1 // © 2016 and later: Unicode, Inc. and others. 2 // License & terms of use: http://www.unicode.org/copyright.html 3 /* 4 ******************************************************************************* 5 * 6 * Copyright (C) 1999-2012, International Business Machines 7 * Corporation and others. All Rights Reserved. 8 * 9 ******************************************************************************* 10 * file name: utf16.h 11 * encoding: UTF-8 12 * tab size: 8 (not used) 13 * indentation:4 14 * 15 * created on: 1999sep09 16 * created by: Markus W. Scherer 17 */ 18 19 /** 20 * \file 21 * \brief C API: 16-bit Unicode handling macros 22 * 23 * This file defines macros to deal with 16-bit Unicode (UTF-16) code units and strings. 24 * 25 * For more information see utf.h and the ICU User Guide Strings chapter 26 * (https://unicode-org.github.io/icu/userguide/strings). 27 * 28 * <em>Usage:</em> 29 * ICU coding guidelines for if() statements should be followed when using these macros. 30 * Compound statements (curly braces {}) must be used for if-else-while... 31 * bodies and all macro statements should be terminated with semicolon. 32 */ 33 34 #ifndef __UTF16_H__ 35 #define __UTF16_H__ 36 37 #include <stdbool.h> 38 #include "unicode/umachine.h" 39 #ifndef __UTF_H__ 40 # include "unicode/utf.h" 41 #endif 42 43 /* single-code point definitions -------------------------------------------- */ 44 45 /** 46 * Does this code unit alone encode a code point (BMP, not a surrogate)? 47 * @param c 16-bit code unit 48 * @return true or false 49 * @stable ICU 2.4 50 */ 51 #define U16_IS_SINGLE(c) !U_IS_SURROGATE(c) 52 53 /** 54 * Is this code unit a lead surrogate (U+d800..U+dbff)? 55 * @param c 16-bit code unit 56 * @return true or false 57 * @stable ICU 2.4 58 */ 59 #define U16_IS_LEAD(c) (((c)&0xfffffc00)==0xd800) 60 61 /** 62 * Is this code unit a trail surrogate (U+dc00..U+dfff)? 63 * @param c 16-bit code unit 64 * @return true or false 65 * @stable ICU 2.4 66 */ 67 #define U16_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00) 68 69 /** 70 * Is this code unit a surrogate (U+d800..U+dfff)? 71 * @param c 16-bit code unit 72 * @return true or false 73 * @stable ICU 2.4 74 */ 75 #define U16_IS_SURROGATE(c) U_IS_SURROGATE(c) 76 77 /** 78 * Assuming c is a surrogate code point (U16_IS_SURROGATE(c)), 79 * is it a lead surrogate? 80 * @param c 16-bit code unit 81 * @return true or false 82 * @stable ICU 2.4 83 */ 84 #define U16_IS_SURROGATE_LEAD(c) (((c)&0x400)==0) 85 86 /** 87 * Assuming c is a surrogate code point (U16_IS_SURROGATE(c)), 88 * is it a trail surrogate? 89 * @param c 16-bit code unit 90 * @return true or false 91 * @stable ICU 4.2 92 */ 93 #define U16_IS_SURROGATE_TRAIL(c) (((c)&0x400)!=0) 94 95 /** 96 * Helper constant for U16_GET_SUPPLEMENTARY. 97 * @internal 98 */ 99 #define U16_SURROGATE_OFFSET ((0xd800<<10UL)+0xdc00-0x10000) 100 101 /** 102 * Get a supplementary code point value (U+10000..U+10ffff) 103 * from its lead and trail surrogates. 104 * The result is undefined if the input values are not 105 * lead and trail surrogates. 106 * 107 * @param lead lead surrogate (U+d800..U+dbff) 108 * @param trail trail surrogate (U+dc00..U+dfff) 109 * @return supplementary code point (U+10000..U+10ffff) 110 * @stable ICU 2.4 111 */ 112 #define U16_GET_SUPPLEMENTARY(lead, trail) \ 113 (((UChar32)(lead)<<10UL)+(UChar32)(trail)-U16_SURROGATE_OFFSET) 114 115 116 /** 117 * Get the lead surrogate (0xd800..0xdbff) for a 118 * supplementary code point (0x10000..0x10ffff). 