1 /*
2 *******************************************************************************
3 *
4 * Copyright (C) 2001-2008, International Business Machines
5 * Corporation and others. All Rights Reserved.
6 *
7 *******************************************************************************
8 * file name: unormimp.h
9 * encoding: US-ASCII
10 * tab size: 8 (not used)
11 * indentation:4
12 *
13 * created on: 2001may25
14 * created by: Markus W. Scherer
15 */
16
17 #ifndef __UNORMIMP_H__
18 #define __UNORMIMP_H__
19
20 #include "unicode/utypes.h"
21
22 #if !UCONFIG_NO_NORMALIZATION
23
24 #ifdef XP_CPLUSPLUS
25 #include "unicode/uniset.h"
26 #endif
27
28 #include "unicode/uiter.h"
29 #include "unicode/unorm.h"
30 #include "unicode/uset.h"
31 #include "utrie2.h"
32 #include "ustr_imp.h"
33 #include "udataswp.h"
34
35 /*
36 * This new implementation of the normalization code loads its data from
37 * unorm.icu, which is generated with the gennorm tool.
38 * The format of that file is described at the end of this file.
39 */
40
41 /* norm32 value constants */
42 enum {
43 /* quick check flags 0..3 set mean "no" for their forms */
44 _NORM_QC_NFC=0x11, /* no|maybe */
45 _NORM_QC_NFKC=0x22, /* no|maybe */
46 _NORM_QC_NFD=4, /* no */
47 _NORM_QC_NFKD=8, /* no */
48
49 _NORM_QC_ANY_NO=0xf,
50
51 /* quick check flags 4..5 mean "maybe" for their forms; test flags>=_NORM_QC_MAYBE */
52 _NORM_QC_MAYBE=0x10,
53 _NORM_QC_ANY_MAYBE=0x30,
54
55 _NORM_QC_MASK=0x3f,
56
57 _NORM_COMBINES_FWD=0x40,
58 _NORM_COMBINES_BACK=0x80,
59 _NORM_COMBINES_ANY=0xc0,
60
61 _NORM_CC_SHIFT=8, /* UnicodeData.txt combining class in bits 15..8 */
62 _NORM_CC_MASK=0xff00,
63
64 _NORM_EXTRA_SHIFT=16, /* 16 bits for the index to UChars and other extra data */
65 _NORM_EXTRA_INDEX_TOP=0xfc00, /* start of surrogate specials after shift */
66
67 _NORM_EXTRA_SURROGATE_MASK=0x3ff,
68 _NORM_EXTRA_SURROGATE_TOP=0x3f0, /* hangul etc. */
69
70 _NORM_EXTRA_HANGUL=_NORM_EXTRA_SURROGATE_TOP,
71 _NORM_EXTRA_JAMO_L,
72 _NORM_EXTRA_JAMO_V,
73 _NORM_EXTRA_JAMO_T
74 };
75
76 /* norm32 value constants using >16 bits */
77 #define _NORM_MIN_SPECIAL 0xfc000000
78 #define _NORM_SURROGATES_TOP 0xfff00000
79 #define _NORM_MIN_HANGUL 0xfff00000
80 #define _NORM_MIN_JAMO_V 0xfff20000
81 #define _NORM_JAMO_V_TOP 0xfff30000
82
83 /* value constants for auxTrie */
84 enum {
85 _NORM_AUX_COMP_EX_SHIFT=10,
86 _NORM_AUX_UNSAFE_SHIFT=11,
87 _NORM_AUX_NFC_SKIPPABLE_F_SHIFT=12
88 };
89
90 #define _NORM_AUX_MAX_FNC ((int32_t)1<<_NORM_AUX_COMP_EX_SHIFT)
91
92 #define _NORM_AUX_FNC_MASK (uint32_t)(_NORM_AUX_MAX_FNC-1)
93 #define _NORM_AUX_COMP_EX_MASK ((uint32_t)1<<_NORM_AUX_COMP_EX_SHIFT)
94 #define _NORM_AUX_UNSAFE_MASK ((uint32_t)1<<_NORM_AUX_UNSAFE_SHIFT)
95 #define _NORM_AUX_NFC_SKIP_F_MASK ((uint32_t)1<<_NORM_AUX_NFC_SKIPPABLE_F_SHIFT)
96
97 /* canonStartSets[0..31] contains indexes for what is in the array */
98 enum {
99 _NORM_SET_INDEX_CANON_SETS_LENGTH, /* number of uint16_t in canonical starter sets */
100 _NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH, /* number of uint16_t in the BMP search table (contains pairs) */
101 _NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH,/* number of uint16_t in the supplementary search table (contains triplets) */
102
103 /* from formatVersion 2.3: */
104 _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET, /* uint16_t offset from canonStartSets[0] to the
105 exclusion set for CJK compatibility characters */
106 _NORM_SET_INDEX_NX_UNICODE32_OFFSET, /* uint16_t offset from canonStartSets[0] to the
