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) 1999-2015, International Business Machines 7 * Corporation and others. All Rights Reserved. 8 * 9 ******************************************************************************* 10 * file name: utf8.h 11 * encoding: UTF-8 12 * tab size: 8 (not used) 13 * indentation:4 14 * 15 * created on: 1999sep13 16 * created by: Markus W. Scherer 17 */ 18 19 /** 20 * \file 21 * \brief C API: 8-bit Unicode handling macros 22 * 23 * This file defines macros to deal with 8-bit Unicode (UTF-8) code units (bytes) 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 __UTF8_H__ 35 #define __UTF8_H__ 36 37 #include <stdbool.h> 38 #include "unicode/umachine.h" 39 #ifndef __UTF_H__ 40 # include "unicode/utf.h" 41 #endif 42 43 /* internal definitions ----------------------------------------------------- */ 44 45 /** 46 * Counts the trail bytes for a UTF-8 lead byte. 47 * Returns 0 for 0..0xc1 as well as for 0xf5..0xff. 48 * leadByte might be evaluated multiple times. 49 * 50 * This is internal since it is not meant to be called directly by external clients; 51 * however it is called by public macros in this file and thus must remain stable. 52 * 53 * @param leadByte The first byte of a UTF-8 sequence. Must be 0..0xff. 54 * @internal 55 */ 56 #define U8_COUNT_TRAIL_BYTES(leadByte) \ 57 (U8_IS_LEAD(leadByte) ? \ 58 ((uint8_t)(leadByte)>=0xe0)+((uint8_t)(leadByte)>=0xf0)+1 : 0) 59 60 /** 61 * Counts the trail bytes for a UTF-8 lead byte of a valid UTF-8 sequence. 62 * Returns 0 for 0..0xc1. Undefined for 0xf5..0xff. 63 * leadByte might be evaluated multiple times. 64 * 65 * This is internal since it is not meant to be called directly by external clients; 66 * however it is called by public macros in this file and thus must remain stable. 67 * 68 * @param leadByte The first byte of a UTF-8 sequence. Must be 0..0xff. 69 * @internal 70 */ 71 #define U8_COUNT_TRAIL_BYTES_UNSAFE(leadByte) \ 72 (((uint8_t)(leadByte)>=0xc2)+((uint8_t)(leadByte)>=0xe0)+((uint8_t)(leadByte)>=0xf0)) 73 74 /** 75 * Mask a UTF-8 lead byte, leave only the lower bits that form part of the code point value. 76 * 77 * This is internal since it is not meant to be called directly by external clients; 78 * however it is called by public macros in this file and thus must remain stable. 79 * @internal 80 */ 81 #define U8_MASK_LEAD_BYTE(leadByte, countTrailBytes) ((leadByte)&=(1<<(6-(countTrailBytes)))-1) 82 83 /** 84 * Internal bit vector for 3-byte UTF-8 validity check, for use in U8_IS_VALID_LEAD3_AND_T1. 85 * Each bit indicates whether one lead byte + first trail byte pair starts a valid sequence. 86 * Lead byte E0..EF bits 3..0 are used as byte index, 87 * first trail byte bits 7..5 are used as bit index into that byte. 88 * @see U8_IS_VALID_LEAD3_AND_T1 89 * @internal 90 */ 91 #define U8_LEAD3_T1_BITS "\x20\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x30\x10\x30\x30" 92 93 /** 94 * Internal 3-byte UTF-8 validity check. 95 * Non-zero if lead byte E0..EF and first trail byte 00..FF start a valid sequence. 96 * @internal 97 */ 98 #define U8_IS_VALID_LEAD3_AND_T1(lead, t1) (U8_LEAD3_T1_BITS[(lead)&0xf]&(1<<((uint8_t)(t1)>>5))) 99 100 /** 101 * Internal bit vector for 4-byte UTF-8 validity check, for use in U8_IS_VALID_LEAD4_AND_T1. 102 * Each bit indicates whether one lead byte + first trail byte pair starts a valid sequence. 103 * First trail byte bits 7..4 are used as byte index, 104 * lead byte F0..F4 bits 2..0 are used as bit index into that byte. 105 * @see U8_IS_VALID_LEAD4_AND_T1 106 * @internal 107 */ 108 #define U8_LEAD4_T1_BITS "\x00\x00\x00\x00\x00\x00\x00\x00\x1E\x0F\x0F\x0F\x00\x00\x00\x00" 109 110 /** 111 * Internal 4-byte UTF-8 validity check. 112 * Non-zero if lead byte F0..F4 and first trail byte 00..FF start a valid sequence. 113 * @internal 114 */ 115 #define U8_IS_VALID_LEAD4_AND_T1(lead, t1) (U8_LEAD4_T1_BITS[(uint8_t)(t1)>>4]&(1<<((lead)&7))) 116 117 /** 118 * Function for handling "next code point" with error-checking. 