J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Portions Copyright 2000-2004 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | /* |
| 27 | * (C) Copyright IBM Corp. 1999-2003 - All Rights Reserved |
| 28 | * |
| 29 | * The original version of this source code and documentation is |
| 30 | * copyrighted and owned by IBM. These materials are provided |
| 31 | * under terms of a License Agreement between IBM and Sun. |
| 32 | * This technology is protected by multiple US and International |
| 33 | * patents. This notice and attribution to IBM may not be removed. |
| 34 | */ |
| 35 | |
| 36 | /* |
| 37 | * |
| 38 | ****************************************************************************** |
| 39 | * file name: ubidi.c |
| 40 | * encoding: US-ASCII |
| 41 | * tab size: 8 (not used) |
| 42 | * indentation:4 |
| 43 | * |
| 44 | * created on: 1999jul27 |
| 45 | * created by: Markus W. Scherer |
| 46 | */ |
| 47 | |
| 48 | /* set import/export definitions */ |
| 49 | #ifndef U_COMMON_IMPLEMENTATION |
| 50 | # define U_COMMON_IMPLEMENTATION |
| 51 | #endif |
| 52 | |
| 53 | #include "cmemory.h" |
| 54 | #include "utypes.h" |
| 55 | #include "uchardir.h" |
| 56 | #include "ubidi.h" |
| 57 | #include "ubidiimp.h" |
| 58 | |
| 59 | /* |
| 60 | * General implementation notes: |
| 61 | * |
| 62 | * Throughout the implementation, there are comments like (W2) that refer to |
| 63 | * rules of the BiDi algorithm in its version 5, in this example to the second |
| 64 | * rule of the resolution of weak types. |
| 65 | * |
| 66 | * For handling surrogate pairs, where two UChar's form one "abstract" (or UTF-32) |
| 67 | * character according to UTF-16, the second UChar gets the directional property of |
| 68 | * the entire character assigned, while the first one gets a BN, a boundary |
| 69 | * neutral, type, which is ignored by most of the algorithm according to |
| 70 | * rule (X9) and the implementation suggestions of the BiDi algorithm. |
| 71 | * |
| 72 | * Later, adjustWSLevels() will set the level for each BN to that of the |
| 73 | * following character (UChar), which results in surrogate pairs getting the |
| 74 | * same level on each of their surrogates. |
| 75 | * |
| 76 | * In a UTF-8 implementation, the same thing could be done: the last byte of |
| 77 | * a multi-byte sequence would get the "real" property, while all previous |
| 78 | * bytes of that sequence would get BN. |
| 79 | * |
| 80 | * It is not possible to assign all those parts of a character the same real |
| 81 | * property because this would fail in the resolution of weak types with rules |
| 82 | * that look at immediately surrounding types. |
| 83 | * |
| 84 | * As a related topic, this implementation does not remove Boundary Neutral |
| 85 | * types from the input, but ignores them whereever this is relevant. |
| 86 | * For example, the loop for the resolution of the weak types reads |
| 87 | * types until it finds a non-BN. |
| 88 | * Also, explicit embedding codes are neither changed into BN nor removed. |
| 89 | * They are only treated the same way real BNs are. |
| 90 | * As stated before, adjustWSLevels() takes care of them at the end. |
| 91 | * For the purpose of conformance, the levels of all these codes |
| 92 | * do not matter. |
| 93 | * |
| 94 | * Note that this implementation never modifies the dirProps |
| 95 | * after the initial setup. |
| 96 | * |
| 97 | * |
| 98 | * In this implementation, the resolution of weak types (Wn), |
| 99 | * neutrals (Nn), and the assignment of the resolved level (In) |
| 100 | * are all done in one single loop, in resolveImplicitLevels(). |
| 101 | * Changes of dirProp values are done on the fly, without writing |
| 102 | * them back to the dirProps array. |
| 103 | * |
| 104 | * |
| 105 | * This implementation contains code that allows to bypass steps of the |
| 106 | * algorithm that are not needed on the specific paragraph |
| 107 | * in order to speed up the most common cases considerably, |
| 108 | * like text that is entirely LTR, or RTL text without numbers. |
| 109 | * |
| 110 | * Most of this is done by setting a bit for each directional property |
| 111 | * in a flags variable and later checking for whether there are |
| 112 | * any LTR characters or any RTL characters, or both, whether |
| 113 | * there are any explicit embedding codes, etc. |
| 114 | * |
| 115 | * If the (Xn) steps are performed, then the flags are re-evaluated, |
| 116 | * because they will then not contain the embedding codes any more |
| 117 | * and will be adjusted for override codes, so that subsequently |
| 118 | * more bypassing may be possible than what the initial flags suggested. |
| 119 | * |
| 120 | * If the text is not mixed-directional, then the |
| 121 | * algorithm steps for the weak type resolution are not performed, |
| 122 | * and all levels are set to the paragraph level. |
| 123 | * |
| 124 | * If there are no explicit embedding codes, then the (Xn) steps |
| 125 | * are not performed. |
| 126 | * |
| 127 | * If embedding levels are supplied as a parameter, then all |
| 128 | * explicit embedding codes are ignored, and the (Xn) steps |
| 129 | * are not performed. |
| 130 | * |
| 131 | * White Space types could get the level of the run they belong to, |
| 132 | * and are checked with a test of (flags&MASK_EMBEDDING) to |
| 133 | * consider if the paragraph direction should be considered in |
| 134 | * the flags variable. |
| 135 | * |
| 136 | * If there are no White Space types in the paragraph, then |
| 137 | * (L1) is not necessary in adjustWSLevels(). |
| 138 | */ |
| 139 | |
| 140 | /* prototypes --------------------------------------------------------------- */ |
| 141 | |
| 142 | static void |
| 143 | getDirProps(UBiDi *pBiDi, const UChar *text); |
| 144 | |
| 145 | static UBiDiDirection |
| 146 | resolveExplicitLevels(UBiDi *pBiDi); |
| 147 | |
| 148 | static UBiDiDirection |
| 149 | checkExplicitLevels(UBiDi *pBiDi, UErrorCode *pErrorCode); |
| 150 | |
| 151 | static UBiDiDirection |
| 152 | directionFromFlags(Flags flags); |
| 153 | |
| 154 | static void |
| 155 | resolveImplicitLevels(UBiDi *pBiDi, |
| 156 | int32_t start, int32_t limit, |
| 157 | DirProp sor, DirProp eor); |
| 158 | |
| 159 | static void |
| 160 | adjustWSLevels(UBiDi *pBiDi); |
| 161 | |
| 162 | /* to avoid some conditional statements, use tiny constant arrays */ |
| 163 | static const Flags flagLR[2]={ DIRPROP_FLAG(L), DIRPROP_FLAG(R) }; |
| 164 | static const Flags flagE[2]={ DIRPROP_FLAG(LRE), DIRPROP_FLAG(RLE) }; |
| 165 | static const Flags flagO[2]={ DIRPROP_FLAG(LRO), DIRPROP_FLAG(RLO) }; |