119 * @param supplementary 32-bit code point (U+10000..U+10ffff) 120 * @return lead surrogate (U+d800..U+dbff) for supplementary 121 * @stable ICU 2.4 122 */ 123 #define U16_LEAD(supplementary) (UChar)(((supplementary)>>10)+0xd7c0) 124 125 /** 126 * Get the trail surrogate (0xdc00..0xdfff) for a 127 * supplementary code point (0x10000..0x10ffff). 128 * @param supplementary 32-bit code point (U+10000..U+10ffff) 129 * @return trail surrogate (U+dc00..U+dfff) for supplementary 130 * @stable ICU 2.4 131 */ 132 #define U16_TRAIL(supplementary) (UChar)(((supplementary)&0x3ff)|0xdc00) 133 134 /** 135 * How many 16-bit code units are used to encode this Unicode code point? (1 or 2) 136 * The result is not defined if c is not a Unicode code point (U+0000..U+10ffff). 137 * @param c 32-bit code point 138 * @return 1 or 2 139 * @stable ICU 2.4 140 */ 141 #define U16_LENGTH(c) ((uint32_t)(c)<=0xffff ? 1 : 2) 142 143 /** 144 * The maximum number of 16-bit code units per Unicode code point (U+0000..U+10ffff). 145 * @return 2 146 * @stable ICU 2.4 147 */ 148 #define U16_MAX_LENGTH 2 149 150 /** 151 * Get a code point from a string at a random-access offset, 152 * without changing the offset. 153 * "Unsafe" macro, assumes well-formed UTF-16. 154 * 155 * The offset may point to either the lead or trail surrogate unit 156 * for a supplementary code point, in which case the macro will read 157 * the adjacent matching surrogate as well. 158 * The result is undefined if the offset points to a single, unpaired surrogate. 159 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT. 160 * 161 * @param s const UChar * string 162 * @param i string offset 163 * @param c output UChar32 variable 164 * @see U16_GET 165 * @stable ICU 2.4 166 */ 167 #define U16_GET_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 168 (c)=(s)[i]; \ 169 if(U16_IS_SURROGATE(c)) { \ 170 if(U16_IS_SURROGATE_LEAD(c)) { \ 171 (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)+1]); \ 172 } else { \ 173 (c)=U16_GET_SUPPLEMENTARY((s)[(i)-1], (c)); \ 174 } \ 175 } \ 176 } UPRV_BLOCK_MACRO_END 177 178 /** 179 * Get a code point from a string at a random-access offset, 180 * without changing the offset. 181 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 182 * 183 * The offset may point to either the lead or trail surrogate unit 184 * for a supplementary code point, in which case the macro will read 185 * the adjacent matching surrogate as well. 186 * 187 * The length can be negative for a NUL-terminated string. 188 * 189 * If the offset points to a single, unpaired surrogate, then 190 * c is set to that unpaired surrogate. 191 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT. 192 * 193 * @param s const UChar * string 194 * @param start starting string offset (usually 0) 195 * @param i string offset, must be start<=i<length 196 * @param length string length 197 * @param c output UChar32 variable 198 * @see U16_GET_UNSAFE 199 * @stable ICU 2.4 200 */ 201 #define U16_GET(s, start, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \ 202 (c)=(s)[i]; \ 203 if(U16_IS_SURROGATE(c)) { \ 204 uint16_t __c2; \ 205 if(U16_IS_SURROGATE_LEAD(c)) { \ 206 if((i)+1!=(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \ 207 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \ 208 } \ 209 } else { \ 210 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \ 211 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \ 212 } \ 213 } \ 214 } \ 215 } UPRV_BLOCK_MACRO_END 216 217 /** 218 * Get a code point from a string at a random-access offset, 219 * without changing the offset. 