119 * 120 * This is internal since it is not meant to be called directly by external clients; 121 * however it is called by public macros in this 122 * file and thus must remain stable, and should not be hidden when other internal 123 * functions are hidden (otherwise public macros would fail to compile). 124 * @internal 125 */ 126 U_CAPI UChar32 U_EXPORT2 127 utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict); 128 129 /** 130 * Function for handling "append code point" with error-checking. 131 * 132 * This is internal since it is not meant to be called directly by external clients; 133 * however it is called by public macros in this 134 * file and thus must remain stable, and should not be hidden when other internal 135 * functions are hidden (otherwise public macros would fail to compile). 136 * @internal 137 */ 138 U_CAPI int32_t U_EXPORT2 139 utf8_appendCharSafeBody(uint8_t *s, int32_t i, int32_t length, UChar32 c, UBool *pIsError); 140 141 /** 142 * Function for handling "previous code point" with error-checking. 143 * 144 * This is internal since it is not meant to be called directly by external clients; 145 * however it is called by public macros in this 146 * file and thus must remain stable, and should not be hidden when other internal 147 * functions are hidden (otherwise public macros would fail to compile). 148 * @internal 149 */ 150 U_CAPI UChar32 U_EXPORT2 151 utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, UBool strict); 152 153 /** 154 * Function for handling "skip backward one code point" with error-checking. 155 * 156 * This is internal since it is not meant to be called directly by external clients; 157 * however it is called by public macros in this 158 * file and thus must remain stable, and should not be hidden when other internal 159 * functions are hidden (otherwise public macros would fail to compile). 160 * @internal 161 */ 162 U_CAPI int32_t U_EXPORT2 163 utf8_back1SafeBody(const uint8_t *s, int32_t start, int32_t i); 164 165 /* single-code point definitions -------------------------------------------- */ 166 167 /** 168 * Does this code unit (byte) encode a code point by itself (US-ASCII 0..0x7f)? 169 * @param c 8-bit code unit (byte) 170 * @return true or false 171 * @stable ICU 2.4 172 */ 173 #define U8_IS_SINGLE(c) (((c)&0x80)==0) 174 175 /** 176 * Is this code unit (byte) a UTF-8 lead byte? (0xC2..0xF4) 177 * @param c 8-bit code unit (byte) 178 * @return true or false 179 * @stable ICU 2.4 180 */ 181 #define U8_IS_LEAD(c) ((uint8_t)((c)-0xc2)<=0x32) 182 // 0x32=0xf4-0xc2 183 184 /** 185 * Is this code unit (byte) a UTF-8 trail byte? (0x80..0xBF) 186 * @param c 8-bit code unit (byte) 187 * @return true or false 188 * @stable ICU 2.4 189 */ 190 #define U8_IS_TRAIL(c) ((int8_t)(c)<-0x40) 191 192 /** 193 * How many code units (bytes) are used for the UTF-8 encoding 194 * of this Unicode code point? 195 * @param c 32-bit code point 196 * @return 1..4, or 0 if c is a surrogate or not a Unicode code point 197 * @stable ICU 2.4 198 */ 199 #define U8_LENGTH(c) \ 200 ((uint32_t)(c)<=0x7f ? 1 : \ 201 ((uint32_t)(c)<=0x7ff ? 2 : \ 202 ((uint32_t)(c)<=0xd7ff ? 3 : \ 203 ((uint32_t)(c)<=0xdfff || (uint32_t)(c)>0x10ffff ? 0 : \ 204 ((uint32_t)(c)<=0xffff ? 3 : 4)\ 205 ) \ 206 ) \ 207 ) \ 208 ) 209 210 /** 211 * The maximum number of UTF-8 code units (bytes) per Unicode code point (U+0000..U+10ffff). 212 * @return 4 213 * @stable ICU 2.4 214 */ 215 #define U8_MAX_LENGTH 4 216 217 /** 218 * Get a code point from a string at a random-access offset, 219 * without changing the offset. 220 * The offset may point to either the lead byte or one of the trail bytes 221 * for a code point, in which case the macro will read all of the bytes 222 * for the code point. 223 * The result is undefined if the offset points to an illegal UTF-8 224 * byte sequence. 