| 166 | |
| 167 | #define DIRPROP_FLAG_LR(level) flagLR[(level)&1] |
| 168 | #define DIRPROP_FLAG_E(level) flagE[(level)&1] |
| 169 | #define DIRPROP_FLAG_O(level) flagO[(level)&1] |
| 170 | |
| 171 | /* UBiDi object management -------------------------------------------------- */ |
| 172 | |
| 173 | U_CAPI UBiDi * U_EXPORT2 |
| 174 | ubidi_open(void) |
| 175 | { |
| 176 | UErrorCode errorCode=U_ZERO_ERROR; |
| 177 | return ubidi_openSized(0, 0, &errorCode); |
| 178 | } |
| 179 | |
| 180 | U_CAPI UBiDi * U_EXPORT2 |
| 181 | ubidi_openSized(int32_t maxLength, int32_t maxRunCount, UErrorCode *pErrorCode) { |
| 182 | UBiDi *pBiDi; |
| 183 | |
| 184 | /* check the argument values */ |
| 185 | if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) { |
| 186 | return NULL; |
| 187 | } else if(maxLength<0 || maxRunCount<0) { |
| 188 | *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR; |
| 189 | return NULL; /* invalid arguments */ |
| 190 | } |
| 191 | |
| 192 | /* allocate memory for the object */ |
| 193 | pBiDi=(UBiDi *)icu_malloc(sizeof(UBiDi)); |
| 194 | if(pBiDi==NULL) { |
| 195 | *pErrorCode=U_MEMORY_ALLOCATION_ERROR; |
| 196 | return NULL; |
| 197 | } |
| 198 | |
| 199 | /* reset the object, all pointers NULL, all flags FALSE, all sizes 0 */ |
| 200 | icu_memset(pBiDi, 0, sizeof(UBiDi)); |
| 201 | |
| 202 | /* allocate memory for arrays as requested */ |
| 203 | if(maxLength>0) { |
| 204 | if( !getInitialDirPropsMemory(pBiDi, maxLength) || |
| 205 | !getInitialLevelsMemory(pBiDi, maxLength) |
| 206 | ) { |
| 207 | *pErrorCode=U_MEMORY_ALLOCATION_ERROR; |
| 208 | } |
| 209 | } else { |
| 210 | pBiDi->mayAllocateText=TRUE; |
| 211 | } |
| 212 | |
| 213 | if(maxRunCount>0) { |
| 214 | if(maxRunCount==1) { |
| 215 | /* use simpleRuns[] */ |
| 216 | pBiDi->runsSize=sizeof(Run); |
| 217 | } else if(!getInitialRunsMemory(pBiDi, maxRunCount)) { |
| 218 | *pErrorCode=U_MEMORY_ALLOCATION_ERROR; |
| 219 | } |
| 220 | } else { |
| 221 | pBiDi->mayAllocateRuns=TRUE; |
| 222 | } |
| 223 | |
| 224 | if(U_SUCCESS(*pErrorCode)) { |
| 225 | return pBiDi; |
| 226 | } else { |
| 227 | ubidi_close(pBiDi); |
| 228 | return NULL; |
| 229 | } |
| 230 | } |
| 231 | |
| 232 | /* |
| 233 | * We are allowed to allocate memory if memory==NULL or |
| 234 | * mayAllocate==TRUE for each array that we need. |
| 235 | * We also try to grow and shrink memory as needed if we |
| 236 | * allocate it. |
| 237 | * |
| 238 | * Assume sizeNeeded>0. |
| 239 | * If *pMemory!=NULL, then assume *pSize>0. |
| 240 | * |
| 241 | * ### this realloc() may unnecessarily copy the old data, |
| 242 | * which we know we don't need any more; |
| 243 | * is this the best way to do this?? |
| 244 | */ |
| 245 | extern bool_t |
| 246 | ubidi_getMemory(void **pMemory, int32_t *pSize, bool_t mayAllocate, int32_t sizeNeeded) { |
| 247 | /* check for existing memory */ |
| 248 | if(*pMemory==NULL) { |
| 249 | /* we need to allocate memory */ |
| 250 | if(mayAllocate && (*pMemory=icu_malloc(sizeNeeded))!=NULL) { |
| 251 | *pSize=sizeNeeded; |
| 252 | return TRUE; |
| 253 | } else { |
| 254 | return FALSE; |
| 255 | } |
| 256 | } else { |
| 257 | /* there is some memory, is it enough or too much? */ |
| 258 | if(sizeNeeded>*pSize && !mayAllocate) { |
| 259 | /* not enough memory, and we must not allocate */ |
| 260 | return FALSE; |
| 261 | } else if(sizeNeeded!=*pSize && mayAllocate) { |
| 262 | /* we may try to grow or shrink */ |
| 263 | void *memory; |
| 264 | |
| 265 | if((memory=icu_realloc(*pMemory, sizeNeeded))!=NULL) { |
| 266 | *pMemory=memory; |
| 267 | *pSize=sizeNeeded; |
| 268 | return TRUE; |
| 269 | } else { |
| 270 | /* we failed to grow */ |
| 271 | return FALSE; |
| 272 | } |
| 273 | } else { |
| 274 | /* we have at least enough memory and must not allocate */ |
| 275 | return TRUE; |
| 276 | } |
| 277 | } |
| 278 | } |
| 279 | |
| 280 | U_CAPI void U_EXPORT2 |
| 281 | ubidi_close(UBiDi *pBiDi) { |
| 282 | if(pBiDi!=NULL) { |
| 283 | if(pBiDi->dirPropsMemory!=NULL) { |
| 284 | icu_free(pBiDi->dirPropsMemory); |
| 285 | } |
| 286 | if(pBiDi->levelsMemory!=NULL) { |
| 287 | icu_free(pBiDi->levelsMemory); |
| 288 | } |
| 289 | if(pBiDi->runsMemory!=NULL) { |
| 290 | icu_free(pBiDi->runsMemory); |
| 291 | } |
| 292 | icu_free(pBiDi); |
| 293 | } |
| 294 | } |
| 295 | |
| 296 | /* set to approximate "inverse BiDi" ---------------------------------------- */ |
| 297 | |
| 298 | U_CAPI void U_EXPORT2 |
| 299 | ubidi_setInverse(UBiDi *pBiDi, bool_t isInverse) { |
| 300 | if(pBiDi!=NULL) { |
| 301 | pBiDi->isInverse=isInverse; |
| 302 | } |
| 303 | } |
| 304 | |
| 305 | U_CAPI bool_t U_EXPORT2 |
| 306 | ubidi_isInverse(UBiDi *pBiDi) { |
| 307 | if(pBiDi!=NULL) { |
| 308 | return pBiDi->isInverse; |
| 309 | } else { |
| 310 | return FALSE; |
| 311 | } |
| 312 | } |
| 313 | |
| 314 | /* ubidi_setPara ------------------------------------------------------------ */ |
| 315 | |
| 316 | U_CAPI void U_EXPORT2 |
| 317 | ubidi_setPara(UBiDi *pBiDi, const UChar *text, int32_t length, |
| 318 | UBiDiLevel paraLevel, UBiDiLevel *embeddingLevels, |
| 319 | UErrorCode *pErrorCode) { |
| 320 | UBiDiDirection direction; |
| 321 | |
| 322 | /* check the argument values */ |
| 323 | if(pErrorCode==NULL || U_FAILURE(*pErrorCode)) { |
| 324 | return; |
| 325 | } else if(pBiDi==NULL || text==NULL || |
| 326 | ((UBIDI_MAX_EXPLICIT_LEVEL<paraLevel) && !IS_DEFAULT_LEVEL(paraLevel)) || |
| 327 | length<-1 |
| 328 | ) { |
| 329 | *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR; |
| 330 | return; |
| 331 | } |
| 332 | |
| 333 | if(length==-1) { |
| 334 | // length=u_strlen(text); |
| 335 | const UChar *p = text - 1; |
| 336 | while(*++p); |
| 337 | length = p - text; |
| 338 | } |
| 339 | |
| 340 | /* initialize the UBiDi structure */ |
| 341 | pBiDi->text=text; |
| 342 | pBiDi->length=length; |
| 343 | pBiDi->paraLevel=paraLevel; |
| 344 | pBiDi->direction=UBIDI_LTR; |
| 345 | pBiDi->trailingWSStart=length; /* the levels[] will reflect the WS run */ |
| 346 | |
| 347 | pBiDi->dirProps=NULL; |
| 348 | pBiDi->levels=NULL; |
| 349 | pBiDi->runs=NULL; |
| 350 | |
| 351 | if(length==0) { |
| 352 | /* |
| 353 | * For an empty paragraph, create a UBiDi object with the paraLevel and |
| 354 | * the flags and the direction set but without allocating zero-length arrays. |
| 355 | * There is nothing more to do. |
| 356 | */ |
| 357 | if(IS_DEFAULT_LEVEL(paraLevel)) { |
| 358 | pBiDi->paraLevel&=1; |
| 359 | } |
| 360 | if(paraLevel&1) { |
| 361 | pBiDi->flags=DIRPROP_FLAG(R); |
| 362 | pBiDi->direction=UBIDI_RTL; |