107 exclusion set for Unicode 3.2 characters */
108 _NORM_SET_INDEX_NX_RESERVED_OFFSET, /* uint16_t offset from canonStartSets[0] to the
109 end of the previous exclusion set */
110
111 _NORM_SET_INDEX_TOP=32 /* changing this requires a new formatVersion */
112 };
113
114 /* more constants for canonical starter sets */
115
116 /* 14 bit indexes to canonical USerializedSets */
117 #define _NORM_MAX_CANON_SETS 0x4000
118
119 /* single-code point BMP sets are encoded directly in the search table except if result=0x4000..0x7fff */
120 #define _NORM_CANON_SET_BMP_MASK 0xc000
121 #define _NORM_CANON_SET_BMP_IS_INDEX 0x4000
122
123 /* indexes[] value names */
124 enum {
125 _NORM_INDEX_TRIE_SIZE, /* number of bytes in normalization trie */
126 _NORM_INDEX_UCHAR_COUNT, /* number of UChars in extra data */
127
128 _NORM_INDEX_COMBINE_DATA_COUNT, /* number of uint16_t words for combining data */
129 _NORM_INDEX_COMBINE_FWD_COUNT, /* number of code points that combine forward */
130 _NORM_INDEX_COMBINE_BOTH_COUNT, /* number of code points that combine forward and backward */
131 _NORM_INDEX_COMBINE_BACK_COUNT, /* number of code points that combine backward */
132
133 _NORM_INDEX_MIN_NFC_NO_MAYBE, /* first code point with quick check NFC NO/MAYBE */
134 _NORM_INDEX_MIN_NFKC_NO_MAYBE, /* first code point with quick check NFKC NO/MAYBE */
135 _NORM_INDEX_MIN_NFD_NO_MAYBE, /* first code point with quick check NFD NO/MAYBE */
136 _NORM_INDEX_MIN_NFKD_NO_MAYBE, /* first code point with quick check NFKD NO/MAYBE */
137
138 _NORM_INDEX_FCD_TRIE_SIZE, /* number of bytes in FCD trie */
139
140 _NORM_INDEX_AUX_TRIE_SIZE, /* number of bytes in the auxiliary trie */
141 _NORM_INDEX_CANON_SET_COUNT, /* number of uint16_t in the array of serialized USet */
142
143 _NORM_INDEX_TOP=32 /* changing this requires a new formatVersion */
144 };
145
146 enum {
147 /* FCD check: everything below this code point is known to have a 0 lead combining class */
148 _NORM_MIN_WITH_LEAD_CC=0x300
149 };
150
151 enum {
152 /**
153 * Bit 7 of the length byte for a decomposition string in extra data is
154 * a flag indicating whether the decomposition string is
155 * preceded by a 16-bit word with the leading and trailing cc
156 * of the decomposition (like for A-umlaut);
157 * if not, then both cc's are zero (like for compatibility ideographs).
158 */
159 _NORM_DECOMP_FLAG_LENGTH_HAS_CC=0x80,
160 /**
161 * Bits 6..0 of the length byte contain the actual length.
162 */
163 _NORM_DECOMP_LENGTH_MASK=0x7f
164 };
165
166 #endif /* #if !UCONFIG_NO_NORMALIZATION */
167
168 /* Korean Hangul and Jamo constants */
169 enum {
170 JAMO_L_BASE=0x1100, /* "lead" jamo */
171 JAMO_V_BASE=0x1161, /* "vowel" jamo */
172 JAMO_T_BASE=0x11a7, /* "trail" jamo */
173
174 HANGUL_BASE=0xac00,
175
176 JAMO_L_COUNT=19,
177 JAMO_V_COUNT=21,
178 JAMO_T_COUNT=28,
179
180 HANGUL_COUNT=JAMO_L_COUNT*JAMO_V_COUNT*JAMO_T_COUNT
181 };
182
183 #if !UCONFIG_NO_NORMALIZATION
184
185 /* Constants for options flags for normalization. @draft ICU 2.6 */
186 enum {
187 /** Options bit 0, do not decompose Hangul syllables. @draft ICU 2.6 */
188 UNORM_NX_HANGUL=1,
189 /** Options bit 1, do not decompose CJK compatibility characters. @draft ICU 2.6 */
190 UNORM_NX_CJK_COMPAT=2,
191 /**
192 * Options bit 8, use buggy recomposition described in
193 * Unicode Public Review Issue #29
194 * at http://www.unicode.org/review/resolved-pri.html#pri29
195 *
196 * Used in IDNA implementation according to strict interpretation
197 * of IDNA definition based on Unicode 3.2 which predates PRI #29.
