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1 /*
2 *******************************************************************************
3 *
4 * Copyright (C) 1999-2004, 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://oss.software.ibm.com/icu/userguide/).
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 * @internal
49 */
50 #ifdef U_UTF8_IMPL
51 U_INTERNAL const uint8_t
52 #elif defined(U_STATIC_IMPLEMENTATION)
53 U_CFUNC const uint8_t
54 #else
55 U_CFUNC U_IMPORT const uint8_t /* U_IMPORT2? */ /*U_IMPORT*/
56 #endif
57 utf8_countTrailBytes[256];
58
59 /**
60 * Count the trail bytes for a UTF-8 lead byte.
61 * @internal
62 */
63 #define U8_COUNT_TRAIL_BYTES(leadByte) (utf8_countTrailBytes[(uint8_t)leadByte])
64
65 /**
66 * Mask a UTF-8 lead byte, leave only the lower bits that form part of the code point value.
67 * @internal
68 */
69 #define U8_MASK_LEAD_BYTE(leadByte, countTrailBytes) ((leadByte)&=(1<<(6-(countTrailBytes)))-1)
70
71 /**
72 * Function for handling "next code point" with error-checking.
73 * @internal
74 */
75 U_INTERNAL UChar32 U_EXPORT2
76 utf8_nextCharSafeBody(const uint8_t *s, int32_t *pi, int32_t length, UChar32 c, UBool strict);
77
78 /**
79 * Function for handling "append code point" with error-checking.
80 * @internal
81 */
82 U_INTERNAL int32_t U_EXPORT2
83 utf8_appendCharSafeBody(uint8_t *s, int32_t i, int32_t length, UChar32 c, UBool *pIsError);
84
85 /**
86 * Function for handling "previous code point" with error-checking.
87 * @internal
88 */
89 U_INTERNAL UChar32 U_EXPORT2
90 utf8_prevCharSafeBody(const uint8_t *s, int32_t start, int32_t *pi, UChar32 c, UBool strict);
91
92 /**
93 * Function for handling "skip backward one code point" with error-checking.
94 * @internal
95 */
96 U_INTERNAL int32_t U_EXPORT2
97 utf8_back1SafeBody(const uint8_t *s, int32_t start, int32_t i);
98
99 /* single-code point definitions -------------------------------------------- */
100
101 /**
102 * Does this code unit (byte) encode a code point by itself (US-ASCII 0..0x7f)?
103 * @param c 8-bit code unit (byte)
104 * @return TRUE or FALSE
105 * @stable ICU 2.4
106 */
107 #define U8_IS_SINGLE(c) (((c)&0x80)==0)
108
109 /**
110 * Is this code unit (byte) a UTF-8 lead byte?
111 * @param c 8-bit code unit (byte)
112 * @return TRUE or FALSE
113 * @stable ICU 2.4
114 */
115 #define U8_IS_LEAD(c) ((uint8_t)((c)-0xc0)<0x3e)
116
117 /**
118 * Is this code unit (byte) a UTF-8 trail byte?
119 * @param c 8-bit code unit (byte)
120 * @return TRUE or FALSE
121 * @stable ICU 2.4
122 */
123 #define U8_IS_TRAIL(c) (((c)&0xc0)==0x80)
124
125 /**
126 * How many code units (bytes) are used for the UTF-8 encoding
127 * of this Unicode code point?
128 * @param c 32-bit code point
129 * @return 1..4, or 0 if c is a surrogate or not a Unicode code point
130 * @stable ICU 2.4
131 */
132 #define U8_LENGTH(c) \
133 ((uint32_t)(c)<=0x7f ? 1 : \
134 ((uint32_t)(c)<=0x7ff ? 2 : \
135 ((uint32_t)(c)<=0xd7ff ? 3 : \
136 ((uint32_t)(c)<=0xdfff || (uint32_t)(c)>0x10ffff ? 0 : \
137 ((uint32_t)(c)<=0xffff ? 3 : 4)\
138 ) \
139 ) \
140 ) \
141 )
142
143 /**
144 * The maximum number of UTF-8 code units (bytes) per Unicode code point (U+0000..U+10ffff).
145 * @return 4
146 * @stable ICU 2.4
147 */
148 #define U8_MAX_LENGTH 4
149
150 /**
151 * Get a code point from a string at a random-access offset,
152 * without changing the offset.
153 * The offset may point to either the lead byte or one of the trail bytes
154 * for a code point, in which case the macro will read all of the bytes
155 * for the code point.
