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1 /*
2 *******************************************************************************
3 *
4 *   Copyright (C) 2001-2010, 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 #include "udataswp.h"
25 
26 /*
27  * The 2001-2010 implementation of the normalization code loads its data from
28  * unorm.icu, which is generated with the gennorm tool.
29  * The format of that file is described at the end of this file.
30  */
31 
32 /* norm32 value constants */
33 enum {
34     /* quick check flags 0..3 set mean "no" for their forms */
35     _NORM_QC_NFC=0x11,          /* no|maybe */
36     _NORM_QC_NFKC=0x22,         /* no|maybe */
37     _NORM_QC_NFD=4,             /* no */
38     _NORM_QC_NFKD=8,            /* no */
39 
40     _NORM_QC_ANY_NO=0xf,
41 
42     /* quick check flags 4..5 mean "maybe" for their forms; test flags>=_NORM_QC_MAYBE */
43     _NORM_QC_MAYBE=0x10,
44     _NORM_QC_ANY_MAYBE=0x30,
45 
46     _NORM_QC_MASK=0x3f,
47 
48     _NORM_COMBINES_FWD=0x40,
49     _NORM_COMBINES_BACK=0x80,
50     _NORM_COMBINES_ANY=0xc0,
51 
52     _NORM_CC_SHIFT=8,           /* UnicodeData.txt combining class in bits 15..8 */
53     _NORM_CC_MASK=0xff00,
54 
55     _NORM_EXTRA_SHIFT=16,               /* 16 bits for the index to UChars and other extra data */
56     _NORM_EXTRA_INDEX_TOP=0xfc00,       /* start of surrogate specials after shift */
57 
58     _NORM_EXTRA_SURROGATE_MASK=0x3ff,
59     _NORM_EXTRA_SURROGATE_TOP=0x3f0,    /* hangul etc. */
60 
61     _NORM_EXTRA_HANGUL=_NORM_EXTRA_SURROGATE_TOP,
62     _NORM_EXTRA_JAMO_L,
63     _NORM_EXTRA_JAMO_V,
64     _NORM_EXTRA_JAMO_T
65 };
66 
67 /* norm32 value constants using >16 bits */
68 #define _NORM_MIN_SPECIAL       0xfc000000
69 #define _NORM_SURROGATES_TOP    0xfff00000
70 #define _NORM_MIN_HANGUL        0xfff00000
71 #define _NORM_MIN_JAMO_V        0xfff20000
72 #define _NORM_JAMO_V_TOP        0xfff30000
73 
74 /* value constants for auxTrie */
75 enum {
76     _NORM_AUX_COMP_EX_SHIFT=10,
77     _NORM_AUX_UNSAFE_SHIFT=11,
78     _NORM_AUX_NFC_SKIPPABLE_F_SHIFT=12
79 };
80 
81 #define _NORM_AUX_MAX_FNC           ((int32_t)1<<_NORM_AUX_COMP_EX_SHIFT)
82 
83 #define _NORM_AUX_FNC_MASK          (uint32_t)(_NORM_AUX_MAX_FNC-1)
84 #define _NORM_AUX_COMP_EX_MASK      ((uint32_t)1<<_NORM_AUX_COMP_EX_SHIFT)
85 #define _NORM_AUX_UNSAFE_MASK       ((uint32_t)1<<_NORM_AUX_UNSAFE_SHIFT)
86 #define _NORM_AUX_NFC_SKIP_F_MASK   ((uint32_t)1<<_NORM_AUX_NFC_SKIPPABLE_F_SHIFT)
87 
88 /* canonStartSets[0..31] contains indexes for what is in the array */
89 enum {
90     _NORM_SET_INDEX_CANON_SETS_LENGTH,      /* number of uint16_t in canonical starter sets */
91     _NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH, /* number of uint16_t in the BMP search table (contains pairs) */
92     _NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH,/* number of uint16_t in the supplementary search table (contains triplets) */
93 
94     /* from formatVersion 2.3: */
95     _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET,   /* uint16_t offset from canonStartSets[0] to the
96                                                exclusion set for CJK compatibility characters */
97     _NORM_SET_INDEX_NX_UNICODE32_OFFSET,    /* uint16_t offset from canonStartSets[0] to the