198 */
199 UNORM_BEFORE_PRI_29=0x100
200 };
201
202 /**
203 * Is the normalizer data loaded?
204 * This is used internally before other internal normalizer functions
205 * are called.
206 * It saves this check in each of many normalization calls that
207 * are made for, e.g., collation.
208 *
209 * @param pErrorCode as usual
210 * @return boolean value for whether the normalization data is loaded
211 *
212 * @internal
213 */
214 U_CAPI UBool U_EXPORT2
215 unorm_haveData(UErrorCode *pErrorCode);
216
217 /**
218 * Internal API for normalizing.
219 * Does not check for bad input.
220 * @internal
221 */
222 U_CAPI int32_t U_EXPORT2
223 unorm_internalNormalize(UChar *dest, int32_t destCapacity,
224 const UChar *src, int32_t srcLength,
225 UNormalizationMode mode, int32_t options,
226 UErrorCode *pErrorCode);
227
228 #ifdef XP_CPLUSPLUS
229
230 /**
231 * Internal API for normalizing.
232 * Does not check for bad input.
233 * Requires _haveData() to be true.
234 * @internal
235 */
236 U_CFUNC int32_t
237 unorm_internalNormalizeWithNX(UChar *dest, int32_t destCapacity,
238 const UChar *src, int32_t srcLength,
239 UNormalizationMode mode, int32_t options, const U_NAMESPACE_QUALIFIER UnicodeSet *nx,
240 UErrorCode *pErrorCode);
241
242 #endif
243
244 /**
245 * internal API, used by normlzr.cpp
246 * @internal
247 */
248 U_CAPI int32_t U_EXPORT2
249 unorm_decompose(UChar *dest, int32_t destCapacity,
250 const UChar *src, int32_t srcLength,
251 UBool compat, int32_t options,
252 UErrorCode *pErrorCode);
253
254 /**
255 * internal API, used by normlzr.cpp
256 * @internal
257 */
258 U_CAPI int32_t U_EXPORT2
259 unorm_compose(UChar *dest, int32_t destCapacity,
260 const UChar *src, int32_t srcLength,
261 UBool compat, int32_t options,
262 UErrorCode *pErrorCode);
263
264 #ifdef XP_CPLUSPLUS
265
266 /**
267 * internal API, used by unormcmp.cpp
268 * @internal
269 */
270 U_CFUNC UNormalizationCheckResult
271 unorm_internalQuickCheck(const UChar *src,
272 int32_t srcLength,
273 UNormalizationMode mode,
274 UBool allowMaybe,
275 const U_NAMESPACE_QUALIFIER UnicodeSet *nx,
276 UErrorCode *pErrorCode);
277
278 #endif
279
280 #endif /* #if !UCONFIG_NO_NORMALIZATION */
281
282 /**
283 * Internal option for unorm_cmpEquivFold() for decomposing.
284 * If not set, just do strcasecmp().
285 * @internal
286 */
287 #define _COMPARE_EQUIV 0x80000
288
289 #ifndef U_COMPARE_IGNORE_CASE
290 /* see also unorm.h */
291 /**
292 * Option bit for unorm_compare:
293 * Perform case-insensitive comparison.
294 * @draft ICU 2.2
295 */
296 #define U_COMPARE_IGNORE_CASE 0x10000
297 #endif
298
299 /**
300 * Internal option for unorm_cmpEquivFold() for strncmp style.
301 * If set, checks for both string length and terminating NUL.
302 * @internal
303 */
304 #define _STRNCMP_STYLE 0x1000
305
306 #if !UCONFIG_NO_NORMALIZATION
307
308 /**
309 * Internal API to get the 16-bit FCD value (lccc + tccc) for c,
310 * for u_getIntPropertyValue().
311 * @internal
312 */
313 U_CFUNC uint16_t U_EXPORT2
314 unorm_getFCD16FromCodePoint(UChar32 c);
315
316 #ifdef XP_CPLUSPLUS
317
318 /**
319 * Internal API, used by collation code.
