intl/icu/source/common/unicode/utf16.h

Wed, 31 Dec 2014 06:09:35 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Wed, 31 Dec 2014 06:09:35 +0100
changeset 0
6474c204b198
permissions
-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

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

mercurial