225 * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT. 226 * 227 * @param s const uint8_t * string 228 * @param i string offset 229 * @param c output UChar32 variable 230 * @see U8_GET 231 * @stable ICU 2.4 232 */ 233 #define U8_GET_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 234 int32_t _u8_get_unsafe_index=(int32_t)(i); \ 235 U8_SET_CP_START_UNSAFE(s, _u8_get_unsafe_index); \ 236 U8_NEXT_UNSAFE(s, _u8_get_unsafe_index, c); \ 237 } UPRV_BLOCK_MACRO_END 238 239 /** 240 * Get a code point from a string at a random-access offset, 241 * without changing the offset. 242 * The offset may point to either the lead byte or one of the trail bytes 243 * for a code point, in which case the macro will read all of the bytes 244 * for the code point. 245 * 246 * The length can be negative for a NUL-terminated string. 247 * 248 * If the offset points to an illegal UTF-8 byte sequence, then 249 * c is set to a negative value. 250 * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT. 251 * 252 * @param s const uint8_t * string 253 * @param start int32_t starting string offset 254 * @param i int32_t string offset, must be start<=i<length 255 * @param length int32_t string length 256 * @param c output UChar32 variable, set to <0 in case of an error 257 * @see U8_GET_UNSAFE 258 * @stable ICU 2.4 259 */ 260 #define U8_GET(s, start, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \ 261 int32_t _u8_get_index=(i); \ 262 U8_SET_CP_START(s, start, _u8_get_index); \ 263 U8_NEXT(s, _u8_get_index, length, c); \ 264 } UPRV_BLOCK_MACRO_END 265 266 /** 267 * Get a code point from a string at a random-access offset, 268 * without changing the offset. 269 * The offset may point to either the lead byte or one of the trail bytes 270 * for a code point, in which case the macro will read all of the bytes 271 * for the code point. 272 * 273 * The length can be negative for a NUL-terminated string. 274 * 275 * If the offset points to an illegal UTF-8 byte sequence, then 276 * c is set to U+FFFD. 277 * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT_OR_FFFD. 278 * 279 * This macro does not distinguish between a real U+FFFD in the text 280 * and U+FFFD returned for an ill-formed sequence. 281 * Use U8_GET() if that distinction is important. 282 * 283 * @param s const uint8_t * string 284 * @param start int32_t starting string offset 285 * @param i int32_t string offset, must be start<=i<length 286 * @param length int32_t string length 287 * @param c output UChar32 variable, set to U+FFFD in case of an error 288 * @see U8_GET 289 * @stable ICU 51 290 */ 291 #define U8_GET_OR_FFFD(s, start, i, length, c) UPRV_BLOCK_MACRO_BEGIN { \ 292 int32_t _u8_get_index=(i); \ 293 U8_SET_CP_START(s, start, _u8_get_index); \ 294 U8_NEXT_OR_FFFD(s, _u8_get_index, length, c); \ 295 } UPRV_BLOCK_MACRO_END 296 297 /* definitions with forward iteration --------------------------------------- */ 298 299 /** 300 * Get a code point from a string at a code point boundary offset, 301 * and advance the offset to the next code point boundary. 302 * (Post-incrementing forward iteration.) 303 * "Unsafe" macro, assumes well-formed UTF-8. 304 * 305 * The offset may point to the lead byte of a multi-byte sequence, 306 * in which case the macro will read the whole sequence. 307 * The result is undefined if the offset points to a trail byte 308 * or an illegal UTF-8 sequence. 309 * 310 * @param s const uint8_t * string 311 * @param i string offset 312 * @param c output UChar32 variable 313 * @see U8_NEXT 314 * @stable ICU 2.4 315 */ 316 #define U8_NEXT_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 317 (c)=(uint8_t)(s)[(i)++]; \ 318 if(!U8_IS_SINGLE(c)) { \ 319 if((c)<0xe0) { \ 320 (c)=(((c)&0x1f)<<6)|((s)[(i)++]&0x3f); \ 321 } else if((c)<0xf0) { \ 322 /* no need for (c&0xf) because the upper bits are truncated after <<12 in the cast to (UChar) */ \ 323 (c)=(UChar)(((c)<<12)|(((s)[i]&0x3f)<<6)|((s)[(i)+1]&0x3f)); \ 324 (i)+=2; \ 325 } else { \ 326 (c)=(((c)&7)<<18)|(((s)[i]&0x3f)<<12)|(((s)[(i)+1]&0x3f)<<6)|((s)[(i)+2]&0x3f); \ 327 (i)+=3; \ 328 } \ 329 } \ 330 } UPRV_BLOCK_MACRO_END 331 332 /** 333 * Get a code point from a string at a code point boundary offset, 334 * and advance the offset to the next code point boundary. 