98                                                exclusion set for Unicode 3.2 characters */
99     _NORM_SET_INDEX_NX_RESERVED_OFFSET,     /* uint16_t offset from canonStartSets[0] to the
100                                                end of the previous exclusion set */
101 
102     _NORM_SET_INDEX_TOP=32                  /* changing this requires a new formatVersion */
103 };
104 
105 /* more constants for canonical starter sets */
106 
107 /* 14 bit indexes to canonical USerializedSets */
108 #define _NORM_MAX_CANON_SETS            0x4000
109 
110 /* single-code point BMP sets are encoded directly in the search table except if result=0x4000..0x7fff */
111 #define _NORM_CANON_SET_BMP_MASK        0xc000
112 #define _NORM_CANON_SET_BMP_IS_INDEX    0x4000
113 
114 /* indexes[] value names */
115 enum {
116     _NORM_INDEX_TRIE_SIZE,              /* number of bytes in normalization trie */
117     _NORM_INDEX_UCHAR_COUNT,            /* number of UChars in extra data */
118 
119     _NORM_INDEX_COMBINE_DATA_COUNT,     /* number of uint16_t words for combining data */
120     _NORM_INDEX_COMBINE_FWD_COUNT,      /* number of code points that combine forward */
121     _NORM_INDEX_COMBINE_BOTH_COUNT,     /* number of code points that combine forward and backward */
122     _NORM_INDEX_COMBINE_BACK_COUNT,     /* number of code points that combine backward */
123 
124     _NORM_INDEX_MIN_NFC_NO_MAYBE,       /* first code point with quick check NFC NO/MAYBE */
125     _NORM_INDEX_MIN_NFKC_NO_MAYBE,      /* first code point with quick check NFKC NO/MAYBE */
126     _NORM_INDEX_MIN_NFD_NO_MAYBE,       /* first code point with quick check NFD NO/MAYBE */
127     _NORM_INDEX_MIN_NFKD_NO_MAYBE,      /* first code point with quick check NFKD NO/MAYBE */
128 
129     _NORM_INDEX_FCD_TRIE_SIZE,          /* number of bytes in FCD trie */
130 
131     _NORM_INDEX_AUX_TRIE_SIZE,          /* number of bytes in the auxiliary trie */
132     _NORM_INDEX_CANON_SET_COUNT,        /* number of uint16_t in the array of serialized USet */
133 
134     _NORM_INDEX_TOP=32                  /* changing this requires a new formatVersion */
135 };
136 
137 enum {
138     /* FCD check: everything below this code point is known to have a 0 lead combining class */
139     _NORM_MIN_WITH_LEAD_CC=0x300
140 };
141 
142 enum {
143     /**
144      * Bit 7 of the length byte for a decomposition string in extra data is
145      * a flag indicating whether the decomposition string is
146      * preceded by a 16-bit word with the leading and trailing cc
147      * of the decomposition (like for A-umlaut);
148      * if not, then both cc's are zero (like for compatibility ideographs).
149      */
150     _NORM_DECOMP_FLAG_LENGTH_HAS_CC=0x80,
151     /**
152      * Bits 6..0 of the length byte contain the actual length.
153      */
154     _NORM_DECOMP_LENGTH_MASK=0x7f
155 };
156 
157 /* Constants for options flags for normalization. @draft ICU 2.6 */
158 enum {
159     /** Options bit 0, do not decompose Hangul syllables. @draft ICU 2.6 */
160     UNORM_NX_HANGUL=1,
161     /** Options bit 1, do not decompose CJK compatibility characters. @draft ICU 2.6 */
162     UNORM_NX_CJK_COMPAT=2
163 };
164 
165 /**
166  * Swap unorm.icu. See udataswp.h.
