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      1 /*
      2 *******************************************************************************
      3 *
      4 *   Copyright (C) 2001-2011, 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. */
    158 enum {
    159     /** Options bit 0, do not decompose Hangul syllables. */
    160     UNORM_NX_HANGUL=1,
    161     /** Options bit 1, do not decompose CJK compatibility characters. */
    162     UNORM_NX_CJK_COMPAT=2
    163 };
    164 
    165 /**
    166  * Description of the format of unorm.icu version 2.3.
    167  *
    168  * Main change from version 1 to version 2:
    169  * Use of new, common UTrie instead of normalization-specific tries.
    170  * Change to version 2.1: add third/auxiliary trie with associated data.
    171  * Change to version 2.2: add skippable (f) flag data (_NORM_AUX_NFC_SKIP_F_MASK).
    172  * Change to version 2.3: add serialized sets for normalization exclusions
    173  *                        stored inside canonStartSets[]
    174  *
    175  * For more details of how to use the data structures see the code
    176  * in unorm.cpp (runtime normalization code) and
    177  * in gennorm.c and gennorm/store.c (build-time data generation).
    178  *
    179  * For the serialized format of UTrie see utrie.c/UTrieHeader.
    180  *
    181  * - Overall partition
    182  *
    183  * unorm.dat customarily begins with a UDataInfo structure, see udata.h and .c.
    184  * After that there are the following structures:
    185  *
    186  * int32_t indexes[_NORM_INDEX_TOP];            -- _NORM_INDEX_TOP=32, see enum in this file
    187  *
    188  * UTrie normTrie;                              -- size in bytes=indexes[_NORM_INDEX_TRIE_SIZE]
    189  *
    190  * uint16_t extraData[extraDataTop];            -- extraDataTop=indexes[_NORM_INDEX_UCHAR_COUNT]
    191  *                                                 extraData[0] contains the number of units for
    192  *                                                 FC_NFKC_Closure (formatVersion>=2.1)
    193  *
    194  * uint16_t combiningTable[combiningTableTop];  -- combiningTableTop=indexes[_NORM_INDEX_COMBINE_DATA_COUNT]
    195  *                                                 combiningTableTop may include one 16-bit padding unit
    196  *                                                 to make sure that fcdTrie is 32-bit-aligned
    197  *
    198  * UTrie fcdTrie;                               -- size in bytes=indexes[_NORM_INDEX_FCD_TRIE_SIZE]
    199  *
    200  * UTrie auxTrie;                               -- size in bytes=indexes[_NORM_INDEX_AUX_TRIE_SIZE]
    201  *
    202  * uint16_t canonStartSets[canonStartSetsTop]   -- canonStartSetsTop=indexes[_NORM_INDEX_CANON_SET_COUNT]
    203  *                                                 serialized USets and binary search tables, see below
    204  *
    205  *
    206  * The indexes array contains lengths and sizes of the following arrays and structures
    207  * as well as the following values:
    208  *  indexes[_NORM_INDEX_COMBINE_FWD_COUNT]=combineFwdTop
    209  *      -- one more than the highest combining index computed for forward-only-combining characters
    210  *  indexes[_NORM_INDEX_COMBINE_BOTH_COUNT]=combineBothTop-combineFwdTop
    211  *      -- number of combining indexes computed for both-ways-combining characters
    212  *  indexes[_NORM_INDEX_COMBINE_BACK_COUNT]=combineBackTop-combineBothTop
    213  *      -- number of combining indexes computed for backward-only-combining characters
    214  *
    215  *  indexes[_NORM_INDEX_MIN_NF*_NO_MAYBE] (where *={ C, D, KC, KD })
    216  *      -- first code point with a quick check NF* value of NO/MAYBE
    217  *
    218  *
    219  * - Tries
    220  *
    221  * The main structures are two UTrie tables ("compact arrays"),
    222  * each with one index array and one data array.
    223  * See utrie.h and utrie.c.
    224  *
    225  *
    226  * - Tries in unorm.dat
    227  *
    228  * The first trie (normTrie above)
    229  * provides data for the NF* quick checks and normalization.