335 * (Post-incrementing forward iteration.) 336 * "Safe" macro, checks for illegal sequences and for string boundaries. 337 * 338 * The length can be negative for a NUL-terminated string. 339 * 340 * The offset may point to the lead byte of a multi-byte sequence, 341 * in which case the macro will read the whole sequence. 342 * If the offset points to a trail byte or an illegal UTF-8 sequence, then 343 * c is set to a negative value. 344 * 345 * @param s const uint8_t * string 346 * @param i int32_t string offset, must be i<length 347 * @param length int32_t string length 348 * @param c output UChar32 variable, set to <0 in case of an error 349 * @see U8_NEXT_UNSAFE 350 * @stable ICU 2.4 351 */ 352 #define U8_NEXT(s, i, length, c) U8_INTERNAL_NEXT_OR_SUB(s, i, length, c, U_SENTINEL) 353 354 /** 355 * Get a code point from a string at a code point boundary offset, 356 * and advance the offset to the next code point boundary. 357 * (Post-incrementing forward iteration.) 358 * "Safe" macro, checks for illegal sequences and for string boundaries. 359 * 360 * The length can be negative for a NUL-terminated string. 361 * 362 * The offset may point to the lead byte of a multi-byte sequence, 363 * in which case the macro will read the whole sequence. 364 * If the offset points to a trail byte or an illegal UTF-8 sequence, then 365 * c is set to U+FFFD. 366 * 367 * This macro does not distinguish between a real U+FFFD in the text 368 * and U+FFFD returned for an ill-formed sequence. 369 * Use U8_NEXT() if that distinction is important. 370 * 371 * @param s const uint8_t * string 372 * @param i int32_t string offset, must be i<length 373 * @param length int32_t string length 374 * @param c output UChar32 variable, set to U+FFFD in case of an error 375 * @see U8_NEXT 376 * @stable ICU 51 377 */ 378 #define U8_NEXT_OR_FFFD(s, i, length, c) U8_INTERNAL_NEXT_OR_SUB(s, i, length, c, 0xfffd) 379 380 /** @internal */ 381 #define U8_INTERNAL_NEXT_OR_SUB(s, i, length, c, sub) UPRV_BLOCK_MACRO_BEGIN { \ 382 (c)=(uint8_t)(s)[(i)++]; \ 383 if(!U8_IS_SINGLE(c)) { \ 384 uint8_t __t = 0; \ 385 if((i)!=(length) && \ 386 /* fetch/validate/assemble all but last trail byte */ \ 387 ((c)>=0xe0 ? \ 388 ((c)<0xf0 ? /* U+0800..U+FFFF except surrogates */ \ 389 U8_LEAD3_T1_BITS[(c)&=0xf]&(1<<((__t=(s)[i])>>5)) && \ 390 (__t&=0x3f, 1) \ 391 : /* U+10000..U+10FFFF */ \ 392 ((c)-=0xf0)<=4 && \ 393 U8_LEAD4_T1_BITS[(__t=(s)[i])>>4]&(1<<(c)) && \ 394 ((c)=((c)<<6)|(__t&0x3f), ++(i)!=(length)) && \ 395 (__t=(s)[i]-0x80)<=0x3f) && \ 396 /* valid second-to-last trail byte */ \ 397 ((c)=((c)<<6)|__t, ++(i)!=(length)) \ 398 : /* U+0080..U+07FF */ \ 399 (c)>=0xc2 && ((c)&=0x1f, 1)) && \ 400 /* last trail byte */ \ 401 (__t=(s)[i]-0x80)<=0x3f && \ 402 ((c)=((c)<<6)|__t, ++(i), 1)) { \ 403 } else { \ 404 (c)=(sub); /* ill-formed*/ \ 405 } \ 406 } \ 407 } UPRV_BLOCK_MACRO_END 408 409 /** 410 * Append a code point to a string, overwriting 1 to 4 bytes. 411 * The offset points to the current end of the string contents 412 * and is advanced (post-increment). 413 * "Unsafe" macro, assumes a valid code point and sufficient space in the string. 414 * Otherwise, the result is undefined. 415 * 416 * @param s const uint8_t * string buffer 417 * @param i string offset 418 * @param c code point to append 419 * @see U8_APPEND 420 * @stable ICU 2.4 421 */ 422 #define U8_APPEND_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 423 uint32_t __uc=(c); \ 424 if(__uc<=0x7f) { \ 425 (s)[(i)++]=(uint8_t)__uc; \ 426 } else { \ 427 if(__uc<=0x7ff) { \ 428 (s)[(i)++]=(uint8_t)((__uc>>6)|0xc0); \ 429 } else { \ 430 if(__uc<=0xffff) { \ 431 (s)[(i)++]=(uint8_t)((__uc>>12)|0xe0); \ 432 } else { \ 433 (s)[(i)++]=(uint8_t)((__uc>>18)|0xf0); \ 434 (s)[(i)++]=(uint8_t)(((__uc>>12)&0x3f)|0x80); \ 435 } \ 436 (s)[(i)++]=(uint8_t)(((__uc>>6)&0x3f)|0x80); \ 437 } \ 438 (s)[(i)++]=(uint8_t)((__uc&0x3f)|0x80); \ 439 } \ 440 } UPRV_BLOCK_MACRO_END 441 442 /** 443 * Append a code point to a string, overwriting 1 to 4 bytes. 