fontservices/textshaperplugin/IcuSource/common/unormimp.h
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     1 /*
       
     2 *******************************************************************************
       
     3 *
       
     4 *   Copyright (C) 2001-2004, 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 "utrie.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 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 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_CAPI uint16_t U_EXPORT2
       
   314 unorm_getFCD16FromCodePoint(UChar32 c);
       
   315 
       
   316 /**
       
   317  * Internal API, used by collation code.
       
   318  * Get access to the internal FCD trie table to be able to perform
       
   319  * incremental, per-code unit, FCD checks in collation.
       
   320  * One pointer is sufficient because the trie index values are offset
       
   321  * by the index size, so that the same pointer is used to access the trie data.
       
   322  * @internal
       
   323  */
       
   324 U_CAPI const uint16_t * U_EXPORT2
       
   325 unorm_getFCDTrie(UErrorCode *pErrorCode);
       
   326 
       
   327 #ifdef XP_CPLUSPLUS
       
   328 
       
   329 U_NAMESPACE_BEGIN
       
   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 instead of combining classes the value
       
   338  * is used in unorm_getFCD16FromSurrogatePair() to get the real value
       
   339  * of the supplementary code point.
       
   340  *
       
   341  * @internal
       
   342  */
       
   343 inline uint16_t
       
   344 unorm_getFCD16(const uint16_t *fcdTrieIndex, UChar c) {
       
   345     return
       
   346         fcdTrieIndex[
       
   347             (fcdTrieIndex[
       
   348                 c>>UTRIE_SHIFT
       
   349             ]<<UTRIE_INDEX_SHIFT)+
       
   350             (c&UTRIE_MASK)
       
   351         ];
       
   352 }
       
   353 
       
   354 /**
       
   355  * Internal API, used by collation code.
       
   356  * Get the FCD value for a supplementary code point, with
       
   357  * bits 15..8   lead combining class
       
   358  * bits  7..0   trail combining class
       
   359  *
       
   360  * @param fcd16  The FCD value for the lead surrogate, not 0.
       
   361  * @param c2     The trail surrogate code unit.
       
   362  *
       
   363  * @internal
       
   364  */
       
   365 inline uint16_t
       
   366 unorm_getFCD16FromSurrogatePair(const uint16_t *fcdTrieIndex, uint16_t fcd16, UChar c2) {
       
   367     return
       
   368         fcdTrieIndex[
       
   369             (fcdTrieIndex[
       
   370                 (int32_t)fcd16+((c2&0x3ff)>>UTRIE_SHIFT)
       
   371             ]<<UTRIE_INDEX_SHIFT)+
       
   372             (c2&UTRIE_MASK)
       
   373         ];
       
   374 }
       
   375 
       
   376 U_NAMESPACE_END
       
   377 
       
   378 #endif
       
   379 
       
   380 /**
       
   381  * internal API, used by StringPrep
       
   382  * @internal
       
   383  */
       
   384 U_CAPI void U_EXPORT2
       
   385 unorm_getUnicodeVersion(UVersionInfo *versionInfo, UErrorCode *pErrorCode);
       
   386 
       
   387 /**
       
   388  * Get the canonical decomposition for one code point.
       
   389  * Requires unorm_haveData() and buffer!=NULL and pLength!=NULL.
       
   390  * @param c code point
       
   391  * @param buffer out-only buffer for algorithmic decompositions of Hangul
       
   392  * @param length out-only, takes the length of the decomposition, if any
       
   393  * @return pointer to decomposition, or 0 if none
       
   394  * @internal
       
   395  */
       
   396 U_CFUNC const UChar *
       
   397 unorm_getCanonicalDecomposition(UChar32 c, UChar buffer[4], int32_t *pLength);
       
   398 
       
   399 /**
       
   400  * internal API, used by the canonical iterator
       
   401  * TODO Consider using signature similar to unorm_getCanonicalDecomposition()
       
