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Issue 18836004: Move ICU headers from public/{common,i18n} to source/{common,i18n} (Closed) Base URL: https://chromium.googlesource.com/chromium/deps/icu46.git@master
Patch Set: same as ps #3. retry uploading Created 7 years, 5 months ago
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1 /*
2 *******************************************************************************
3 *
4 * Copyright (C) 1999-2009, International Business Machines
5 * Corporation and others. All Rights Reserved.
6 *
7 *******************************************************************************
8 * file name: utf8.h
9 * encoding: US-ASCII
10 * tab size: 8 (not used)
11 * indentation:4
12 *
13 * created on: 1999sep13
14 * created by: Markus W. Scherer
15 */
16
17 /**
18 * \file
19 * \brief C API: 8-bit Unicode handling macros
20 *
21 * This file defines macros to deal with 8-bit Unicode (UTF-8) code units (bytes ) and strings.
22 * utf8.h is included by utf.h after unicode/umachine.h
23 * and some common definitions.
24 *
25 * For more information see utf.h and the ICU User Guide Strings chapter
26 * (http://icu-project.org/userguide/strings.html).
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 /* utf.h must be included first. */
38 #ifndef __UTF_H__
39 # include "unicode/utf.h"
40 #endif
41
42 /* internal definitions ----------------------------------------------------- */
43
44 /**
45 * \var utf8_countTrailBytes
46 * Internal array with numbers of trail bytes for any given byte used in
47 * lead byte position.
48 *
49 * This is internal since it is not meant to be called directly by external clie nts;
50 * however it is called by public macros in this file and thus must remain stabl e,
51 * and should not be hidden when other internal functions are hidden (otherwise
52 * public macros would fail to compile).
53 * @internal
54 */
55 #ifdef U_UTF8_IMPL
56 U_EXPORT const uint8_t
57 #elif defined(U_STATIC_IMPLEMENTATION) || defined(U_COMMON_IMPLEMENTATION)
58 U_CFUNC const uint8_t
59 #else
60 U_CFUNC U_IMPORT const uint8_t /* U_IMPORT2? */ /*U_IMPORT*/
61 #endif
62 utf8_countTrailBytes[256];
63
64 /**
65 * Count the trail bytes for a UTF-8 lead byte.
66 *
67 * This is internal since it is not meant to be called directly by external clie nts;
68 * however it is called by public macros in this file and thus must remain stabl e.
69 * @internal
70 */
71 #define U8_COUNT_TRAIL_BYTES(leadByte) (utf8_countTrailBytes[(uint8_t)leadByte])
72
73 /**
74 * Mask a UTF-8 lead byte, leave only the lower bits that form part of the code point value.
75 *
76 * This is internal since it is not meant to be called directly by external clie nts;
77 * however it is called by public macros in this file and thus must remain stabl e.
78 * @internal
79 */
80 #define U8_MASK_LEAD_BYTE(leadByte, countTrailBytes) ((leadByte)&=(1<<(6-(countT railBytes)))-1)
81
82 /**
83 * Function for handling "next code point" with error-checking.
84 *
85 * This is internal since it is not meant to be called directly by external clie nts;
86 * however it is U_STABLE (not U_INTERNAL) since it is called by public macros i n this
87 * file and thus must remain stable, and should not be hidden when other interna l
88 * functions are hidden (otherwise public macros would fail to compile).
89 * @internal
90 */
91 U_STABLE UChar32 U_EXPORT2
92 utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict);
93
94 /**
95 * Function for handling "append code point" with error-checking.
96 *
97 * This is internal since it is not meant to be called directly by external clie nts;
98 * however it is U_STABLE (not U_INTERNAL) since it is called by public macros i n this
99 * file and thus must remain stable, and should not be hidden when other interna l
100 * functions are hidden (otherwise public macros would fail to compile).
101 * @internal
102 */
103 U_STABLE int32_t U_EXPORT2
104 utf8_appendCharSafeBody(uint8_t *s, int32_t i, int32_t length, UChar32 c, UBool *pIsError);
105
106 /**
107 * Function for handling "previous code point" with error-checking.
108 *
109 * This is internal since it is not meant to be called directly by external clie nts;
110 * however it is U_STABLE (not U_INTERNAL) since it is called by public macros i n this
111 * file and thus must remain stable, and should not be hidden when other interna l
112 * functions are hidden (otherwise public macros would fail to compile).