444 * The offset points to the current end of the string contents 445 * and is advanced (post-increment). 446 * "Safe" macro, checks for a valid code point. 447 * If a non-ASCII code point is written, checks for sufficient space in the string. 448 * If the code point is not valid or trail bytes do not fit, 449 * then isError is set to true. 450 * 451 * @param s const uint8_t * string buffer 452 * @param i int32_t string offset, must be i<capacity 453 * @param capacity int32_t size of the string buffer 454 * @param c UChar32 code point to append 455 * @param isError output UBool set to true if an error occurs, otherwise not modified 456 * @see U8_APPEND_UNSAFE 457 * @stable ICU 2.4 458 */ 459 #define U8_APPEND(s, i, capacity, c, isError) UPRV_BLOCK_MACRO_BEGIN { \ 460 uint32_t __uc=(c); \ 461 if(__uc<=0x7f) { \ 462 (s)[(i)++]=(uint8_t)__uc; \ 463 } else if(__uc<=0x7ff && (i)+1<(capacity)) { \ 464 (s)[(i)++]=(uint8_t)((__uc>>6)|0xc0); \ 465 (s)[(i)++]=(uint8_t)((__uc&0x3f)|0x80); \ 466 } else if((__uc<=0xd7ff || (0xe000<=__uc && __uc<=0xffff)) && (i)+2<(capacity)) { \ 467 (s)[(i)++]=(uint8_t)((__uc>>12)|0xe0); \ 468 (s)[(i)++]=(uint8_t)(((__uc>>6)&0x3f)|0x80); \ 469 (s)[(i)++]=(uint8_t)((__uc&0x3f)|0x80); \ 470 } else if(0xffff<__uc && __uc<=0x10ffff && (i)+3<(capacity)) { \ 471 (s)[(i)++]=(uint8_t)((__uc>>18)|0xf0); \ 472 (s)[(i)++]=(uint8_t)(((__uc>>12)&0x3f)|0x80); \ 473 (s)[(i)++]=(uint8_t)(((__uc>>6)&0x3f)|0x80); \ 474 (s)[(i)++]=(uint8_t)((__uc&0x3f)|0x80); \ 475 } else { \ 476 (isError)=true; \ 477 } \ 478 } UPRV_BLOCK_MACRO_END 479 480 /** 481 * Advance the string offset from one code point boundary to the next. 482 * (Post-incrementing iteration.) 483 * "Unsafe" macro, assumes well-formed UTF-8. 484 * 485 * @param s const uint8_t * string 486 * @param i string offset 487 * @see U8_FWD_1 488 * @stable ICU 2.4 489 */ 490 #define U8_FWD_1_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 491 (i)+=1+U8_COUNT_TRAIL_BYTES_UNSAFE((s)[i]); \ 492 } UPRV_BLOCK_MACRO_END 493 494 /** 495 * Advance the string offset from one code point boundary to the next. 496 * (Post-incrementing iteration.) 497 * "Safe" macro, checks for illegal sequences and for string boundaries. 498 * 499 * The length can be negative for a NUL-terminated string. 500 * 501 * @param s const uint8_t * string 502 * @param i int32_t string offset, must be i<length 503 * @param length int32_t string length 504 * @see U8_FWD_1_UNSAFE 505 * @stable ICU 2.4 506 */ 507 #define U8_FWD_1(s, i, length) UPRV_BLOCK_MACRO_BEGIN { \ 508 uint8_t __b=(s)[(i)++]; \ 509 if(U8_IS_LEAD(__b) && (i)!=(length)) { \ 510 uint8_t __t1=(s)[i]; \ 511 if((0xe0<=__b && __b<0xf0)) { \ 512 if(U8_IS_VALID_LEAD3_AND_T1(__b, __t1) && \ 513 ++(i)!=(length) && U8_IS_TRAIL((s)[i])) { \ 514 ++(i); \ 515 } \ 516 } else if(__b<0xe0) { \ 517 if(U8_IS_TRAIL(__t1)) { \ 518 ++(i); \ 519 } \ 520 } else /* c>=0xf0 */ { \ 521 if(U8_IS_VALID_LEAD4_AND_T1(__b, __t1) && \ 522 ++(i)!=(length) && U8_IS_TRAIL((s)[i]) && \ 523 ++(i)!=(length) && U8_IS_TRAIL((s)[i])) { \ 524 ++(i); \ 525 } \ 526 } \ 527 } \ 528 } UPRV_BLOCK_MACRO_END 529 530 /** 531 * Advance the string offset from one code point boundary to the n-th next one, 532 * i.e., move forward by n code points. 533 * (Post-incrementing iteration.) 534 * "Unsafe" macro, assumes well-formed UTF-8. 535 * 536 * @param s const uint8_t * string 537 * @param i string offset 538 * @param n number of code points to skip 539 * @see U8_FWD_N 540 * @stable ICU 2.4 541 */ 542 #define U8_FWD_N_UNSAFE(s, i, n) UPRV_BLOCK_MACRO_BEGIN { \ 543 int32_t __N=(n); \ 544 while(__N>0) { \ 545 U8_FWD_1_UNSAFE(s, i); \ 546 --__N; \ 547 } \ 548 } UPRV_BLOCK_MACRO_END 549 550 /** 551 * Advance the string offset from one code point boundary to the n-th next one, 552 * i.e., move forward by n code points. 553 * (Post-incrementing iteration.) 554 * "Safe" macro, checks for illegal sequences and for string boundaries. 