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unormimp.h (21227B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
*
*   Copyright (C) 2001-2011, International Business Machines
*   Corporation and others.  All Rights Reserved.
*
*******************************************************************************
*   file name:  unormimp.h
*   encoding:   UTF-8
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2001may25
*   created by: Markus W. Scherer
*/

#ifndef __UNORMIMP_H__
#define __UNORMIMP_H__

#include "unicode/utypes.h"

#if !UCONFIG_NO_NORMALIZATION

#include "udataswp.h"

/*
* The 2001-2010 implementation of the normalization code loads its data from
* unorm.icu, which is generated with the gennorm tool.
* The format of that file is described at the end of this file.
*/

/* norm32 value constants */
enum {
   /* quick check flags 0..3 set mean "no" for their forms */
   _NORM_QC_NFC=0x11,          /* no|maybe */
   _NORM_QC_NFKC=0x22,         /* no|maybe */
   _NORM_QC_NFD=4,             /* no */
   _NORM_QC_NFKD=8,            /* no */

   _NORM_QC_ANY_NO=0xf,

   /* quick check flags 4..5 mean "maybe" for their forms; test flags>=_NORM_QC_MAYBE */
   _NORM_QC_MAYBE=0x10,
   _NORM_QC_ANY_MAYBE=0x30,

   _NORM_QC_MASK=0x3f,

   _NORM_COMBINES_FWD=0x40,
   _NORM_COMBINES_BACK=0x80,
   _NORM_COMBINES_ANY=0xc0,

   _NORM_CC_SHIFT=8,           /* UnicodeData.txt combining class in bits 15..8 */
   _NORM_CC_MASK=0xff00,

   _NORM_EXTRA_SHIFT=16,               /* 16 bits for the index to UChars and other extra data */
   _NORM_EXTRA_INDEX_TOP=0xfc00,       /* start of surrogate specials after shift */

   _NORM_EXTRA_SURROGATE_MASK=0x3ff,
   _NORM_EXTRA_SURROGATE_TOP=0x3f0,    /* hangul etc. */

   _NORM_EXTRA_HANGUL=_NORM_EXTRA_SURROGATE_TOP,
   _NORM_EXTRA_JAMO_L,
   _NORM_EXTRA_JAMO_V,
   _NORM_EXTRA_JAMO_T
};

/* norm32 value constants using >16 bits */
#define _NORM_MIN_SPECIAL       0xfc000000
#define _NORM_SURROGATES_TOP    0xfff00000
#define _NORM_MIN_HANGUL        0xfff00000
#define _NORM_MIN_JAMO_V        0xfff20000
#define _NORM_JAMO_V_TOP        0xfff30000

/* value constants for auxTrie */
enum {
   _NORM_AUX_COMP_EX_SHIFT=10,
   _NORM_AUX_UNSAFE_SHIFT=11,
   _NORM_AUX_NFC_SKIPPABLE_F_SHIFT=12
};

#define _NORM_AUX_MAX_FNC           ((int32_t)1<<_NORM_AUX_COMP_EX_SHIFT)

#define _NORM_AUX_FNC_MASK          (uint32_t)(_NORM_AUX_MAX_FNC-1)
#define _NORM_AUX_COMP_EX_MASK      ((uint32_t)1<<_NORM_AUX_COMP_EX_SHIFT)
#define _NORM_AUX_UNSAFE_MASK       ((uint32_t)1<<_NORM_AUX_UNSAFE_SHIFT)
#define _NORM_AUX_NFC_SKIP_F_MASK   ((uint32_t)1<<_NORM_AUX_NFC_SKIPPABLE_F_SHIFT)

/* canonStartSets[0..31] contains indexes for what is in the array */
enum {
   _NORM_SET_INDEX_CANON_SETS_LENGTH,      /* number of uint16_t in canonical starter sets */
   _NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH, /* number of uint16_t in the BMP search table (contains pairs) */
   _NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH,/* number of uint16_t in the supplementary search table (contains triplets) */

