064 levels[i]=paraLevel; | |
| 1065 } | |
| 1066 | |
| 1067 /* reset BN to the next character's paraLevel until B/S, which restarts above loop */ | |
| 1068 /* here, i+1 is guaranteed to be <length */ | |
| 1069 while(i>0) { | |
| 1070 flag=DIRPROP_FLAG(dirProps[--i]); | |
| 1071 if(flag&MASK_BN_EXPLICIT) { | |
| 1072 levels[i]=levels[i+1]; | |
| 1073 } else if(flag&MASK_B_S) { | |
| 1074 levels[i]=paraLevel; | |
| 1075 break; | |
| 1076 } | |
| 1077 } | |
| 1078 } | |
| 1079 } | |
| 1080 | |
| 1081 /* now remove the NSBIDI_LEVEL_OVERRIDE flags, if any */ | |
| 1082 /* (a separate loop can be optimized more easily by a compiler) */ | |
| 1083 if(mFlags&MASK_OVERRIDE) { | |
| 1084 for(i=mTrailingWSStart; i>0;) { | |
| 1085 levels[--i]&=~NSBIDI_LEVEL_OVERRIDE; | |
| 1086 } | |
| 1087 } | |
| 1088 } | |
| 1089 | |
| 1090 nsresult nsBidi::GetDirection(nsBidiDirection* aDirection) | |
| 1091 { | |
| 1092 *aDirection = mDirection; | |
| 1093 return NS_OK; | |
| 1094 } | |
| 1095 | |
| 1096 nsresult nsBidi::GetParaLevel(nsBidiLevel* aParaLevel) | |
| 1097 { | |
| 1098 *aParaLevel = mParaLevel; | |
| 1099 return NS_OK; | |
| 1100 } | |
| 1101 #ifdef FULL_BIDI_ENGINE | |
| 1102 | |
| 1103 /* -------------------------------------------------------------------------- */ | |
| 1104 | |
| 1105 nsresult nsBidi::GetLength(int32_t* aLength) | |
| 1106 { | |
| 1107 *aLength = mLength; | |
| 1108 return NS_OK; | |
| 1109 } | |
| 1110 | |
| 1111 /* | |
| 1112 * General remarks about the functions in this section: | |
| 1113 * | |
| 1114 * These functions deal with the aspects of potentially mixed-directional | |
| 1115 * text in a single paragraph or in a line of a single paragraph | |
| 1116 * which has already been processed according to | |
| 1117 * the Unicode 3.0 Bidi algorithm as defined in | |
| 1118 * http://www.unicode.org/unicode/reports/tr9/ , version 5, | |
| 1119 * also described in The Unicode Standard, Version 3.0 . | |
| 1120 * | |
| 1121 * This means that there is a nsBidi object with a levels | |
| 1122 * and a dirProps array. | |
| 1123 * paraLevel and direction are also set. | |
| 1124 * Only if the length of the text is zero, then levels==dirProps==nullptr. | |
| 1125 * | |
| 1126 * The overall directionality of the paragraph | |
| 1127 * or line is used to bypass the reordering steps if possible. | |
| 1128 * Even purely RTL text does not need reordering there because | |
| 1129 * the getLogical/VisualIndex() functions can compute the | |
| 1130 * index on the fly in such a case. | |
| 1131 * | |
| 1132 * The implementation of the access to same-level-runs and of the reordering | |
| 1133 * do attempt to provide better performance and less memory usage compared to | |
| 1134 * a direct implementation of especially rule (L2) with an array of | |
| 1135 * one (32-bit) integer per text character. | |
| 1136 * | |
| 1137 * Here, the levels array is scanned as soon as necessary, and a vector of | |
| 1138 * same-level-runs is created. Reordering then is done on this vector. | |
| 1139 * For each run of text positions that were resolved to the same level, | |
| 1140 * only 8 bytes are stored: the first text position of the run and the visual | |
| 1141 * position behind the run after reordering. | |
| 1142 * One sign bit is used to hold the directionality of the run. | |
| 1143 * This is inefficient if there are many very short runs. If the average run | |
| 1144 * length is <2, then this uses more memory. | |
| 1145 * | |
| 1146 * In a further attempt to save memory, the levels array is never changed | |
| 1147 * after all the resolution rules (Xn, Wn, Nn, In). | |
| 1148 * Many functions have to consider the field trailingWSStart: | |
| 1149 * if it is less than length, then there is an implicit trailing run | |
| 1150 * at the paraLevel, | |
| 1151 * which is not reflected in the levels array. | |
| 1152 * This allows a line nsBidi object to use the same levels array as | |
| 1153 * its paragraph parent object. | |
| 1154 * | |
| 1155 * When a nsBidi object is created for a line of a paragraph, then the | |
| 1156 * paragraph's levels and dirProps arrays are reused by way of setting | |
| 1157 * a pointer into them, not by copying. This again saves memory and forbids to | |
| 1158 * change the now shared levels for (L1). | |
| 1159 */ | |
| 1160 nsresult nsBidi::SetLine(nsIBidi* aParaBidi, int32_t aStart, int32_t aLimit) | |
| 1161 { | |
| 1162 nsBidi* pParent = (nsBidi*)aParaBidi; | |
| 1163 int32_t length; | |
| 1164 | |
| 1165 /* check the argument values */ | |
| 1166 if(pParent==nullptr) { | |
| 1167 return NS_ERROR_INVALID_POINTER; | |
| 1168 } else if(aStart<0 || aStart>aLimit || aLimit>pParent->mLength) { | |
| 1169 return NS_ERROR_INVALID_ARG; | |
| 1170 } | |
| 1171 | |
| 1172 /* set members from our aParaBidi parent */ | |
| 1173 length=mLength=aLimit-aStart; | |
| 1174 mParaLevel=pParent->mParaLevel; | |
| 1175 | |
| 1176 mRuns=nullptr; | |
| 1177 mFlags=0; | |
| 1178 | |
| 1179 if(length>0) { | |
| 1180 mDirProps=pParent->mDirProps+aStart; | |
| 1181 mLevels=pParent->mLevels+aStart; | |
| 1182 mRunCount=-1; | |
| 1183 | |
| 1184 if(pParent->mDirection!=NSBIDI_MIXED) { | |
| 1185 /* the parent is already trivial */ | |
