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