167  * @internal
168  */
169 U_CAPI int32_t U_EXPORT2
170 unorm_swap(const UDataSwapper *ds,
171            const void *inData, int32_t length, void *outData,
172            UErrorCode *pErrorCode);
173 
174 /**
175  * Description of the format of unorm.icu version 2.3.
176  *
177  * Main change from version 1 to version 2:
178  * Use of new, common UTrie instead of normalization-specific tries.
179  * Change to version 2.1: add third/auxiliary trie with associated data.
180  * Change to version 2.2: add skippable (f) flag data (_NORM_AUX_NFC_SKIP_F_MASK).
181  * Change to version 2.3: add serialized sets for normalization exclusions
182  *                        stored inside canonStartSets[]
183  *
184  * For more details of how to use the data structures see the code
185  * in unorm.cpp (runtime normalization code) and
186  * in gennorm.c and gennorm/store.c (build-time data generation).
187  *
188  * For the serialized format of UTrie see utrie.c/UTrieHeader.
189  *
190  * - Overall partition
191  *
192  * unorm.dat customarily begins with a UDataInfo structure, see udata.h and .c.
193  * After that there are the following structures:
194  *
195  * int32_t indexes[_NORM_INDEX_TOP];            -- _NORM_INDEX_TOP=32, see enum in this file
196  *
197  * UTrie normTrie;                              -- size in bytes=indexes[_NORM_INDEX_TRIE_SIZE]
198  *
199  * uint16_t extraData[extraDataTop];            -- extraDataTop=indexes[_NORM_INDEX_UCHAR_COUNT]
200  *                                                 extraData[0] contains the number of units for
201  *                                                 FC_NFKC_Closure (formatVersion>=2.1)
202  *
203  * uint16_t combiningTable[combiningTableTop];  -- combiningTableTop=indexes[_NORM_INDEX_COMBINE_DATA_COUNT]
204  *                                                 combiningTableTop may include one 16-bit padding unit
205  *                                                 to make sure that fcdTrie is 32-bit-aligned
206  *
207  * UTrie fcdTrie;                               -- size in bytes=indexes[_NORM_INDEX_FCD_TRIE_SIZE]
208  *
209  * UTrie auxTrie;                               -- size in bytes=indexes[_NORM_INDEX_AUX_TRIE_SIZE]
210  *
211  * uint16_t canonStartSets[canonStartSetsTop]   -- canonStartSetsTop=indexes[_NORM_INDEX_CANON_SET_COUNT]
212  *                                                 serialized USets and binary search tables, see below
213  *
214  *
215  * The indexes array contains lengths and sizes of the following arrays and structures
216  * as well as the following values:
217  *  indexes[_NORM_INDEX_COMBINE_FWD_COUNT]=combineFwdTop
218  *      -- one more than the highest combining index computed for forward-only-combining characters
219  *  indexes[_NORM_INDEX_COMBINE_BOTH_COUNT]=combineBothTop-combineFwdTop
220  *      -- number of combining indexes computed for both-ways-combining characters
221  *  indexes[_NORM_INDEX_COMBINE_BACK_COUNT]=combineBackTop-combineBothTop
222  *      -- number of combining indexes computed for backward-only-combining characters
223  *
224  *  indexes[_NORM_INDEX_MIN_NF*_NO_MAYBE] (where *={ C, D, KC, KD })
225  *      -- first code point with a quick check NF* value of NO/MAYBE
226  *
227  *
228  * - Tries
229  *
230  * The main structures are two UTrie tables ("compact arrays"),
231  * each with one index array and one data array.
232  * See utrie.h and utrie.c.
233  *
234  *
235  * - Tries in unorm.dat
236  *
237  * The first trie (normTrie above)
238  * provides data for the NF* quick checks and normalization.