| 363 | } else { |
| 364 | pBiDi->flags=DIRPROP_FLAG(L); |
| 365 | pBiDi->direction=UBIDI_LTR; |
| 366 | } |
| 367 | |
| 368 | pBiDi->runCount=0; |
| 369 | return; |
| 370 | } |
| 371 | |
| 372 | pBiDi->runCount=-1; |
| 373 | |
| 374 | /* |
| 375 | * Get the directional properties, |
| 376 | * the flags bit-set, and |
| 377 | * determine the partagraph level if necessary. |
| 378 | */ |
| 379 | if(getDirPropsMemory(pBiDi, length)) { |
| 380 | pBiDi->dirProps=pBiDi->dirPropsMemory; |
| 381 | getDirProps(pBiDi, text); |
| 382 | } else { |
| 383 | *pErrorCode=U_MEMORY_ALLOCATION_ERROR; |
| 384 | return; |
| 385 | } |
| 386 | |
| 387 | /* are explicit levels specified? */ |
| 388 | if(embeddingLevels==NULL) { |
| 389 | /* no: determine explicit levels according to the (Xn) rules */\ |
| 390 | if(getLevelsMemory(pBiDi, length)) { |
| 391 | pBiDi->levels=pBiDi->levelsMemory; |
| 392 | direction=resolveExplicitLevels(pBiDi); |
| 393 | } else { |
| 394 | *pErrorCode=U_MEMORY_ALLOCATION_ERROR; |
| 395 | return; |
| 396 | } |
| 397 | } else { |
| 398 | /* set BN for all explicit codes, check that all levels are paraLevel..UBIDI_MAX_EXPLICIT_LEVEL */ |
| 399 | pBiDi->levels=embeddingLevels; |
| 400 | direction=checkExplicitLevels(pBiDi, pErrorCode); |
| 401 | if(U_FAILURE(*pErrorCode)) { |
| 402 | return; |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | /* |
| 407 | * The steps after (X9) in the UBiDi algorithm are performed only if |
| 408 | * the paragraph text has mixed directionality! |
| 409 | */ |
| 410 | pBiDi->direction=direction; |
| 411 | switch(direction) { |
| 412 | case UBIDI_LTR: |
| 413 | /* make sure paraLevel is even */ |
| 414 | pBiDi->paraLevel=(UBiDiLevel)((pBiDi->paraLevel+1)&~1); |
| 415 | |
| 416 | /* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */ |
| 417 | pBiDi->trailingWSStart=0; |
| 418 | break; |
| 419 | case UBIDI_RTL: |
| 420 | /* make sure paraLevel is odd */ |
| 421 | pBiDi->paraLevel|=1; |
| 422 | |
| 423 | /* all levels are implicitly at paraLevel (important for ubidi_getLevels()) */ |
| 424 | pBiDi->trailingWSStart=0; |
| 425 | break; |
| 426 | default: |
| 427 | /* |
| 428 | * If there are no external levels specified and there |
| 429 | * are no significant explicit level codes in the text, |
| 430 | * then we can treat the entire paragraph as one run. |
| 431 | * Otherwise, we need to perform the following rules on runs of |
| 432 | * the text with the same embedding levels. (X10) |
| 433 | * "Significant" explicit level codes are ones that actually |
| 434 | * affect non-BN characters. |
| 435 | * Examples for "insignificant" ones are empty embeddings |
| 436 | * LRE-PDF, LRE-RLE-PDF-PDF, etc. |
| 437 | */ |
| 438 | if(embeddingLevels==NULL && !(pBiDi->flags&DIRPROP_FLAG_MULTI_RUNS)) { |
| 439 | resolveImplicitLevels(pBiDi, 0, length, |
| 440 | GET_LR_FROM_LEVEL(pBiDi->paraLevel), |
| 441 | GET_LR_FROM_LEVEL(pBiDi->paraLevel)); |
| 442 | } else { |
| 443 | /* sor, eor: start and end types of same-level-run */ |
| 444 | UBiDiLevel *levels=pBiDi->levels; |
| 445 | int32_t start, limit=0; |
| 446 | UBiDiLevel level, nextLevel; |
| 447 | DirProp sor, eor; |
| 448 | |
| 449 | /* determine the first sor and set eor to it because of the loop body (sor=eor there) */ |
| 450 | level=pBiDi->paraLevel; |
| 451 | nextLevel=levels[0]; |
| 452 | if(level<nextLevel) { |
| 453 | eor=GET_LR_FROM_LEVEL(nextLevel); |
| 454 | } else { |
| 455 | eor=GET_LR_FROM_LEVEL(level); |
| 456 | } |
| 457 | |
| 458 | do { |
| 459 | /* determine start and limit of the run (end points just behind the run) */ |
| 460 | |
| 461 | /* the values for this run's start are the same as for the previous run's end */ |
| 462 | sor=eor; |
| 463 | start=limit; |
| 464 | level=nextLevel; |
| 465 | |
| 466 | /* search for the limit of this run */ |
| 467 | while(++limit<length && levels[limit]==level) {} |
| 468 | |
| 469 | /* get the correct level of the next run */ |
| 470 | if(limit<length) { |
| 471 | nextLevel=levels[limit]; |
| 472 | } else { |
| 473 | nextLevel=pBiDi->paraLevel; |
| 474 | } |
| 475 | |
| 476 | /* determine eor from max(level, nextLevel); sor is last run's eor */ |
| 477 | if((level&~UBIDI_LEVEL_OVERRIDE)<(nextLevel&~UBIDI_LEVEL_OVERRIDE)) { |
| 478 | eor=GET_LR_FROM_LEVEL(nextLevel); |
| 479 | } else { |
| 480 | eor=GET_LR_FROM_LEVEL(level); |
| 481 | } |
| 482 | |
| 483 | /* if the run consists of overridden directional types, then there |
| 484 | are no implicit types to be resolved */ |
| 485 | if(!(level&UBIDI_LEVEL_OVERRIDE)) { |
| 486 | resolveImplicitLevels(pBiDi, start, limit, sor, eor); |
| 487 | } else { |
| 488 | /* remove the UBIDI_LEVEL_OVERRIDE flags */ |
| 489 | do { |
| 490 | levels[start++]&=~UBIDI_LEVEL_OVERRIDE; |
| 491 | } while(start<limit); |
| 492 | } |
| 493 | } while(limit<length); |
| 494 | } |
| 495 | |
| 496 | /* reset the embedding levels for some non-graphic characters (L1), (X9) */ |
| 497 | adjustWSLevels(pBiDi); |
| 498 | |
| 499 | /* for "inverse BiDi", ubidi_getRuns() modifies the levels of numeric runs following RTL runs */ |
| 500 | if(pBiDi->isInverse) { |
| 501 | if(!ubidi_getRuns(pBiDi)) { |
| 502 | *pErrorCode=U_MEMORY_ALLOCATION_ERROR; |
| 503 | return; |
| 504 | } |
| 505 | } |
| 506 | break; |
| 507 | } |
| 508 | } |
| 509 | |
| 510 | /* perform (P2)..(P3) ------------------------------------------------------- */ |
| 511 | |
| 512 | /* |
| 513 | * Get the directional properties for the text, |
| 514 | * calculate the flags bit-set, and |
| 515 | * determine the partagraph level if necessary. |
| 516 | */ |
| 517 | static void |
| 518 | getDirProps(UBiDi *pBiDi, const UChar *text) { |
| 519 | DirProp *dirProps=pBiDi->dirPropsMemory; /* pBiDi->dirProps is const */ |
| 520 | |
| 521 | int32_t i=0, i0, i1, length=pBiDi->length; |
| 522 | Flags flags=0; /* collect all directionalities in the text */ |
| 523 | UChar uchar; |
| 524 | DirProp dirProp; |
| 525 | |
| 526 | if(IS_DEFAULT_LEVEL(pBiDi->paraLevel)) { |
| 527 | /* determine the paragraph level (P2..P3) */ |
| 528 | for(;;) { |
| 529 | uchar=text[i]; |
| 530 | if(!IS_FIRST_SURROGATE(uchar) || i+1==length || !IS_SECOND_SURROGATE(text[i+1])) { |
| 531 | /* not a surrogate pair */ |
| 532 | flags|=DIRPROP_FLAG(dirProps[i]=dirProp=u_charDirection(uchar)); |
| 533 | } else { |
| 534 | /* a surrogate pair */ |
| 535 | dirProps[i++]=BN; /* first surrogate in the pair gets the BN type */ |
| 536 | flags|=DIRPROP_FLAG(dirProps[i]=dirProp=u_surrogatePairDirection(uchar, text[i]))|DIRPROP_FLAG(BN); |
| 537 | } |
| 538 | ++i; |
| 539 | if(dirProp==L) { |
| 540 | pBiDi->paraLevel=0; |