| 1186 mDirection=pParent->mDirection; | |
| 1187 | |
| 1188 /* | |
| 1189 * The parent's levels are all either | |
| 1190 * implicitly or explicitly ==paraLevel; | |
| 1191 * do the same here. | |
| 1192 */ | |
| 1193 if(pParent->mTrailingWSStart<=aStart) { | |
| 1194 mTrailingWSStart=0; | |
| 1195 } else if(pParent->mTrailingWSStart<aLimit) { | |
| 1196 mTrailingWSStart=pParent->mTrailingWSStart-aStart; | |
| 1197 } else { | |
| 1198 mTrailingWSStart=length; | |
| 1199 } | |
| 1200 } else { | |
| 1201 const nsBidiLevel *levels=mLevels; | |
| 1202 int32_t i, trailingWSStart; | |
| 1203 nsBidiLevel level; | |
| 1204 Flags flags=0; | |
| 1205 | |
| 1206 SetTrailingWSStart(); | |
| 1207 trailingWSStart=mTrailingWSStart; | |
| 1208 | |
| 1209 /* recalculate pLineBidi->direction */ | |
| 1210 if(trailingWSStart==0) { | |
| 1211 /* all levels are at paraLevel */ | |
| 1212 mDirection=(nsBidiDirection)(mParaLevel&1); | |
| 1213 } else { | |
| 1214 /* get the level of the first character */ | |
| 1215 level=levels[0]&1; | |
| 1216 | |
| 1217 /* if there is anything of a different level, then the line is mixed */ | |
| 1218 if(trailingWSStart<length && (mParaLevel&1)!=level) { | |
| 1219 /* the trailing WS is at paraLevel, which differs from levels[0] */ | |
| 1220 mDirection=NSBIDI_MIXED; | |
| 1221 } else { | |
| 1222 /* see if levels[1..trailingWSStart-1] have the same direction as levels[0] and paraLevel */ | |
| 1223 i=1; | |
| 1224 for(;;) { | |
| 1225 if(i==trailingWSStart) { | |
| 1226 /* the direction values match those in level */ | |
| 1227 mDirection=(nsBidiDirection)level; | |
| 1228 break; | |
| 1229 } else if((levels[i]&1)!=level) { | |
| 1230 mDirection=NSBIDI_MIXED; | |
| 1231 break; | |
| 1232 } | |
| 1233 ++i; | |
| 1234 } | |
| 1235 } | |
| 1236 } | |
| 1237 | |
| 1238 switch(mDirection) { | |
| 1239 case NSBIDI_LTR: | |
| 1240 /* make sure paraLevel is even */ | |
| 1241 mParaLevel=(mParaLevel+1)&~1; | |
| 1242 | |
| 1243 /* all levels are implicitly at paraLevel (important for GetLevels()) */ | |
| 1244 mTrailingWSStart=0; | |
| 1245 break; | |
| 1246 case NSBIDI_RTL: | |
| 1247 /* make sure paraLevel is odd */ | |
| 1248 mParaLevel|=1; | |
| 1249 | |
| 1250 /* all levels are implicitly at paraLevel (important for GetLevels()) */ | |
| 1251 mTrailingWSStart=0; | |
| 1252 break; | |
| 1253 default: | |
| 1254 break; | |
| 1255 } | |
| 1256 } | |
| 1257 } else { | |
| 1258 /* create an object for a zero-length line */ | |
| 1259 mDirection=mParaLevel&1 ? NSBIDI_RTL : NSBIDI_LTR; | |
| 1260 mTrailingWSStart=mRunCount=0; | |
| 1261 | |
| 1262 mDirProps=nullptr; | |
| 1263 mLevels=nullptr; | |
| 1264 } | |
| 1265 return NS_OK; | |
| 1266 } | |
| 1267 | |
| 1268 /* handle trailing WS (L1) -------------------------------------------------- */ | |
| 1269 | |
| 1270 /* | |
| 1271 * SetTrailingWSStart() sets the start index for a trailing | |
| 1272 * run of WS in the line. This is necessary because we do not modify | |
| 1273 * the paragraph's levels array that we just point into. | |
| 1274 * Using trailingWSStart is another form of performing (L1). | |
| 1275 * | |
| 1276 * To make subsequent operations easier, we also include the run | |
| 1277 * before the WS if it is at the paraLevel - we merge the two here. | |
| 1278 */ | |
| 1279 void nsBidi::SetTrailingWSStart() { | |
| 1280 /* mDirection!=NSBIDI_MIXED */ | |
| 1281 | |
| 1282 const DirProp *dirProps=mDirProps; | |
| 1283 nsBidiLevel *levels=mLevels; | |
| 1284 int32_t start=mLength; | |
| 1285 nsBidiLevel paraLevel=mParaLevel; | |
| 1286 | |
| 1287 /* go backwards across all WS, BN, explicit codes */ | |
| 1288 while(start>0 && DIRPROP_FLAG(dirProps[start-1])&MASK_WS) { | |
| 1289 --start; | |
| 1290 } | |
| 1291 | |
| 1292 /* if the WS run can be merged with the previous run then do so here */ | |
| 1293 while(start>0 && levels[start-1]==paraLevel) { | |
| 1294 --start; | |
| 1295 } | |
| 1296 | |
| 1297 mTrailingWSStart=start; | |
| 1298 } | |
| 1299 | |
| 1300 nsresult nsBidi::GetLevelAt(int32_t aCharIndex, nsBidiLevel* aLevel) | |
| 1301 { | |
| 1302 /* return paraLevel if in the trailing WS run, otherwise the real level */ | |
| 1303 if(aCharIndex<0 || mLength<=aCharIndex) { | |
| 1304 *aLevel = 0; | |
| 1305 } else if(mDirection!=NSBIDI_MIXED || aCharIndex>=mTrailingWSStart) { | |
| 1306 *aLevel = mParaLevel; | |
| 1307 } else { | |
| 1308 *aLevel = mLevels[aCharIndex]; | |
| 1309 } | |
| 1310 return NS_OK; | |
| 1311 } | |
| 1312 | |
| 1313 nsresult nsBidi::GetLevels(nsBidiLevel** aLevels) | |
| 1314 { | |
| 1315 int32_t start, length; | |
| 1316 | |
| 1317 length = mLength; | |
| 1318 if(length<=0) { | |
| 1319 *aLevels = nullptr; | |
| 1320 return NS_ERROR_INVALID_ARG; | |
| 1321 } | |
| 1322 | |
| 1323 start = mTrailingWSStart; | |
| 1324 if(start==length) { | |
| 1325 /* the current levels array reflects the WS run */ | |
| 1326 *aLevels = mLevels; | |
| 1327 return NS_OK; | |
| 1328 } | |
| 1329 | |
| 1330 /* | |
| 1331 * After the previous if(), we know that the levels array | |
| 1332 * has an implicit trailing WS run and therefore does not fully | |
| 1333 * reflect itself all the levels. | |
| 1334 * This must be a nsBidi object for a line, and | |
