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2 *******************************************************************************
4 * Copyright (C) 1999-2010, International Business Machines
5 * Corporation and others. All Rights Reserved.
7 *******************************************************************************
10 * tab size: 8 (not used)
13 * created on: 1999sep09
14 * created by: Markus W. Scherer
19 * \brief C API: 16-bit Unicode handling macros
21 * This file defines macros to deal with 16-bit Unicode (UTF-16) code units and strings.
22 * utf16.h is included by utf.h after unicode/umachine.h
23 * and some common definitions.
25 * For more information see utf.h and the ICU User Guide Strings chapter
26 * (http://icu-project.org/userguide/strings.html).
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.
37 /* utf.h must be included first. */
39 # include "unicode/utf.h"
42 /* single-code point definitions -------------------------------------------- */
45 * Does this code unit alone encode a code point (BMP, not a surrogate)?
46 * @param c 16-bit code unit
47 * @return TRUE or FALSE
50 #define U16_IS_SINGLE(c) !U_IS_SURROGATE(c)
53 * Is this code unit a lead surrogate (U+d800..U+dbff)?
54 * @param c 16-bit code unit
55 * @return TRUE or FALSE
58 #define U16_IS_LEAD(c) (((c)&0xfffffc00)==0xd800)
61 * Is this code unit a trail surrogate (U+dc00..U+dfff)?
62 * @param c 16-bit code unit
63 * @return TRUE or FALSE
66 #define U16_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00)
69 * Is this code unit a surrogate (U+d800..U+dfff)?
70 * @param c 16-bit code unit
71 * @return TRUE or FALSE
74 #define U16_IS_SURROGATE(c) U_IS_SURROGATE(c)
77 * Assuming c is a surrogate code point (U16_IS_SURROGATE(c)),
78 * is it a lead surrogate?
79 * @param c 16-bit code unit
80 * @return TRUE or FALSE
83 #define U16_IS_SURROGATE_LEAD(c) (((c)&0x400)==0)
86 * Assuming c is a surrogate code point (U16_IS_SURROGATE(c)),
87 * is it a trail surrogate?
88 * @param c 16-bit code unit
89 * @return TRUE or FALSE
92 #define U16_IS_SURROGATE_TRAIL(c) (((c)&0x400)!=0)
95 * Helper constant for U16_GET_SUPPLEMENTARY.
98 #define U16_SURROGATE_OFFSET ((0xd800<<10UL)+0xdc00-0x10000)
101 * Get a supplementary code point value (U+10000..U+10ffff)
102 * from its lead and trail surrogates.
103 * The result is undefined if the input values are not
104 * lead and trail surrogates.
106 * @param lead lead surrogate (U+d800..U+dbff)
107 * @param trail trail surrogate (U+dc00..U+dfff)
108 * @return supplementary code point (U+10000..U+10ffff)
111 #define U16_GET_SUPPLEMENTARY(lead, trail) \
112 (((UChar32)(lead)<<10UL)+(UChar32)(trail)-U16_SURROGATE_OFFSET)
116 * Get the lead surrogate (0xd800..0xdbff) for a
117 * supplementary code point (0x10000..0x10ffff).
118 * @param supplementary 32-bit code point (U+10000..U+10ffff)
119 * @return lead surrogate (U+d800..U+dbff) for supplementary
122 #define U16_LEAD(supplementary) (UChar)(((supplementary)>>10)+0xd7c0)
125 * Get the trail surrogate (0xdc00..0xdfff) for a
126 * supplementary code point (0x10000..0x10ffff).
127 * @param supplementary 32-bit code point (U+10000..U+10ffff)
128 * @return trail surrogate (U+dc00..U+dfff) for supplementary
131 #define U16_TRAIL(supplementary) (UChar)(((supplementary)&0x3ff)|0xdc00)
134 * How many 16-bit code units are used to encode this Unicode code point? (1 or 2)
135 * The result is not defined if c is not a Unicode code point (U+0000..U+10ffff).
136 * @param c 32-bit code point
140 #define U16_LENGTH(c) ((uint32_t)(c)<=0xffff ? 1 : 2)
143 * The maximum number of 16-bit code units per Unicode code point (U+0000..U+10ffff).