| 541 | break; |
| 542 | } else if(dirProp==R || dirProp==AL) { |
| 543 | pBiDi->paraLevel=1; |
| 544 | break; |
| 545 | } else if(i>=length) { |
| 546 | /* |
| 547 | * see comment in ubidi.h: |
| 548 | * the DEFAULT_XXX values are designed so that |
| 549 | * their bit 0 alone yields the intended default |
| 550 | */ |
| 551 | pBiDi->paraLevel&=1; |
| 552 | break; |
| 553 | } |
| 554 | } |
| 555 | } else { |
| 556 | flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel); |
| 557 | } |
| 558 | |
| 559 | /* get the rest of the directional properties and the flags bits */ |
| 560 | while(i<length) { |
| 561 | uchar=text[i]; |
| 562 | if(!IS_FIRST_SURROGATE(uchar) || i+1==length || !IS_SECOND_SURROGATE(text[i+1])) { |
| 563 | /* not a surrogate pair */ |
| 564 | flags|=DIRPROP_FLAG(dirProps[i]=u_charDirection(uchar)); |
| 565 | } else { |
| 566 | /* a surrogate pair */ |
| 567 | dirProps[i++]=BN; /* first surrogate in the pair gets the BN type */ |
| 568 | flags|=DIRPROP_FLAG(dirProps[i]=dirProp=u_surrogatePairDirection(uchar, text[i]))|DIRPROP_FLAG(BN); |
| 569 | } |
| 570 | ++i; |
| 571 | } |
| 572 | if(flags&MASK_EMBEDDING) { |
| 573 | flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel); |
| 574 | } |
| 575 | |
| 576 | pBiDi->flags=flags; |
| 577 | } |
| 578 | |
| 579 | /* perform (X1)..(X9) ------------------------------------------------------- */ |
| 580 | |
| 581 | /* |
| 582 | * Resolve the explicit levels as specified by explicit embedding codes. |
| 583 | * Recalculate the flags to have them reflect the real properties |
| 584 | * after taking the explicit embeddings into account. |
| 585 | * |
| 586 | * The BiDi algorithm is designed to result in the same behavior whether embedding |
| 587 | * levels are externally specified (from "styled text", supposedly the preferred |
| 588 | * method) or set by explicit embedding codes (LRx, RLx, PDF) in the plain text. |
| 589 | * That is why (X9) instructs to remove all explicit codes (and BN). |
| 590 | * However, in a real implementation, this removal of these codes and their index |
| 591 | * positions in the plain text is undesirable since it would result in |
| 592 | * reallocated, reindexed text. |
| 593 | * Instead, this implementation leaves the codes in there and just ignores them |
| 594 | * in the subsequent processing. |
| 595 | * In order to get the same reordering behavior, positions with a BN or an |
| 596 | * explicit embedding code just get the same level assigned as the last "real" |
| 597 | * character. |
| 598 | * |
| 599 | * Some implementations, not this one, then overwrite some of these |
| 600 | * directionality properties at "real" same-level-run boundaries by |
| 601 | * L or R codes so that the resolution of weak types can be performed on the |
| 602 | * entire paragraph at once instead of having to parse it once more and |
| 603 | * perform that resolution on same-level-runs. |
| 604 | * This limits the scope of the implicit rules in effectively |
| 605 | * the same way as the run limits. |
| 606 | * |
| 607 | * Instead, this implementation does not modify these codes. |
| 608 | * On one hand, the paragraph has to be scanned for same-level-runs, but |
| 609 | * on the other hand, this saves another loop to reset these codes, |
| 610 | * or saves making and modifying a copy of dirProps[]. |
| 611 | * |
| 612 | * |
| 613 | * Note that (Pn) and (Xn) changed significantly from version 4 of the BiDi algorithm. |
| 614 | * |
| 615 | * |
| 616 | * Handling the stack of explicit levels (Xn): |
| 617 | * |
| 618 | * With the BiDi stack of explicit levels, |
| 619 | * as pushed with each LRE, RLE, LRO, and RLO and popped with each PDF, |
| 620 | * the explicit level must never exceed UBIDI_MAX_EXPLICIT_LEVEL==61. |
| 621 | * |
| 622 | * In order to have a correct push-pop semantics even in the case of overflows, |
| 623 | * there are two overflow counters: |
| 624 | * - countOver60 is incremented with each LRx at level 60 |
| 625 | * - from level 60, one RLx increases the level to 61 |
| 626 | * - countOver61 is incremented with each LRx and RLx at level 61 |
| 627 | * |
| 628 | * Popping levels with PDF must work in the opposite order so that level 61 |
| 629 | * is correct at the correct point. Underflows (too many PDFs) must be checked. |
| 630 | * |
| 631 | * This implementation assumes that UBIDI_MAX_EXPLICIT_LEVEL is odd. |
| 632 | */ |
| 633 | |
| 634 | static UBiDiDirection |
| 635 | resolveExplicitLevels(UBiDi *pBiDi) { |
| 636 | const DirProp *dirProps=pBiDi->dirProps; |
| 637 | UBiDiLevel *levels=pBiDi->levels; |
| 638 | |
| 639 | int32_t i=0, length=pBiDi->length; |
| 640 | Flags flags=pBiDi->flags; /* collect all directionalities in the text */ |
| 641 | DirProp dirProp; |
| 642 | UBiDiLevel level=pBiDi->paraLevel; |
| 643 | |
| 644 | UBiDiDirection direction; |
| 645 | |
| 646 | /* determine if the text is mixed-directional or single-directional */ |
| 647 | direction=directionFromFlags(flags); |
| 648 | |
| 649 | /* we may not need to resolve any explicit levels */ |
| 650 | if(direction!=UBIDI_MIXED) { |
| 651 | /* not mixed directionality: levels don't matter - trailingWSStart will be 0 */ |
| 652 | } else if(!(flags&MASK_EXPLICIT) || pBiDi->isInverse) { |
| 653 | /* mixed, but all characters are at the same embedding level */ |
| 654 | /* or we are in "inverse BiDi" */ |
| 655 | /* set all levels to the paragraph level */ |
| 656 | for(i=0; i<length; ++i) { |
| 657 | levels[i]=level; |
| 658 | } |
| 659 | } else { |
| 660 | /* continue to perform (Xn) */ |
| 661 | |
| 662 | /* (X1) level is set for all codes, embeddingLevel keeps track of the push/pop operations */ |
| 663 | /* both variables may carry the UBIDI_LEVEL_OVERRIDE flag to indicate the override status */ |
| 664 | UBiDiLevel embeddingLevel=level, newLevel, stackTop=0; |
| 665 | |
| 666 | UBiDiLevel stack[UBIDI_MAX_EXPLICIT_LEVEL]; /* we never push anything >=UBIDI_MAX_EXPLICIT_LEVEL */ |
| 667 | uint32_t countOver60=0, countOver61=0; /* count overflows of explicit levels */ |
| 668 | |
| 669 | /* recalculate the flags */ |
| 670 | flags=0; |
| 671 | |
| 672 | /* since we assume that this is a single paragraph, we ignore (X8) */ |
| 673 | for(i=0; i<length; ++i) { |
| 674 | dirProp=dirProps[i]; |
| 675 | switch(dirProp) { |
| 676 | case LRE: |
| 677 | case LRO: |
| 678 | /* (X3, X5) */ |
| 679 | newLevel=(UBiDiLevel)((embeddingLevel+2)&~(UBIDI_LEVEL_OVERRIDE|1)); /* least greater even level */ |
| 680 | if(newLevel<=UBIDI_MAX_EXPLICIT_LEVEL) { |
| 681 | stack[stackTop]=embeddingLevel; |
| 682 | ++stackTop; |