| 1335 * we need to create a new levels array. | |
| 1336 */ | |
| 1337 | |
| 1338 if(GETLEVELSMEMORY(length)) { | |
| 1339 nsBidiLevel *levels=mLevelsMemory; | |
| 1340 | |
| 1341 if(start>0 && levels!=mLevels) { | |
| 1342 memcpy(levels, mLevels, start); | |
| 1343 } | |
| 1344 memset(levels+start, mParaLevel, length-start); | |
| 1345 | |
| 1346 /* this new levels array is set for the line and reflects the WS run */ | |
| 1347 mTrailingWSStart=length; | |
| 1348 *aLevels=mLevels=levels; | |
| 1349 return NS_OK; | |
| 1350 } else { | |
| 1351 /* out of memory */ | |
| 1352 *aLevels = nullptr; | |
| 1353 return NS_ERROR_OUT_OF_MEMORY; | |
| 1354 } | |
| 1355 } | |
| 1356 #endif // FULL_BIDI_ENGINE | |
| 1357 | |
| 1358 nsresult nsBidi::GetCharTypeAt(int32_t aCharIndex, nsCharType* pType) | |
| 1359 { | |
| 1360 if(aCharIndex<0 || mLength<=aCharIndex) { | |
| 1361 return NS_ERROR_INVALID_ARG; | |
| 1362 } | |
| 1363 *pType = (nsCharType)mDirProps[aCharIndex]; | |
| 1364 return NS_OK; | |
| 1365 } | |
| 1366 | |
| 1367 nsresult nsBidi::GetLogicalRun(int32_t aLogicalStart, int32_t *aLogicalLimit, nsBidiLevel *aLevel) | |
| 1368 { | |
| 1369 int32_t length = mLength; | |
| 1370 | |
| 1371 if(aLogicalStart<0 || length<=aLogicalStart) { | |
| 1372 return NS_ERROR_INVALID_ARG; | |
| 1373 } | |
| 1374 | |
| 1375 if(mDirection!=NSBIDI_MIXED || aLogicalStart>=mTrailingWSStart) { | |
| 1376 if(aLogicalLimit!=nullptr) { | |
| 1377 *aLogicalLimit=length; | |
| 1378 } | |
| 1379 if(aLevel!=nullptr) { | |
| 1380 *aLevel=mParaLevel; | |
| 1381 } | |
| 1382 } else { | |
| 1383 nsBidiLevel *levels=mLevels; | |
| 1384 nsBidiLevel level=levels[aLogicalStart]; | |
| 1385 | |
| 1386 /* search for the end of the run */ | |
| 1387 length=mTrailingWSStart; | |
| 1388 while(++aLogicalStart<length && level==levels[aLogicalStart]) {} | |
| 1389 | |
| 1390 if(aLogicalLimit!=nullptr) { | |
| 1391 *aLogicalLimit=aLogicalStart; | |
| 1392 } | |
| 1393 if(aLevel!=nullptr) { | |
| 1394 *aLevel=level; | |
| 1395 } | |
| 1396 } | |
| 1397 return NS_OK; | |
| 1398 } | |
| 1399 | |
| 1400 /* runs API functions ------------------------------------------------------- */ | |
| 1401 | |
| 1402 nsresult nsBidi::CountRuns(int32_t* aRunCount) | |
| 1403 { | |
| 1404 if(mRunCount<0 && !GetRuns()) { | |
| 1405 return NS_ERROR_OUT_OF_MEMORY; | |
| 1406 } else { | |
| 1407 if (aRunCount) | |
| 1408 *aRunCount = mRunCount; | |
| 1409 return NS_OK; | |
| 1410 } | |
| 1411 } | |
| 1412 | |
| 1413 nsresult nsBidi::GetVisualRun(int32_t aRunIndex, int32_t *aLogicalStart, int32_t *aLength, nsBidiDirection *aDirection) | |
| 1414 { | |
| 1415 if( aRunIndex<0 || | |
| 1416 (mRunCount==-1 && !GetRuns()) || | |
| 1417 aRunIndex>=mRunCount | |
| 1418 ) { | |
| 1419 *aDirection = NSBIDI_LTR; | |
| 1420 return NS_OK; | |
| 1421 } else { | |
| 1422 int32_t start=mRuns[aRunIndex].logicalStart; | |
| 1423 if(aLogicalStart!=nullptr) { | |
| 1424 *aLogicalStart=GET_INDEX(start); | |
| 1425 } | |
| 1426 if(aLength!=nullptr) { | |
| 1427 if(aRunIndex>0) { | |
| 1428 *aLength=mRuns[aRunIndex].visualLimit- | |
| 1429 mRuns[aRunIndex-1].visualLimit; | |
| 1430 } else { | |
| 1431 *aLength=mRuns[0].visualLimit; | |
| 1432 } | |
| 1433 } | |
| 1434 *aDirection = (nsBidiDirection)GET_ODD_BIT(start); | |
| 1435 return NS_OK; | |
| 1436 } | |
| 1437 } | |
| 1438 | |
| 1439 /* compute the runs array --------------------------------------------------- */ | |
| 1440 | |
| 1441 /* | |
| 1442 * Compute the runs array from the levels array. | |
| 1443 * After GetRuns() returns true, runCount is guaranteed to be >0 | |
| 1444 * and the runs are reordered. | |
| 1445 * Odd-level runs have visualStart on their visual right edge and | |
| 1446 * they progress visually to the left. | |
| 1447 */ | |
| 1448 bool nsBidi::GetRuns() | |
| 1449 { | |
| 1450 if(mDirection!=NSBIDI_MIXED) { | |
| 1451 /* simple, single-run case - this covers length==0 */ | |
| 1452 GetSingleRun(mParaLevel); | |
| 1453 } else /* NSBIDI_MIXED, length>0 */ { | |
| 1454 /* mixed directionality */ | |
| 1455 int32_t length=mLength, limit=length; | |
| 1456 | |
| 1457 /* | |
| 1458 * If there are WS characters at the end of the line | |
| 1459 * and the run preceding them has a level different from | |
| 1460 * paraLevel, then they will form their own run at paraLevel (L1). | |
| 1461 * Count them separately. | |
| 1462 * We need some special treatment for this in order to not | |
| 1463 * modify the levels array which a line nsBidi object shares | |
| 1464 * with its paragraph parent and its other line siblings. | |
| 1465 * In other words, for the trailing WS, it may be | |
| 1466 * levels[]!=paraLevel but we have to treat it like it were so. | |
| 1467 */ | |
| 1468 limit=mTrailingWSStart; | |
| 1469 if(limit==0) { | |
| 1470 /* there is only WS on this line */ | |
| 1471 GetSingleRun(mParaLevel); | |
| 1472 } else { | |
| 1473 nsBidiLevel *levels=mLevels; | |
| 1474 int32_t i, runCount; | |
| 1475 nsBidiLevel level=NSBIDI_DEFAULT_LTR; /* initialize with no valid level */ | |
| 1476 | |
| 1477 /* count the runs, there is at least one non-WS run, and limit>0 */ | |
| 1478 runCount=0; | |
| 1479 for(i=0; i<limit; ++i) { | |