220 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 221 * 222 * The offset may point to either the lead or trail surrogate unit 223 * for a supplementary code point, in which case the macro will read 224 * the adjacent matching surrogate as well. 225 * 226 * The length can be negative for a NUL-terminated string. 227 * 228 * If the offset points to a single, unpaired surrogate, then 229 * c is set to U+FFFD. 230 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT_OR_FFFD. 231 * 232 * @param s const UChar * string 233 * @param start starting string offset (usually 0) 234 * @param i string offset, must be start<=i<length 235 * @param length string length 236 * @param c output UChar32 variable 237 * @see U16_GET_UNSAFE 238 * @stable ICU 60 239 */ 240 #define U16_GET_OR_FFFD(s, start, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \ 241 (c)=(s)[i]; \ 242 if(U16_IS_SURROGATE(c)) { \ 243 uint16_t __c2; \ 244 if(U16_IS_SURROGATE_LEAD(c)) { \ 245 if((i)+1!=(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \ 246 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \ 247 } else { \ 248 (c)=0xfffd; \ 249 } \ 250 } else { \ 251 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \ 252 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \ 253 } else { \ 254 (c)=0xfffd; \ 255 } \ 256 } \ 257 } \ 258 } UPRV_BLOCK_MACRO_END 259 260 /* definitions with forward iteration --------------------------------------- */ 261 262 /** 263 * Get a code point from a string at a code point boundary offset, 264 * and advance the offset to the next code point boundary. 265 * (Post-incrementing forward iteration.) 266 * "Unsafe" macro, assumes well-formed UTF-16. 267 * 268 * The offset may point to the lead surrogate unit 269 * for a supplementary code point, in which case the macro will read 270 * the following trail surrogate as well. 271 * If the offset points to a trail surrogate, then that itself 272 * will be returned as the code point. 273 * The result is undefined if the offset points to a single, unpaired lead surrogate. 274 * 275 * @param s const UChar * string 276 * @param i string offset 277 * @param c output UChar32 variable 278 * @see U16_NEXT 279 * @stable ICU 2.4 280 */ 281 #define U16_NEXT_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 282 (c)=(s)[(i)++]; \ 283 if(U16_IS_LEAD(c)) { \ 284 (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)++]); \ 285 } \ 286 } UPRV_BLOCK_MACRO_END 287 288 /** 289 * Get a code point from a string at a code point boundary offset, 290 * and advance the offset to the next code point boundary. 291 * (Post-incrementing forward iteration.) 292 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 293 * 294 * The length can be negative for a NUL-terminated string. 295 * 296 * The offset may point to the lead surrogate unit 297 * for a supplementary code point, in which case the macro will read 298 * the following trail surrogate as well. 299 * If the offset points to a trail surrogate or 300 * to a single, unpaired lead surrogate, then c is set to that unpaired surrogate. 301 * 302 * @param s const UChar * string 303 * @param i string offset, must be i<length 304 * @param length string length 305 * @param c output UChar32 variable 306 * @see U16_NEXT_UNSAFE 307 * @stable ICU 2.4 308 */ 309 #define U16_NEXT(s, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \ 310 (c)=(s)[(i)++]; \ 311 if(U16_IS_LEAD(c)) { \ 312 uint16_t __c2; \ 313 if((i)!=(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \ 314 ++(i); \ 315 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \ 316 } \ 317 } \ 318 } UPRV_BLOCK_MACRO_END 319 320 /** 321 * Get a code point from a string at a code point boundary offset, 322 * and advance the offset to the next code point boundary. 