   402  * for more efficiency
       
   403  * @internal
       
   404  */
       
   405 U_CAPI int32_t U_EXPORT2
       
   406 unorm_getDecomposition(UChar32 c, UBool compat,
       
   407                        UChar *dest, int32_t destCapacity);
       
   408 
       
   409 /**
       
   410  * internal API, used by uprops.cpp
       
   411  * @internal
       
   412  */
       
   413 U_CAPI UBool U_EXPORT2
       
   414 unorm_internalIsFullCompositionExclusion(UChar32 c);
       
   415 
       
   416 /**
       
   417  * Internal API, used by enumeration of canonically equivalent strings
       
   418  * @internal
       
   419  */
       
   420 U_CAPI UBool U_EXPORT2
       
   421 unorm_isCanonSafeStart(UChar32 c);
       
   422 
       
   423 /**
       
   424  * Internal API, used by enumeration of canonically equivalent strings
       
   425  * @internal
       
   426  */
       
   427 U_CAPI UBool U_EXPORT2
       
   428 unorm_getCanonStartSet(UChar32 c, USerializedSet *fillSet);
       
   429 
       
   430 /**
       
   431  * Is c an NF<mode>-skippable code point? See unormimp.h.
       
   432  * @internal
       
   433  */
       
   434 U_CAPI UBool U_EXPORT2
       
   435 unorm_isNFSkippable(UChar32 c, UNormalizationMode mode);
       
   436 
       
   437 #ifdef XP_CPLUSPLUS
       
   438 
       
   439 /**
       
   440  * Get normalization exclusion set for the options.
       
   441  * Requires unorm_haveData().
       
   442  * @internal
       
   443  */
       
   444 U_CFUNC const UnicodeSet *
       
   445 unorm_getNX(int32_t options, UErrorCode *pErrorCode);
       
   446 
       
   447 #endif
       
   448 
       
   449 /**
       
   450  * Enumerate each normalization data trie and add the
       
   451  * start of each range of same properties to the set.
       
   452  * @internal
       
   453  */
       
   454 U_CAPI void U_EXPORT2
       
   455 unorm_addPropertyStarts(const USetAdder *sa, UErrorCode *pErrorCode);
       
   456 
       
   457 /**
       
   458  * Swap unorm.icu. See udataswp.h.
       
   459  * @internal
       
   460  */
       
   461 U_CAPI int32_t U_EXPORT2
       
   462 unorm_swap(const UDataSwapper *ds,
       
   463            const void *inData, int32_t length, void *outData,
       
   464            UErrorCode *pErrorCode);
       
   465 
       
   466 /**
       
   467  * Get the NF*_QC property for a code point, for u_getIntPropertyValue().
       
   468  * @internal
       
   469  */
       
   470 U_CAPI UNormalizationCheckResult U_EXPORT2
       
   471 unorm_getQuickCheck(UChar32 c, UNormalizationMode mode);
       
   472 
       
   473 /**
       
   474  * Description of the format of unorm.icu version 2.3.
       
   475  *
       
   476  * Main change from version 1 to version 2:
       
   477  * Use of new, common UTrie instead of normalization-specific tries.
       
   478  * Change to version 2.1: add third/auxiliary trie with associated data.
       
   479  * Change to version 2.2: add skippable (f) flag data (_NORM_AUX_NFC_SKIP_F_MASK).
       
   480  * Change to version 2.3: add serialized sets for normalization exclusions
       
   481  *                        stored inside canonStartSets[]
       
   482  *
       
   483  * For more details of how to use the data structures see the code
       
   484  * in unorm.cpp (runtime normalization code) and
       
   485  * in gennorm.c and gennorm/store.c (build-time data generation).
       
   486  *
       
   487  * For the serialized format of UTrie see utrie.c/UTrieHeader.
       
   488  *
       
   489  * - Overall partition
       
   490  *
       
   491  * unorm.dat customarily begins with a UDataInfo structure, see udata.h and .c.
       