555 * 556 * The length can be negative for a NUL-terminated string. 557 * 558 * @param s const uint8_t * string 559 * @param i int32_t string offset, must be i<length 560 * @param length int32_t string length 561 * @param n number of code points to skip 562 * @see U8_FWD_N_UNSAFE 563 * @stable ICU 2.4 564 */ 565 #define U8_FWD_N(s, i, length, n) UPRV_BLOCK_MACRO_BEGIN { \ 566 int32_t __N=(n); \ 567 while(__N>0 && ((i)<(length) || ((length)<0 && (s)[i]!=0))) { \ 568 U8_FWD_1(s, i, length); \ 569 --__N; \ 570 } \ 571 } UPRV_BLOCK_MACRO_END 572 573 /** 574 * Adjust a random-access offset to a code point boundary 575 * at the start of a code point. 576 * If the offset points to a UTF-8 trail byte, 577 * then the offset is moved backward to the corresponding lead byte. 578 * Otherwise, it is not modified. 579 * "Unsafe" macro, assumes well-formed UTF-8. 580 * 581 * @param s const uint8_t * string 582 * @param i string offset 583 * @see U8_SET_CP_START 584 * @stable ICU 2.4 585 */ 586 #define U8_SET_CP_START_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 587 while(U8_IS_TRAIL((s)[i])) { --(i); } \ 588 } UPRV_BLOCK_MACRO_END 589 590 /** 591 * Adjust a random-access offset to a code point boundary 592 * at the start of a code point. 593 * If the offset points to a UTF-8 trail byte, 594 * then the offset is moved backward to the corresponding lead byte. 595 * Otherwise, it is not modified. 596 * 597 * "Safe" macro, checks for illegal sequences and for string boundaries. 598 * Unlike U8_TRUNCATE_IF_INCOMPLETE(), this macro always reads s[i]. 599 * 600 * @param s const uint8_t * string 601 * @param start int32_t starting string offset (usually 0) 602 * @param i int32_t string offset, must be start<=i 603 * @see U8_SET_CP_START_UNSAFE 604 * @see U8_TRUNCATE_IF_INCOMPLETE 605 * @stable ICU 2.4 606 */ 607 #define U8_SET_CP_START(s, start, i) UPRV_BLOCK_MACRO_BEGIN { \ 608 if(U8_IS_TRAIL((s)[(i)])) { \ 609 (i)=utf8_back1SafeBody(s, start, (i)); \ 610 } \ 611 } UPRV_BLOCK_MACRO_END 612 613 /** 614 * If the string ends with a UTF-8 byte sequence that is valid so far 615 * but incomplete, then reduce the length of the string to end before 616 * the lead byte of that incomplete sequence. 617 * For example, if the string ends with E1 80, the length is reduced by 2. 618 * 619 * In all other cases (the string ends with a complete sequence, or it is not 620 * possible for any further trail byte to extend the trailing sequence) 621 * the length remains unchanged. 622 * 623 * Useful for processing text split across multiple buffers 624 * (save the incomplete sequence for later) 625 * and for optimizing iteration 626 * (check for string length only once per character). 627 * 628 * "Safe" macro, checks for illegal sequences and for string boundaries. 629 * Unlike U8_SET_CP_START(), this macro never reads s[length]. 630 * 631 * (In UTF-16, simply check for U16_IS_LEAD(last code unit).) 632 * 633 * @param s const uint8_t * string 634 * @param start int32_t starting string offset (usually 0) 635 * @param length int32_t string length (usually start<=length) 636 * @see U8_SET_CP_START 637 * @stable ICU 61 638 */ 639 #define U8_TRUNCATE_IF_INCOMPLETE(s, start, length) UPRV_BLOCK_MACRO_BEGIN { \ 640 if((length)>(start)) { \ 641 uint8_t __b1=s[(length)-1]; \ 642 if(U8_IS_SINGLE(__b1)) { \ 643 /* common ASCII character */ \ 644 } else if(U8_IS_LEAD(__b1)) { \ 645 --(length); \ 646 } else if(U8_IS_TRAIL(__b1) && ((length)-2)>=(start)) { \ 647 uint8_t __b2=s[(length)-2]; \ 648 if(0xe0<=__b2 && __b2<=0xf4) { \ 649 if(__b2<0xf0 ? U8_IS_VALID_LEAD3_AND_T1(__b2, __b1) : \ 650 U8_IS_VALID_LEAD4_AND_T1(__b2, __b1)) { \ 651 (length)-=2; \ 652 } \ 653 } else if(U8_IS_TRAIL(__b2) && ((length)-3)>=(start)) { \ 654 uint8_t __b3=s[(length)-3]; \ 655 if(0xf0<=__b3 && __b3<=0xf4 && U8_IS_VALID_LEAD4_AND_T1(__b3, __b2)) { \ 656 (length)-=3; \ 657 } \ 658 } \ 659 } \ 660 } \ 661 } UPRV_BLOCK_MACRO_END 662 663 /* definitions with backward iteration -------------------------------------- */ 664 665 /** 666 * Move the string offset from one code point boundary to the previous one 667 * and get the code point between them. 668 * (Pre-decrementing backward iteration.) 