| 683 | embeddingLevel=newLevel; |
| 684 | if(dirProp==LRO) { |
| 685 | embeddingLevel|=UBIDI_LEVEL_OVERRIDE; |
| 686 | } else { |
| 687 | embeddingLevel&=~UBIDI_LEVEL_OVERRIDE; |
| 688 | } |
| 689 | } else if((embeddingLevel&~UBIDI_LEVEL_OVERRIDE)==UBIDI_MAX_EXPLICIT_LEVEL) { |
| 690 | ++countOver61; |
| 691 | } else /* (embeddingLevel&~UBIDI_LEVEL_OVERRIDE)==UBIDI_MAX_EXPLICIT_LEVEL-1 */ { |
| 692 | ++countOver60; |
| 693 | } |
| 694 | flags|=DIRPROP_FLAG(BN); |
| 695 | break; |
| 696 | case RLE: |
| 697 | case RLO: |
| 698 | /* (X2, X4) */ |
| 699 | newLevel=(UBiDiLevel)(((embeddingLevel&~UBIDI_LEVEL_OVERRIDE)+1)|1); /* least greater odd level */ |
| 700 | if(newLevel<=UBIDI_MAX_EXPLICIT_LEVEL) { |
| 701 | stack[stackTop]=embeddingLevel; |
| 702 | ++stackTop; |
| 703 | embeddingLevel=newLevel; |
| 704 | if(dirProp==RLO) { |
| 705 | embeddingLevel|=UBIDI_LEVEL_OVERRIDE; |
| 706 | } else { |
| 707 | embeddingLevel&=~UBIDI_LEVEL_OVERRIDE; |
| 708 | } |
| 709 | } else { |
| 710 | ++countOver61; |
| 711 | } |
| 712 | flags|=DIRPROP_FLAG(BN); |
| 713 | break; |
| 714 | case PDF: |
| 715 | /* (X7) */ |
| 716 | /* handle all the overflow cases first */ |
| 717 | if(countOver61>0) { |
| 718 | --countOver61; |
| 719 | } else if(countOver60>0 && (embeddingLevel&~UBIDI_LEVEL_OVERRIDE)!=UBIDI_MAX_EXPLICIT_LEVEL) { |
| 720 | /* handle LRx overflows from level 60 */ |
| 721 | --countOver60; |
| 722 | } else if(stackTop>0) { |
| 723 | /* this is the pop operation; it also pops level 61 while countOver60>0 */ |
| 724 | --stackTop; |
| 725 | embeddingLevel=stack[stackTop]; |
| 726 | /* } else { (underflow) */ |
| 727 | } |
| 728 | flags|=DIRPROP_FLAG(BN); |
| 729 | break; |
| 730 | case B: |
| 731 | /* |
| 732 | * We do not really expect to see a paragraph separator (B), |
| 733 | * but we should do something reasonable with it, |
| 734 | * especially at the end of the text. |
| 735 | */ |
| 736 | stackTop=0; |
| 737 | countOver60=countOver61=0; |
| 738 | embeddingLevel=level=pBiDi->paraLevel; |
| 739 | flags|=DIRPROP_FLAG(B); |
| 740 | break; |
| 741 | case BN: |
| 742 | /* BN, LRE, RLE, and PDF are supposed to be removed (X9) */ |
| 743 | /* they will get their levels set correctly in adjustWSLevels() */ |
| 744 | flags|=DIRPROP_FLAG(BN); |
| 745 | break; |
| 746 | default: |
| 747 | /* all other types get the "real" level */ |
| 748 | if(level!=embeddingLevel) { |
| 749 | level=embeddingLevel; |
| 750 | if(level&UBIDI_LEVEL_OVERRIDE) { |
| 751 | flags|=DIRPROP_FLAG_O(level)|DIRPROP_FLAG_MULTI_RUNS; |
| 752 | } else { |
| 753 | flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG_MULTI_RUNS; |
| 754 | } |
| 755 | } |
| 756 | if(!(level&UBIDI_LEVEL_OVERRIDE)) { |
| 757 | flags|=DIRPROP_FLAG(dirProp); |
| 758 | } |
| 759 | break; |
| 760 | } |
| 761 | |
| 762 | /* |
| 763 | * We need to set reasonable levels even on BN codes and |
| 764 | * explicit codes because we will later look at same-level runs (X10). |
| 765 | */ |
| 766 | levels[i]=level; |
| 767 | } |
| 768 | if(flags&MASK_EMBEDDING) { |
| 769 | flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel); |
| 770 | } |
| 771 | |
| 772 | /* subsequently, ignore the explicit codes and BN (X9) */ |
| 773 | |
| 774 | /* again, determine if the text is mixed-directional or single-directional */ |
| 775 | pBiDi->flags=flags; |
| 776 | direction=directionFromFlags(flags); |
| 777 | } |
| 778 | return direction; |
| 779 | } |
| 780 | |
| 781 | /* |
| 782 | * Use a pre-specified embedding levels array: |
| 783 | * |
| 784 | * Adjust the directional properties for overrides (->LEVEL_OVERRIDE), |
| 785 | * ignore all explicit codes (X9), |
| 786 | * and check all the preset levels. |
| 787 | * |
| 788 | * Recalculate the flags to have them reflect the real properties |
| 789 | * after taking the explicit embeddings into account. |
| 790 | */ |
| 791 | static UBiDiDirection |
| 792 | checkExplicitLevels(UBiDi *pBiDi, UErrorCode *pErrorCode) { |
| 793 | const DirProp *dirProps=pBiDi->dirProps; |
| 794 | UBiDiLevel *levels=pBiDi->levels; |
| 795 | |
| 796 | int32_t i, length=pBiDi->length; |
| 797 | Flags flags=0; /* collect all directionalities in the text */ |
| 798 | UBiDiLevel level, paraLevel=pBiDi->paraLevel; |
| 799 | |
| 800 | for(i=0; i<length; ++i) { |
| 801 | // dlf: we special case levels array for java, 0 means base level, not actually 0 |
| 802 | if (levels[i] == 0) { |
| 803 | levels[i] = paraLevel; |
| 804 | } |
| 805 | level=levels[i]; |
| 806 | if(level&UBIDI_LEVEL_OVERRIDE) { |
| 807 | /* keep the override flag in levels[i] but adjust the flags */ |
| 808 | level&=~UBIDI_LEVEL_OVERRIDE; /* make the range check below simpler */ |
| 809 | flags|=DIRPROP_FLAG_O(level); |
| 810 | } else { |
| 811 | /* set the flags */ |
| 812 | flags|=DIRPROP_FLAG_E(level)|DIRPROP_FLAG(dirProps[i]); |
| 813 | } |
| 814 | if(level<paraLevel || UBIDI_MAX_EXPLICIT_LEVEL<level) { |
| 815 | /* level out of bounds */ |
| 816 | *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR; |
| 817 | return UBIDI_LTR; |
| 818 | } |
| 819 | } |
| 820 | if(flags&MASK_EMBEDDING) { |
| 821 | flags|=DIRPROP_FLAG_LR(pBiDi->paraLevel); |
| 822 | } |
| 823 | |
| 824 | /* determine if the text is mixed-directional or single-directional */ |
| 825 | pBiDi->flags=flags; |
| 826 | return directionFromFlags(flags); |
| 827 | } |
| 828 | |
| 829 | /* determine if the text is mixed-directional or single-directional */ |
| 830 | static UBiDiDirection |
| 831 | directionFromFlags(Flags flags) { |
| 832 | /* if the text contains AN and neutrals, then some neutrals may become RTL */ |
| 833 | if(!(flags&MASK_RTL || ((flags&DIRPROP_FLAG(AN)) && (flags&MASK_POSSIBLE_N)))) { |
| 834 | return UBIDI_LTR; |
| 835 | } else if(!(flags&MASK_LTR)) { |
| 836 | return UBIDI_RTL; |
| 837 | } else { |
| 838 | return UBIDI_MIXED; |
| 839 | } |
| 840 | } |
| 841 | |
| 842 | /* perform rules (Wn), (Nn), and (In) on a run of the text ------------------ */ |
| 843 | |
| 844 | /* |
| 845 | * This implementation of the (Wn) rules applies all rules in one pass. |
| 846 | * In order to do so, it needs a look-ahead of typically 1 character |
| 847 | * (except for W5: sequences of ET) and keeps track of changes |
| 848 | * in a rule Wp that affect a later Wq (p<q). |
| 849 | * |
| 850 | * historyOfEN is a variable-saver: it contains 4 boolean states; |
| 851 | * a bit in it set to 1 means: |
| 852 | * bit 0: the current code is an EN after W2 |
| 853 | * bit 1: the current code is an EN after W4 |
| 854 | * bit 2: the previous code was an EN after W2 |
| 855 | * bit 3: the previous code was an EN after W4 |