   492  * After that there are the following structures:
       
   493  *
       
   494  * int32_t indexes[_NORM_INDEX_TOP];            -- _NORM_INDEX_TOP=32, see enum in this file
       
   495  *
       
   496  * UTrie normTrie;                              -- size in bytes=indexes[_NORM_INDEX_TRIE_SIZE]
       
   497  * 
       
   498  * uint16_t extraData[extraDataTop];            -- extraDataTop=indexes[_NORM_INDEX_UCHAR_COUNT]
       
   499  *                                                 extraData[0] contains the number of units for
       
   500  *                                                 FC_NFKC_Closure (formatVersion>=2.1)
       
   501  *
       
   502  * uint16_t combiningTable[combiningTableTop];  -- combiningTableTop=indexes[_NORM_INDEX_COMBINE_DATA_COUNT]
       
   503  *                                                 combiningTableTop may include one 16-bit padding unit
       
   504  *                                                 to make sure that fcdTrie is 32-bit-aligned
       
   505  *
       
   506  * UTrie fcdTrie;                               -- size in bytes=indexes[_NORM_INDEX_FCD_TRIE_SIZE]
       
   507  *
       
   508  * UTrie auxTrie;                               -- size in bytes=indexes[_NORM_INDEX_AUX_TRIE_SIZE]
       
   509  *
       
   510  * uint16_t canonStartSets[canonStartSetsTop]   -- canonStartSetsTop=indexes[_NORM_INDEX_CANON_SET_COUNT]
       
   511  *                                                 serialized USets and binary search tables, see below
       
   512  *
       
   513  *
       
   514  * The indexes array contains lengths and sizes of the following arrays and structures
       
   515  * as well as the following values:
       
   516  *  indexes[_NORM_INDEX_COMBINE_FWD_COUNT]=combineFwdTop
       
   517  *      -- one more than the highest combining index computed for forward-only-combining characters
       
   518  *  indexes[_NORM_INDEX_COMBINE_BOTH_COUNT]=combineBothTop-combineFwdTop
       
   519  *      -- number of combining indexes computed for both-ways-combining characters
       
   520  *  indexes[_NORM_INDEX_COMBINE_BACK_COUNT]=combineBackTop-combineBothTop
       
   521  *      -- number of combining indexes computed for backward-only-combining characters
       
   522  *
       
   523  *  indexes[_NORM_INDEX_MIN_NF*_NO_MAYBE] (where *={ C, D, KC, KD })
       
   524  *      -- first code point with a quick check NF* value of NO/MAYBE
       
   525  *
       
   526  *
       
   527  * - Tries
       
   528  *
       
   529  * The main structures are two UTrie tables ("compact arrays"),
       
   530  * each with one index array and one data array.
       
   531  * See utrie.h and utrie.c.
       
   532  *
       
   533  *
       
   534  * - Tries in unorm.dat
       
   535  *
       
   536  * The first trie (normTrie above)
       
   537  * provides data for the NF* quick checks and normalization.
       
   538  * The second trie (fcdTrie above) provides data just for FCD checks.
       
   539  *
       
   540  *
       
   541  * - norm32 data words from the first trie
       
   542  *
       
   543  * The norm32Table contains one 32-bit word "norm32" per code point.
       
   544  * It contains the following bit fields:
       
   545  * 31..16   extra data index, _NORM_EXTRA_SHIFT is used to shift this field down
       
   546  *          if this index is <_NORM_EXTRA_INDEX_TOP then it is an index into
       
   547  *              extraData[] where variable-length normalization data for this
       
   548  *              code point is found
       
   549  *          if this index is <_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
       
   550  *              then this is a norm32 for a leading surrogate, and the index
       
   551  *              value is used together with the following trailing surrogate
       
   552  *              code unit in the second trie access
       
   553  *          if this index is >=_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
       
   554  *              then this is a norm32 for a "special" character,
       
   555  *              i.e., the character is a Hangul syllable or a Jamo
       
   556  *              see _NORM_EXTRA_HANGUL etc.
       
   557  *          generally, instead of extracting this index from the norm32 and
       
   558  *              comparing it with the above constants,
       
   559  *              the normalization code compares the entire norm32 value
       
   560  *              with _NORM_MIN_SPECIAL, _NORM_SURROGATES_TOP, _NORM_MIN_HANGUL etc.
       