| 1480 /* increment runCount at the start of each run */ | |
| 1481 if(levels[i]!=level) { | |
| 1482 ++runCount; | |
| 1483 level=levels[i]; | |
| 1484 } | |
| 1485 } | |
| 1486 | |
| 1487 /* | |
| 1488 * We don't need to see if the last run can be merged with a trailing | |
| 1489 * WS run because SetTrailingWSStart() would have done that. | |
| 1490 */ | |
| 1491 if(runCount==1 && limit==length) { | |
| 1492 /* There is only one non-WS run and no trailing WS-run. */ | |
| 1493 GetSingleRun(levels[0]); | |
| 1494 } else /* runCount>1 || limit<length */ { | |
| 1495 /* allocate and set the runs */ | |
| 1496 Run *runs; | |
| 1497 int32_t runIndex, start; | |
| 1498 nsBidiLevel minLevel=NSBIDI_MAX_EXPLICIT_LEVEL+1, maxLevel=0; | |
| 1499 | |
| 1500 /* now, count a (non-mergable) WS run */ | |
| 1501 if(limit<length) { | |
| 1502 ++runCount; | |
| 1503 } | |
| 1504 | |
| 1505 /* runCount>1 */ | |
| 1506 if(GETRUNSMEMORY(runCount)) { | |
| 1507 runs=mRunsMemory; | |
| 1508 } else { | |
| 1509 return false; | |
| 1510 } | |
| 1511 | |
| 1512 /* set the runs */ | |
| 1513 /* this could be optimized, e.g.: 464->444, 484->444, 575->555, 595->555 */ | |
| 1514 /* however, that would take longer and make other functions more complicated */ | |
| 1515 runIndex=0; | |
| 1516 | |
| 1517 /* search for the run ends */ | |
| 1518 start=0; | |
| 1519 level=levels[0]; | |
| 1520 if(level<minLevel) { | |
| 1521 minLevel=level; | |
| 1522 } | |
| 1523 if(level>maxLevel) { | |
| 1524 maxLevel=level; | |
| 1525 } | |
| 1526 | |
| 1527 /* initialize visualLimit values with the run lengths */ | |
| 1528 for(i=1; i<limit; ++i) { | |
| 1529 if(levels[i]!=level) { | |
| 1530 /* i is another run limit */ | |
| 1531 runs[runIndex].logicalStart=start; | |
| 1532 runs[runIndex].visualLimit=i-start; | |
| 1533 start=i; | |
| 1534 | |
| 1535 level=levels[i]; | |
| 1536 if(level<minLevel) { | |
| 1537 minLevel=level; | |
| 1538 } | |
| 1539 if(level>maxLevel) { | |
| 1540 maxLevel=level; | |
| 1541 } | |
| 1542 ++runIndex; | |
| 1543 } | |
| 1544 } | |
| 1545 | |
| 1546 /* finish the last run at i==limit */ | |
| 1547 runs[runIndex].logicalStart=start; | |
| 1548 runs[runIndex].visualLimit=limit-start; | |
| 1549 ++runIndex; | |
| 1550 | |
| 1551 if(limit<length) { | |
| 1552 /* there is a separate WS run */ | |
| 1553 runs[runIndex].logicalStart=limit; | |
| 1554 runs[runIndex].visualLimit=length-limit; | |
| 1555 if(mParaLevel<minLevel) { | |
| 1556 minLevel=mParaLevel; | |
| 1557 } | |
| 1558 } | |
| 1559 | |
| 1560 /* set the object fields */ | |
| 1561 mRuns=runs; | |
| 1562 mRunCount=runCount; | |
| 1563 | |
| 1564 ReorderLine(minLevel, maxLevel); | |
| 1565 | |
| 1566 /* now add the direction flags and adjust the visualLimit's to be just that */ | |
| 1567 ADD_ODD_BIT_FROM_LEVEL(runs[0].logicalStart, levels[runs[0].logicalStart]); | |
| 1568 limit=runs[0].visualLimit; | |
| 1569 for(i=1; i<runIndex; ++i) { | |
| 1570 ADD_ODD_BIT_FROM_LEVEL(runs[i].logicalStart, levels[runs[i].logicalStart]); | |
| 1571 limit=runs[i].visualLimit+=limit; | |
| 1572 } | |
| 1573 | |
| 1574 /* same for the trailing WS run */ | |
| 1575 if(runIndex<runCount) { | |
| 1576 ADD_ODD_BIT_FROM_LEVEL(runs[i].logicalStart, mParaLevel); | |
| 1577 runs[runIndex].visualLimit+=limit; | |
| 1578 } | |
| 1579 } | |
| 1580 } | |
| 1581 } | |
| 1582 return true; | |
| 1583 } | |
| 1584 | |
| 1585 /* in trivial cases there is only one trivial run; called by GetRuns() */ | |
| 1586 void nsBidi::GetSingleRun(nsBidiLevel aLevel) | |
| 1587 { | |
| 1588 /* simple, single-run case */ | |
| 1589 mRuns=mSimpleRuns; | |
| 1590 mRunCount=1; | |
| 1591 | |
| 1592 /* fill and reorder the single run */ | |
| 1593 mRuns[0].logicalStart=MAKE_INDEX_ODD_PAIR(0, aLevel); | |
| 1594 mRuns[0].visualLimit=mLength; | |
| 1595 } | |
| 1596 | |
| 1597 /* reorder the runs array (L2) ---------------------------------------------- */ | |
| 1598 | |
| 1599 /* | |
| 1600 * Reorder the same-level runs in the runs array. | |
| 1601 * Here, runCount>1 and maxLevel>=minLevel>=paraLevel. | |
| 1602 * All the visualStart fields=logical start before reordering. | |
| 1603 * The "odd" bits are not set yet. | |
| 1604 * | |
| 1605 * Reordering with this data structure lends itself to some handy shortcuts: | |
| 1606 * | |
| 1607 * Since each run is moved but not modified, and since at the initial maxLevel | |
| 1608 * each sequence of same-level runs consists of only one run each, we | |
| 1609 * don't need to do anything there and can predecrement maxLevel. | |
| 1610 * In many simple cases, the reordering is thus done entirely in the | |
| 1611 * index mapping. | |
| 1612 * Also, reordering occurs only down to the lowest odd level that occurs, | |
| 1613 * which is minLevel|1. However, if the lowest level itself is odd, then | |
| 1614 * in the last reordering the sequence of the runs at this level or higher | |
| 1615 * will be all runs, and we don't need the elaborate loop to search for them. | |
| 1616 * This is covered by ++minLevel instead of minLevel|=1 followed | |
| 1617 * by an extra reorder-all after the reorder-some loop. | |
| 1618 * About a trailing WS run: | |
| 1619 * Such a run would need special treatment because its level is not | |