320 * Get access to the internal FCD trie table to be able to perform
321 * incremental, per-code unit, FCD checks in collation.
322 * One pointer is sufficient because the trie index values are offset
323 * by the index size, so that the same pointer is used to access the trie data.
324 * Code points at fcdHighStart and above have a zero FCD value.
325 * @internal
326 */
327 U_CAPI const uint16_t * U_EXPORT2
328 unorm_getFCDTrieIndex(UChar32 &fcdHighStart, UErrorCode *pErrorCode);
329
330 /**
331 * Internal API, used by collation code.
332 * Get the FCD value for a code unit, with
333 * bits 15..8 lead combining class
334 * bits 7..0 trail combining class
335 *
336 * If c is a lead surrogate and the value is not 0,
337 * then some of c's associated supplementary code points have a non-zero FCD value.
338 *
339 * @internal
340 */
341 static inline uint16_t
unorm_getFCD16(const uint16_t * fcdTrieIndex,UChar c)342 unorm_getFCD16(const uint16_t *fcdTrieIndex, UChar c) {
343 return fcdTrieIndex[_UTRIE2_INDEX_FROM_U16_SINGLE_LEAD(fcdTrieIndex, c)];
344 }
345
346 /**
347 * Internal API, used by collation code.
348 * Get the FCD value of the next code point (post-increment), with
349 * bits 15..8 lead combining class
350 * bits 7..0 trail combining class
351 *
352 * @internal
353 */
354 static inline uint16_t
unorm_nextFCD16(const uint16_t * fcdTrieIndex,UChar32 fcdHighStart,const UChar * & s,const UChar * limit)355 unorm_nextFCD16(const uint16_t *fcdTrieIndex, UChar32 fcdHighStart,
356 const UChar *&s, const UChar *limit) {
357 UChar32 c=*s++;
358 uint16_t fcd=fcdTrieIndex[_UTRIE2_INDEX_FROM_U16_SINGLE_LEAD(fcdTrieIndex, c)];
359 if(fcd!=0 && U16_IS_LEAD(c)) {
360 UChar c2;
361 if(s!=limit && U16_IS_TRAIL(c2=*s)) {
362 ++s;
363 c=U16_GET_SUPPLEMENTARY(c, c2);
364 if(c<fcdHighStart) {
365 fcd=fcdTrieIndex[_UTRIE2_INDEX_FROM_SUPP(fcdTrieIndex, c)];
366 } else {
367 fcd=0;
368 }
369 } else /* unpaired lead surrogate */ {
370 fcd=0;
371 }
372 }
373 return fcd;
374 }
375
376 /**
377 * Internal API, used by collation code.
378 * Get the FCD value of the previous code point (pre-decrement), with
379 * bits 15..8 lead combining class
380 * bits 7..0 trail combining class
381 *
382 * @internal
383 */
384 static inline uint16_t
unorm_prevFCD16(const uint16_t * fcdTrieIndex,UChar32 fcdHighStart,const UChar * start,const UChar * & s)385 unorm_prevFCD16(const uint16_t *fcdTrieIndex, UChar32 fcdHighStart,
386 const UChar *start, const UChar *&s) {
387 UChar32 c=*--s;
388 uint16_t fcd;
389 if(!U16_IS_SURROGATE(c)) {
390 fcd=fcdTrieIndex[_UTRIE2_INDEX_FROM_U16_SINGLE_LEAD(fcdTrieIndex, c)];
391 } else {
392 UChar c2;
393 if(U16_IS_SURROGATE_TRAIL(c) && s!=start && U16_IS_LEAD(c2=*(s-1))) {
394 --s;
395 c=U16_GET_SUPPLEMENTARY(c2, c);
396 if(c<fcdHighStart) {
397 fcd=fcdTrieIndex[_UTRIE2_INDEX_FROM_SUPP(fcdTrieIndex, c)];
398 } else {
399 fcd=0;
400 }
401 } else /* unpaired surrogate */ {
402 fcd=0;
403 }
404 }
405 return fcd;
406 }
407
408 #endif
409
410 /**
411 * internal API, used by StringPrep
412 * @internal
413 */
414 U_CAPI void U_EXPORT2
415 unorm_getUnicodeVersion(UVersionInfo *versionInfo, UErrorCode *pErrorCode);
416
417 /**
418 * Get the canonical decomposition for one code point.