   561  *
       
   562  * 15..8    combining class (cc) according to UnicodeData.txt
       
   563  *
       
   564  *  7..6    _NORM_COMBINES_ANY flags, used in composition to see if a character
       
   565  *              combines with any following or preceding character(s)
       
   566  *              at all
       
   567  *     7    _NORM_COMBINES_BACK
       
   568  *     6    _NORM_COMBINES_FWD
       
   569  *
       
   570  *  5..0    quick check flags, set for "no" or "maybe", with separate flags for
       
   571  *              each normalization form
       
   572  *              the higher bits are "maybe" flags; for NF*D there are no such flags
       
   573  *              the lower bits are "no" flags for all forms, in the same order
       
   574  *              as the "maybe" flags,
       
   575  *              which is (MSB to LSB): NFKD NFD NFKC NFC
       
   576  *  5..4    _NORM_QC_ANY_MAYBE
       
   577  *  3..0    _NORM_QC_ANY_NO
       
   578  *              see further related constants
       
   579  *
       
   580  *
       
   581  * - Extra data per code point
       
   582  *
       
   583  * "Extra data" is referenced by the index in norm32.
       
   584  * It is variable-length data. It is only present, and only those parts
       
   585  * of it are, as needed for a given character.
       
   586  * The norm32 extra data index is added to the beginning of extraData[]
       
   587  * to get to a vector of 16-bit words with data at the following offsets:
       
   588  *
       
   589  * [-1]     Combining index for composition.
       
   590  *              Stored only if norm32&_NORM_COMBINES_ANY .
       
   591  * [0]      Lengths of the canonical and compatibility decomposition strings.
       
   592  *              Stored only if there are decompositions, i.e.,
       
   593  *              if norm32&(_NORM_QC_NFD|_NORM_QC_NFKD)
       
   594  *          High byte: length of NFKD, or 0 if none
       
   595  *          Low byte: length of NFD, or 0 if none
       
   596  *          Each length byte also has another flag:
       
   597  *              Bit 7 of a length byte is set if there are non-zero
       
   598  *              combining classes (cc's) associated with the respective
       
   599  *              decomposition. If this flag is set, then the decomposition
       
   600  *              is preceded by a 16-bit word that contains the
       
   601  *              leading and trailing cc's.
       
   602  *              Bits 6..0 of a length byte are the length of the
       
   603  *              decomposition string, not counting the cc word.
       
   604  * [1..n]   NFD
       
   605  * [n+1..]  NFKD
       
   606  *
       
   607  * Each of the two decompositions consists of up to two parts:
       
   608  * - The 16-bit words with the leading and trailing cc's.
       
   609  *   This is only stored if bit 7 of the corresponding length byte
       
   610  *   is set. In this case, at least one of the cc's is not zero.
       
   611  *   High byte: leading cc==cc of the first code point in the decomposition string
       
   612  *   Low byte: trailing cc==cc of the last code point in the decomposition string
       
   613  * - The decomposition string in UTF-16, with length code units.
       
   614  *
       
   615  *
       
   616  * - Combining indexes and combiningTable[]
       
   617  *
       
   618  * Combining indexes are stored at the [-1] offset of the extra data
       
   619  * if the character combines forward or backward with any other characters.
       
   620  * They are used for (re)composition in NF*C.
       
   621  * Values of combining indexes are arranged according to whether a character
       
   622  * combines forward, backward, or both ways:
       
   623  *    forward-only < both ways < backward-only
       
   624  *
       
   625  * The index values for forward-only and both-ways combining characters
       
   626  * are indexes into the combiningTable[].
       
   627  * The index values for backward-only combining characters are simply
       
   628  * incremented from the preceding index values to be unique.
       
   629  *
       
   630  * In the combiningTable[], a variable-length list
       
   631  * of variable-length (back-index, code point) pair entries is stored
       
   632  * for each forward-combining character.
       
   633  *
       
   634  * These back-indexes are the combining indexes of both-ways or backward-only
       
   635  * combining characters that the forward-combining character combines with.
       
   636  *
       
   637  * Each list is sorted in ascending order of back-indexes.
       
   638  * Each list is terminated with the last back-index having bit 15 set.
       