239  * The second trie (fcdTrie above) provides data just for FCD checks.
240  *
241  *
242  * - norm32 data words from the first trie
243  *
244  * The norm32Table contains one 32-bit word "norm32" per code point.
245  * It contains the following bit fields:
246  * 31..16   extra data index, _NORM_EXTRA_SHIFT is used to shift this field down
247  *          if this index is <_NORM_EXTRA_INDEX_TOP then it is an index into
248  *              extraData[] where variable-length normalization data for this
249  *              code point is found
250  *          if this index is <_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
251  *              then this is a norm32 for a leading surrogate, and the index
252  *              value is used together with the following trailing surrogate
253  *              code unit in the second trie access
254  *          if this index is >=_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
255  *              then this is a norm32 for a "special" character,
256  *              i.e., the character is a Hangul syllable or a Jamo
257  *              see _NORM_EXTRA_HANGUL etc.
258  *          generally, instead of extracting this index from the norm32 and
259  *              comparing it with the above constants,
260  *              the normalization code compares the entire norm32 value
261  *              with _NORM_MIN_SPECIAL, _NORM_SURROGATES_TOP, _NORM_MIN_HANGUL etc.
262  *
263  * 15..8    combining class (cc) according to UnicodeData.txt
264  *
265  *  7..6    _NORM_COMBINES_ANY flags, used in composition to see if a character
266  *              combines with any following or preceding character(s)
267  *              at all
268  *     7    _NORM_COMBINES_BACK
269  *     6    _NORM_COMBINES_FWD
270  *
271  *  5..0    quick check flags, set for "no" or "maybe", with separate flags for
272  *              each normalization form
273  *              the higher bits are "maybe" flags; for NF*D there are no such flags
274  *              the lower bits are "no" flags for all forms, in the same order
275  *              as the "maybe" flags,
276  *              which is (MSB to LSB): NFKD NFD NFKC NFC
277  *  5..4    _NORM_QC_ANY_MAYBE
278  *  3..0    _NORM_QC_ANY_NO
279  *              see further related constants
280  *
281  *
282  * - Extra data per code point
283  *
284  * "Extra data" is referenced by the index in norm32.
285  * It is variable-length data. It is only present, and only those parts
286  * of it are, as needed for a given character.
287  * The norm32 extra data index is added to the beginning of extraData[]
288  * to get to a vector of 16-bit words with data at the following offsets:
289  *
290  * [-1]     Combining index for composition.
291  *              Stored only if norm32&_NORM_COMBINES_ANY .
292  * [0]      Lengths of the canonical and compatibility decomposition strings.
293  *              Stored only if there are decompositions, i.e.,
294  *              if norm32&(_NORM_QC_NFD|_NORM_QC_NFKD)
295  *          High byte: length of NFKD, or 0 if none
296  *          Low byte: length of NFD, or 0 if none
297  *          Each length byte also has another flag:
298  *              Bit 7 of a length byte is set if there are non-zero
299  *              combining classes (cc's) associated with the respective
300  *              decomposition. If this flag is set, then the decomposition
301  *              is preceded by a 16-bit word that contains the
302  *              leading and trailing cc's.
303  *              Bits 6..0 of a length byte are the length of the
304  *              decomposition string, not counting the cc word.
305  * [1..n]   NFD
306  * [n+1..]  NFKD
307  *
308  * Each of the two decompositions consists of up to two parts:
309  * - The 16-bit words with the leading and trailing cc's.
310  *   This is only stored if bit 7 of the corresponding length byte
311  *   is set. In this case, at least one of the cc's is not zero.
312  *   High byte: leading cc==cc of the first code point in the decomposition string
313  *   Low byte: trailing cc==cc of the last code point in the decomposition string
314  * - The decomposition string in UTF-16, with length code units.
315  *
316  *
317  * - Combining indexes and combiningTable[]
318  *
319  * Combining indexes are stored at the [-1] offset of the extra data
320  * if the character combines forward or backward with any other characters.