| 856 | * In other words, b0..1 have transitions of EN in the current iteration, |
| 857 | * while b2..3 have the transitions of EN in the previous iteration. |
| 858 | * A simple historyOfEN<<=2 suffices for the propagation. |
| 859 | * |
| 860 | * The (Nn) and (In) rules are also performed in that same single loop, |
| 861 | * but effectively one iteration behind for white space. |
| 862 | * |
| 863 | * Since all implicit rules are performed in one step, it is not necessary |
| 864 | * to actually store the intermediate directional properties in dirProps[]. |
| 865 | */ |
| 866 | |
| 867 | #define EN_SHIFT 2 |
| 868 | #define EN_AFTER_W2 1 |
| 869 | #define EN_AFTER_W4 2 |
| 870 | #define EN_ALL 3 |
| 871 | #define PREV_EN_AFTER_W2 4 |
| 872 | #define PREV_EN_AFTER_W4 8 |
| 873 | |
| 874 | static void |
| 875 | resolveImplicitLevels(UBiDi *pBiDi, |
| 876 | int32_t start, int32_t limit, |
| 877 | DirProp sor, DirProp eor) { |
| 878 | const DirProp *dirProps=pBiDi->dirProps; |
| 879 | UBiDiLevel *levels=pBiDi->levels; |
| 880 | |
| 881 | int32_t i, next, neutralStart=-1; |
| 882 | DirProp prevDirProp, dirProp, nextDirProp, lastStrong, beforeNeutral=L; |
| 883 | UBiDiLevel numberLevel; |
| 884 | uint8_t historyOfEN; |
| 885 | |
| 886 | /* initialize: current at sor, next at start (it is start<limit) */ |
| 887 | next=start; |
| 888 | dirProp=lastStrong=sor; |
| 889 | nextDirProp=dirProps[next]; |
| 890 | historyOfEN=0; |
| 891 | |
| 892 | if(pBiDi->isInverse) { |
| 893 | /* |
| 894 | * For "inverse BiDi", we set the levels of numbers just like for |
| 895 | * regular L characters, plus a flag that ubidi_getRuns() will use |
| 896 | * to set a similar flag on the corresponding output run. |
| 897 | */ |
| 898 | numberLevel=levels[start]; |
| 899 | if(numberLevel&1) { |
| 900 | ++numberLevel; |
| 901 | } |
| 902 | } else { |
| 903 | /* normal BiDi: least greater even level */ |
| 904 | numberLevel=(UBiDiLevel)((levels[start]+2)&~1); |
| 905 | } |
| 906 | |
| 907 | /* |
| 908 | * In all steps of this implementation, BN and explicit embedding codes |
| 909 | * must be treated as if they didn't exist (X9). |
| 910 | * They will get levels set before a non-neutral character, and remain |
| 911 | * undefined before a neutral one, but adjustWSLevels() will take care |
| 912 | * of all of them. |
| 913 | */ |
| 914 | while(DIRPROP_FLAG(nextDirProp)&MASK_BN_EXPLICIT) { |
| 915 | if(++next<limit) { |
| 916 | nextDirProp=dirProps[next]; |
| 917 | } else { |
| 918 | nextDirProp=eor; |
| 919 | break; |
| 920 | } |
| 921 | } |
| 922 | |
| 923 | /* |
| 924 | * Note: at the end of this file, there is a prototype |
| 925 | * of a version of this function that uses a statetable |
| 926 | * at the core of this state machine. |
| 927 | * If you make changes to this state machine, |
| 928 | * please update that prototype as well. |
| 929 | */ |
| 930 | |
| 931 | /* loop for entire run */ |
| 932 | while(next<limit) { |
| 933 | /* advance */ |
| 934 | prevDirProp=dirProp; |
| 935 | dirProp=nextDirProp; |
| 936 | i=next; |
| 937 | do { |
| 938 | if(++next<limit) { |
| 939 | nextDirProp=dirProps[next]; |
| 940 | } else { |
| 941 | nextDirProp=eor; |
| 942 | break; |
| 943 | } |
| 944 | } while(DIRPROP_FLAG(nextDirProp)&MASK_BN_EXPLICIT); |
| 945 | historyOfEN<<=EN_SHIFT; |
| 946 | |
| 947 | /* (W1..W7) */ |
| 948 | switch(dirProp) { |
| 949 | case L: |
| 950 | lastStrong=L; |
| 951 | break; |
| 952 | case R: |
| 953 | lastStrong=R; |
| 954 | break; |
| 955 | case AL: |
| 956 | /* (W3) */ |
| 957 | lastStrong=AL; |
| 958 | dirProp=R; |
| 959 | break; |
| 960 | case EN: |
| 961 | /* we have to set historyOfEN correctly */ |
| 962 | if(lastStrong==AL) { |
| 963 | /* (W2) */ |
| 964 | dirProp=AN; |
| 965 | } else { |
| 966 | if(lastStrong==L) { |
| 967 | /* (W7) */ |
| 968 | dirProp=L; |
| 969 | } |
| 970 | /* this EN stays after (W2) and (W4) - at least before (W7) */ |
| 971 | historyOfEN|=EN_ALL; |
| 972 | } |
| 973 | break; |
| 974 | case ES: |
| 975 | if( historyOfEN&PREV_EN_AFTER_W2 && /* previous was EN before (W4) */ |
| 976 | nextDirProp==EN && lastStrong!=AL /* next is EN and (W2) won't make it AN */ |
| 977 | ) { |
| 978 | /* (W4) */ |
| 979 | if(lastStrong!=L) { |
| 980 | dirProp=EN; |
| 981 | } else { |
| 982 | /* (W7) */ |
| 983 | dirProp=L; |
| 984 | } |
| 985 | historyOfEN|=EN_AFTER_W4; |
| 986 | } else { |
| 987 | /* (W6) */ |
| 988 | dirProp=ON; |
| 989 | } |
| 990 | break; |
| 991 | case CS: |
| 992 | if( historyOfEN&PREV_EN_AFTER_W2 && /* previous was EN before (W4) */ |
| 993 | nextDirProp==EN && lastStrong!=AL /* next is EN and (W2) won't make it AN */ |
| 994 | ) { |
| 995 | /* (W4) */ |
| 996 | if(lastStrong!=L) { |
| 997 | dirProp=EN; |
| 998 | } else { |
| 999 | /* (W7) */ |
| 1000 | dirProp=L; |
| 1001 | } |
| 1002 | historyOfEN|=EN_AFTER_W4; |
| 1003 | } else if(prevDirProp==AN && /* previous was AN */ |
| 1004 | (nextDirProp==AN || /* next is AN */ |
| 1005 | (nextDirProp==EN && lastStrong==AL)) /* or (W2) will make it one */ |
| 1006 | ) { |
| 1007 | /* (W4) */ |
| 1008 | dirProp=AN; |
| 1009 | } else { |
| 1010 | /* (W6) */ |
| 1011 | dirProp=ON; |
| 1012 | } |
| 1013 | break; |
| 1014 | case ET: |
| 1015 | /* get sequence of ET; advance only next, not current, previous or historyOfEN */ |
| 1016 | if(next<limit) { |
| 1017 | while(DIRPROP_FLAG(nextDirProp)&MASK_ET_NSM_BN /* (W1), (X9) */) { |
| 1018 | if(++next<limit) { |
| 1019 | nextDirProp=dirProps[next]; |
| 1020 | } else { |
| 1021 | nextDirProp=eor; |
| 1022 | break; |
| 1023 | } |
| 1024 | } |
| 1025 | } |
| 1026 | |
| 1027 | /* now process the sequence of ET like a single ET */ |
| 1028 | if((historyOfEN&PREV_EN_AFTER_W4) || /* previous was EN before (W5) */ |
| 1029 | (nextDirProp==EN && lastStrong!=AL) /* next is EN and (W2) won't make it AN */ |
| 1030 | ) { |
| 1031 | /* (W5) */ |
| 1032 | if(lastStrong!=L) { |
| 1033 | dirProp=EN; |
| 1034 | } else { |
| 1035 | /* (W7) */ |
| 1036 | dirProp=L; |
| 1037 | } |
| 1038 | } else { |
| 1039 | /* (W6) */ |
| 1040 | dirProp=ON; |
| 1041 | } |
| 1042 | |
| 1043 | /* apply the result of (W1), (W5)..(W7) to the entire sequence of ET */ |
| 1044 | break; |
| 1045 | case NSM: |
| 1046 | /* (W1) */ |
| 1047 | dirProp=prevDirProp; |
| 1048 | /* set historyOfEN back to prevDirProp's historyOfEN */ |
| 1049 | historyOfEN>>=EN_SHIFT; |
| 1050 | /* |
| 1051 | * Technically, this should be done before the switch() in the form |
| 1052 | * if(nextDirProp==NSM) { |
| 1053 | * dirProps[next]=nextDirProp=dirProp; |
| 1054 | * } |
| 1055 | * |
| 1056 | * - effectively one iteration ahead. |