147 #define U16_MAX_LENGTH 2
150 * Get a code point from a string at a random-access offset,
151 * without changing the offset.
152 * "Unsafe" macro, assumes well-formed UTF-16.
154 * The offset may point to either the lead or trail surrogate unit
155 * for a supplementary code point, in which case the macro will read
156 * the adjacent matching surrogate as well.
157 * The result is undefined if the offset points to a single, unpaired surrogate.
158 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.
160 * @param s const UChar * string
161 * @param i string offset
162 * @param c output UChar32 variable
166 #define U16_GET_UNSAFE(s, i, c) { \
168 if(U16_IS_SURROGATE(c)) { \
169 if(U16_IS_SURROGATE_LEAD(c)) { \
170 (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)+1]); \
172 (c)=U16_GET_SUPPLEMENTARY((s)[(i)-1], (c)); \
178 * Get a code point from a string at a random-access offset,
179 * without changing the offset.
180 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
182 * The offset may point to either the lead or trail surrogate unit
183 * for a supplementary code point, in which case the macro will read
184 * the adjacent matching surrogate as well.
185 * If the offset points to a single, unpaired surrogate, then that itself
186 * will be returned as the code point.
187 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.
189 * @param s const UChar * string
190 * @param start starting string offset (usually 0)
191 * @param i string offset, must be start<=i<length
192 * @param length string length
193 * @param c output UChar32 variable
194 * @see U16_GET_UNSAFE
197 #define U16_GET(s, start, i, length, c) { \
199 if(U16_IS_SURROGATE(c)) { \
201 if(U16_IS_SURROGATE_LEAD(c)) { \
202 if((i)+1<(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \
203 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \
206 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
207 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
213 /* definitions with forward iteration --------------------------------------- */
216 * Get a code point from a string at a code point boundary offset,
217 * and advance the offset to the next code point boundary.
218 * (Post-incrementing forward iteration.)
219 * "Unsafe" macro, assumes well-formed UTF-16.
221 * The offset may point to the lead surrogate unit
222 * for a supplementary code point, in which case the macro will read
223 * the following trail surrogate as well.
224 * If the offset points to a trail surrogate, then that itself
225 * will be returned as the code point.
226 * The result is undefined if the offset points to a single, unpaired lead surrogate.
228 * @param s const UChar * string
229 * @param i string offset
230 * @param c output UChar32 variable
234 #define U16_NEXT_UNSAFE(s, i, c) { \
236 if(U16_IS_LEAD(c)) { \
237 (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)++]); \
242 * Get a code point from a string at a code point boundary offset,
243 * and advance the offset to the next code point boundary.
244 * (Post-incrementing forward iteration.)
245 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
247 * The offset may point to the lead surrogate unit
248 * for a supplementary code point, in which case the macro will read
249 * the following trail surrogate as well.
250 * If the offset points to a trail surrogate or
251 * to a single, unpaired lead surrogate, then that itself
252 * will be returned as the code point.
254 * @param s const UChar * string
255 * @param i string offset, must be i<length
256 * @param length string length
257 * @param c output UChar32 variable
258 * @see U16_NEXT_UNSAFE
261 #define U16_NEXT(s, i, length, c) { \
263 if(U16_IS_LEAD(c)) { \
265 if((i)<(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \
267 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \
273 * Append a code point to a string, overwriting 1 or 2 code units.
274 * The offset points to the current end of the string contents
275 * and is advanced (post-increment).
276 * "Unsafe" macro, assumes a valid code point and sufficient space in the string.
277 * Otherwise, the result is undefined.
279 * @param s const UChar * string buffer
280 * @param i string offset
281 * @param c code point to append
285 #define U16_APPEND_UNSAFE(s, i, c) { \
286 if((uint32_t)(c)<=0xffff) { \
287 (s)[(i)++]=(uint16_t)(c); \
289 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \
290 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \
295 * Append a code point to a string, overwriting 1 or 2 code units.
296 * The offset points to the current end of the string contents
297 * and is advanced (post-increment).
298 * "Safe" macro, checks for a valid code point.
299 * If a surrogate pair is written, checks for sufficient space in the string.
300 * If the code point is not valid or a trail surrogate does not fit,
301 * then isError is set to TRUE.