419 * Requires unorm_haveData() and buffer!=NULL and pLength!=NULL.
420 * @param c code point
421 * @param buffer out-only buffer for algorithmic decompositions of Hangul
422 * @param length out-only, takes the length of the decomposition, if any
423 * @return pointer to decomposition, or 0 if none
424 * @internal
425 */
426 U_CFUNC const UChar *
427 unorm_getCanonicalDecomposition(UChar32 c, UChar buffer[4], int32_t *pLength);
428
429 /**
430 * internal API, used by the canonical iterator
431 * TODO Consider using signature similar to unorm_getCanonicalDecomposition()
432 * for more efficiency
433 * @internal
434 */
435 U_CAPI int32_t U_EXPORT2
436 unorm_getDecomposition(UChar32 c, UBool compat,
437 UChar *dest, int32_t destCapacity);
438
439 /**
440 * internal API, used by uprops.cpp
441 * @internal
442 */
443 U_CFUNC UBool U_EXPORT2
444 unorm_internalIsFullCompositionExclusion(UChar32 c);
445
446 /**
447 * Internal API, used by enumeration of canonically equivalent strings
448 * @internal
449 */
450 U_CFUNC UBool U_EXPORT2
451 unorm_isCanonSafeStart(UChar32 c);
452
453 /**
454 * Internal API, used by enumeration of canonically equivalent strings
455 * @internal
456 */
457 U_CAPI UBool U_EXPORT2
458 unorm_getCanonStartSet(UChar32 c, USerializedSet *fillSet);
459
460 /**
461 * Is c an NF<mode>-skippable code point? See unormimp.h.
462 * @internal
463 */
464 U_CAPI UBool U_EXPORT2
465 unorm_isNFSkippable(UChar32 c, UNormalizationMode mode);
466
467 #ifdef XP_CPLUSPLUS
468
469 /**
470 * Get normalization exclusion set for the options.
471 * Requires unorm_haveData().
472 * @internal
473 */
474 U_CFUNC const U_NAMESPACE_QUALIFIER UnicodeSet *
475 unorm_getNX(int32_t options, UErrorCode *pErrorCode);
476
477 #endif
478
479 /**
480 * Enumerate each normalization data trie and add the
481 * start of each range of same properties to the set.
482 * @internal
483 */
484 U_CAPI void U_EXPORT2
485 unorm_addPropertyStarts(const USetAdder *sa, UErrorCode *pErrorCode);
486
487 /**
488 * Swap unorm.icu. See udataswp.h.
489 * @internal
490 */
491 U_CAPI int32_t U_EXPORT2
492 unorm_swap(const UDataSwapper *ds,
493 const void *inData, int32_t length, void *outData,
494 UErrorCode *pErrorCode);
495
496 /**
497 * Get the NF*_QC property for a code point, for u_getIntPropertyValue().
498 * @internal
499 */
500 U_CFUNC UNormalizationCheckResult U_EXPORT2
501 unorm_getQuickCheck(UChar32 c, UNormalizationMode mode);
502
503 /**
504 * Description of the format of unorm.icu version 2.3.
505 *
506 * Main change from version 1 to version 2:
507 * Use of new, common UTrie instead of normalization-specific tries.
508 * Change to version 2.1: add third/auxiliary trie with associated data.
509 * Change to version 2.2: add skippable (f) flag data (_NORM_AUX_NFC_SKIP_F_MASK).
510 * Change to version 2.3: add serialized sets for normalization exclusions
511 * stored inside canonStartSets[]
512 *
513 * For more details of how to use the data structures see the code
514 * in unorm.cpp (runtime normalization code) and
515 * in gennorm.c and gennorm/store.c (build-time data generation).
516 *
517 * For the serialized format of UTrie see utrie.c/UTrieHeader.
518 *
519 * - Overall partition
520 *
521 * unorm.dat customarily begins with a UDataInfo structure, see udata.h and .c.