321  * They are used for (re)composition in NF*C.
322  * Values of combining indexes are arranged according to whether a character
323  * combines forward, backward, or both ways:
324  *    forward-only < both ways < backward-only
325  *
326  * The index values for forward-only and both-ways combining characters
327  * are indexes into the combiningTable[].
328  * The index values for backward-only combining characters are simply
329  * incremented from the preceding index values to be unique.
330  *
331  * In the combiningTable[], a variable-length list
332  * of variable-length (back-index, code point) pair entries is stored
333  * for each forward-combining character.
334  *
335  * These back-indexes are the combining indexes of both-ways or backward-only
336  * combining characters that the forward-combining character combines with.
337  *
338  * Each list is sorted in ascending order of back-indexes.
339  * Each list is terminated with the last back-index having bit 15 set.
340  *
341  * Each pair (back-index, code point) takes up either 2 or 3
342  * 16-bit words.
343  * The first word of a list entry is the back-index, with its bit 15 set if
344  * this is the last pair in the list.
345  *
346  * The second word contains flags in bits 15..13 that determine
347  * if there is a third word and how the combined character is encoded:
348  * 15   set if there is a third word in this list entry
349  * 14   set if the result is a supplementary character
350  * 13   set if the result itself combines forward
351  *
352  * According to these bits 15..14 of the second word,
353  * the result character is encoded as follows:
354  * 00 or 01 The result is <=0x1fff and stored in bits 12..0 of
355  *          the second word.
356  * 10       The result is 0x2000..0xffff and stored in the third word.
357  *          Bits 12..0 of the second word are not used.
358  * 11       The result is a supplementary character.
359  *          Bits 9..0 of the leading surrogate are in bits 9..0 of
360  *          the second word.
361  *          Add 0xd800 to these bits to get the complete surrogate.
362  *          Bits 12..10 of the second word are not used.
363  *          The trailing surrogate is stored in the third word.
364  *
365  *
366  * - FCD trie
367  *
368  * The FCD trie is very simple.
369  * It is a folded trie with 16-bit data words.
370  * In each word, the high byte contains the leading cc of the character,
371  * and the low byte contains the trailing cc of the character.
372  * These cc's are the cc's of the first and last code points in the
373  * canonical decomposition of the character.
374  *
375  * Since all 16 bits are used for cc's, lead surrogates must be tested
376  * by checking the code unit instead of the trie data.
377  * This is done only if the 16-bit data word is not zero.
378  * If the code unit is a leading surrogate and the data word is not zero,
379  * then instead of cc's it contains the offset for the second trie lookup.
380  *
381  *
382  * - Auxiliary trie and data
383  *
384  * The auxiliary 16-bit trie contains data for additional properties.
385  * Bits
386  * 15..13   reserved
387  *     12   not NFC_Skippable (f) (formatVersion>=2.2)
388  *     11   flag: not a safe starter for canonical closure
389  *     10   composition exclusion
390  *  9.. 0   index into extraData[] to FC_NFKC_Closure string
391  *          (not for lead surrogate),
392  *          or lead surrogate offset (for lead surrogate, if 9..0 not zero)
393  *
394  * - FC_NFKC_Closure strings in extraData[]
395  *
396  * Strings are either stored as a single code unit or as the length
397  * followed by that many units.
398  *   const UChar *s=extraData+(index from auxTrie data bits 9..0);
399  *   int32_t length;
400  *   if(*s<0xff00) {
401  *     // s points to the single-unit string
402  *     length=1;
403  *   } else {
404  *     length=*s&0xff;
405  *     ++s;
406  *   }
407  *
408  * Conditions for "NF* Skippable" from Mark Davis' com.ibm.text.UCD.NFSkippable:
409  * (used in NormalizerTransliterator)
410  *
411  * A skippable character is
412  * a) unassigned, or ALL of the following:
413  * b) of combining class 0.
414  * c) not decomposed by this normalization form.