    230  * The second trie (fcdTrie above) provides data just for FCD checks.
    231  *
    232  *
    233  * - norm32 data words from the first trie
    234  *
    235  * The norm32Table contains one 32-bit word "norm32" per code point.
    236  * It contains the following bit fields:
    237  * 31..16   extra data index, _NORM_EXTRA_SHIFT is used to shift this field down
    238  *          if this index is <_NORM_EXTRA_INDEX_TOP then it is an index into
    239  *              extraData[] where variable-length normalization data for this
    240  *              code point is found
    241  *          if this index is <_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
    242  *              then this is a norm32 for a leading surrogate, and the index
    243  *              value is used together with the following trailing surrogate
    244  *              code unit in the second trie access
    245  *          if this index is >=_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
    246  *              then this is a norm32 for a "special" character,
    247  *              i.e., the character is a Hangul syllable or a Jamo
    248  *              see _NORM_EXTRA_HANGUL etc.
    249  *          generally, instead of extracting this index from the norm32 and
    250  *              comparing it with the above constants,
    251  *              the normalization code compares the entire norm32 value
    252  *              with _NORM_MIN_SPECIAL, _NORM_SURROGATES_TOP, _NORM_MIN_HANGUL etc.
    253  *
    254  * 15..8    combining class (cc) according to UnicodeData.txt
    255  *
    256  *  7..6    _NORM_COMBINES_ANY flags, used in composition to see if a character
    257  *              combines with any following or preceding character(s)
    258  *              at all
    259  *     7    _NORM_COMBINES_BACK
    260  *     6    _NORM_COMBINES_FWD
    261  *
    262  *  5..0    quick check flags, set for "no" or "maybe", with separate flags for
    263  *              each normalization form
    264  *              the higher bits are "maybe" flags; for NF*D there are no such flags
    265  *              the lower bits are "no" flags for all forms, in the same order
    266  *              as the "maybe" flags,
    267  *              which is (MSB to LSB): NFKD NFD NFKC NFC
    268  *  5..4    _NORM_QC_ANY_MAYBE
    269  *  3..0    _NORM_QC_ANY_NO
    270  *              see further related constants
    271  *
    272  *
    273  * - Extra data per code point
    274  *
    275  * "Extra data" is referenced by the index in norm32.
    276  * It is variable-length data. It is only present, and only those parts
    277  * of it are, as needed for a given character.
    278  * The norm32 extra data index is added to the beginning of extraData[]
    279  * to get to a vector of 16-bit words with data at the following offsets:
    280  *
    281  * [-1]     Combining index for composition.
    282  *              Stored only if norm32&_NORM_COMBINES_ANY .
    283  * [0]      Lengths of the canonical and compatibility decomposition strings.
    284  *              Stored only if there are decompositions, i.e.,
    285  *              if norm32&(_NORM_QC_NFD|_NORM_QC_NFKD)
    286  *          High byte: length of NFKD, or 0 if none
    287  *          Low byte: length of NFD, or 0 if none
    288  *          Each length byte also has another flag:
    289  *              Bit 7 of a length byte is set if there are non-zero
    290  *              combining classes (cc's) associated with the respective
    291  *              decomposition. If this flag is set, then the decomposition
    292  *              is preceded by a 16-bit word that contains the
    293  *              leading and trailing cc's.
    294  *              Bits 6..0 of a length byte are the length of the
    295  *              decomposition string, not counting the cc word.
    296  * [1..n]   NFD
    297  * [n+1..]  NFKD
    298  *
    299  * Each of the two decompositions consists of up to two parts:
    300  * - The 16-bit words with the leading and trailing cc's.
    301  *   This is only stored if bit 7 of the corresponding length byte
    302  *   is set. In this case, at least one of the cc's is not zero.
    303  *   High byte: leading cc==cc of the first code point in the decomposition string
    304  *   Low byte: trailing cc==cc of the last code point in the decomposition string
    305  * - The decomposition string in UTF-16, with length code units.
    306  *
    307  *
    308  * - Combining indexes and combiningTable[]
    309  *
    310  * Combining indexes are stored at the [-1] offset of the extra data
    311  * if the character combines forward or backward with any other characters.