| 1620 * reflected in levels[] if this is not a paragraph object. | |
| 1621 * Instead, all characters from trailingWSStart on are implicitly at | |
| 1622 * paraLevel. | |
| 1623 * However, for all maxLevel>paraLevel, this run will never be reordered | |
| 1624 * and does not need to be taken into account. maxLevel==paraLevel is only reordered | |
| 1625 * if minLevel==paraLevel is odd, which is done in the extra segment. | |
| 1626 * This means that for the main reordering loop we don't need to consider | |
| 1627 * this run and can --runCount. If it is later part of the all-runs | |
| 1628 * reordering, then runCount is adjusted accordingly. | |
| 1629 */ | |
| 1630 void nsBidi::ReorderLine(nsBidiLevel aMinLevel, nsBidiLevel aMaxLevel) | |
| 1631 { | |
| 1632 Run *runs; | |
| 1633 nsBidiLevel *levels; | |
| 1634 int32_t firstRun, endRun, limitRun, runCount, temp; | |
| 1635 | |
| 1636 /* nothing to do? */ | |
| 1637 if(aMaxLevel<=(aMinLevel|1)) { | |
| 1638 return; | |
| 1639 } | |
| 1640 | |
| 1641 /* | |
| 1642 * Reorder only down to the lowest odd level | |
| 1643 * and reorder at an odd aMinLevel in a separate, simpler loop. | |
| 1644 * See comments above for why aMinLevel is always incremented. | |
| 1645 */ | |
| 1646 ++aMinLevel; | |
| 1647 | |
| 1648 runs=mRuns; | |
| 1649 levels=mLevels; | |
| 1650 runCount=mRunCount; | |
| 1651 | |
| 1652 /* do not include the WS run at paraLevel<=old aMinLevel except in the simple loop */ | |
| 1653 if(mTrailingWSStart<mLength) { | |
| 1654 --runCount; | |
| 1655 } | |
| 1656 | |
| 1657 while(--aMaxLevel>=aMinLevel) { | |
| 1658 firstRun=0; | |
| 1659 | |
| 1660 /* loop for all sequences of runs */ | |
| 1661 for(;;) { | |
| 1662 /* look for a sequence of runs that are all at >=aMaxLevel */ | |
| 1663 /* look for the first run of such a sequence */ | |
| 1664 while(firstRun<runCount && levels[runs[firstRun].logicalStart]<aMaxLevel) { | |
| 1665 ++firstRun; | |
| 1666 } | |
| 1667 if(firstRun>=runCount) { | |
| 1668 break; /* no more such runs */ | |
| 1669 } | |
| 1670 | |
| 1671 /* look for the limit run of such a sequence (the run behind it) */ | |
| 1672 for(limitRun=firstRun; ++limitRun<runCount && levels[runs[limitRun].logicalStart]>=aMaxLevel;) {} | |
| 1673 | |
| 1674 /* Swap the entire sequence of runs from firstRun to limitRun-1. */ | |
| 1675 endRun=limitRun-1; | |
| 1676 while(firstRun<endRun) { | |
| 1677 temp=runs[firstRun].logicalStart; | |
| 1678 runs[firstRun].logicalStart=runs[endRun].logicalStart; | |
| 1679 runs[endRun].logicalStart=temp; | |
| 1680 | |
| 1681 temp=runs[firstRun].visualLimit; | |
| 1682 runs[firstRun].visualLimit=runs[endRun].visualLimit; | |
| 1683 runs[endRun].visualLimit=temp; | |
| 1684 | |
| 1685 ++firstRun; | |
| 1686 --endRun; | |
| 1687 } | |
| 1688 | |
| 1689 if(limitRun==runCount) { | |
| 1690 break; /* no more such runs */ | |
| 1691 } else { | |
| 1692 firstRun=limitRun+1; | |
| 1693 } | |
| 1694 } | |
| 1695 } | |
| 1696 | |
| 1697 /* now do aMaxLevel==old aMinLevel (==odd!), see above */ | |
| 1698 if(!(aMinLevel&1)) { | |
| 1699 firstRun=0; | |
| 1700 | |
| 1701 /* include the trailing WS run in this complete reordering */ | |
| 1702 if(mTrailingWSStart==mLength) { | |
| 1703 --runCount; | |
| 1704 } | |
| 1705 | |
| 1706 /* Swap the entire sequence of all runs. (endRun==runCount) */ | |
| 1707 while(firstRun<runCount) { | |
| 1708 temp=runs[firstRun].logicalStart; | |
| 1709 runs[firstRun].logicalStart=runs[runCount].logicalStart; | |
| 1710 runs[runCount].logicalStart=temp; | |
| 1711 | |
| 1712 temp=runs[firstRun].visualLimit; | |
| 1713 runs[firstRun].visualLimit=runs[runCount].visualLimit; | |
| 1714 runs[runCount].visualLimit=temp; | |
| 1715 | |
| 1716 ++firstRun; | |
| 1717 --runCount; | |
| 1718 } | |
| 1719 } | |
| 1720 } | |
| 1721 | |
| 1722 nsresult nsBidi::ReorderVisual(const nsBidiLevel *aLevels, int32_t aLength, int32_t *aIndexMap) | |
| 1723 { | |
| 1724 int32_t start, end, limit, temp; | |
| 1725 nsBidiLevel minLevel, maxLevel; | |
| 1726 | |
| 1727 if(aIndexMap==nullptr || | |
| 1728 !PrepareReorder(aLevels, aLength, aIndexMap, &minLevel, &maxLevel)) { | |
| 1729 return NS_OK; | |
| 1730 } | |
| 1731 | |
| 1732 /* nothing to do? */ | |
| 1733 if(minLevel==maxLevel && (minLevel&1)==0) { | |
| 1734 return NS_OK; | |
| 1735 } | |
| 1736 | |
| 1737 /* reorder only down to the lowest odd level */ | |
| 1738 minLevel|=1; | |
| 1739 | |
| 1740 /* loop maxLevel..minLevel */ | |
| 1741 do { | |
| 1742 start=0; | |
| 1743 | |
| 1744 /* loop for all sequences of levels to reorder at the current maxLevel */ | |
| 1745 for(;;) { | |
| 1746 /* look for a sequence of levels that are all at >=maxLevel */ | |
| 1747 /* look for the first index of such a sequence */ | |
| 1748 while(start<aLength && aLevels[start]<maxLevel) { | |
| 1749 ++start; | |
| 1750 } | |
| 1751 if(start>=aLength) { | |
| 1752 break; /* no more such runs */ | |
| 1753 } | |
| 1754 | |
| 1755 /* look for the limit of such a sequence (the index behind it) */ | |
| 1756 for(limit=start; ++limit<aLength && aLevels[limit]>=maxLevel;) {} | |
| 1757 | |
| 1758 /* | |
| 1759 * Swap the entire interval of indexes from start to limit-1. | |