415  * AND if NFC or NFKC,
416  * d) can never compose with a previous character.
417  * e) can never compose with a following character.
418  * f) can never change if another character is added.
419  *    Example: a-breve might satisfy all but f, but if you
420  *    add an ogonek it changes to a-ogonek + breve
421  *
422  * a)..e) must be tested from norm32.
423  * Since f) is more complicated, the (not-)NFC_Skippable flag (f) is built
424  * into the auxiliary trie.
425  * The same bit is used for NFC and NFKC; (c) differs for them.
426  * As usual, we build the "not skippable" flags so that unassigned
427  * code points get a 0 bit.
428  * This bit is only valid after (a)..(e) test FALSE; test NFD_NO before (f) as well.
429  * Test Hangul LV syllables entirely in code.
430  *
431  *
432  * - structure inside canonStartSets[]
433  *
434  * This array maps from code points c to sets of code points (USerializedSet).
435  * The result sets are the code points whose canonical decompositions start
436  * with c.
437  *
438  * canonStartSets[] contains the following sub-arrays:
439  *
440  * indexes[_NORM_SET_INDEX_TOP]
441  *   - contains lengths of sub-arrays etc.
442  *
443  * startSets[indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH]-_NORM_SET_INDEX_TOP]
444  *   - contains serialized sets (USerializedSet) of canonical starters for
445  *     enumerating canonically equivalent strings
446  *     indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH] includes _NORM_SET_INDEX_TOP
447  *     for details about the structure see uset.c
448  *
449  * bmpTable[indexes[_NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH]]
450  *   - a sorted search table for BMP code points whose results are
451  *     either indexes to USerializedSets or single code points for
452  *     single-code point sets;
453  *     each entry is a pair of { code point, result } with result=(binary) yy xxxxxx xxxxxxxx
454  *     if yy==01 then there is a USerializedSet at canonStartSets+x
455  *     else build a USerializedSet with result as the single code point
456  *
457  * suppTable[indexes[_NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH]]
458  *   - a sorted search table for supplementary code points whose results are
459  *     either indexes to USerializedSets or single code points for
460  *     single-code point sets;
461  *     each entry is a triplet of { high16(cp), low16(cp), result }
462  *     each code point's high-word may contain extra data in bits 15..5:
463  *     if the high word has bit 15 set, then build a set with a single code point
464  *     which is (((high16(cp)&0x1f00)<<8)|result;
465  *     else there is a USerializedSet at canonStartSets+result
466  *
467  * FormatVersion 2.3 adds 2 serialized sets for normalization exclusions.
468  * They are stored in the data file so that the runtime normalization code need
469  * not depend on other properties and their data and implementation files.
470  * The _NORM_SET_INDEX_NX_..._OFFSET offsets in the canonStartSets index table
471  * give the location for each set.
472  * There is no set stored for UNORM_NX_HANGUL because it's trivial to create
473  * without using properties.
474  *
475  * Set contents:
476  *
477  * _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET (for UNORM_NX_CJK_COMPAT)
478  *     [[:Ideographic:]&[:NFD_QC=No:]]
479  *     =[CJK Ideographs]&[has canonical decomposition]
480  *
481  * _NORM_SET_INDEX_NX_UNICODE32_OFFSET (for UNORM_UNICODE_3_2)
482  *     [:^Age=3.2:]
483  *     =set with all code points that were not designated by the specified Unicode version
484  *
485  * _NORM_SET_INDEX_NX_RESERVED_OFFSET
486  *     This is an offset that points to where the next, future set would start.
487  *     Currently it indicates where the previous set ends, and thus its length.
488  *     The name for this enum constant may in the future be applied to different
489  *     index slots. In order to get the limit of a set, use its index slot and
490  *     the immediately following one regardless of that one's enum name.
491  */
492 
493 #endif /* #if !UCONFIG_NO_NORMALIZATION */
494 
495 #endif
496