156 * The result is undefined if the offset points to an illegal UTF-8
157 * byte sequence.
158 * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT.
159 *
160 * @param s const uint8_t * string
161 * @param i string offset
162 * @param c output UChar32 variable
163 * @see U8_GET
164 * @stable ICU 2.4
165 */
166 #define U8_GET_UNSAFE(s, i, c) { \
167 int32_t _u8_get_unsafe_index=(int32_t)(i); \
168 U8_SET_CP_START_UNSAFE(s, _u8_get_unsafe_index); \
169 U8_NEXT_UNSAFE(s, _u8_get_unsafe_index, c); \
170 }
171
172 /**
173 * Get a code point from a string at a random-access offset,
174 * without changing the offset.
175 * The offset may point to either the lead byte or one of the trail bytes
176 * for a code point, in which case the macro will read all of the bytes
177 * for the code point.
178 * If the offset points to an illegal UTF-8 byte sequence, then
179 * c is set to a negative value.
180 * Iteration through a string is more efficient with U8_NEXT_UNSAFE or U8_NEXT.
181 *
182 * @param s const uint8_t * string
183 * @param start starting string offset
184 * @param i string offset, start<=i<length
185 * @param length string length
186 * @param c output UChar32 variable, set to <0 in case of an error
187 * @see U8_GET_UNSAFE
188 * @stable ICU 2.4
189 */
190 #define U8_GET(s, start, i, length, c) { \
191 int32_t _u8_get_index=(int32_t)(i); \
192 U8_SET_CP_START(s, start, _u8_get_index); \
193 U8_NEXT(s, _u8_get_index, length, c); \
194 }
195
196 /* definitions with forward iteration --------------------------------------- */
197
198 /**
199 * Get a code point from a string at a code point boundary offset,
200 * and advance the offset to the next code point boundary.
201 * (Post-incrementing forward iteration.)
202 * "Unsafe" macro, assumes well-formed UTF-8.
203 *
204 * The offset may point to the lead byte of a multi-byte sequence,
205 * in which case the macro will read the whole sequence.
206 * The result is undefined if the offset points to a trail byte
207 * or an illegal UTF-8 sequence.
208 *
209 * @param s const uint8_t * string
210 * @param i string offset
211 * @param c output UChar32 variable
212 * @see U8_NEXT
213 * @stable ICU 2.4
214 */
215 #define U8_NEXT_UNSAFE(s, i, c) { \
216 (c)=(s)[(i)++]; \
217 if((uint8_t)((c)-0xc0)<0x35) { \
218 uint8_t __count=U8_COUNT_TRAIL_BYTES(c); \
219 U8_MASK_LEAD_BYTE(c, __count); \
220 switch(__count) { \
221 /* each following branch falls through to the next one */ \
222 case 3: \
223 (c)=((c)<<6)|((s)[(i)++]&0x3f); \
224 case 2: \
225 (c)=((c)<<6)|((s)[(i)++]&0x3f); \
226 case 1: \
227 (c)=((c)<<6)|((s)[(i)++]&0x3f); \
228 /* no other branches to optimize switch() */ \
229 break; \
230 } \
231 } \
232 }
233
234 /**
235 * Get a code point from a string at a code point boundary offset,
236 * and advance the offset to the next code point boundary.
237 * (Post-incrementing forward iteration.)
238 * "Safe" macro, checks for illegal sequences and for string boundaries.
239 *
240 * The offset may point to the lead byte of a multi-byte sequence,
241 * in which case the macro will read the whole sequence.
242 * If the offset points to a trail byte or an illegal UTF-8 sequence, then
243 * c is set to a negative value.
244 *
245 * @param s const uint8_t * string
246 * @param i string offset, i<length
247 * @param length string length
248 * @param c output UChar32 variable, set to <0 in case of an error
249 * @see U8_NEXT_UNSAFE
250 * @stable ICU 2.4
251 */
252 #define U8_NEXT(s, i, length, c) { \
253 (c)=(s)[(i)++]; \
254 if(((uint8_t)(c))>=0x80) { \
255 if(U8_IS_LEAD(c)) { \
256 (c)=utf8_nextCharSafeBody((const uint8_t *)s, &(i), (int32_t)(length), c, -1); \
257 } else { \
258 (c)=U_SENTINEL; \
259 } \
260 } \
261 }
262
263 /**
264 * Append a code point to a string, overwriting 1 to 4 bytes.