113 * @internal
114 */
115 U_STABLE UChar32 U_EXPORT2
116 utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, U Bool strict);
117
118 /**
119 * Function for handling "skip backward one code point" with error-checking.
120 *
121 * This is internal since it is not meant to be called directly by external clie nts;
122 * however it is U_STABLE (not U_INTERNAL) since it is called by public macros i n this
123 * file and thus must remain stable, and should not be hidden when other interna l
124 * functions are hidden (otherwise public macros would fail to compile).
125 * @internal
126 */
127 U_STABLE int32_t U_EXPORT2
128 utf8_back1SafeBody(const uint8_t *s, int32_t start, int32_t i);
129
130 /* single-code point definitions -------------------------------------------- */
131
132 /**
133 * Does this code unit (byte) encode a code point by itself (US-ASCII 0..0x7f)?
134 * @param c 8-bit code unit (byte)
135 * @return TRUE or FALSE
136 * @stable ICU 2.4
137 */
138 #define U8_IS_SINGLE(c) (((c)&0x80)==0)
139
140 /**
141 * Is this code unit (byte) a UTF-8 lead byte?
142 * @param c 8-bit code unit (byte)
143 * @return TRUE or FALSE
144 * @stable ICU 2.4
145 */
146 #define U8_IS_LEAD(c) ((uint8_t)((c)-0xc0)<0x3e)
147
148 /**
149 * Is this code unit (byte) a UTF-8 trail byte?
150 * @param c 8-bit code unit (byte)
151 * @return TRUE or FALSE
152 * @stable ICU 2.4
153 */
154 #define U8_IS_TRAIL(c) (((c)&0xc0)==0x80)
155
156 /**
157 * How many code units (bytes) are used for the UTF-8 encoding
158 * of this Unicode code point?
159 * @param c 32-bit code point
160 * @return 1..4, or 0 if c is a surrogate or not a Unicode code point
161 * @stable ICU 2.4
162 */
163 #define U8_LENGTH(c) \
164 ((uint32_t)(c)<=0x7f ? 1 : \
165 ((uint32_t)(c)<=0x7ff ? 2 : \
166 ((uint32_t)(c)<=0xd7ff ? 3 : \
167 ((uint32_t)(c)<=0xdfff || (uint32_t)(c)>0x10ffff ? 0 : \
168 ((uint32_t)(c)<=0xffff ? 3 : 4)\
169 ) \
170 ) \
171 ) \
172 )
173
174 /**
175 * The maximum number of UTF-8 code units (bytes) per Unicode code point (U+0000 ..U+10ffff).
176 * @return 4
177 * @stable ICU 2.4
178 */
179 #define U8_MAX_LENGTH 4
180
181 /**
182 * Get a code point from a string at a random-access offset,
183 * without changing the offset.
184 * The offset may point to either the lead byte or one of the trail bytes
185 * for a code point, in which case the macro will read all of the bytes
186 * for the code point.
187 * The result is undefined if the offset points to an illegal UTF-8
188 * byte sequence.
189 * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT.
190 *
191 * @param s const uint8_t * string
192 * @param i string offset
193 * @param c output UChar32 variable
194 * @see U8_GET
195 * @stable ICU 2.4
196 */
197 #define U8_GET_UNSAFE(s, i, c) { \
198 int32_t _u8_get_unsafe_index=(int32_t)(i); \
199 U8_SET_CP_START_UNSAFE(s, _u8_get_unsafe_index); \
200 U8_NEXT_UNSAFE(s, _u8_get_unsafe_index, c); \
201 }
202
203 /**
204 * Get a code point from a string at a random-access offset,
205 * without changing the offset.
206 * The offset may point to either the lead byte or one of the trail bytes
207 * for a code point, in which case the macro will read all of the bytes
208 * for the code point.
209 * If the offset points to an illegal UTF-8 byte sequence, then
210 * c is set to a negative value.
211 * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT.
212 *
213 * @param s const uint8_t * string
214 * @param start starting string offset
215 * @param i string offset, must be start<=i<length
216 * @param length string length
217 * @param c output UChar32 variable, set to <0 in case of an error
218 * @see U8_GET_UNSAFE
219 * @stable ICU 2.4
220 */
221 #define U8_GET(s, start, i, length, c) { \
222 int32_t _u8_get_index=(int32_t)(i); \
223 U8_SET_CP_START(s, start, _u8_get_index); \
224 U8_NEXT(s, _u8_get_index, length, c); \
225 }
226
227 /* definitions with forward iteration --------------------------------------- */
228
229 /**
230 * Get a code point from a string at a code point boundary offset,
231 * and advance the offset to the next code point boundary.