| 1760 * We don't need to swap the levels for the purpose of this | |
| 1761 * algorithm: the sequence of levels that we look at does not | |
| 1762 * move anyway. | |
| 1763 */ | |
| 1764 end=limit-1; | |
| 1765 while(start<end) { | |
| 1766 temp=aIndexMap[start]; | |
| 1767 aIndexMap[start]=aIndexMap[end]; | |
| 1768 aIndexMap[end]=temp; | |
| 1769 | |
| 1770 ++start; | |
| 1771 --end; | |
| 1772 } | |
| 1773 | |
| 1774 if(limit==aLength) { | |
| 1775 break; /* no more such sequences */ | |
| 1776 } else { | |
| 1777 start=limit+1; | |
| 1778 } | |
| 1779 } | |
| 1780 } while(--maxLevel>=minLevel); | |
| 1781 | |
| 1782 return NS_OK; | |
| 1783 } | |
| 1784 | |
| 1785 bool nsBidi::PrepareReorder(const nsBidiLevel *aLevels, int32_t aLength, | |
| 1786 int32_t *aIndexMap, | |
| 1787 nsBidiLevel *aMinLevel, nsBidiLevel *aMaxLevel) | |
| 1788 { | |
| 1789 int32_t start; | |
| 1790 nsBidiLevel level, minLevel, maxLevel; | |
| 1791 | |
| 1792 if(aLevels==nullptr || aLength<=0) { | |
| 1793 return false; | |
| 1794 } | |
| 1795 | |
| 1796 /* determine minLevel and maxLevel */ | |
| 1797 minLevel=NSBIDI_MAX_EXPLICIT_LEVEL+1; | |
| 1798 maxLevel=0; | |
| 1799 for(start=aLength; start>0;) { | |
| 1800 level=aLevels[--start]; | |
| 1801 if(level>NSBIDI_MAX_EXPLICIT_LEVEL+1) { | |
| 1802 return false; | |
| 1803 } | |
| 1804 if(level<minLevel) { | |
| 1805 minLevel=level; | |
| 1806 } | |
| 1807 if(level>maxLevel) { | |
| 1808 maxLevel=level; | |
| 1809 } | |
| 1810 } | |
| 1811 *aMinLevel=minLevel; | |
| 1812 *aMaxLevel=maxLevel; | |
| 1813 | |
| 1814 /* initialize the index map */ | |
| 1815 for(start=aLength; start>0;) { | |
| 1816 --start; | |
| 1817 aIndexMap[start]=start; | |
| 1818 } | |
| 1819 | |
| 1820 return true; | |
| 1821 } | |
| 1822 | |
| 1823 #ifdef FULL_BIDI_ENGINE | |
| 1824 /* API functions for logical<->visual mapping ------------------------------- */ | |
| 1825 | |
| 1826 nsresult nsBidi::GetVisualIndex(int32_t aLogicalIndex, int32_t* aVisualIndex) { | |
| 1827 if(aLogicalIndex<0 || mLength<=aLogicalIndex) { | |
| 1828 return NS_ERROR_INVALID_ARG; | |
| 1829 } else { | |
| 1830 /* we can do the trivial cases without the runs array */ | |
| 1831 switch(mDirection) { | |
| 1832 case NSBIDI_LTR: | |
| 1833 *aVisualIndex = aLogicalIndex; | |
| 1834 return NS_OK; | |
| 1835 case NSBIDI_RTL: | |
| 1836 *aVisualIndex = mLength-aLogicalIndex-1; | |
| 1837 return NS_OK; | |
| 1838 default: | |
| 1839 if(mRunCount<0 && !GetRuns()) { | |
| 1840 return NS_ERROR_OUT_OF_MEMORY; | |
| 1841 } else { | |
| 1842 Run *runs=mRuns; | |
| 1843 int32_t i, visualStart=0, offset, length; | |
| 1844 | |
| 1845 /* linear search for the run, search on the visual runs */ | |
| 1846 for(i=0;; ++i) { | |
| 1847 length=runs[i].visualLimit-visualStart; | |
| 1848 offset=aLogicalIndex-GET_INDEX(runs[i].logicalStart); | |
| 1849 if(offset>=0 && offset<length) { | |
| 1850 if(IS_EVEN_RUN(runs[i].logicalStart)) { | |
| 1851 /* LTR */ | |
| 1852 *aVisualIndex = visualStart+offset; | |
| 1853 return NS_OK; | |
| 1854 } else { | |
| 1855 /* RTL */ | |
| 1856 *aVisualIndex = visualStart+length-offset-1; | |
| 1857 return NS_OK; | |
| 1858 } | |
| 1859 } | |
| 1860 visualStart+=length; | |
| 1861 } | |
| 1862 } | |
| 1863 } | |
| 1864 } | |
| 1865 } | |
| 1866 | |
| 1867 nsresult nsBidi::GetLogicalIndex(int32_t aVisualIndex, int32_t *aLogicalIndex) | |
| 1868 { | |
| 1869 if(aVisualIndex<0 || mLength<=aVisualIndex) { | |
| 1870 return NS_ERROR_INVALID_ARG; | |
| 1871 } else { | |
| 1872 /* we can do the trivial cases without the runs array */ | |
| 1873 switch(mDirection) { | |
| 1874 case NSBIDI_LTR: | |
| 1875 *aLogicalIndex = aVisualIndex; | |
| 1876 return NS_OK; | |
| 1877 case NSBIDI_RTL: | |
| 1878 *aLogicalIndex = mLength-aVisualIndex-1; | |
| 1879 return NS_OK; | |
| 1880 default: | |
| 1881 if(mRunCount<0 && !GetRuns()) { | |
| 1882 return NS_ERROR_OUT_OF_MEMORY; | |
| 1883 } else { | |
| 1884 Run *runs=mRuns; | |
| 1885 int32_t i, runCount=mRunCount, start; | |
| 1886 | |
| 1887 if(runCount<=10) { | |
| 1888 /* linear search for the run */ | |
| 1889 for(i=0; aVisualIndex>=runs[i].visualLimit; ++i) {} | |
| 1890 } else { | |
| 1891 /* binary search for the run */ | |
| 1892 int32_t start=0, limit=runCount; | |
| 1893 | |
| 1894 /* the middle if() will guaranteed find the run, we don't need a loop limit */ | |
| 1895 for(;;) { | |
| 1896 i=(start+limit)/2; | |
| 1897 if(aVisualIndex>=runs[i].visualLimit) { | |
| 1898 start=i+1; | |
| 1899 } else if(i==0 || aVisualIndex>=runs[i-1].visualLimit) { | |
| 1900 break; | |
| 1901 } else { | |
| 1902 limit=i; | |
| 1903 } | |
| 1904 } | |
| 1905 } | |
| 1906 | |
| 1907 start=runs[i].logicalStart; | |
| 1908 if(IS_EVEN_RUN(start)) { | |
| 1909 /* LTR */ | |
| 1910 /* the offset in runs[i] is aVisualIndex-runs[i-1].visualLimit */ | |
| 1911 if(i>0) { | |
| 1912 aVisualIndex-=runs[i-1].visualLimit; | |
| 1913 } | |
| 1914 *aLogicalIndex = GET_INDEX(start)+aVisualIndex; | |
| 1915 return NS_OK; | |
| 1916 } else { | |
| 1917 /* RTL */ | |
| 1918 *aLogicalIndex = GET_INDEX(start)+runs[i].visualLimit-aVisualIndex-1; | |
| 1919 return NS_OK; | |
| 1920 } | |
| 1921 } | |
| 1922 } | |
| 1923 } | |
| 1924 } | |