| 1057 | * However, whether the next dirProp is NSM or is equal to the current dirProp |
| 1058 | * does not change the outcome of any condition in (W2)..(W7). |
| 1059 | */ |
| 1060 | break; |
| 1061 | default: |
| 1062 | break; |
| 1063 | } |
| 1064 | |
| 1065 | /* here, it is always [prev,this,next]dirProp!=BN; it may be next>i+1 */ |
| 1066 | |
| 1067 | /* perform (Nn) - here, only L, R, EN, AN, and neutrals are left */ |
| 1068 | /* for "inverse BiDi", treat neutrals like L */ |
| 1069 | /* this is one iteration late for the neutrals */ |
| 1070 | if(DIRPROP_FLAG(dirProp)&MASK_N) { |
| 1071 | if(neutralStart<0) { |
| 1072 | /* start of a sequence of neutrals */ |
| 1073 | neutralStart=i; |
| 1074 | beforeNeutral=prevDirProp; |
| 1075 | } |
| 1076 | } else /* not a neutral, can be only one of { L, R, EN, AN } */ { |
| 1077 | /* |
| 1078 | * Note that all levels[] values are still the same at this |
| 1079 | * point because this function is called for an entire |
| 1080 | * same-level run. |
| 1081 | * Therefore, we need to read only one actual level. |
| 1082 | */ |
| 1083 | UBiDiLevel level=levels[i]; |
| 1084 | |
| 1085 | if(neutralStart>=0) { |
| 1086 | UBiDiLevel final; |
| 1087 | /* end of a sequence of neutrals (dirProp is "afterNeutral") */ |
| 1088 | if(!(pBiDi->isInverse)) { |
| 1089 | if(beforeNeutral==L) { |
| 1090 | if(dirProp==L) { |
| 1091 | final=0; /* make all neutrals L (N1) */ |
| 1092 | } else { |
| 1093 | final=level; /* make all neutrals "e" (N2) */ |
| 1094 | } |
| 1095 | } else /* beforeNeutral is one of { R, EN, AN } */ { |
| 1096 | if(dirProp==L) { |
| 1097 | final=level; /* make all neutrals "e" (N2) */ |
| 1098 | } else { |
| 1099 | final=1; /* make all neutrals R (N1) */ |
| 1100 | } |
| 1101 | } |
| 1102 | } else { |
| 1103 | /* "inverse BiDi": collapse [before]dirProps L, EN, AN into L */ |
| 1104 | if(beforeNeutral!=R) { |
| 1105 | if(dirProp!=R) { |
| 1106 | final=0; /* make all neutrals L (N1) */ |
| 1107 | } else { |
| 1108 | final=level; /* make all neutrals "e" (N2) */ |
| 1109 | } |
| 1110 | } else /* beforeNeutral is one of { R, EN, AN } */ { |
| 1111 | if(dirProp!=R) { |
| 1112 | final=level; /* make all neutrals "e" (N2) */ |
| 1113 | } else { |
| 1114 | final=1; /* make all neutrals R (N1) */ |
| 1115 | } |
| 1116 | } |
| 1117 | } |
| 1118 | /* perform (In) on the sequence of neutrals */ |
| 1119 | if((level^final)&1) { |
| 1120 | /* do something only if we need to _change_ the level */ |
| 1121 | do { |
| 1122 | ++levels[neutralStart]; |
| 1123 | } while(++neutralStart<i); |
| 1124 | } |
| 1125 | neutralStart=-1; |
| 1126 | } |
| 1127 | |
| 1128 | /* perform (In) on the non-neutral character */ |
| 1129 | /* |
| 1130 | * in the cases of (W5), processing a sequence of ET, |
| 1131 | * and of (X9), skipping BN, |
| 1132 | * there may be multiple characters from i to <next |
| 1133 | * that all get (virtually) the same dirProp and (really) the same level |
| 1134 | */ |
| 1135 | if(dirProp==L) { |
| 1136 | if(level&1) { |
| 1137 | ++level; |
| 1138 | } else { |
| 1139 | i=next; /* we keep the levels */ |
| 1140 | } |
| 1141 | } else if(dirProp==R) { |
| 1142 | if(!(level&1)) { |
| 1143 | ++level; |
| 1144 | } else { |
| 1145 | i=next; /* we keep the levels */ |
| 1146 | } |
| 1147 | } else /* EN or AN */ { |
| 1148 | /* this level depends on whether we do "inverse BiDi" */ |
| 1149 | level=numberLevel; |
| 1150 | } |
| 1151 | |
| 1152 | /* apply the new level to the sequence, if necessary */ |
| 1153 | while(i<next) { |
| 1154 | levels[i++]=level; |
| 1155 | } |
| 1156 | } |
| 1157 | } |
| 1158 | |
| 1159 | /* perform (Nn) - here, |
| 1160 | the character after the the neutrals is eor, which is either L or R */ |
| 1161 | /* this is one iteration late for the neutrals */ |
| 1162 | if(neutralStart>=0) { |
| 1163 | /* |
| 1164 | * Note that all levels[] values are still the same at this |
| 1165 | * point because this function is called for an entire |
| 1166 | * same-level run. |
| 1167 | * Therefore, we need to read only one actual level. |
| 1168 | */ |
| 1169 | UBiDiLevel level=levels[neutralStart], final; |
| 1170 | |
| 1171 | /* end of a sequence of neutrals (eor is "afterNeutral") */ |
| 1172 | if(!(pBiDi->isInverse)) { |
| 1173 | if(beforeNeutral==L) { |
| 1174 | if(eor==L) { |
| 1175 | final=0; /* make all neutrals L (N1) */ |
| 1176 | } else { |
| 1177 | final=level; /* make all neutrals "e" (N2) */ |
| 1178 | } |
| 1179 | } else /* beforeNeutral is one of { R, EN, AN } */ { |
| 1180 | if(eor==L) { |
| 1181 | final=level; /* make all neutrals "e" (N2) */ |
| 1182 | } else { |
| 1183 | final=1; /* make all neutrals R (N1) */ |
| 1184 | } |
| 1185 | } |
| 1186 | } else { |
| 1187 | /* "inverse BiDi": collapse [before]dirProps L, EN, AN into L */ |
| 1188 | if(beforeNeutral!=R) { |
| 1189 | if(eor!=R) { |
| 1190 | final=0; /* make all neutrals L (N1) */ |
| 1191 | } else { |
| 1192 | final=level; /* make all neutrals "e" (N2) */ |
| 1193 | } |
| 1194 | } else /* beforeNeutral is one of { R, EN, AN } */ { |
| 1195 | if(eor!=R) { |
| 1196 | final=level; /* make all neutrals "e" (N2) */ |
| 1197 | } else { |
| 1198 | final=1; /* make all neutrals R (N1) */ |
| 1199 | } |
| 1200 | } |
| 1201 | } |
| 1202 | /* perform (In) on the sequence of neutrals */ |
| 1203 | if((level^final)&1) { |
| 1204 | /* do something only if we need to _change_ the level */ |
| 1205 | do { |
| 1206 | ++levels[neutralStart]; |
| 1207 | } while(++neutralStart<limit); |
| 1208 | } |
| 1209 | } |
| 1210 | } |
| 1211 | |
| 1212 | /* perform (L1) and (X9) ---------------------------------------------------- */ |
| 1213 | |
| 1214 | /* |
| 1215 | * Reset the embedding levels for some non-graphic characters (L1). |
| 1216 | * This function also sets appropriate levels for BN, and |
| 1217 | * explicit embedding types that are supposed to have been removed |
| 1218 | * from the paragraph in (X9). |
| 1219 | */ |
| 1220 | static void |
| 1221 | adjustWSLevels(UBiDi *pBiDi) { |
| 1222 | const DirProp *dirProps=pBiDi->dirProps; |
| 1223 | UBiDiLevel *levels=pBiDi->levels; |
| 1224 | int32_t i; |
| 1225 | |
| 1226 | if(pBiDi->flags&MASK_WS) { |
| 1227 | UBiDiLevel paraLevel=pBiDi->paraLevel; |
| 1228 | Flags flag; |
| 1229 | |
| 1230 | i=pBiDi->trailingWSStart; |
| 1231 | while(i>0) { |
| 1232 | /* reset a sequence of WS/BN before eop and B/S to the paragraph paraLevel */ |
| 1233 | while(i>0 && DIRPROP_FLAG(dirProps[--i])&MASK_WS) { |
| 1234 | levels[i]=paraLevel; |
| 1235 | } |
| 1236 | |
| 1237 | /* reset BN to the next character's paraLevel until B/S, which restarts above loop */ |