232 * (Post-incrementing forward iteration.)
233 * "Unsafe" macro, assumes well-formed UTF-8.
234 *
235 * The offset may point to the lead byte of a multi-byte sequence,
236 * in which case the macro will read the whole sequence.
237 * The result is undefined if the offset points to a trail byte
238 * or an illegal UTF-8 sequence.
239 *
240 * @param s const uint8_t * string
241 * @param i string offset
242 * @param c output UChar32 variable
243 * @see U8_NEXT
244 * @stable ICU 2.4
245 */
246 #define U8_NEXT_UNSAFE(s, i, c) { \
247 (c)=(uint8_t)(s)[(i)++]; \
248 if((uint8_t)((c)-0xc0)<0x35) { \
249 uint8_t __count=U8_COUNT_TRAIL_BYTES(c); \
250 U8_MASK_LEAD_BYTE(c, __count); \
251 switch(__count) { \
252 /* each following branch falls through to the next one */ \
253 case 3: \
254 (c)=((c)<<6)|((s)[(i)++]&0x3f); \
255 case 2: \
256 (c)=((c)<<6)|((s)[(i)++]&0x3f); \
257 case 1: \
258 (c)=((c)<<6)|((s)[(i)++]&0x3f); \
259 /* no other branches to optimize switch() */ \
260 break; \
261 } \
262 } \
263 }
264
265 /**
266 * Get a code point from a string at a code point boundary offset,
267 * and advance the offset to the next code point boundary.
268 * (Post-incrementing forward iteration.)
269 * "Safe" macro, checks for illegal sequences and for string boundaries.
270 *
271 * The offset may point to the lead byte of a multi-byte sequence,
272 * in which case the macro will read the whole sequence.
273 * If the offset points to a trail byte or an illegal UTF-8 sequence, then
274 * c is set to a negative value.
275 *
276 * @param s const uint8_t * string
277 * @param i string offset, must be i<length
278 * @param length string length
279 * @param c output UChar32 variable, set to <0 in case of an error
280 * @see U8_NEXT_UNSAFE
281 * @stable ICU 2.4
282 */
283 #define U8_NEXT(s, i, length, c) { \
284 (c)=(uint8_t)(s)[(i)++]; \
285 if((c)>=0x80) { \
286 uint8_t __t1, __t2; \
287 if( /* handle U+1000..U+CFFF inline */ \
288 (0xe0<(c) && (c)<=0xec) && \
289 (((i)+1)<(length)) && \
290 (__t1=(uint8_t)((s)[i]-0x80))<=0x3f && \
291 (__t2=(uint8_t)((s)[(i)+1]-0x80))<= 0x3f \
292 ) { \
293 /* no need for (c&0xf) because the upper bits are truncated after << 12 in the cast to (UChar) */ \
294 (c)=(UChar)(((c)<<12)|(__t1<<6)|__t2); \
295 (i)+=2; \
296 } else if( /* handle U+0080..U+07FF inline */ \
297 ((c)<0xe0 && (c)>=0xc2) && \
298 ((i)<(length)) && \
299 (__t1=(uint8_t)((s)[i]-0x80))<=0x3f \
300 ) { \
301 (c)=(UChar)((((c)&0x1f)<<6)|__t1); \
302 ++(i); \
303 } else if(U8_IS_LEAD(c)) { \
304 /* function call for "complicated" and error cases */ \
305 (c)=utf8_nextCharSafeBody((const uint8_t *)s, &(i), (int32_t)(length ), c, -1); \
306 } else { \
307 (c)=U_SENTINEL; \
308 } \
309 } \
310 }
311
312 /**
313 * Append a code point to a string, overwriting 1 to 4 bytes.
314 * The offset points to the current end of the string contents
315 * and is advanced (post-increment).
316 * "Unsafe" macro, assumes a valid code point and sufficient space in the string .
317 * Otherwise, the result is undefined.