303 * @param s const UChar * string buffer
304 * @param i string offset, must be i<capacity
305 * @param capacity size of the string buffer
306 * @param c code point to append
307 * @param isError output UBool set to TRUE if an error occurs, otherwise not modified
308 * @see U16_APPEND_UNSAFE
311 #define U16_APPEND(s, i, capacity, c, isError) { \
312 if((uint32_t)(c)<=0xffff) { \
313 (s)[(i)++]=(uint16_t)(c); \
314 } else if((uint32_t)(c)<=0x10ffff && (i)+1<(capacity)) { \
315 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \
316 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \
317 } else /* c>0x10ffff or not enough space */ { \
323 * Advance the string offset from one code point boundary to the next.
324 * (Post-incrementing iteration.)
325 * "Unsafe" macro, assumes well-formed UTF-16.
327 * @param s const UChar * string
328 * @param i string offset
332 #define U16_FWD_1_UNSAFE(s, i) { \
333 if(U16_IS_LEAD((s)[(i)++])) { \
339 * Advance the string offset from one code point boundary to the next.
340 * (Post-incrementing iteration.)
341 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
343 * @param s const UChar * string
344 * @param i string offset, must be i<length
345 * @param length string length
346 * @see U16_FWD_1_UNSAFE
349 #define U16_FWD_1(s, i, length) { \
350 if(U16_IS_LEAD((s)[(i)++]) && (i)<(length) && U16_IS_TRAIL((s)[i])) { \
356 * Advance the string offset from one code point boundary to the n-th next one,
357 * i.e., move forward by n code points.
358 * (Post-incrementing iteration.)
359 * "Unsafe" macro, assumes well-formed UTF-16.
361 * @param s const UChar * string
362 * @param i string offset
363 * @param n number of code points to skip
367 #define U16_FWD_N_UNSAFE(s, i, n) { \
370 U16_FWD_1_UNSAFE(s, i); \
376 * Advance the string offset from one code point boundary to the n-th next one,
377 * i.e., move forward by n code points.
378 * (Post-incrementing iteration.)
379 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
381 * @param s const UChar * string
382 * @param i string offset, must be i<length
383 * @param length string length
384 * @param n number of code points to skip
385 * @see U16_FWD_N_UNSAFE
388 #define U16_FWD_N(s, i, length, n) { \
390 while(__N>0 && (i)<(length)) { \
391 U16_FWD_1(s, i, length); \
397 * Adjust a random-access offset to a code point boundary
398 * at the start of a code point.
399 * If the offset points to the trail surrogate of a surrogate pair,
400 * then the offset is decremented.
401 * Otherwise, it is not modified.
402 * "Unsafe" macro, assumes well-formed UTF-16.
404 * @param s const UChar * string
405 * @param i string offset
406 * @see U16_SET_CP_START
409 #define U16_SET_CP_START_UNSAFE(s, i) { \
410 if(U16_IS_TRAIL((s)[i])) { \
416 * Adjust a random-access offset to a code point boundary
417 * at the start of a code point.
418 * If the offset points to the trail surrogate of a surrogate pair,
419 * then the offset is decremented.
420 * Otherwise, it is not modified.
421 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
423 * @param s const UChar * string
424 * @param start starting string offset (usually 0)
425 * @param i string offset, must be start<=i
426 * @see U16_SET_CP_START_UNSAFE
429 #define U16_SET_CP_START(s, start, i) { \
430 if(U16_IS_TRAIL((s)[i]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \
435 /* definitions with backward iteration -------------------------------------- */
438 * Move the string offset from one code point boundary to the previous one
439 * and get the code point between them.
440 * (Pre-decrementing backward iteration.)
441 * "Unsafe" macro, assumes well-formed UTF-16.
443 * The input offset may be the same as the string length.
444 * If the offset is behind a trail surrogate unit
445 * for a supplementary code point, then the macro will read
446 * the preceding lead surrogate as well.
447 * If the offset is behind a lead surrogate, then that itself
448 * will be returned as the code point.
449 * The result is undefined if the offset is behind a single, unpaired trail surrogate.