522 * After that there are the following structures:
523 *
524 * int32_t indexes[_NORM_INDEX_TOP]; -- _NORM_INDEX_TOP=32, see enum in this file
525 *
526 * UTrie normTrie; -- size in bytes=indexes[_NORM_INDEX_TRIE_SIZE]
527 *
528 * uint16_t extraData[extraDataTop]; -- extraDataTop=indexes[_NORM_INDEX_UCHAR_COUNT]
529 * extraData[0] contains the number of units for
530 * FC_NFKC_Closure (formatVersion>=2.1)
531 *
532 * uint16_t combiningTable[combiningTableTop]; -- combiningTableTop=indexes[_NORM_INDEX_COMBINE_DATA_COUNT]
533 * combiningTableTop may include one 16-bit padding unit
534 * to make sure that fcdTrie is 32-bit-aligned
535 *
536 * UTrie fcdTrie; -- size in bytes=indexes[_NORM_INDEX_FCD_TRIE_SIZE]
537 *
538 * UTrie auxTrie; -- size in bytes=indexes[_NORM_INDEX_AUX_TRIE_SIZE]
539 *
540 * uint16_t canonStartSets[canonStartSetsTop] -- canonStartSetsTop=indexes[_NORM_INDEX_CANON_SET_COUNT]
541 * serialized USets and binary search tables, see below
542 *
543 *
544 * The indexes array contains lengths and sizes of the following arrays and structures
545 * as well as the following values:
546 * indexes[_NORM_INDEX_COMBINE_FWD_COUNT]=combineFwdTop
547 * -- one more than the highest combining index computed for forward-only-combining characters
548 * indexes[_NORM_INDEX_COMBINE_BOTH_COUNT]=combineBothTop-combineFwdTop
549 * -- number of combining indexes computed for both-ways-combining characters
550 * indexes[_NORM_INDEX_COMBINE_BACK_COUNT]=combineBackTop-combineBothTop
551 * -- number of combining indexes computed for backward-only-combining characters
552 *
553 * indexes[_NORM_INDEX_MIN_NF*_NO_MAYBE] (where *={ C, D, KC, KD })
554 * -- first code point with a quick check NF* value of NO/MAYBE
555 *
556 *
557 * - Tries
558 *
559 * The main structures are two UTrie tables ("compact arrays"),
560 * each with one index array and one data array.
561 * See utrie.h and utrie.c.
562 *
563 *
564 * - Tries in unorm.dat
565 *
566 * The first trie (normTrie above)
567 * provides data for the NF* quick checks and normalization.
568 * The second trie (fcdTrie above) provides data just for FCD checks.
569 *
570 *
571 * - norm32 data words from the first trie
572 *
573 * The norm32Table contains one 32-bit word "norm32" per code point.
574 * It contains the following bit fields:
575 * 31..16 extra data index, _NORM_EXTRA_SHIFT is used to shift this field down
576 * if this index is <_NORM_EXTRA_INDEX_TOP then it is an index into
577 * extraData[] where variable-length normalization data for this
578 * code point is found
579 * if this index is <_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
580 * then this is a norm32 for a leading surrogate, and the index
581 * value is used together with the following trailing surrogate
582 * code unit in the second trie access
583 * if this index is >=_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
584 * then this is a norm32 for a "special" character,
585 * i.e., the character is a Hangul syllable or a Jamo
586 * see _NORM_EXTRA_HANGUL etc.
587 * generally, instead of extracting this index from the norm32 and
588 * comparing it with the above constants,
589 * the normalization code compares the entire norm32 value
590 * with _NORM_MIN_SPECIAL, _NORM_SURROGATES_TOP, _NORM_MIN_HANGUL etc.
591 *
592 * 15..8 combining class (cc) according to UnicodeData.txt
593 *
594 * 7..6 _NORM_COMBINES_ANY flags, used in composition to see if a character
595 * combines with any following or preceding character(s)
596 * at all
597 * 7 _NORM_COMBINES_BACK
598 * 6 _NORM_COMBINES_FWD
599 *
600 * 5..0 quick check flags, set for "no" or "maybe", with separate flags for
601 * each normalization form
602 * the higher bits are "maybe" flags; for NF*D there are no such flags
603 * the lower bits are "no" flags for all forms, in the same order
604 * as the "maybe" flags,
605 * which is (MSB to LSB): NFKD NFD NFKC NFC
606 * 5..4 _NORM_QC_ANY_MAYBE
607 * 3..0 _NORM_QC_ANY_NO
608 * see further related constants
609 *
610 *
611 * - Extra data per code point
612 *
613 * "Extra data" is referenced by the index in norm32.
614 * It is variable-length data. It is only present, and only those parts
615 * of it are, as needed for a given character.
616 * The norm32 extra data index is added to the beginning of extraData[]
617 * to get to a vector of 16-bit words with data at the following offsets:
618 *
619 * [-1] Combining index for composition.
620 * Stored only if norm32&_NORM_COMBINES_ANY .
621 * [0] Lengths of the canonical and compatibility decomposition strings.