265 * The offset points to the current end of the string contents
266 * and is advanced (post-increment).
267 * "Unsafe" macro, assumes a valid code point and sufficient space in the string.
268 * Otherwise, the result is undefined.
269 *
270 * @param s const uint8_t * string buffer
271 * @param i string offset
272 * @param c code point to append
273 * @see U8_APPEND
274 * @stable ICU 2.4
275 */
276 #define U8_APPEND_UNSAFE(s, i, c) { \
277 if((uint32_t)(c)<=0x7f) { \
278 (s)[(i)++]=(uint8_t)(c); \
279 } else { \
280 if((uint32_t)(c)<=0x7ff) { \
281 (s)[(i)++]=(uint8_t)(((c)>>6)|0xc0); \
282 } else { \
283 if((uint32_t)(c)<=0xffff) { \
284 (s)[(i)++]=(uint8_t)(((c)>>12)|0xe0); \
285 } else { \
286 (s)[(i)++]=(uint8_t)(((c)>>18)|0xf0); \
287 (s)[(i)++]=(uint8_t)((((c)>>12)&0x3f)|0x80); \
288 } \
289 (s)[(i)++]=(uint8_t)((((c)>>6)&0x3f)|0x80); \
290 } \
291 (s)[(i)++]=(uint8_t)(((c)&0x3f)|0x80); \
292 } \
293 }
294
295 /**
296 * Append a code point to a string, overwriting 1 or 2 code units.
297 * The offset points to the current end of the string contents
298 * and is advanced (post-increment).
299 * "Safe" macro, checks for a valid code point.
300 * If a non-ASCII code point is written, checks for sufficient space in the string.
301 * If the code point is not valid or trail bytes do not fit,
302 * then isError is set to TRUE.
303 *
304 * @param s const uint8_t * string buffer
305 * @param i string offset, i<length
306 * @param length size of the string buffer
307 * @param c code point to append
308 * @param isError output UBool set to TRUE if an error occurs, otherwise not modified
309 * @see U8_APPEND_UNSAFE
310 * @stable ICU 2.4
311 */
312 #define U8_APPEND(s, i, length, c, isError) { \
313 if((uint32_t)(c)<=0x7f) { \
314 (s)[(i)++]=(uint8_t)(c); \
315 } else { \
316 (i)=utf8_appendCharSafeBody(s, (int32_t)(i), (int32_t)(length), c, &(isError)); \
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-8.
324 *
325 * @param s const uint8_t * string
326 * @param i string offset
327 * @see U8_FWD_1
328 * @stable ICU 2.4
329 */
330 #define U8_FWD_1_UNSAFE(s, i) { \
331 (i)+=1+U8_COUNT_TRAIL_BYTES((s)[i]); \
332 }
333
334 /**
335 * Advance the string offset from one code point boundary to the next.
336 * (Post-incrementing iteration.)
337 * "Safe" macro, checks for illegal sequences and for string boundaries.
338 *
339 * @param s const uint8_t * string
340 * @param i string offset, i<length
341 * @param length string length
342 * @see U8_FWD_1_UNSAFE
343 * @stable ICU 2.4
344 */
345 #define U8_FWD_1(s, i, length) { \
346 uint8_t __b=(s)[(i)++]; \
347 if(U8_IS_LEAD(__b)) { \
348 uint8_t __count=U8_COUNT_TRAIL_BYTES(__b); \
349 if((i)+__count>(length)) { \
350 __count=(uint8_t)((length)-(i)); \
351 } \
352 while(__count>0 && U8_IS_TRAIL((s)[i])) { \
353 ++(i); \
354 --__count; \
355 } \
356 } \
357 }
358
359 /**
360 * Advance the string offset from one code point boundary to the n-th next one,
361 * i.e., move forward by n code points.
362 * (Post-incrementing iteration.)
363 * "Unsafe" macro, assumes well-formed UTF-8.
364 *
365 * @param s const uint8_t * string
366 * @param i string offset
367 * @param n number of code points to skip
368 * @see U8_FWD_N
369 * @stable ICU 2.4
370 */
371 #define U8_FWD_N_UNSAFE(s, i, n) { \
372 int32_t __N=(n); \
373 while(__N>0) { \
374 U8_FWD_1_UNSAFE(s, i); \
375 --__N; \
376 } \
377 }
378
379 /**
380 * Advance the string offset from one code point boundary to the n-th next one,
381 * i.e., move forward by n code points.
382 * (Post-incrementing iteration.)