   639  *
       
   640  * Each pair (back-index, code point) takes up either 2 or 3
       
   641  * 16-bit words.
       
   642  * The first word of a list entry is the back-index, with its bit 15 set if
       
   643  * this is the last pair in the list.
       
   644  *
       
   645  * The second word contains flags in bits 15..13 that determine
       
   646  * if there is a third word and how the combined character is encoded:
       
   647  * 15   set if there is a third word in this list entry
       
   648  * 14   set if the result is a supplementary character
       
   649  * 13   set if the result itself combines forward
       
   650  *
       
   651  * According to these bits 15..14 of the second word,
       
   652  * the result character is encoded as follows:
       
   653  * 00 or 01 The result is <=0x1fff and stored in bits 12..0 of
       
   654  *          the second word.
       
   655  * 10       The result is 0x2000..0xffff and stored in the third word.
       
   656  *          Bits 12..0 of the second word are not used.
       
   657  * 11       The result is a supplementary character.
       
   658  *          Bits 9..0 of the leading surrogate are in bits 9..0 of
       
   659  *          the second word.
       
   660  *          Add 0xd800 to these bits to get the complete surrogate.
       
   661  *          Bits 12..10 of the second word are not used.
       
   662  *          The trailing surrogate is stored in the third word.
       
   663  *
       
   664  *
       
   665  * - FCD trie
       
   666  *
       
   667  * The FCD trie is very simple.
       
   668  * It is a folded trie with 16-bit data words.
       
   669  * In each word, the high byte contains the leading cc of the character,
       
   670  * and the low byte contains the trailing cc of the character.
       
   671  * These cc's are the cc's of the first and last code points in the
       
   672  * canonical decomposition of the character.
       
   673  *
       
   674  * Since all 16 bits are used for cc's, lead surrogates must be tested
       
   675  * by checking the code unit instead of the trie data.
       
   676  * This is done only if the 16-bit data word is not zero.
       
   677  * If the code unit is a leading surrogate and the data word is not zero,
       
   678  * then instead of cc's it contains the offset for the second trie lookup.
       
   679  *
       
   680  *
       
   681  * - Auxiliary trie and data
       
   682  *
       
   683  * The auxiliary 16-bit trie contains data for additional properties.
       
   684  * Bits
       
   685  * 15..13   reserved
       
   686  *     12   not NFC_Skippable (f) (formatVersion>=2.2)
       
   687  *     11   flag: not a safe starter for canonical closure
       
   688  *     10   composition exclusion
       
   689  *  9.. 0   index into extraData[] to FC_NFKC_Closure string
       
   690  *          (not for lead surrogate),
       
   691  *          or lead surrogate offset (for lead surrogate, if 9..0 not zero)
       
   692  *
       
   693  * - FC_NFKC_Closure strings in extraData[]
       
   694  *
       
   695  * Strings are either stored as a single code unit or as the length
       
   696  * followed by that many units.
       
   697  *   const UChar *s=extraData+(index from auxTrie data bits 9..0);
       
   698  *   int32_t length;
       
   699  *   if(*s<0xff00) {
       
   700  *     // s points to the single-unit string
       
   701  *     length=1;
       
   702  *   } else {
       
   703  *     length=*s&0xff;
       
   704  *     ++s;
       
   705  *   }
       
   706  *
       
   707  * Conditions for "NF* Skippable" from Mark Davis' com.ibm.text.UCD.NFSkippable:
       
   708  * (used in NormalizerTransliterator)
       
   709  *
       
   710  * A skippable character is
       
   711  * a) unassigned, or ALL of the following:
       
   712  * b) of combining class 0.
       
   713  * c) not decomposed by this normalization form.
       
   714  * AND if NFC or NFKC,
       
   715  * d) can never compose with a previous character.
       
   716  * e) can never compose with a following character.
       
   717  * f) can never change if another character is added.
       
   718  *    Example: a-breve might satisfy all but f, but if you
       
   719  *    add an ogonek it changes to a-ogonek + breve
       
   720  *
       
   721  * a)..e) must be tested from norm32.
       