669 * "Unsafe" macro, assumes well-formed UTF-8. 670 * 671 * The input offset may be the same as the string length. 672 * If the offset is behind a multi-byte sequence, then the macro will read 673 * the whole sequence. 674 * If the offset is behind a lead byte, then that itself 675 * will be returned as the code point. 676 * The result is undefined if the offset is behind an illegal UTF-8 sequence. 677 * 678 * @param s const uint8_t * string 679 * @param i string offset 680 * @param c output UChar32 variable 681 * @see U8_PREV 682 * @stable ICU 2.4 683 */ 684 #define U8_PREV_UNSAFE(s, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 685 (c)=(uint8_t)(s)[--(i)]; \ 686 if(U8_IS_TRAIL(c)) { \ 687 uint8_t __b, __count=1, __shift=6; \ 688 \ 689 /* c is a trail byte */ \ 690 (c)&=0x3f; \ 691 for(;;) { \ 692 __b=(s)[--(i)]; \ 693 if(__b>=0xc0) { \ 694 U8_MASK_LEAD_BYTE(__b, __count); \ 695 (c)|=(UChar32)__b<<__shift; \ 696 break; \ 697 } else { \ 698 (c)|=(UChar32)(__b&0x3f)<<__shift; \ 699 ++__count; \ 700 __shift+=6; \ 701 } \ 702 } \ 703 } \ 704 } UPRV_BLOCK_MACRO_END 705 706 /** 707 * Move the string offset from one code point boundary to the previous one 708 * and get the code point between them. 709 * (Pre-decrementing backward iteration.) 710 * "Safe" macro, checks for illegal sequences and for string boundaries. 711 * 712 * The input offset may be the same as the string length. 713 * If the offset is behind a multi-byte sequence, then the macro will read 714 * the whole sequence. 715 * If the offset is behind a lead byte, then that itself 716 * will be returned as the code point. 717 * If the offset is behind an illegal UTF-8 sequence, then c is set to a negative value. 718 * 719 * @param s const uint8_t * string 720 * @param start int32_t starting string offset (usually 0) 721 * @param i int32_t string offset, must be start<i 722 * @param c output UChar32 variable, set to <0 in case of an error 723 * @see U8_PREV_UNSAFE 724 * @stable ICU 2.4 725 */ 726 #define U8_PREV(s, start, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 727 (c)=(uint8_t)(s)[--(i)]; \ 728 if(!U8_IS_SINGLE(c)) { \ 729 (c)=utf8_prevCharSafeBody((const uint8_t *)s, start, &(i), c, -1); \ 730 } \ 731 } UPRV_BLOCK_MACRO_END 732 733 /** 734 * Move the string offset from one code point boundary to the previous one 735 * and get the code point between them. 736 * (Pre-decrementing backward iteration.) 737 * "Safe" macro, checks for illegal sequences and for string boundaries. 738 * 739 * The input offset may be the same as the string length. 740 * If the offset is behind a multi-byte sequence, then the macro will read 741 * the whole sequence. 742 * If the offset is behind a lead byte, then that itself 743 * will be returned as the code point. 744 * If the offset is behind an illegal UTF-8 sequence, then c is set to U+FFFD. 745 * 746 * This macro does not distinguish between a real U+FFFD in the text 747 * and U+FFFD returned for an ill-formed sequence. 748 * Use U8_PREV() if that distinction is important. 749 * 750 * @param s const uint8_t * string 751 * @param start int32_t starting string offset (usually 0) 752 * @param i int32_t string offset, must be start<i 753 * @param c output UChar32 variable, set to U+FFFD in case of an error 754 * @see U8_PREV 755 * @stable ICU 51 756 */ 757 #define U8_PREV_OR_FFFD(s, start, i, c) UPRV_BLOCK_MACRO_BEGIN { \ 758 (c)=(uint8_t)(s)[--(i)]; \ 759 if(!U8_IS_SINGLE(c)) { \ 760 (c)=utf8_prevCharSafeBody((const uint8_t *)s, start, &(i), c, -3); \ 761 } \ 762 } UPRV_BLOCK_MACRO_END 763 764 /** 765 * Move the string offset from one code point boundary to the previous one. 766 * (Pre-decrementing backward iteration.) 767 * The input offset may be the same as the string length. 768 * "Unsafe" macro, assumes well-formed UTF-8. 