| 1238 | /* here, i+1 is guaranteed to be <length */ |
| 1239 | while(i>0) { |
| 1240 | flag=DIRPROP_FLAG(dirProps[--i]); |
| 1241 | if(flag&MASK_BN_EXPLICIT) { |
| 1242 | levels[i]=levels[i+1]; |
| 1243 | } else if(flag&MASK_B_S) { |
| 1244 | levels[i]=paraLevel; |
| 1245 | break; |
| 1246 | } |
| 1247 | } |
| 1248 | } |
| 1249 | } |
| 1250 | |
| 1251 | /* now remove the UBIDI_LEVEL_OVERRIDE flags, if any */ |
| 1252 | /* (a separate loop can be optimized more easily by a compiler) */ |
| 1253 | if(pBiDi->flags&MASK_OVERRIDE) { |
| 1254 | for(i=pBiDi->trailingWSStart; i>0;) { |
| 1255 | levels[--i]&=~UBIDI_LEVEL_OVERRIDE; |
| 1256 | } |
| 1257 | } |
| 1258 | } |
| 1259 | |
| 1260 | /* -------------------------------------------------------------------------- */ |
| 1261 | |
| 1262 | U_CAPI UBiDiDirection U_EXPORT2 |
| 1263 | ubidi_getDirection(const UBiDi *pBiDi) { |
| 1264 | if(pBiDi!=NULL) { |
| 1265 | return pBiDi->direction; |
| 1266 | } else { |
| 1267 | return UBIDI_LTR; |
| 1268 | } |
| 1269 | } |
| 1270 | |
| 1271 | U_CAPI const UChar * U_EXPORT2 |
| 1272 | ubidi_getText(const UBiDi *pBiDi) { |
| 1273 | if(pBiDi!=NULL) { |
| 1274 | return pBiDi->text; |
| 1275 | } else { |
| 1276 | return NULL; |
| 1277 | } |
| 1278 | } |
| 1279 | |
| 1280 | U_CAPI int32_t U_EXPORT2 |
| 1281 | ubidi_getLength(const UBiDi *pBiDi) { |
| 1282 | if(pBiDi!=NULL) { |
| 1283 | return pBiDi->length; |
| 1284 | } else { |
| 1285 | return 0; |
| 1286 | } |
| 1287 | } |
| 1288 | |
| 1289 | U_CAPI UBiDiLevel U_EXPORT2 |
| 1290 | ubidi_getParaLevel(const UBiDi *pBiDi) { |
| 1291 | if(pBiDi!=NULL) { |
| 1292 | return pBiDi->paraLevel; |
| 1293 | } else { |
| 1294 | return 0; |
| 1295 | } |
| 1296 | } |
| 1297 | |
| 1298 | /* statetable prototype ----------------------------------------------------- */ |
| 1299 | |
| 1300 | /* |
| 1301 | * This is here for possible future |
| 1302 | * performance work and is not compiled right now. |
| 1303 | */ |
| 1304 | |
| 1305 | #if 0 |
| 1306 | /* |
| 1307 | * This is a piece of code that could be part of ubidi.c/resolveImplicitLevels(). |
| 1308 | * It replaces in the (Wn) state machine the switch()-if()-cascade with |
| 1309 | * just a few if()s and a state table. |
| 1310 | */ |
| 1311 | |
| 1312 | /* use the state table only for the following dirProp's */ |
| 1313 | #define MASK_W_TABLE (FLAG(L)|FLAG(R)|FLAG(AL)|FLAG(EN)|FLAG(ES)|FLAG(CS)|FLAG(ET)|FLAG(AN)) |
| 1314 | |
| 1315 | /* |
| 1316 | * inputs: |
| 1317 | * |
| 1318 | * 0..1 historyOfEN - 2b |
| 1319 | * 2 prevDirProp==AN - 1b |
| 1320 | * 3..4 lastStrong, one of { L, R, AL, none } - 2b |
| 1321 | * 5..7 dirProp, one of { L, R, AL, EN, ES, CS, ET, AN } - 3b |
| 1322 | * 8..9 nextDirProp, one of { EN, AN, other } |
| 1323 | * |
| 1324 | * total: 10b=1024 states |
| 1325 | */ |
| 1326 | enum { _L, _R, _AL, _EN, _ES, _CS, _ET, _AN, _OTHER }; /* lastStrong, dirProp */ |
| 1327 | enum { __EN, __AN, __OTHER }; /* nextDirProp */ |
| 1328 | |
| 1329 | #define LAST_STRONG_SHIFT 3 |
| 1330 | #define DIR_PROP_SHIFT 5 |
| 1331 | #define NEXT_DIR_PROP_SHIFT 8 |
| 1332 | |
| 1333 | /* masks after shifting */ |
| 1334 | #define LAST_STRONG_MASK 3 |
| 1335 | #define DIR_PROP_MASK 7 |
| 1336 | #define STATE_MASK 0x1f |
| 1337 | |
| 1338 | /* convert dirProp into _dirProp (above enum) */ |
| 1339 | static DirProp inputDirProp[dirPropCount]={ _X<<DIR_PROP_SHIFT, ... }; |
| 1340 | |
| 1341 | /* convert dirProp into __dirProp (above enum) */ |
| 1342 | static DirProp inputNextDirProp[dirPropCount]={ __X<<NEXT_DIR_PROP_SHIFT, ... }; |
| 1343 | |
| 1344 | /* |
| 1345 | * outputs: |
| 1346 | * |
| 1347 | * dirProp, one of { L, R, EN, AN, ON } - 3b |
| 1348 | * |
| 1349 | * 0..1 historyOfEN - 2b |
| 1350 | * 2 prevDirProp==AN - 1b |
| 1351 | * 3..4 lastStrong, one of { L, R, AL, none } - 2b |
| 1352 | * 5..7 new dirProp, one of { L, R, EN, AN, ON } |
| 1353 | * |
| 1354 | * total: 8 bits=1 byte per state |
| 1355 | */ |
| 1356 | enum { ___L, ___R, ___EN, ___AN, ___ON, ___count }; |
| 1357 | |
| 1358 | /* convert ___dirProp into dirProp (above enum) */ |
| 1359 | static DirProp outputDirProp[___count]={ X, ... }; |
| 1360 | |
| 1361 | /* state table */ |
| 1362 | static uint8_t wnTable[1024]={ /* calculate with switch()-if()-cascade */ }; |
| 1363 | |
| 1364 | static void |
| 1365 | resolveImplicitLevels(BiDi *pBiDi, |
| 1366 | Index start, Index end, |
| 1367 | DirProp sor, DirProp eor) { |
| 1368 | /* new variable */ |
| 1369 | uint8_t state; |
| 1370 | |
| 1371 | /* remove variable lastStrong */ |
| 1372 | |
| 1373 | /* set initial state (set lastStrong, the rest is 0) */ |
| 1374 | state= sor==L ? 0 : _R<<LAST_STRONG_SHIFT; |
| 1375 | |
| 1376 | while(next<limit) { |
| 1377 | /* advance */ |
| 1378 | prevDirProp=dirProp; |
| 1379 | dirProp=nextDirProp; |
| 1380 | i=next; |
| 1381 | do { |
| 1382 | if(++next<limit) { |
| 1383 | nextDirProp=dirProps[next]; |
| 1384 | } else { |
| 1385 | nextDirProp=eor; |
| 1386 | break; |
| 1387 | } |
| 1388 | } while(FLAG(nextDirProp)&MASK_BN_EXPLICIT); |
| 1389 | |
| 1390 | /* (W1..W7) */ |
| 1391 | /* ### This may be more efficient with a switch(dirProp). */ |
| 1392 | if(FLAG(dirProp)&MASK_W_TABLE) { |
| 1393 | state=wnTable[ |
| 1394 | ((int)state)| |
| 1395 | inputDirProp[dirProp]| |
| 1396 | inputNextDirProp[nextDirProp] |
| 1397 | ]; |
| 1398 | dirProp=outputDirProp[state>>DIR_PROP_SHIFT]; |
| 1399 | state&=STATE_MASK; |
| 1400 | } else if(dirProp==ET) { |
| 1401 | /* get sequence of ET; advance only next, not current, previous or historyOfEN */ |
| 1402 | while(next<limit && FLAG(nextDirProp)&MASK_ET_NSM_BN /* (W1), (X9) */) { |
| 1403 | if(++next<limit) { |
| 1404 | nextDirProp=dirProps[next]; |
| 1405 | } else { |
| 1406 | nextDirProp=eor; |
| 1407 | break; |
| 1408 | } |
| 1409 | } |
| 1410 | |
| 1411 | state=wnTable[ |
| 1412 | ((int)state)| |
| 1413 | _ET<<DIR_PROP_SHIFT| |
| 1414 | inputNextDirProp[nextDirProp] |
| 1415 | ]; |
| 1416 | dirProp=outputDirProp[state>>DIR_PROP_SHIFT]; |
| 1417 | state&=STATE_MASK; |
| 1418 | |
| 1419 | /* apply the result of (W1), (W5)..(W7) to the entire sequence of ET */ |
| 1420 | } else if(dirProp==NSM) { |
| 1421 | /* (W1) */ |
| 1422 | dirProp=prevDirProp; |
| 1423 | /* keep prevDirProp's EN and AN states! */ |
| 1424 | } else /* other */ { |
| 1425 | /* set EN and AN states to 0 */ |
| 1426 | state&=LAST_STRONG_MASK<<LAST_STRONG_SHIFT; |
| 1427 | } |
| 1428 | |
| 1429 | /* perform (Nn) and (In) as usual */ |
| 1430 | } |
| 1431 | /* perform (Nn) and (In) as usual */ |
| 1432 | } |
| 1433 | #endif |