323 * (Post-incrementing forward iteration.) 324 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 325 * 326 * The length can be negative for a NUL-terminated string. 327 * 328 * The offset may point to the lead surrogate unit 329 * for a supplementary code point, in which case the macro will read 330 * the following trail surrogate as well. 331 * If the offset points to a trail surrogate or 332 * to a single, unpaired lead surrogate, then c is set to U+FFFD. 333 * 334 * @param s const UChar * string 335 * @param i string offset, must be i<length 336 * @param length string length 337 * @param c output UChar32 variable 338 * @see U16_NEXT_UNSAFE 339 * @stable ICU 60 340 */ 341 #define U16_NEXT_OR_FFFD(s, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \ 342 (c)=(s)[(i)++]; \ 343 if(U16_IS_SURROGATE(c)) { \ 344 uint16_t __c2; \ 345 if(U16_IS_SURROGATE_LEAD(c) && (i)!=(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \ 346 ++(i); \ 347 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \ 348 } else { \ 349 (c)=0xfffd; \ 350 } \ 351 } \ 352 } UPRV_BLOCK_MACRO_END 353 354 /** 355 * Append a code point to a string, overwriting 1 or 2 code units. 356 * The offset points to the current end of the string contents 357 * and is advanced (post-increment). 358 * "Unsafe" macro, assumes a valid code point and sufficient space in the string. 359 * Otherwise, the result is undefined. 360 * 361 * @param s const UChar * string buffer 362 * @param i string offset 363 * @param c code point to append 364 * @see U16_APPEND 365 * @stable ICU 2.4 366 */ 367 #define U16_APPEND_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 368 if((uint32_t)(c)<=0xffff) { \ 369 (s)[(i)++]=(uint16_t)(c); \ 370 } else { \ 371 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \ 372 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \ 373 } \ 374 } UPRV_BLOCK_MACRO_END 375 376 /** 377 * Append a code point to a string, overwriting 1 or 2 code units. 378 * The offset points to the current end of the string contents 379 * and is advanced (post-increment). 380 * "Safe" macro, checks for a valid code point. 381 * If a surrogate pair is written, checks for sufficient space in the string. 382 * If the code point is not valid or a trail surrogate does not fit, 383 * then isError is set to true. 384 * 385 * @param s const UChar * string buffer 386 * @param i string offset, must be i<capacity 387 * @param capacity size of the string buffer 388 * @param c code point to append 389 * @param isError output UBool set to true if an error occurs, otherwise not modified 390 * @see U16_APPEND_UNSAFE 391 * @stable ICU 2.4 392 */ 393 #define U16_APPEND(s, i, capacity, c, isError) UPRV_BLOCK_MACRO_BEGIN { \ 394 if((uint32_t)(c)<=0xffff) { \ 395 (s)[(i)++]=(uint16_t)(c); \ 396 } else if((uint32_t)(c)<=0x10ffff && (i)+1<(capacity)) { \ 397 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \ 398 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \ 399 } else /* c>0x10ffff or not enough space */ { \ 400 (isError)=true; \ 401 } \ 402 } UPRV_BLOCK_MACRO_END 403 404 /** 405 * Advance the string offset from one code point boundary to the next. 406 * (Post-incrementing iteration.) 407 * "Unsafe" macro, assumes well-formed UTF-16. 408 * 409 * @param s const UChar * string 410 * @param i string offset 411 * @see U16_FWD_1 412 * @stable ICU 2.4 413 */ 414 #define U16_FWD_1_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 415 if(U16_IS_LEAD((s)[(i)++])) { \ 416 ++(i); \ 417 } \ 418 } UPRV_BLOCK_MACRO_END 419 420 /** 421 * Advance the string offset from one code point boundary to the next. 422 * (Post-incrementing iteration.) 