1 /* 2 ******************************************************************************* 3 * 4 * Copyright (C) 1999-2011, 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 * If the offset points to a single, unpaired surrogate, then that itself 184 * will be returned as the code point. 185 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT. 186 * 187 * @param s const UChar * string 188 * @param start starting string offset (usually 0) 189 * @param i string offset, must be start<=i<length 190 * @param length string length 191 * @param c output UChar32 variable 192 * @see U16_GET_UNSAFE 193 * @stable ICU 2.4 194 */ 195 #define U16_GET(s, start, i, length, c) { \ 196 (c)=(s)[i]; \ 197 if(U16_IS_SURROGATE(c)) { \ 198 uint16_t __c2; \ 199 if(U16_IS_SURROGATE_LEAD(c)) { \ 200 if((i)+1<(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \ 201 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \ 202 } \ 203 } else { \ 204 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \ 205 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \ 206 } \ 207 } \ 208 } \ 209 } 210 211 /* definitions with forward iteration --------------------------------------- */ 212 213 /** 214 * Get a code point from a string at a code point boundary offset, 215 * and advance the offset to the next code point boundary. 216 * (Post-incrementing forward iteration.) 217 * "Unsafe" macro, assumes well-formed UTF-16. 218 * 219 * The offset may point to the lead surrogate unit 220 * for a supplementary code point, in which case the macro will read 221 * the following trail surrogate as well. 222 * If the offset points to a trail surrogate, then that itself 223 * will be returned as the code point. 224 * The result is undefined if the offset points to a single, unpaired lead surrogate. 225 * 226 * @param s const UChar * string 227 * @param i string offset 228 * @param c output UChar32 variable 229 * @see U16_NEXT 230 * @stable ICU 2.4 231 */ 232 #define U16_NEXT_UNSAFE(s, i, c) { \ 233 (c)=(s)[(i)++]; \ 234 if(U16_IS_LEAD(c)) { \ 235 (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)++]); \ 236 } \ 237 } 238 239 /** 240 * Get a code point from a string at a code point boundary offset, 241 * and advance the offset to the next code point boundary. 242 * (Post-incrementing forward iteration.) 243 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 244 * 245 * The offset may point to the lead surrogate unit 246 * for a supplementary code point, in which case the macro will read 247 * the following trail surrogate as well. 248 * If the offset points to a trail surrogate or 249 * to a single, unpaired lead surrogate, then that itself 250 * will be returned as the code point. 251 * 252 * @param s const UChar * string 253 * @param i string offset, must be i<length 254 * @param length string length 255 * @param c output UChar32 variable 256 * @see U16_NEXT_UNSAFE 257 * @stable ICU 2.4 258 */ 259 #define U16_NEXT(s, i, length, c) { \ 260 (c)=(s)[(i)++]; \ 261 if(U16_IS_LEAD(c)) { \ 262 uint16_t __c2; \ 263 if((i)<(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \ 264 ++(i); \ 265 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \ 266 } \ 267 } \ 268 } 269 270 /** 271 * Append a code point to a string, overwriting 1 or 2 code units. 272 * The offset points to the current end of the string contents 273 * and is advanced (post-increment). 274 * "Unsafe" macro, assumes a valid code point and sufficient space in the string. 275 * Otherwise, the result is undefined. 276 * 277 * @param s const UChar * string buffer 278 * @param i string offset 279 * @param c code point to append 280 * @see U16_APPEND 281 * @stable ICU 2.4 282 */ 283 #define U16_APPEND_UNSAFE(s, i, c) { \ 284 if((uint32_t)(c)<=0xffff) { \ 285 (s)[(i)++]=(uint16_t)(c); \ 286 } else { \ 287 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \ 288 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \ 289 } \ 290 } 291 292 /** 293 * Append a code point to a string, overwriting 1 or 2 code units. 294 * The offset points to the current end of the string contents 295 * and is advanced (post-increment). 296 * "Safe" macro, checks for a valid code point. 297 * If a surrogate pair is written, checks for sufficient space in the string. 298 * If the code point is not valid or a trail surrogate does not fit, 299 * then isError is set to TRUE. 300 * 301 * @param s const UChar * string buffer 302 * @param i string offset, must be i<capacity 303 * @param capacity size of the string buffer 304 * @param c code point to append 305 * @param isError output UBool set to TRUE if an error occurs, otherwise not modified 306 * @see U16_APPEND_UNSAFE 307 * @stable ICU 2.4 308 */ 309 #define U16_APPEND(s, i, capacity, c, isError) { \ 310 if((uint32_t)(c)<=0xffff) { \ 311 (s)[(i)++]=(uint16_t)(c); \ 312 } else if((uint32_t)(c)<=0x10ffff && (i)+1<(capacity)) { \ 313 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \ 314 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \ 315 } else /* c>0x10ffff or not enough space */ { \ 316 (isError)=TRUE; \ 317 } \ 318 } 319 320 /** 321 * Advance the string offset from one code point boundary to the next. 322 * (Post-incrementing iteration.) 