318 *
319 * @param s const uint8_t * string buffer
320 * @param i string offset
321 * @param c code point to append
322 * @see U8_APPEND
323 * @stable ICU 2.4
324 */
325 #define U8_APPEND_UNSAFE(s, i, c) { \
326 if((uint32_t)(c)<=0x7f) { \
327 (s)[(i)++]=(uint8_t)(c); \
328 } else { \
329 if((uint32_t)(c)<=0x7ff) { \
330 (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); \
331 } else { \
332 if((uint32_t)(c)<=0xffff) { \
333 (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); \
334 } else { \
335 (s)[(i)++]=(uint8_t)(((c)>>18)|0xf0); \
336 (s)[(i)++]=(uint8_t)((((c)>>12)&0x3f)|0x80); \
337 } \
338 (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); \
339 } \
340 (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \
341 } \
342 }
343
344 /**
345 * Append a code point to a string, overwriting 1 to 4 bytes.
346 * The offset points to the current end of the string contents
347 * and is advanced (post-increment).
348 * "Safe" macro, checks for a valid code point.
349 * If a non-ASCII code point is written, checks for sufficient space in the stri ng.
350 * If the code point is not valid or trail bytes do not fit,
351 * then isError is set to TRUE.
352 *
353 * @param s const uint8_t * string buffer
354 * @param i string offset, must be i<capacity
355 * @param capacity size of the string buffer
356 * @param c code point to append
357 * @param isError output UBool set to TRUE if an error occurs, otherwise not mod ified
358 * @see U8_APPEND_UNSAFE
359 * @stable ICU 2.4
360 */
361 #define U8_APPEND(s, i, capacity, c, isError) { \
362 if((uint32_t)(c)<=0x7f) { \
363 (s)[(i)++]=(uint8_t)(c); \
364 } else if((uint32_t)(c)<=0x7ff && (i)+1<(capacity)) { \
365 (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); \
366 (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \
367 } else if((uint32_t)(c)<=0xd7ff && (i)+2<(capacity)) { \
368 (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); \
369 (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); \
370 (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \
371 } else { \
372 (i)=utf8_appendCharSafeBody(s, (int32_t)(i), (int32_t)(capacity), c, &(i sError)); \
373 } \
374 }
375
376 /**
377 * Advance the string offset from one code point boundary to the next.
378 * (Post-incrementing iteration.)
379 * "Unsafe" macro, assumes well-formed UTF-8.
380 *
381 * @param s const uint8_t * string
382 * @param i string offset
383 * @see U8_FWD_1
384 * @stable ICU 2.4
385 */
386 #define U8_FWD_1_UNSAFE(s, i) { \
387 (i)+=1+U8_COUNT_TRAIL_BYTES((s)[i]); \
388 }
389
390 /**
391 * Advance the string offset from one code point boundary to the next.
392 * (Post-incrementing iteration.)
393 * "Safe" macro, checks for illegal sequences and for string boundaries.
394 *
395 * @param s const uint8_t * string
396 * @param i string offset, must be i<length
397 * @param length string length
398 * @see U8_FWD_1_UNSAFE
399 * @stable ICU 2.4
400 */
401 #define U8_FWD_1(s, i, length) { \
402 uint8_t __b=(uint8_t)(s)[(i)++]; \
403 if(U8_IS_LEAD(__b)) { \
404 uint8_t __count=U8_COUNT_TRAIL_BYTES(__b); \
405 if((i)+__count>(length)) { \
406 __count=(uint8_t)((length)-(i)); \
407 } \
408 while(__count>0 && U8_IS_TRAIL((s)[i])) { \
409 ++(i); \
410 --__count; \
411 } \
412 } \
413 }
414
415 /**
416 * Advance the string offset from one code point boundary to the n-th next one,
417 * i.e., move forward by n code points.
418 * (Post-incrementing iteration.)
419 * "Unsafe" macro, assumes well-formed UTF-8.
420 *
421 * @param s const uint8_t * string
422 * @param i string offset
423 * @param n number of code points to skip
424 * @see U8_FWD_N
425 * @stable ICU 2.4
426 */
427 #define U8_FWD_N_UNSAFE(s, i, n) { \
428 int32_t __N=(n); \
429 while(__N>0) { \
430 U8_FWD_1_UNSAFE(s, i); \
431 --__N; \
432 } \
433 }
434
435 /**
436 * Advance the string offset from one code point boundary to the n-th next one,
437 * i.e., move forward by n code points.
438 * (Post-incrementing iteration.)
439 * "Safe" macro, checks for illegal sequences and for string boundaries.