423 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 424 * 425 * The length can be negative for a NUL-terminated string. 426 * 427 * @param s const UChar * string 428 * @param i string offset, must be i<length 429 * @param length string length 430 * @see U16_FWD_1_UNSAFE 431 * @stable ICU 2.4 432 */ 433 #define U16_FWD_1(s, i, length) UPRV_BLOCK_MACRO_BEGIN { \ 434 if(U16_IS_LEAD((s)[(i)++]) && (i)!=(length) && U16_IS_TRAIL((s)[i])) { \ 435 ++(i); \ 436 } \ 437 } UPRV_BLOCK_MACRO_END 438 439 /** 440 * Advance the string offset from one code point boundary to the n-th next one, 441 * i.e., move forward by n code points. 442 * (Post-incrementing iteration.) 443 * "Unsafe" macro, assumes well-formed UTF-16. 444 * 445 * @param s const UChar * string 446 * @param i string offset 447 * @param n number of code points to skip 448 * @see U16_FWD_N 449 * @stable ICU 2.4 450 */ 451 #define U16_FWD_N_UNSAFE(s, i, n) UPRV_BLOCK_MACRO_BEGIN { \ 452 int32_t __N=(n); \ 453 while(__N>0) { \ 454 U16_FWD_1_UNSAFE(s, i); \ 455 --__N; \ 456 } \ 457 } UPRV_BLOCK_MACRO_END 458 459 /** 460 * Advance the string offset from one code point boundary to the n-th next one, 461 * i.e., move forward by n code points. 462 * (Post-incrementing iteration.) 463 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 464 * 465 * The length can be negative for a NUL-terminated string. 466 * 467 * @param s const UChar * string 468 * @param i int32_t string offset, must be i<length 469 * @param length int32_t string length 470 * @param n number of code points to skip 471 * @see U16_FWD_N_UNSAFE 472 * @stable ICU 2.4 473 */ 474 #define U16_FWD_N(s, i, length, n) UPRV_BLOCK_MACRO_BEGIN { \ 475 int32_t __N=(n); \ 476 while(__N>0 && ((i)<(length) || ((length)<0 && (s)[i]!=0))) { \ 477 U16_FWD_1(s, i, length); \ 478 --__N; \ 479 } \ 480 } UPRV_BLOCK_MACRO_END 481 482 /** 483 * Adjust a random-access offset to a code point boundary 484 * at the start of a code point. 485 * If the offset points to the trail surrogate of a surrogate pair, 486 * then the offset is decremented. 487 * Otherwise, it is not modified. 488 * "Unsafe" macro, assumes well-formed UTF-16. 489 * 490 * @param s const UChar * string 491 * @param i string offset 492 * @see U16_SET_CP_START 493 * @stable ICU 2.4 494 */ 495 #define U16_SET_CP_START_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 496 if(U16_IS_TRAIL((s)[i])) { \ 497 --(i); \ 498 } \ 499 } UPRV_BLOCK_MACRO_END 500 501 /** 502 * Adjust a random-access offset to a code point boundary 503 * at the start of a code point. 504 * If the offset points to the trail surrogate of a surrogate pair, 505 * then the offset is decremented. 506 * Otherwise, it is not modified. 507 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 508 * 509 * @param s const UChar * string 510 * @param start starting string offset (usually 0) 511 * @param i string offset, must be start<=i 512 * @see U16_SET_CP_START_UNSAFE 513 * @stable ICU 2.4 514 */ 515 #define U16_SET_CP_START(s, start, i) UPRV_BLOCK_MACRO_BEGIN { \ 516 if(U16_IS_TRAIL((s)[i]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \ 517 --(i); \ 518 } \ 519 } UPRV_BLOCK_MACRO_END 520 521 /* definitions with backward iteration -------------------------------------- */ 522 523 /** 524 * Move the string offset from one code point boundary to the previous one 525 * and get the code point between them. 526 * (Pre-decrementing backward iteration.) 527 * "Unsafe" macro, assumes well-formed UTF-16. 528 * 529 * The input offset may be the same as the string length. 