323 * "Unsafe" macro, assumes well-formed UTF-16. 324 * 325 * @param s const UChar * string 326 * @param i string offset 327 * @see U16_FWD_1 328 * @stable ICU 2.4 329 */ 330 #define U16_FWD_1_UNSAFE(s, i) { \ 331 if(U16_IS_LEAD((s)[(i)++])) { \ 332 ++(i); \ 333 } \ 334 } 335 336 /** 337 * Advance the string offset from one code point boundary to the next. 338 * (Post-incrementing iteration.) 339 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 340 * 341 * @param s const UChar * string 342 * @param i string offset, must be i<length 343 * @param length string length 344 * @see U16_FWD_1_UNSAFE 345 * @stable ICU 2.4 346 */ 347 #define U16_FWD_1(s, i, length) { \ 348 if(U16_IS_LEAD((s)[(i)++]) && (i)<(length) && U16_IS_TRAIL((s)[i])) { \ 349 ++(i); \ 350 } \ 351 } 352 353 /** 354 * Advance the string offset from one code point boundary to the n-th next one, 355 * i.e., move forward by n code points. 356 * (Post-incrementing iteration.) 357 * "Unsafe" macro, assumes well-formed UTF-16. 358 * 359 * @param s const UChar * string 360 * @param i string offset 361 * @param n number of code points to skip 362 * @see U16_FWD_N 363 * @stable ICU 2.4 364 */ 365 #define U16_FWD_N_UNSAFE(s, i, n) { \ 366 int32_t __N=(n); \ 367 while(__N>0) { \ 368 U16_FWD_1_UNSAFE(s, i); \ 369 --__N; \ 370 } \ 371 } 372 373 /** 374 * Advance the string offset from one code point boundary to the n-th next one, 375 * i.e., move forward by n code points. 376 * (Post-incrementing iteration.) 377 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 378 * 379 * @param s const UChar * string 380 * @param i string offset, must be i<length 381 * @param length string length 382 * @param n number of code points to skip 383 * @see U16_FWD_N_UNSAFE 384 * @stable ICU 2.4 385 */ 386 #define U16_FWD_N(s, i, length, n) { \ 387 int32_t __N=(n); \ 388 while(__N>0 && (i)<(length)) { \ 389 U16_FWD_1(s, i, length); \ 390 --__N; \ 391 } \ 392 } 393 394 /** 395 * Adjust a random-access offset to a code point boundary 396 * at the start of a code point. 397 * If the offset points to the trail surrogate of a surrogate pair, 398 * then the offset is decremented. 399 * Otherwise, it is not modified. 400 * "Unsafe" macro, assumes well-formed UTF-16. 401 * 402 * @param s const UChar * string 403 * @param i string offset 404 * @see U16_SET_CP_START 405 * @stable ICU 2.4 406 */ 407 #define U16_SET_CP_START_UNSAFE(s, i) { \ 408 if(U16_IS_TRAIL((s)[i])) { \ 409 --(i); \ 410 } \ 411 } 412 413 /** 414 * Adjust a random-access offset to a code point boundary 415 * at the start of a code point. 416 * If the offset points to the trail surrogate of a surrogate pair, 417 * then the offset is decremented. 418 * Otherwise, it is not modified. 419 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 420 * 421 * @param s const UChar * string 422 * @param start starting string offset (usually 0) 423 * @param i string offset, must be start<=i 424 * @see U16_SET_CP_START_UNSAFE 425 * @stable ICU 2.4 426 */ 427 #define U16_SET_CP_START(s, start, i) { \ 428 if(U16_IS_TRAIL((s)[i]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \ 429 --(i); \ 430 } \ 431 } 432 433 /* definitions with backward iteration -------------------------------------- */ 434 435 /** 436 * Move the string offset from one code point boundary to the previous one 437 * and get the code point between them. 438 * (Pre-decrementing backward iteration.) 439 * "Unsafe" macro, assumes well-formed UTF-16. 440 * 441 * The input offset may be the same as the string length. 442 * If the offset is behind a trail surrogate unit 443 * for a supplementary code point, then the macro will read 444 * the preceding lead surrogate as well. 445 * If the offset is behind a lead surrogate, then that itself 446 * will be returned as the code point. 447 * The result is undefined if the offset is behind a single, unpaired trail surrogate. 448 * 449 * @param s const UChar * string 450 * @param i string offset 451 * @param c output UChar32 variable 452 * @see U16_PREV 453 * @stable ICU 2.4 454 */ 455 #define U16_PREV_UNSAFE(s, i, c) { \ 456 (c)=(s)[--(i)]; \ 457 if(U16_IS_TRAIL(c)) { \ 458 (c)=U16_GET_SUPPLEMENTARY((s)[--(i)], (c)); \ 459 } \ 460 } 461 462 /** 463 * Move the string offset from one code point boundary to the previous one 464 * and get the code point between them. 465 * (Pre-decrementing backward iteration.) 