    312  * They are used for (re)composition in NF*C.
    313  * Values of combining indexes are arranged according to whether a character
    314  * combines forward, backward, or both ways:
    315  *    forward-only < both ways < backward-only
    316  *
    317  * The index values for forward-only and both-ways combining characters
    318  * are indexes into the combiningTable[].
    319  * The index values for backward-only combining characters are simply
    320  * incremented from the preceding index values to be unique.
    321  *
    322  * In the combiningTable[], a variable-length list
    323  * of variable-length (back-index, code point) pair entries is stored
    324  * for each forward-combining character.
    325  *
    326  * These back-indexes are the combining indexes of both-ways or backward-only
    327  * combining characters that the forward-combining character combines with.
    328  *
    329  * Each list is sorted in ascending order of back-indexes.
    330  * Each list is terminated with the last back-index having bit 15 set.
    331  *
    332  * Each pair (back-index, code point) takes up either 2 or 3
    333  * 16-bit words.
    334  * The first word of a list entry is the back-index, with its bit 15 set if
    335  * this is the last pair in the list.
    336  *
    337  * The second word contains flags in bits 15..13 that determine
    338  * if there is a third word and how the combined character is encoded:
    339  * 15   set if there is a third word in this list entry
    340  * 14   set if the result is a supplementary character
    341  * 13   set if the result itself combines forward
    342  *
    343  * According to these bits 15..14 of the second word,
    344  * the result character is encoded as follows:
    345  * 00 or 01 The result is <=0x1fff and stored in bits 12..0 of
    346  *          the second word.
    347  * 10       The result is 0x2000..0xffff and stored in the third word.
    348  *          Bits 12..0 of the second word are not used.
    349  * 11       The result is a supplementary character.
    350  *          Bits 9..0 of the leading surrogate are in bits 9..0 of
    351  *          the second word.
    352  *          Add 0xd800 to these bits to get the complete surrogate.
    353  *          Bits 12..10 of the second word are not used.
    354  *          The trailing surrogate is stored in the third word.
    355  *
    356  *
    357  * - FCD trie
    358  *
    359  * The FCD trie is very simple.
    360  * It is a folded trie with 16-bit data words.
    361  * In each word, the high byte contains the leading cc of the character,
    362  * and the low byte contains the trailing cc of the character.
    363  * These cc's are the cc's of the first and last code points in the
    364  * canonical decomposition of the character.
    365  *
    366  * Since all 16 bits are used for cc's, lead surrogates must be tested
    367  * by checking the code unit instead of the trie data.
    368  * This is done only if the 16-bit data word is not zero.
    369  * If the code unit is a leading surrogate and the data word is not zero,
    370  * then instead of cc's it contains the offset for the second trie lookup.
    371  *
    372  *
    373  * - Auxiliary trie and data
    374  *
    375  * The auxiliary 16-bit trie contains data for additional properties.
    376  * Bits
    377  * 15..13   reserved
    378  *     12   not NFC_Skippable (f) (formatVersion>=2.2)
    379  *     11   flag: not a safe starter for canonical closure
    380  *     10   composition exclusion
    381  *  9.. 0   index into extraData[] to FC_NFKC_Closure string
    382  *          (not for lead surrogate),
    383  *          or lead surrogate offset (for lead surrogate, if 9..0 not zero)
    384  *
    385  * - FC_NFKC_Closure strings in extraData[]
    386  *
    387  * Strings are either stored as a single code unit or as the length
    388  * followed by that many units.
    389  *   const UChar *s=extraData+(index from auxTrie data bits 9..0);
    390  *   int32_t length;
    391  *   if(*s<0xff00) {
    392  *     // s points to the single-unit string
    393  *     length=1;
    394  *   } else {
    395  *     length=*s&0xff;
    396  *     ++s;
    397  *   }
    398  *
    399  * Conditions for "NF* Skippable" from Mark Davis' com.ibm.text.UCD.NFSkippable:
    400  * (used in NormalizerTransliterator)
    401  *
    402  * A skippable character is
    403  * a) unassigned, or ALL of the following:
    404  * b) of combining class 0.