| 1925 | |
| 1926 nsresult nsBidi::GetLogicalMap(int32_t *aIndexMap) | |
| 1927 { | |
| 1928 nsBidiLevel *levels; | |
| 1929 nsresult rv; | |
| 1930 | |
| 1931 /* GetLevels() checks all of its and our arguments */ | |
| 1932 rv = GetLevels(&levels); | |
| 1933 if(NS_FAILED(rv)) { | |
| 1934 return rv; | |
| 1935 } else if(aIndexMap==nullptr) { | |
| 1936 return NS_ERROR_INVALID_ARG; | |
| 1937 } else { | |
| 1938 return ReorderLogical(levels, mLength, aIndexMap); | |
| 1939 } | |
| 1940 } | |
| 1941 | |
| 1942 nsresult nsBidi::GetVisualMap(int32_t *aIndexMap) | |
| 1943 { | |
| 1944 int32_t* runCount=nullptr; | |
| 1945 nsresult rv; | |
| 1946 | |
| 1947 /* CountRuns() checks all of its and our arguments */ | |
| 1948 rv = CountRuns(runCount); | |
| 1949 if(NS_FAILED(rv)) { | |
| 1950 return rv; | |
| 1951 } else if(aIndexMap==nullptr) { | |
| 1952 return NS_ERROR_INVALID_ARG; | |
| 1953 } else { | |
| 1954 /* fill a visual-to-logical index map using the runs[] */ | |
| 1955 Run *runs=mRuns, *runsLimit=runs+mRunCount; | |
| 1956 int32_t logicalStart, visualStart, visualLimit; | |
| 1957 | |
| 1958 visualStart=0; | |
| 1959 for(; runs<runsLimit; ++runs) { | |
| 1960 logicalStart=runs->logicalStart; | |
| 1961 visualLimit=runs->visualLimit; | |
| 1962 if(IS_EVEN_RUN(logicalStart)) { | |
| 1963 do { /* LTR */ | |
| 1964 *aIndexMap++ = logicalStart++; | |
| 1965 } while(++visualStart<visualLimit); | |
| 1966 } else { | |
| 1967 REMOVE_ODD_BIT(logicalStart); | |
| 1968 logicalStart+=visualLimit-visualStart; /* logicalLimit */ | |
| 1969 do { /* RTL */ | |
| 1970 *aIndexMap++ = --logicalStart; | |
| 1971 } while(++visualStart<visualLimit); | |
| 1972 } | |
| 1973 /* visualStart==visualLimit; */ | |
| 1974 } | |
| 1975 return NS_OK; | |
| 1976 } | |
| 1977 } | |
| 1978 | |
| 1979 /* reorder a line based on a levels array (L2) ------------------------------ */ | |
| 1980 | |
| 1981 nsresult nsBidi::ReorderLogical(const nsBidiLevel *aLevels, int32_t aLength, int32_t *aIndexMap) | |
| 1982 { | |
| 1983 int32_t start, limit, sumOfSosEos; | |
| 1984 nsBidiLevel minLevel, maxLevel; | |
| 1985 | |
| 1986 if(aIndexMap==nullptr || | |
| 1987 !PrepareReorder(aLevels, aLength, aIndexMap, &minLevel, &maxLevel)) { | |
| 1988 return NS_OK; | |
| 1989 } | |
| 1990 | |
| 1991 /* nothing to do? */ | |
| 1992 if(minLevel==maxLevel && (minLevel&1)==0) { | |
| 1993 return NS_OK; | |
| 1994 } | |
| 1995 | |
| 1996 /* reorder only down to the lowest odd level */ | |
| 1997 minLevel|=1; | |
| 1998 | |
| 1999 /* loop maxLevel..minLevel */ | |
| 2000 do { | |
| 2001 start=0; | |
| 2002 | |
| 2003 /* loop for all sequences of levels to reorder at the current maxLevel */ | |
| 2004 for(;;) { | |
| 2005 /* look for a sequence of levels that are all at >=maxLevel */ | |
| 2006 /* look for the first index of such a sequence */ | |
| 2007 while(start<aLength && aLevels[start]<maxLevel) { | |
| 2008 ++start; | |
| 2009 } | |
| 2010 if(start>=aLength) { | |
| 2011 break; /* no more such sequences */ | |
| 2012 } | |
| 2013 | |
| 2014 /* look for the limit of such a sequence (the index behind it) */ | |
| 2015 for(limit=start; ++limit<aLength && aLevels[limit]>=maxLevel;) {} | |
| 2016 | |
| 2017 /* | |
| 2018 * sos=start of sequence, eos=end of sequence | |
| 2019 * | |
| 2020 * The closed (inclusive) interval from sos to eos includes all the logical | |
| 2021 * and visual indexes within this sequence. They are logically and | |
| 2022 * visually contiguous and in the same range. | |
| 2023 * | |
| 2024 * For each run, the new visual index=sos+eos-old visual index; | |
| 2025 * we pre-add sos+eos into sumOfSosEos -> | |
| 2026 * new visual index=sumOfSosEos-old visual index; | |
| 2027 */ | |
| 2028 sumOfSosEos=start+limit-1; | |
| 2029 | |
| 2030 /* reorder each index in the sequence */ | |
| 2031 do { | |
| 2032 aIndexMap[start]=sumOfSosEos-aIndexMap[start]; | |
| 2033 } while(++start<limit); | |
| 2034 | |
| 2035 /* start==limit */ | |
| 2036 if(limit==aLength) { | |
| 2037 break; /* no more such sequences */ | |
| 2038 } else { | |
| 2039 start=limit+1; | |
| 2040 } | |
| 2041 } | |
| 2042 } while(--maxLevel>=minLevel); | |
| 2043 | |
| 2044 return NS_OK; | |
| 2045 } | |
| 2046 | |
| 2047 nsresult nsBidi::InvertMap(const int32_t *aSrcMap, int32_t *aDestMap, int32_t aLength) | |
| 2048 { | |
| 2049 if(aSrcMap!=nullptr && aDestMap!=nullptr) { | |
| 2050 aSrcMap+=aLength; | |
| 2051 while(aLength>0) { | |
| 2052 aDestMap[*--aSrcMap]=--aLength; | |
| 2053 } | |
| 2054 } | |
| 2055 return NS_OK; | |
| 2056 } | |
| 2057 | |
| 2058 int32_t nsBidi::doWriteReverse(const char16_t *src, int32_t srcLength, | |
| 2059 char16_t *dest, uint16_t options) { | |
| 2060 /* | |
| 2061 * RTL run - | |
| 2062 * | |
| 2063 * RTL runs need to be copied to the destination in reverse order | |
| 2064 * of code points, not code units, to keep Unicode characters intact. | |
| 2065 * | |
| 2066 * The general strategy for this is to read the source text | |
| 2067 * in backward order, collect all code units for a code point | |
| 2068 * (and optionally following combining characters, see below), | |
| 2069 * and copy all these code units in ascending order | |
| 2070 * to the destination for this run. | |