383 * "Safe" macro, checks for illegal sequences and for string boundaries.
384 *
385 * @param s const uint8_t * string
386 * @param i string offset, i<length
387 * @param length string length
388 * @param n number of code points to skip
389 * @see U8_FWD_N_UNSAFE
390 * @stable ICU 2.4
391 */
392 #define U8_FWD_N(s, i, length, n) { \
393 int32_t __N=(n); \
394 while(__N>0 && (i)<(length)) { \
395 U8_FWD_1(s, i, length); \
396 --__N; \
397 } \
398 }
399
400 /**
401 * Adjust a random-access offset to a code point boundary
402 * at the start of a code point.
403 * If the offset points to a UTF-8 trail byte,
404 * then the offset is moved backward to the corresponding lead byte.
405 * Otherwise, it is not modified.
406 * "Unsafe" macro, assumes well-formed UTF-8.
407 *
408 * @param s const uint8_t * string
409 * @param i string offset
410 * @see U8_SET_CP_START
411 * @stable ICU 2.4
412 */
413 #define U8_SET_CP_START_UNSAFE(s, i) { \
414 while(U8_IS_TRAIL((s)[i])) { --(i); } \
415 }
416
417 /**
418 * Adjust a random-access offset to a code point boundary
419 * at the start of a code point.
420 * If the offset points to a UTF-8 trail byte,
421 * then the offset is moved backward to the corresponding lead byte.
422 * Otherwise, it is not modified.
423 * "Safe" macro, checks for illegal sequences and for string boundaries.
424 *
425 * @param s const uint8_t * string
426 * @param start starting string offset (usually 0)
427 * @param i string offset, start<=i
428 * @see U8_SET_CP_START_UNSAFE
429 * @stable ICU 2.4
430 */
431 #define U8_SET_CP_START(s, start, i) { \
432 if(U8_IS_TRAIL((s)[(i)])) { \
433 (i)=utf8_back1SafeBody(s, start, (int32_t)(i)); \
434 } \
435 }
436
437 /* definitions with backward iteration -------------------------------------- */
438
439 /**
440 * Move the string offset from one code point boundary to the previous one
441 * and get the code point between them.
442 * (Pre-decrementing backward iteration.)
443 * "Unsafe" macro, assumes well-formed UTF-8.
444 *
445 * The input offset may be the same as the string length.
446 * If the offset is behind a multi-byte sequence, then the macro will read
447 * the whole sequence.
448 * If the offset is behind a lead byte, then that itself
449 * will be returned as the code point.
450 * The result is undefined if the offset is behind an illegal UTF-8 sequence.
451 *
452 * @param s const uint8_t * string
453 * @param i string offset
454 * @param c output UChar32 variable
455 * @see U8_PREV
456 * @stable ICU 2.4
457 */
458 #define U8_PREV_UNSAFE(s, i, c) { \
459 (c)=(s)[--(i)]; \
460 if(U8_IS_TRAIL(c)) { \
461 uint8_t __b, __count=1, __shift=6; \
462 \
463 /* c is a trail byte */ \
464 (c)&=0x3f; \
465 for(;;) { \
466 __b=(s)[--(i)]; \
467 if(__b>=0xc0) { \
468 U8_MASK_LEAD_BYTE(__b, __count); \
469 (c)|=(UChar32)__b<<__shift; \
470 break; \
471 } else { \
472 (c)|=(UChar32)(__b&0x3f)<<__shift; \
473 ++__count; \
474 __shift+=6; \
475 } \
476 } \
477 } \
478 }
479
480 /**
481 * Move the string offset from one code point boundary to the previous one
482 * and get the code point between them.
483 * (Pre-decrementing backward iteration.)
484 * "Safe" macro, checks for illegal sequences and for string boundaries.
485 *
486 * The input offset may be the same as the string length.
487 * If the offset is behind a multi-byte sequence, then the macro will read
488 * the whole sequence.
489 * If the offset is behind a lead byte, then that itself
490 * will be returned as the code point.
491 * If the offset is behind an illegal UTF-8 sequence, then c is set to a negative value.
492 *
493 * @param s const uint8_t * string
494 * @param start starting string offset (usually 0)
495 * @param i string offset, start<=i
496 * @param c output UChar32 variable, set to <0 in case of an error
497 * @see U8_PREV_UNSAFE
498 * @stable ICU 2.4
499 */
500 #define U8_PREV(s, start, i, c) { \
501 (c)=(s)[--(i)]; \
502 if((c)>=0x80) { \
503 if((c)<=0xbf) { \
504 (c)=utf8_prevCharSafeBody(s, start, &(i), c, -1); \
505 } else { \
506 (c)=U_SENTINEL; \
507 } \
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 * "Unsafe" macro, assumes well-formed UTF-8.