622 * Stored only if there are decompositions, i.e.,
623 * if norm32&(_NORM_QC_NFD|_NORM_QC_NFKD)
624 * High byte: length of NFKD, or 0 if none
625 * Low byte: length of NFD, or 0 if none
626 * Each length byte also has another flag:
627 * Bit 7 of a length byte is set if there are non-zero
628 * combining classes (cc's) associated with the respective
629 * decomposition. If this flag is set, then the decomposition
630 * is preceded by a 16-bit word that contains the
631 * leading and trailing cc's.
632 * Bits 6..0 of a length byte are the length of the
633 * decomposition string, not counting the cc word.
634 * [1..n] NFD
635 * [n+1..] NFKD
636 *
637 * Each of the two decompositions consists of up to two parts:
638 * - The 16-bit words with the leading and trailing cc's.
639 * This is only stored if bit 7 of the corresponding length byte
640 * is set. In this case, at least one of the cc's is not zero.
641 * High byte: leading cc==cc of the first code point in the decomposition string
642 * Low byte: trailing cc==cc of the last code point in the decomposition string
643 * - The decomposition string in UTF-16, with length code units.
644 *
645 *
646 * - Combining indexes and combiningTable[]
647 *
648 * Combining indexes are stored at the [-1] offset of the extra data
649 * if the character combines forward or backward with any other characters.
650 * They are used for (re)composition in NF*C.
651 * Values of combining indexes are arranged according to whether a character
652 * combines forward, backward, or both ways:
653 * forward-only < both ways < backward-only
654 *
655 * The index values for forward-only and both-ways combining characters
656 * are indexes into the combiningTable[].
657 * The index values for backward-only combining characters are simply
658 * incremented from the preceding index values to be unique.
659 *
660 * In the combiningTable[], a variable-length list
661 * of variable-length (back-index, code point) pair entries is stored
662 * for each forward-combining character.
663 *
664 * These back-indexes are the combining indexes of both-ways or backward-only
665 * combining characters that the forward-combining character combines with.
666 *
667 * Each list is sorted in ascending order of back-indexes.
668 * Each list is terminated with the last back-index having bit 15 set.
669 *
670 * Each pair (back-index, code point) takes up either 2 or 3
671 * 16-bit words.
672 * The first word of a list entry is the back-index, with its bit 15 set if
673 * this is the last pair in the list.
674 *
675 * The second word contains flags in bits 15..13 that determine
676 * if there is a third word and how the combined character is encoded:
677 * 15 set if there is a third word in this list entry
678 * 14 set if the result is a supplementary character
679 * 13 set if the result itself combines forward
680 *
681 * According to these bits 15..14 of the second word,
682 * the result character is encoded as follows:
683 * 00 or 01 The result is <=0x1fff and stored in bits 12..0 of
684 * the second word.
685 * 10 The result is 0x2000..0xffff and stored in the third word.
686 * Bits 12..0 of the second word are not used.
687 * 11 The result is a supplementary character.
688 * Bits 9..0 of the leading surrogate are in bits 9..0 of
689 * the second word.
690 * Add 0xd800 to these bits to get the complete surrogate.
691 * Bits 12..10 of the second word are not used.
692 * The trailing surrogate is stored in the third word.
693 *
694 *
695 * - FCD trie
696 *
697 * The FCD trie is very simple.
698 * It is a folded trie with 16-bit data words.
699 * In each word, the high byte contains the leading cc of the character,
700 * and the low byte contains the trailing cc of the character.
701 * These cc's are the cc's of the first and last code points in the
702 * canonical decomposition of the character.
703 *
704 * Since all 16 bits are used for cc's, lead surrogates must be tested
705 * by checking the code unit instead of the trie data.
706 * This is done only if the 16-bit data word is not zero.
707 * If the code unit is a leading surrogate and the data word is not zero,
708 * then instead of cc's it contains the offset for the second trie lookup.
709 *
710 *
711 * - Auxiliary trie and data
712 *
713 * The auxiliary 16-bit trie contains data for additional properties.
714 * Bits
715 * 15..13 reserved
716 * 12 not NFC_Skippable (f) (formatVersion>=2.2)
717 * 11 flag: not a safe starter for canonical closure
718 * 10 composition exclusion
719 * 9.. 0 index into extraData[] to FC_NFKC_Closure string
720 * (not for lead surrogate),
721 * or lead surrogate offset (for lead surrogate, if 9..0 not zero)
722 *
723 * - FC_NFKC_Closure strings in extraData[]
724 *
725 * Strings are either stored as a single code unit or as the length
726 * followed by that many units.