466 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 467 * 468 * The input offset may be the same as the string length. 469 * If the offset is behind a trail surrogate unit 470 * for a supplementary code point, then the macro will read 471 * the preceding lead surrogate as well. 472 * If the offset is behind a lead surrogate or behind a single, unpaired 473 * trail surrogate, then that itself 474 * will be returned as the code point. 475 * 476 * @param s const UChar * string 477 * @param start starting string offset (usually 0) 478 * @param i string offset, must be start<i 479 * @param c output UChar32 variable 480 * @see U16_PREV_UNSAFE 481 * @stable ICU 2.4 482 */ 483 #define U16_PREV(s, start, i, c) { \ 484 (c)=(s)[--(i)]; \ 485 if(U16_IS_TRAIL(c)) { \ 486 uint16_t __c2; \ 487 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \ 488 --(i); \ 489 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \ 490 } \ 491 } \ 492 } 493 494 /** 495 * Move the string offset from one code point boundary to the previous one. 496 * (Pre-decrementing backward iteration.) 497 * The input offset may be the same as the string length. 498 * "Unsafe" macro, assumes well-formed UTF-16. 499 * 500 * @param s const UChar * string 501 * @param i string offset 502 * @see U16_BACK_1 503 * @stable ICU 2.4 504 */ 505 #define U16_BACK_1_UNSAFE(s, i) { \ 506 if(U16_IS_TRAIL((s)[--(i)])) { \ 507 --(i); \ 508 } \ 509 } 510 511 /** 512 * Move the string offset from one code point boundary to the previous one. 513 * (Pre-decrementing backward iteration.) 514 * The input offset may be the same as the string length. 515 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 516 * 517 * @param s const UChar * string 518 * @param start starting string offset (usually 0) 519 * @param i string offset, must be start<i 520 * @see U16_BACK_1_UNSAFE 521 * @stable ICU 2.4 522 */ 523 #define U16_BACK_1(s, start, i) { \ 524 if(U16_IS_TRAIL((s)[--(i)]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \ 525 --(i); \ 526 } \ 527 } 528 529 /** 530 * Move the string offset from one code point boundary to the n-th one before it, 531 * i.e., move backward by n code points. 532 * (Pre-decrementing backward iteration.) 533 * The input offset may be the same as the string length. 534 * "Unsafe" macro, assumes well-formed UTF-16. 535 * 536 * @param s const UChar * string 537 * @param i string offset 538 * @param n number of code points to skip 539 * @see U16_BACK_N 540 * @stable ICU 2.4 541 */ 542 #define U16_BACK_N_UNSAFE(s, i, n) { \ 543 int32_t __N=(n); \ 544 while(__N>0) { \ 545 U16_BACK_1_UNSAFE(s, i); \ 546 --__N; \ 547 } \ 548 } 549 550 /** 551 * Move the string offset from one code point boundary to the n-th one before it, 552 * i.e., move backward by n code points. 553 * (Pre-decrementing backward iteration.) 554 * The input offset may be the same as the string length. 555 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 556 * 557 * @param s const UChar * string 558 * @param start start of string 559 * @param i string offset, must be start<i 560 * @param n number of code points to skip 561 * @see U16_BACK_N_UNSAFE 562 * @stable ICU 2.4 563 */ 564 #define U16_BACK_N(s, start, i, n) { \ 565 int32_t __N=(n); \ 566 while(__N>0 && (i)>(start)) { \ 567 U16_BACK_1(s, start, i); \ 568 --__N; \ 569 } \ 570 } 571 572 /** 573 * Adjust a random-access offset to a code point boundary after a code point. 574 * If the offset is behind the lead surrogate of a surrogate pair, 575 * then the offset is incremented. 576 * Otherwise, it is not modified. 577 * The input offset may be the same as the string length. 578 * "Unsafe" macro, assumes well-formed UTF-16. 579 * 580 * @param s const UChar * string 581 * @param i string offset 582 * @see U16_SET_CP_LIMIT 583 * @stable ICU 2.4 584 */ 585 #define U16_SET_CP_LIMIT_UNSAFE(s, i) { \ 586 if(U16_IS_LEAD((s)[(i)-1])) { \ 587 ++(i); \ 588 } \ 589 } 590 591 /** 592 * Adjust a random-access offset to a code point boundary after a code point. 593 * If the offset is behind the lead surrogate of a surrogate pair, 594 * then the offset is incremented. 595 * Otherwise, it is not modified. 596 * The input offset may be the same as the string length. 597 * "Safe" macro, handles unpaired surrogates and checks for string boundaries. 598 * 599 * @param s const UChar * string 600 * @param start starting string offset (usually 0) 601 * @param i string offset, start<=i<=length 602 * @param length string length 603 * @see U16_SET_CP_LIMIT_UNSAFE 604 * @stable ICU 2.4 605 */ 606 #define U16_SET_CP_LIMIT(s, start, i, length) { \ 607 if((start)<(i) && (i)<(length) && U16_IS_LEAD((s)[(i)-1]) && U16_IS_TRAIL((s)[i])) { \ 608 ++(i); \ 609 } \ 610 } 611 612 #endif 613