451 * @param s const UChar * string
452 * @param i string offset
453 * @param c output UChar32 variable
457 #define U16_PREV_UNSAFE(s, i, c) { \
459 if(U16_IS_TRAIL(c)) { \
460 (c)=U16_GET_SUPPLEMENTARY((s)[--(i)], (c)); \
465 * Move the string offset from one code point boundary to the previous one
466 * and get the code point between them.
467 * (Pre-decrementing backward iteration.)
468 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
470 * The input offset may be the same as the string length.
471 * If the offset is behind a trail surrogate unit
472 * for a supplementary code point, then the macro will read
473 * the preceding lead surrogate as well.
474 * If the offset is behind a lead surrogate or behind a single, unpaired
475 * trail surrogate, then that itself
476 * will be returned as the code point.
478 * @param s const UChar * string
479 * @param start starting string offset (usually 0)
480 * @param i string offset, must be start<i
481 * @param c output UChar32 variable
482 * @see U16_PREV_UNSAFE
485 #define U16_PREV(s, start, i, c) { \
487 if(U16_IS_TRAIL(c)) { \
489 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
491 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
497 * Move the string offset from one code point boundary to the previous one.
498 * (Pre-decrementing backward iteration.)
499 * The input offset may be the same as the string length.
500 * "Unsafe" macro, assumes well-formed UTF-16.
502 * @param s const UChar * string
503 * @param i string offset
507 #define U16_BACK_1_UNSAFE(s, i) { \
508 if(U16_IS_TRAIL((s)[--(i)])) { \
514 * Move the string offset from one code point boundary to the previous one.
515 * (Pre-decrementing backward iteration.)
516 * The input offset may be the same as the string length.
517 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
519 * @param s const UChar * string
520 * @param start starting string offset (usually 0)
521 * @param i string offset, must be start<i
522 * @see U16_BACK_1_UNSAFE
525 #define U16_BACK_1(s, start, i) { \
526 if(U16_IS_TRAIL((s)[--(i)]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \
532 * Move the string offset from one code point boundary to the n-th one before it,
533 * i.e., move backward by n code points.
534 * (Pre-decrementing backward iteration.)
535 * The input offset may be the same as the string length.
536 * "Unsafe" macro, assumes well-formed UTF-16.
538 * @param s const UChar * string
539 * @param i string offset
540 * @param n number of code points to skip
544 #define U16_BACK_N_UNSAFE(s, i, n) { \
547 U16_BACK_1_UNSAFE(s, i); \
553 * Move the string offset from one code point boundary to the n-th one before it,
554 * i.e., move backward by n code points.
555 * (Pre-decrementing backward iteration.)
556 * The input offset may be the same as the string length.
557 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
559 * @param s const UChar * string
560 * @param start start of string
561 * @param i string offset, must be start<i
562 * @param n number of code points to skip
563 * @see U16_BACK_N_UNSAFE
566 #define U16_BACK_N(s, start, i, n) { \
568 while(__N>0 && (i)>(start)) { \
569 U16_BACK_1(s, start, i); \
575 * Adjust a random-access offset to a code point boundary after a code point.
576 * If the offset is behind the lead surrogate of a surrogate pair,
577 * then the offset is incremented.
578 * Otherwise, it is not modified.
579 * The input offset may be the same as the string length.
580 * "Unsafe" macro, assumes well-formed UTF-16.
582 * @param s const UChar * string
583 * @param i string offset
584 * @see U16_SET_CP_LIMIT
587 #define U16_SET_CP_LIMIT_UNSAFE(s, i) { \
588 if(U16_IS_LEAD((s)[(i)-1])) { \
594 * Adjust a random-access offset to a code point boundary after a code point.
595 * If the offset is behind the lead surrogate of a surrogate pair,
596 * then the offset is incremented.
597 * Otherwise, it is not modified.
598 * The input offset may be the same as the string length.
599 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
601 * @param s const UChar * string
602 * @param start starting string offset (usually 0)
603 * @param i string offset, start<=i<=length
604 * @param length string length
605 * @see U16_SET_CP_LIMIT_UNSAFE
608 #define U16_SET_CP_LIMIT(s, start, i, length) { \
609 if((start)<(i) && (i)<(length) && U16_IS_LEAD((s)[(i)-1]) && U16_IS_TRAIL((s)[i])) { \