   722  * Since f) is more complicated, the (not-)NFC_Skippable flag (f) is built
       
   723  * into the auxiliary trie.
       
   724  * The same bit is used for NFC and NFKC; (c) differs for them.
       
   725  * As usual, we build the "not skippable" flags so that unassigned
       
   726  * code points get a 0 bit.
       
   727  * This bit is only valid after (a)..(e) test FALSE; test NFD_NO before (f) as well.
       
   728  * Test Hangul LV syllables entirely in code.
       
   729  *
       
   730  *
       
   731  * - structure inside canonStartSets[]
       
   732  *
       
   733  * This array maps from code points c to sets of code points (USerializedSet).
       
   734  * The result sets are the code points whose canonical decompositions start
       
   735  * with c.
       
   736  *
       
   737  * canonStartSets[] contains the following sub-arrays:
       
   738  *
       
   739  * indexes[_NORM_SET_INDEX_TOP]
       
   740  *   - contains lengths of sub-arrays etc.
       
   741  *
       
   742  * startSets[indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH]-_NORM_SET_INDEX_TOP]
       
   743  *   - contains serialized sets (USerializedSet) of canonical starters for
       
   744  *     enumerating canonically equivalent strings
       
   745  *     indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH] includes _NORM_SET_INDEX_TOP
       
   746  *     for details about the structure see uset.c
       
   747  *
       
   748  * bmpTable[indexes[_NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH]]
       
   749  *   - a sorted search table for BMP code points whose results are
       
   750  *     either indexes to USerializedSets or single code points for
       
   751  *     single-code point sets;
       
   752  *     each entry is a pair of { code point, result } with result=(binary) yy xxxxxx xxxxxxxx
       
   753  *     if yy==01 then there is a USerializedSet at canonStartSets+x
       
   754  *     else build a USerializedSet with result as the single code point
       
   755  *
       
   756  * suppTable[indexes[_NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH]]
       
   757  *   - a sorted search table for supplementary code points whose results are
       
   758  *     either indexes to USerializedSets or single code points for
       
   759  *     single-code point sets;
       
   760  *     each entry is a triplet of { high16(cp), low16(cp), result }
       
   761  *     each code point's high-word may contain extra data in bits 15..5:
       
   762  *     if the high word has bit 15 set, then build a set with a single code point
       
   763  *     which is (((high16(cp)&0x1f00)<<8)|result;
       
   764  *     else there is a USerializedSet at canonStartSets+result
       
   765  *
       
   766  * FormatVersion 2.3 adds 2 serialized sets for normalization exclusions.
       
   767  * They are stored in the data file so that the runtime normalization code need
       
   768  * not depend on other properties and their data and implementation files.
       
   769  * The _NORM_SET_INDEX_NX_..._OFFSET offsets in the canonStartSets index table
       
   770  * give the location for each set.
       
   771  * There is no set stored for UNORM_NX_HANGUL because it's trivial to create
       
   772  * without using properties.
       
   773  *
       
   774  * Set contents:
       
   775  *
       
   776  * _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET (for UNORM_NX_CJK_COMPAT)
       
   777  *     [[:Ideographic:]&[:NFD_QC=No:]]
       
   778  *     =[CJK Ideographs]&[has canonical decomposition]
       
   779  *
       
   780  * _NORM_SET_INDEX_NX_UNICODE32_OFFSET (for UNORM_UNICODE_3_2)
       
   781  *     [:^Age=3.2:]
       
   782  *     =set with all code points that were not designated by the specified Unicode version
       
   783  *
       
   784  * _NORM_SET_INDEX_NX_RESERVED_OFFSET
       
   785  *     This is an offset that points to where the next, future set would start.
       
   786  *     Currently it indicates where the previous set ends, and thus its length.
       
   787  *     The name for this enum constant may in the future be applied to different
       
   788  *     index slots. In order to get the limit of a set, use its index slot and
       
   789  *     the immediately following one regardless of that one's enum name.
       
   790  */
       
   791 
       
   792 #endif /* #if !UCONFIG_NO_NORMALIZATION */
       
   793 
       
   794 #endif