530 * If the offset is behind a trail surrogate unit 531 * for a supplementary code point, then the macro will read 532 * the preceding lead surrogate as well. 533 * If the offset is behind a lead surrogate, then that itself 534 * will be returned as the code point. 535 * The result is undefined if the offset is behind a single, unpaired trail surrogate. 536 * 537 * @param s const UChar * string 538 * @param i string offset 539 * @param c output UChar32 variable 540 * @see U16_PREV 541 * @stable ICU 2.4 542 */ 543 #define U16_PREV_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 544 (c)=(s)[--(i)]; \ 545 if(U16_IS_TRAIL(c)) { \ 546 (c)=U16_GET_SUPPLEMENTARY((s)[--(i)], (c)); \ 547 } \ 548 } UPRV_BLOCK_MACRO_END 549 550 /** 551 * Move the string offset from one code point boundary to the previous one 552 * and get the code point between them. 553 * (Pre-decrementing backward iteration.) 554 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 555 * 556 * The input offset may be the same as the string length. 557 * If the offset is behind a trail surrogate unit 558 * for a supplementary code point, then the macro will read 559 * the preceding lead surrogate as well. 560 * If the offset is behind a lead surrogate or behind a single, unpaired 561 * trail surrogate, then c is set to that unpaired surrogate. 562 * 563 * @param s const UChar * string 564 * @param start starting string offset (usually 0) 565 * @param i string offset, must be start<i 566 * @param c output UChar32 variable 567 * @see U16_PREV_UNSAFE 568 * @stable ICU 2.4 569 */ 570 #define U16_PREV(s, start, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 571 (c)=(s)[--(i)]; \ 572 if(U16_IS_TRAIL(c)) { \ 573 uint16_t __c2; \ 574 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \ 575 --(i); \ 576 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \ 577 } \ 578 } \ 579 } UPRV_BLOCK_MACRO_END 580 581 /** 582 * Move the string offset from one code point boundary to the previous one 583 * and get the code point between them. 584 * (Pre-decrementing backward iteration.) 585 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 586 * 587 * The input offset may be the same as the string length. 588 * If the offset is behind a trail surrogate unit 589 * for a supplementary code point, then the macro will read 590 * the preceding lead surrogate as well. 591 * If the offset is behind a lead surrogate or behind a single, unpaired 592 * trail surrogate, then c is set to U+FFFD. 593 * 594 * @param s const UChar * string 595 * @param start starting string offset (usually 0) 596 * @param i string offset, must be start<i 597 * @param c output UChar32 variable 598 * @see U16_PREV_UNSAFE 599 * @stable ICU 60 600 */ 601 #define U16_PREV_OR_FFFD(s, start, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 602 (c)=(s)[--(i)]; \ 603 if(U16_IS_SURROGATE(c)) { \ 604 uint16_t __c2; \ 605 if(U16_IS_SURROGATE_TRAIL(c) && (i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \ 606 --(i); \ 607 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \ 608 } else { \ 609 (c)=0xfffd; \ 610 } \ 611 } \ 612 } UPRV_BLOCK_MACRO_END 613 614 /** 615 * Move the string offset from one code point boundary to the previous one. 616 * (Pre-decrementing backward iteration.) 617 * The input offset may be the same as the string length. 618 * "Unsafe" macro, assumes well-formed UTF-16. 619 * 620 * @param s const UChar * string 621 * @param i string offset 622 * @see U16_BACK_1 623 * @stable ICU 2.4 624 */ 625 #define U16_BACK_1_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 626 if(U16_IS_TRAIL((s)[--(i)])) { \ 627 --(i); \ 628 } \ 629 } UPRV_BLOCK_MACRO_END 630 631 /** 632 * Move the string offset from one code point boundary to the previous one. 633 * (Pre-decrementing backward iteration.) 