    405  * c) not decomposed by this normalization form.
    406  * AND if NFC or NFKC,
    407  * d) can never compose with a previous character.
    408  * e) can never compose with a following character.
    409  * f) can never change if another character is added.
    410  *    Example: a-breve might satisfy all but f, but if you
    411  *    add an ogonek it changes to a-ogonek + breve
    412  *
    413  * a)..e) must be tested from norm32.
    414  * Since f) is more complicated, the (not-)NFC_Skippable flag (f) is built
    415  * into the auxiliary trie.
    416  * The same bit is used for NFC and NFKC; (c) differs for them.
    417  * As usual, we build the "not skippable" flags so that unassigned
    418  * code points get a 0 bit.
    419  * This bit is only valid after (a)..(e) test FALSE; test NFD_NO before (f) as well.
    420  * Test Hangul LV syllables entirely in code.
    421  *
    422  *
    423  * - structure inside canonStartSets[]
    424  *
    425  * This array maps from code points c to sets of code points (USerializedSet).
    426  * The result sets are the code points whose canonical decompositions start
    427  * with c.
    428  *
    429  * canonStartSets[] contains the following sub-arrays:
    430  *
    431  * indexes[_NORM_SET_INDEX_TOP]
    432  *   - contains lengths of sub-arrays etc.
    433  *
    434  * startSets[indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH]-_NORM_SET_INDEX_TOP]
    435  *   - contains serialized sets (USerializedSet) of canonical starters for
    436  *     enumerating canonically equivalent strings
    437  *     indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH] includes _NORM_SET_INDEX_TOP
    438  *     for details about the structure see uset.c
    439  *
    440  * bmpTable[indexes[_NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH]]
    441  *   - a sorted search table for BMP code points whose results are
    442  *     either indexes to USerializedSets or single code points for
    443  *     single-code point sets;
    444  *     each entry is a pair of { code point, result } with result=(binary) yy xxxxxx xxxxxxxx
    445  *     if yy==01 then there is a USerializedSet at canonStartSets+x
    446  *     else build a USerializedSet with result as the single code point
    447  *
    448  * suppTable[indexes[_NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH]]
    449  *   - a sorted search table for supplementary code points whose results are
    450  *     either indexes to USerializedSets or single code points for
    451  *     single-code point sets;
    452  *     each entry is a triplet of { high16(cp), low16(cp), result }
    453  *     each code point's high-word may contain extra data in bits 15..5:
    454  *     if the high word has bit 15 set, then build a set with a single code point
    455  *     which is (((high16(cp)&0x1f00)<<8)|result;
    456  *     else there is a USerializedSet at canonStartSets+result
    457  *
    458  * FormatVersion 2.3 adds 2 serialized sets for normalization exclusions.
    459  * They are stored in the data file so that the runtime normalization code need
    460  * not depend on other properties and their data and implementation files.
    461  * The _NORM_SET_INDEX_NX_..._OFFSET offsets in the canonStartSets index table
    462  * give the location for each set.
    463  * There is no set stored for UNORM_NX_HANGUL because it's trivial to create
    464  * without using properties.
    465  *
    466  * Set contents:
    467  *
    468  * _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET (for UNORM_NX_CJK_COMPAT)
    469  *     [[:Ideographic:]&[:NFD_QC=No:]]
    470  *     =[CJK Ideographs]&[has canonical decomposition]
    471  *
    472  * _NORM_SET_INDEX_NX_UNICODE32_OFFSET (for UNORM_UNICODE_3_2)
    473  *     [:^Age=3.2:]
    474  *     =set with all code points that were not designated by the specified Unicode version
    475  *
    476  * _NORM_SET_INDEX_NX_RESERVED_OFFSET
    477  *     This is an offset that points to where the next, future set would start.
    478  *     Currently it indicates where the previous set ends, and thus its length.
    479  *     The name for this enum constant may in the future be applied to different
    480  *     index slots. In order to get the limit of a set, use its index slot and
    481  *     the immediately following one regardless of that one's enum name.
    482  */
    483 
    484 #endif /* #if !UCONFIG_NO_NORMALIZATION */
    485 
    486 #endif
    487