| 2071 * | |
| 2072 * Several options request whether combining characters | |
| 2073 * should be kept after their base characters, | |
| 2074 * whether Bidi control characters should be removed, and | |
| 2075 * whether characters should be replaced by their mirror-image | |
| 2076 * equivalent Unicode characters. | |
| 2077 */ | |
| 2078 int32_t i, j, destSize; | |
| 2079 uint32_t c; | |
| 2080 | |
| 2081 /* optimize for several combinations of options */ | |
| 2082 switch(options&(NSBIDI_REMOVE_BIDI_CONTROLS|NSBIDI_DO_MIRRORING|NSBIDI_KEEP_BASE_COMBINING)) { | |
| 2083 case 0: | |
| 2084 /* | |
| 2085 * With none of the "complicated" options set, the destination | |
| 2086 * run will have the same length as the source run, | |
| 2087 * and there is no mirroring and no keeping combining characters | |
| 2088 * with their base characters. | |
| 2089 */ | |
| 2090 destSize=srcLength; | |
| 2091 | |
| 2092 /* preserve character integrity */ | |
| 2093 do { | |
| 2094 /* i is always after the last code unit known to need to be kept in this segment */ | |
| 2095 i=srcLength; | |
| 2096 | |
| 2097 /* collect code units for one base character */ | |
| 2098 UTF_BACK_1(src, 0, srcLength); | |
| 2099 | |
| 2100 /* copy this base character */ | |
| 2101 j=srcLength; | |
| 2102 do { | |
| 2103 *dest++=src[j++]; | |
| 2104 } while(j<i); | |
| 2105 } while(srcLength>0); | |
| 2106 break; | |
| 2107 case NSBIDI_KEEP_BASE_COMBINING: | |
| 2108 /* | |
| 2109 * Here, too, the destination | |
| 2110 * run will have the same length as the source run, | |
| 2111 * and there is no mirroring. | |
| 2112 * We do need to keep combining characters with their base characters. | |
| 2113 */ | |
| 2114 destSize=srcLength; | |
| 2115 | |
| 2116 /* preserve character integrity */ | |
| 2117 do { | |
| 2118 /* i is always after the last code unit known to need to be kept in this segment */ | |
| 2119 i=srcLength; | |
| 2120 | |
| 2121 /* collect code units and modifier letters for one base character */ | |
| 2122 do { | |
| 2123 UTF_PREV_CHAR(src, 0, srcLength, c); | |
| 2124 } while(srcLength>0 && IsBidiCategory(c, eBidiCat_NSM)); | |
| 2125 | |
| 2126 /* copy this "user character" */ | |
| 2127 j=srcLength; | |
| 2128 do { | |
| 2129 *dest++=src[j++]; | |
| 2130 } while(j<i); | |
| 2131 } while(srcLength>0); | |
| 2132 break; | |
| 2133 default: | |
| 2134 /* | |
| 2135 * With several "complicated" options set, this is the most | |
| 2136 * general and the slowest copying of an RTL run. | |
| 2137 * We will do mirroring, remove Bidi controls, and | |
| 2138 * keep combining characters with their base characters | |
| 2139 * as requested. | |
| 2140 */ | |
| 2141 if(!(options&NSBIDI_REMOVE_BIDI_CONTROLS)) { | |
| 2142 i=srcLength; | |
| 2143 } else { | |
| 2144 /* we need to find out the destination length of the run, | |
| 2145 which will not include the Bidi control characters */ | |
| 2146 int32_t length=srcLength; | |
| 2147 char16_t ch; | |
| 2148 | |
| 2149 i=0; | |
| 2150 do { | |
| 2151 ch=*src++; | |
| 2152 if (!IsBidiControl((uint32_t)ch)) { | |
| 2153 ++i; | |
| 2154 } | |
| 2155 } while(--length>0); | |
| 2156 src-=srcLength; | |
| 2157 } | |
| 2158 destSize=i; | |
| 2159 | |
| 2160 /* preserve character integrity */ | |
| 2161 do { | |
| 2162 /* i is always after the last code unit known to need to be kept in this segment */ | |
| 2163 i=srcLength; | |
| 2164 | |
| 2165 /* collect code units for one base character */ | |
| 2166 UTF_PREV_CHAR(src, 0, srcLength, c); | |
| 2167 if(options&NSBIDI_KEEP_BASE_COMBINING) { | |
| 2168 /* collect modifier letters for this base character */ | |
| 2169 while(srcLength>0 && IsBidiCategory(c, eBidiCat_NSM)) { | |
| 2170 UTF_PREV_CHAR(src, 0, srcLength, c); | |
| 2171 } | |
| 2172 } | |
| 2173 | |
| 2174 if(options&NSBIDI_REMOVE_BIDI_CONTROLS && IsBidiControl(c)) { | |
| 2175 /* do not copy this Bidi control character */ | |
| 2176 continue; | |
| 2177 } | |
| 2178 | |
| 2179 /* copy this "user character" */ | |
| 2180 j=srcLength; | |
| 2181 if(options&NSBIDI_DO_MIRRORING) { | |
| 2182 /* mirror only the base character */ | |
| 2183 c = SymmSwap(c); | |
| 2184 | |
| 2185 int32_t k=0; | |
| 2186 UTF_APPEND_CHAR_UNSAFE(dest, k, c); | |
| 2187 dest+=k; | |
| 2188 j+=k; | |
| 2189 } | |
| 2190 while(j<i) { | |
| 2191 *dest++=src[j++]; | |
| 2192 } | |
| 2193 } while(srcLength>0); | |
| 2194 break; | |
| 2195 } /* end of switch */ | |
| 2196 return destSize; | |
| 2197 } | |
| 2198 | |
| 2199 nsresult nsBidi::WriteReverse(const char16_t *aSrc, int32_t aSrcLength, char16_t *aDest, uint16_t aOptions, int32_t *aDestSize) | |
| 2200 { | |
| 2201 if( aSrc==nullptr || aSrcLength<0 || | |
| 2202 aDest==nullptr | |
| 2203 ) { | |
| 2204 return NS_ERROR_INVALID_ARG; | |
| 2205 } | |
| 2206 | |
| 2207 /* do input and output overlap? */ | |
| 2208 if( aSrc>=aDest && aSrc<aDest+aSrcLength || | |
| 2209 aDest>=aSrc && aDest<aSrc+aSrcLength | |
| 2210 ) { | |
| 2211 return NS_ERROR_INVALID_ARG; | |
| 2212 } | |
| 2213 | |
| 2214 if(aSrcLength>0) { | |
| 2215 *aDestSize = doWriteReverse(aSrc, aSrcLength, aDest, aOptions); | |
| 2216 } | |
| 2217 return NS_OK; | |
| 2218 } | |
| 2219 #endif // FULL_BIDI_ENGINE |