516 *
517 * @param s const uint8_t * string
518 * @param i string offset
519 * @see U8_BACK_1
520 * @stable ICU 2.4
521 */
522 #define U8_BACK_1_UNSAFE(s, i) { \
523 while(U8_IS_TRAIL((s)[--(i)])) {} \
524 }
525
526 /**
527 * Move the string offset from one code point boundary to the previous one.
528 * (Pre-decrementing backward iteration.)
529 * The input offset may be the same as the string length.
530 * "Safe" macro, checks for illegal sequences and for string boundaries.
531 *
532 * @param s const uint8_t * string
533 * @param start starting string offset (usually 0)
534 * @param i string offset, start<=i
535 * @see U8_BACK_1_UNSAFE
536 * @stable ICU 2.4
537 */
538 #define U8_BACK_1(s, start, i) { \
539 if(U8_IS_TRAIL((s)[--(i)])) { \
540 (i)=utf8_back1SafeBody(s, start, (int32_t)(i)); \
541 } \
542 }
543
544 /**
545 * Move the string offset from one code point boundary to the n-th one before it,
546 * i.e., move backward by n code points.
547 * (Pre-decrementing backward iteration.)
548 * The input offset may be the same as the string length.
549 * "Unsafe" macro, assumes well-formed UTF-8.
550 *
551 * @param s const uint8_t * string
552 * @param i string offset
553 * @param n number of code points to skip
554 * @see U8_BACK_N
555 * @stable ICU 2.4
556 */
557 #define U8_BACK_N_UNSAFE(s, i, n) { \
558 int32_t __N=(n); \
559 while(__N>0) { \
560 U8_BACK_1_UNSAFE(s, i); \
561 --__N; \
562 } \
563 }
564
565 /**
566 * Move the string offset from one code point boundary to the n-th one before it,
567 * i.e., move backward by n code points.
568 * (Pre-decrementing backward iteration.)
569 * The input offset may be the same as the string length.
570 * "Safe" macro, checks for illegal sequences and for string boundaries.
571 *
572 * @param s const uint8_t * string
573 * @param start index of the start of the string
574 * @param i string offset, i<length
575 * @param n number of code points to skip
576 * @see U8_BACK_N_UNSAFE
577 * @stable ICU 2.4
578 */
579 #define U8_BACK_N(s, start, i, n) { \
580 int32_t __N=(n); \
581 while(__N>0 && (i)>(start)) { \
582 U8_BACK_1(s, start, i); \
583 --__N; \
584 } \
585 }
586
587 /**
588 * Adjust a random-access offset to a code point boundary after a code point.
589 * If the offset is behind a partial multi-byte sequence,
590 * then the offset is incremented to behind the whole sequence.
591 * Otherwise, it is not modified.
592 * The input offset may be the same as the string length.
593 * "Unsafe" macro, assumes well-formed UTF-8.
594 *
595 * @param s const uint8_t * string
596 * @param i string offset
597 * @see U8_SET_CP_LIMIT
598 * @stable ICU 2.4
599 */
600 #define U8_SET_CP_LIMIT_UNSAFE(s, i) { \
601 U8_BACK_1_UNSAFE(s, i); \
602 U8_FWD_1_UNSAFE(s, i); \
603 }
604
605 /**
606 * Adjust a random-access offset to a code point boundary after a code point.
607 * If the offset is behind a partial multi-byte sequence,
608 * then the offset is incremented to behind the whole sequence.
609 * Otherwise, it is not modified.
610 * The input offset may be the same as the string length.
611 * "Safe" macro, checks for illegal sequences and for string boundaries.
612 *
613 * @param s const uint8_t * string
614 * @param start starting string offset (usually 0)
615 * @param i string offset, start<=i<=length
616 * @param length string length
617 * @see U8_SET_CP_LIMIT_UNSAFE
618 * @stable ICU 2.4
619 */
620 #define U8_SET_CP_LIMIT(s, start, i, length) { \
621 if((start)<(i) && (i)<(length)) { \
622 U8_BACK_1(s, start, i); \
623 U8_FWD_1(s, i, length); \
624 } \
625 }
626
627 #endif