440 *
441 * @param s const uint8_t * string
442 * @param i string offset, must be i<length
443 * @param length string length
444 * @param n number of code points to skip
445 * @see U8_FWD_N_UNSAFE
446 * @stable ICU 2.4
447 */
448 #define U8_FWD_N(s, i, length, n) { \
449 int32_t __N=(n); \
450 while(__N>0 && (i)<(length)) { \
451 U8_FWD_1(s, i, length); \
452 --__N; \
453 } \
454 }
455
456 /**
457 * Adjust a random-access offset to a code point boundary
458 * at the start of a code point.
459 * If the offset points to a UTF-8 trail byte,
460 * then the offset is moved backward to the corresponding lead byte.
461 * Otherwise, it is not modified.
462 * "Unsafe" macro, assumes well-formed UTF-8.
463 *
464 * @param s const uint8_t * string
465 * @param i string offset
466 * @see U8_SET_CP_START
467 * @stable ICU 2.4
468 */
469 #define U8_SET_CP_START_UNSAFE(s, i) { \
470 while(U8_IS_TRAIL((s)[i])) { --(i); } \
471 }
472
473 /**
474 * Adjust a random-access offset to a code point boundary
475 * at the start of a code point.
476 * If the offset points to a UTF-8 trail byte,
477 * then the offset is moved backward to the corresponding lead byte.
478 * Otherwise, it is not modified.
479 * "Safe" macro, checks for illegal sequences and for string boundaries.
480 *
481 * @param s const uint8_t * string
482 * @param start starting string offset (usually 0)
483 * @param i string offset, must be start<=i
484 * @see U8_SET_CP_START_UNSAFE
485 * @stable ICU 2.4
486 */
487 #define U8_SET_CP_START(s, start, i) { \
488 if(U8_IS_TRAIL((s)[(i)])) { \
489 (i)=utf8_back1SafeBody(s, start, (int32_t)(i)); \
490 } \
491 }
492
493 /* definitions with backward iteration -------------------------------------- */
494
495 /**
496 * Move the string offset from one code point boundary to the previous one
497 * and get the code point between them.
498 * (Pre-decrementing backward iteration.)
499 * "Unsafe" macro, assumes well-formed UTF-8.
500 *
501 * The input offset may be the same as the string length.
502 * If the offset is behind a multi-byte sequence, then the macro will read
503 * the whole sequence.
504 * If the offset is behind a lead byte, then that itself
505 * will be returned as the code point.
506 * The result is undefined if the offset is behind an illegal UTF-8 sequence.
507 *
508 * @param s const uint8_t * string
509 * @param i string offset
510 * @param c output UChar32 variable
511 * @see U8_PREV
512 * @stable ICU 2.4
513 */
514 #define U8_PREV_UNSAFE(s, i, c) { \
515 (c)=(uint8_t)(s)[--(i)]; \
516 if(U8_IS_TRAIL(c)) { \
517 uint8_t __b, __count=1, __shift=6; \
518 \
519 /* c is a trail byte */ \
520 (c)&=0x3f; \
521 for(;;) { \
522 __b=(uint8_t)(s)[--(i)]; \
523 if(__b>=0xc0) { \
524 U8_MASK_LEAD_BYTE(__b, __count); \
525 (c)|=(UChar32)__b<<__shift; \
526 break; \
527 } else { \
528 (c)|=(UChar32)(__b&0x3f)<<__shift; \
529 ++__count; \
530 __shift+=6; \
531 } \
532 } \
533 } \
534 }
535
536 /**
537 * Move the string offset from one code point boundary to the previous one
538 * and get the code point between them.
539 * (Pre-decrementing backward iteration.)
540 * "Safe" macro, checks for illegal sequences and for string boundaries.
541 *
542 * The input offset may be the same as the string length.
543 * If the offset is behind a multi-byte sequence, then the macro will read
544 * the whole sequence.
545 * If the offset is behind a lead byte, then that itself
546 * will be returned as the code point.
547 * If the offset is behind an illegal UTF-8 sequence, then c is set to a negativ e value.
548 *
549 * @param s const uint8_t * string
550 * @param start starting string offset (usually 0)
551 * @param i string offset, must be start<i
552 * @param c output UChar32 variable, set to <0 in case of an error
553 * @see U8_PREV_UNSAFE
554 * @stable ICU 2.4
555 */
556 #define U8_PREV(s, start, i, c) { \
557 (c)=(uint8_t)(s)[--(i)]; \
558 if((c)>=0x80) { \
559 if((c)<=0xbf) { \
560 (c)=utf8_prevCharSafeBody((const uint8_t *)s, start, &(i), c, -1); \
561 } else { \
562 (c)=U_SENTINEL; \
563 } \
564 } \
565 }
566
567 /**
568 * Move the string offset from one code point boundary to the previous one.