727 * const UChar *s=extraData+(index from auxTrie data bits 9..0);
728 * int32_t length;
729 * if(*s<0xff00) {
730 * // s points to the single-unit string
731 * length=1;
732 * } else {
733 * length=*s&0xff;
734 * ++s;
735 * }
736 *
737 * Conditions for "NF* Skippable" from Mark Davis' com.ibm.text.UCD.NFSkippable:
738 * (used in NormalizerTransliterator)
739 *
740 * A skippable character is
741 * a) unassigned, or ALL of the following:
742 * b) of combining class 0.
743 * c) not decomposed by this normalization form.
744 * AND if NFC or NFKC,
745 * d) can never compose with a previous character.
746 * e) can never compose with a following character.
747 * f) can never change if another character is added.
748 * Example: a-breve might satisfy all but f, but if you
749 * add an ogonek it changes to a-ogonek + breve
750 *
751 * a)..e) must be tested from norm32.
752 * Since f) is more complicated, the (not-)NFC_Skippable flag (f) is built
753 * into the auxiliary trie.
754 * The same bit is used for NFC and NFKC; (c) differs for them.
755 * As usual, we build the "not skippable" flags so that unassigned
756 * code points get a 0 bit.
757 * This bit is only valid after (a)..(e) test FALSE; test NFD_NO before (f) as well.
758 * Test Hangul LV syllables entirely in code.
759 *
760 *
761 * - structure inside canonStartSets[]
762 *
763 * This array maps from code points c to sets of code points (USerializedSet).
764 * The result sets are the code points whose canonical decompositions start
765 * with c.
766 *
767 * canonStartSets[] contains the following sub-arrays:
768 *
769 * indexes[_NORM_SET_INDEX_TOP]
770 * - contains lengths of sub-arrays etc.
771 *
772 * startSets[indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH]-_NORM_SET_INDEX_TOP]
773 * - contains serialized sets (USerializedSet) of canonical starters for
774 * enumerating canonically equivalent strings
775 * indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH] includes _NORM_SET_INDEX_TOP
776 * for details about the structure see uset.c
777 *
778 * bmpTable[indexes[_NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH]]
779 * - a sorted search table for BMP code points whose results are
780 * either indexes to USerializedSets or single code points for
781 * single-code point sets;
782 * each entry is a pair of { code point, result } with result=(binary) yy xxxxxx xxxxxxxx
783 * if yy==01 then there is a USerializedSet at canonStartSets+x
784 * else build a USerializedSet with result as the single code point
785 *
786 * suppTable[indexes[_NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH]]
787 * - a sorted search table for supplementary code points whose results are
788 * either indexes to USerializedSets or single code points for
789 * single-code point sets;
790 * each entry is a triplet of { high16(cp), low16(cp), result }
791 * each code point's high-word may contain extra data in bits 15..5:
792 * if the high word has bit 15 set, then build a set with a single code point
793 * which is (((high16(cp)&0x1f00)<<8)|result;
794 * else there is a USerializedSet at canonStartSets+result
795 *
796 * FormatVersion 2.3 adds 2 serialized sets for normalization exclusions.
797 * They are stored in the data file so that the runtime normalization code need
798 * not depend on other properties and their data and implementation files.
799 * The _NORM_SET_INDEX_NX_..._OFFSET offsets in the canonStartSets index table
800 * give the location for each set.
801 * There is no set stored for UNORM_NX_HANGUL because it's trivial to create
802 * without using properties.
803 *
804 * Set contents:
805 *
806 * _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET (for UNORM_NX_CJK_COMPAT)
807 * [[:Ideographic:]&[:NFD_QC=No:]]
808 * =[CJK Ideographs]&[has canonical decomposition]
809 *
810 * _NORM_SET_INDEX_NX_UNICODE32_OFFSET (for UNORM_UNICODE_3_2)
811 * [:^Age=3.2:]
812 * =set with all code points that were not designated by the specified Unicode version
813 *
814 * _NORM_SET_INDEX_NX_RESERVED_OFFSET
815 * This is an offset that points to where the next, future set would start.
816 * Currently it indicates where the previous set ends, and thus its length.
817 * The name for this enum constant may in the future be applied to different
818 * index slots. In order to get the limit of a set, use its index slot and
819 * the immediately following one regardless of that one's enum name.
820 */
821
822 #endif /* #if !UCONFIG_NO_NORMALIZATION */
823
824 #endif
825