634 * The input offset may be the same as the string length. 635 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 636 * 637 * @param s const UChar * string 638 * @param start starting string offset (usually 0) 639 * @param i string offset, must be start<i 640 * @see U16_BACK_1_UNSAFE 641 * @stable ICU 2.4 642 */ 643 #define U16_BACK_1(s, start, i) UPRV_BLOCK_MACRO_BEGIN { \ 644 if(U16_IS_TRAIL((s)[--(i)]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \ 645 --(i); \ 646 } \ 647 } UPRV_BLOCK_MACRO_END 648 649 /** 650 * Move the string offset from one code point boundary to the n-th one before it, 651 * i.e., move backward by n code points. 652 * (Pre-decrementing backward iteration.) 653 * The input offset may be the same as the string length. 654 * "Unsafe" macro, assumes well-formed UTF-16. 655 * 656 * @param s const UChar * string 657 * @param i string offset 658 * @param n number of code points to skip 659 * @see U16_BACK_N 660 * @stable ICU 2.4 661 */ 662 #define U16_BACK_N_UNSAFE(s, i, n) UPRV_BLOCK_MACRO_BEGIN { \ 663 int32_t __N=(n); \ 664 while(__N>0) { \ 665 U16_BACK_1_UNSAFE(s, i); \ 666 --__N; \ 667 } \ 668 } UPRV_BLOCK_MACRO_END 669 670 /** 671 * Move the string offset from one code point boundary to the n-th one before it, 672 * i.e., move backward by n code points. 673 * (Pre-decrementing backward iteration.) 674 * The input offset may be the same as the string length. 675 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 676 * 677 * @param s const UChar * string 678 * @param start start of string 679 * @param i string offset, must be start<i 680 * @param n number of code points to skip 681 * @see U16_BACK_N_UNSAFE 682 * @stable ICU 2.4 683 */ 684 #define U16_BACK_N(s, start, i, n) UPRV_BLOCK_MACRO_BEGIN { \ 685 int32_t __N=(n); \ 686 while(__N>0 && (i)>(start)) { \ 687 U16_BACK_1(s, start, i); \ 688 --__N; \ 689 } \ 690 } UPRV_BLOCK_MACRO_END 691 692 /** 693 * Adjust a random-access offset to a code point boundary after a code point. 694 * If the offset is behind the lead surrogate of a surrogate pair, 695 * then the offset is incremented. 696 * Otherwise, it is not modified. 697 * The input offset may be the same as the string length. 698 * "Unsafe" macro, assumes well-formed UTF-16. 699 * 700 * @param s const UChar * string 701 * @param i string offset 702 * @see U16_SET_CP_LIMIT 703 * @stable ICU 2.4 704 */ 705 #define U16_SET_CP_LIMIT_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 706 if(U16_IS_LEAD((s)[(i)-1])) { \ 707 ++(i); \ 708 } \ 709 } UPRV_BLOCK_MACRO_END 710 711 /** 712 * Adjust a random-access offset to a code point boundary after a code point. 713 * If the offset is behind the lead surrogate of a surrogate pair, 714 * then the offset is incremented. 715 * Otherwise, it is not modified. 716 * The input offset may be the same as the string length. 717 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 718 * 719 * The length can be negative for a NUL-terminated string. 720 * 721 * @param s const UChar * string 722 * @param start int32_t starting string offset (usually 0) 723 * @param i int32_t string offset, start<=i<=length 724 * @param length int32_t string length 725 * @see U16_SET_CP_LIMIT_UNSAFE 726 * @stable ICU 2.4 727 */ 728 #define U16_SET_CP_LIMIT(s, start, i, length) UPRV_BLOCK_MACRO_BEGIN { \ 729 if((start)<(i) && ((i)<(length) || (length)<0) && U16_IS_LEAD((s)[(i)-1]) && U16_IS_TRAIL((s)[i])) { \ 730 ++(i); \ 731 } \ 732 } UPRV_BLOCK_MACRO_END 733 734 #endif 735