569 * (Pre-decrementing backward iteration.)
570 * The input offset may be the same as the string length.
571 * "Unsafe" macro, assumes well-formed UTF-8.
572 *
573 * @param s const uint8_t * string
574 * @param i string offset
575 * @see U8_BACK_1
576 * @stable ICU 2.4
577 */
578 #define U8_BACK_1_UNSAFE(s, i) { \
579 while(U8_IS_TRAIL((s)[--(i)])) {} \
580 }
581
582 /**
583 * Move the string offset from one code point boundary to the previous one.
584 * (Pre-decrementing backward iteration.)
585 * The input offset may be the same as the string length.
586 * "Safe" macro, checks for illegal sequences and for string boundaries.
587 *
588 * @param s const uint8_t * string
589 * @param start starting string offset (usually 0)
590 * @param i string offset, must be start<i
591 * @see U8_BACK_1_UNSAFE
592 * @stable ICU 2.4
593 */
594 #define U8_BACK_1(s, start, i) { \
595 if(U8_IS_TRAIL((s)[--(i)])) { \
596 (i)=utf8_back1SafeBody(s, start, (int32_t)(i)); \
597 } \
598 }
599
600 /**
601 * Move the string offset from one code point boundary to the n-th one before it ,
602 * i.e., move backward by n code points.
603 * (Pre-decrementing backward iteration.)
604 * The input offset may be the same as the string length.
605 * "Unsafe" macro, assumes well-formed UTF-8.
606 *
607 * @param s const uint8_t * string
608 * @param i string offset
609 * @param n number of code points to skip
610 * @see U8_BACK_N
611 * @stable ICU 2.4
612 */
613 #define U8_BACK_N_UNSAFE(s, i, n) { \
614 int32_t __N=(n); \
615 while(__N>0) { \
616 U8_BACK_1_UNSAFE(s, i); \
617 --__N; \
618 } \
619 }
620
621 /**
622 * Move the string offset from one code point boundary to the n-th one before it ,
623 * i.e., move backward by n code points.
624 * (Pre-decrementing backward iteration.)
625 * The input offset may be the same as the string length.
626 * "Safe" macro, checks for illegal sequences and for string boundaries.
627 *
628 * @param s const uint8_t * string
629 * @param start index of the start of the string
630 * @param i string offset, must be start<i
631 * @param n number of code points to skip
632 * @see U8_BACK_N_UNSAFE
633 * @stable ICU 2.4
634 */
635 #define U8_BACK_N(s, start, i, n) { \
636 int32_t __N=(n); \
637 while(__N>0 && (i)>(start)) { \
638 U8_BACK_1(s, start, i); \
639 --__N; \
640 } \
641 }
642
643 /**
644 * Adjust a random-access offset to a code point boundary after a code point.
645 * If the offset is behind a partial multi-byte sequence,
646 * then the offset is incremented to behind the whole sequence.
647 * Otherwise, it is not modified.
648 * The input offset may be the same as the string length.
649 * "Unsafe" macro, assumes well-formed UTF-8.
650 *
651 * @param s const uint8_t * string
652 * @param i string offset
653 * @see U8_SET_CP_LIMIT
654 * @stable ICU 2.4
655 */
656 #define U8_SET_CP_LIMIT_UNSAFE(s, i) { \
657 U8_BACK_1_UNSAFE(s, i); \
658 U8_FWD_1_UNSAFE(s, i); \
659 }
660
661 /**
662 * Adjust a random-access offset to a code point boundary after a code point.
663 * If the offset is behind a partial multi-byte sequence,
664 * then the offset is incremented to behind the whole sequence.
665 * Otherwise, it is not modified.
666 * The input offset may be the same as the string length.
667 * "Safe" macro, checks for illegal sequences and for string boundaries.
668 *
669 * @param s const uint8_t * string
670 * @param start starting string offset (usually 0)
671 * @param i string offset, must be start<=i<=length
672 * @param length string length
673 * @see U8_SET_CP_LIMIT_UNSAFE
674 * @stable ICU 2.4
675 */
676 #define U8_SET_CP_LIMIT(s, start, i, length) { \
677 if((start)<(i) && (i)<(length)) { \
678 U8_BACK_1(s, start, i); \
679 U8_FWD_1(s, i, length); \
680 } \
681 }
682
683 #endif
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