769 * 770 * @param s const uint8_t * string 771 * @param i string offset 772 * @see U8_BACK_1 773 * @stable ICU 2.4 774 */ 775 #define U8_BACK_1_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 776 while(U8_IS_TRAIL((s)[--(i)])) {} \ 777 } UPRV_BLOCK_MACRO_END 778 779 /** 780 * Move the string offset from one code point boundary to the previous one. 781 * (Pre-decrementing backward iteration.) 782 * The input offset may be the same as the string length. 783 * "Safe" macro, checks for illegal sequences and for string boundaries. 784 * 785 * @param s const uint8_t * string 786 * @param start int32_t starting string offset (usually 0) 787 * @param i int32_t string offset, must be start<i 788 * @see U8_BACK_1_UNSAFE 789 * @stable ICU 2.4 790 */ 791 #define U8_BACK_1(s, start, i) UPRV_BLOCK_MACRO_BEGIN { \ 792 if(U8_IS_TRAIL((s)[--(i)])) { \ 793 (i)=utf8_back1SafeBody(s, start, (i)); \ 794 } \ 795 } UPRV_BLOCK_MACRO_END 796 797 /** 798 * Move the string offset from one code point boundary to the n-th one before it, 799 * i.e., move backward by n code points. 800 * (Pre-decrementing backward iteration.) 801 * The input offset may be the same as the string length. 802 * "Unsafe" macro, assumes well-formed UTF-8. 803 * 804 * @param s const uint8_t * string 805 * @param i string offset 806 * @param n number of code points to skip 807 * @see U8_BACK_N 808 * @stable ICU 2.4 809 */ 810 #define U8_BACK_N_UNSAFE(s, i, n) UPRV_BLOCK_MACRO_BEGIN { \ 811 int32_t __N=(n); \ 812 while(__N>0) { \ 813 U8_BACK_1_UNSAFE(s, i); \ 814 --__N; \ 815 } \ 816 } UPRV_BLOCK_MACRO_END 817 818 /** 819 * Move the string offset from one code point boundary to the n-th one before it, 820 * i.e., move backward by n code points. 821 * (Pre-decrementing backward iteration.) 822 * The input offset may be the same as the string length. 823 * "Safe" macro, checks for illegal sequences and for string boundaries. 824 * 825 * @param s const uint8_t * string 826 * @param start int32_t index of the start of the string 827 * @param i int32_t string offset, must be start<i 828 * @param n number of code points to skip 829 * @see U8_BACK_N_UNSAFE 830 * @stable ICU 2.4 831 */ 832 #define U8_BACK_N(s, start, i, n) UPRV_BLOCK_MACRO_BEGIN { \ 833 int32_t __N=(n); \ 834 while(__N>0 && (i)>(start)) { \ 835 U8_BACK_1(s, start, i); \ 836 --__N; \ 837 } \ 838 } UPRV_BLOCK_MACRO_END 839 840 /** 841 * Adjust a random-access offset to a code point boundary after a code point. 842 * If the offset is behind a partial multi-byte sequence, 843 * then the offset is incremented to behind the whole sequence. 844 * Otherwise, it is not modified. 845 * The input offset may be the same as the string length. 846 * "Unsafe" macro, assumes well-formed UTF-8. 847 * 848 * @param s const uint8_t * string 849 * @param i string offset 850 * @see U8_SET_CP_LIMIT 851 * @stable ICU 2.4 852 */ 853 #define U8_SET_CP_LIMIT_UNSAFE(s, i) UPRV_BLOCK_MACRO_BEGIN { \ 854 U8_BACK_1_UNSAFE(s, i); \ 855 U8_FWD_1_UNSAFE(s, i); \ 856 } UPRV_BLOCK_MACRO_END 857 858 /** 859 * Adjust a random-access offset to a code point boundary after a code point. 860 * If the offset is behind a partial multi-byte sequence, 861 * then the offset is incremented to behind the whole sequence. 862 * Otherwise, it is not modified. 863 * The input offset may be the same as the string length. 864 * "Safe" macro, checks for illegal sequences and for string boundaries. 865 * 866 * The length can be negative for a NUL-terminated string. 867 * 868 * @param s const uint8_t * string 869 * @param start int32_t starting string offset (usually 0) 870 * @param i int32_t string offset, must be start<=i<=length 871 * @param length int32_t string length 872 * @see U8_SET_CP_LIMIT_UNSAFE 873 * @stable ICU 2.4 874 */ 875 #define U8_SET_CP_LIMIT(s, start, i, length) UPRV_BLOCK_MACRO_BEGIN { \ 876 if((start)<(i) && ((i)<(length) || (length)<0)) { \ 877 U8_BACK_1(s, start, i); \ 878 U8_FWD_1(s, i, length); \ 879 } \ 880 } UPRV_BLOCK_MACRO_END 881 882 #endif 883