   /* from formatVersion 2.3: */
   _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET,   /* uint16_t offset from canonStartSets[0] to the
                                              exclusion set for CJK compatibility characters */
   _NORM_SET_INDEX_NX_UNICODE32_OFFSET,    /* uint16_t offset from canonStartSets[0] to the
                                              exclusion set for Unicode 3.2 characters */
   _NORM_SET_INDEX_NX_RESERVED_OFFSET,     /* uint16_t offset from canonStartSets[0] to the
                                              end of the previous exclusion set */

   _NORM_SET_INDEX_TOP=32                  /* changing this requires a new formatVersion */
};

/* more constants for canonical starter sets */

/* 14 bit indexes to canonical USerializedSets */
#define _NORM_MAX_CANON_SETS            0x4000

/* single-code point BMP sets are encoded directly in the search table except if result=0x4000..0x7fff */
#define _NORM_CANON_SET_BMP_MASK        0xc000
#define _NORM_CANON_SET_BMP_IS_INDEX    0x4000

/* indexes[] value names */
enum {
   _NORM_INDEX_TRIE_SIZE,              /* number of bytes in normalization trie */
   _NORM_INDEX_UCHAR_COUNT,            /* number of UChars in extra data */

   _NORM_INDEX_COMBINE_DATA_COUNT,     /* number of uint16_t words for combining data */
   _NORM_INDEX_COMBINE_FWD_COUNT,      /* number of code points that combine forward */
   _NORM_INDEX_COMBINE_BOTH_COUNT,     /* number of code points that combine forward and backward */
   _NORM_INDEX_COMBINE_BACK_COUNT,     /* number of code points that combine backward */

   _NORM_INDEX_MIN_NFC_NO_MAYBE,       /* first code point with quick check NFC NO/MAYBE */
   _NORM_INDEX_MIN_NFKC_NO_MAYBE,      /* first code point with quick check NFKC NO/MAYBE */
   _NORM_INDEX_MIN_NFD_NO_MAYBE,       /* first code point with quick check NFD NO/MAYBE */
   _NORM_INDEX_MIN_NFKD_NO_MAYBE,      /* first code point with quick check NFKD NO/MAYBE */

   _NORM_INDEX_FCD_TRIE_SIZE,          /* number of bytes in FCD trie */

   _NORM_INDEX_AUX_TRIE_SIZE,          /* number of bytes in the auxiliary trie */
   _NORM_INDEX_CANON_SET_COUNT,        /* number of uint16_t in the array of serialized USet */

   _NORM_INDEX_TOP=32                  /* changing this requires a new formatVersion */
};

enum {
   /* FCD check: everything below this code point is known to have a 0 lead combining class */
   _NORM_MIN_WITH_LEAD_CC=0x300
};

enum {
   /**
    * Bit 7 of the length byte for a decomposition string in extra data is
    * a flag indicating whether the decomposition string is
    * preceded by a 16-bit word with the leading and trailing cc
    * of the decomposition (like for A-umlaut);
    * if not, then both cc's are zero (like for compatibility ideographs).
    */
   _NORM_DECOMP_FLAG_LENGTH_HAS_CC=0x80,
   /**
    * Bits 6..0 of the length byte contain the actual length.
    */
   _NORM_DECOMP_LENGTH_MASK=0x7f
};

/** Constants for options flags for normalization. */
enum {
   /** Options bit 0, do not decompose Hangul syllables. */
   UNORM_NX_HANGUL=1,
   /** Options bit 1, do not decompose CJK compatibility characters. */
   UNORM_NX_CJK_COMPAT=2
};

/**
* Description of the format of unorm.icu version 2.3.
*
* Main change from version 1 to version 2:
* Use of new, common UTrie instead of normalization-specific tries.
* Change to version 2.1: add third/auxiliary trie with associated data.
* Change to version 2.2: add skippable (f) flag data (_NORM_AUX_NFC_SKIP_F_MASK).
* Change to version 2.3: add serialized sets for normalization exclusions
*                        stored inside canonStartSets[]
*
* For more details of how to use the data structures see the code
* in unorm.cpp (runtime normalization code) and
* in gennorm.c and gennorm/store.c (build-time data generation).
*
* For the serialized format of UTrie see utrie.c/UTrieHeader.
*
* - Overall partition
*
* unorm.dat customarily begins with a UDataInfo structure, see udata.h and .c.
* After that there are the following structures:
*
* int32_t indexes[_NORM_INDEX_TOP];            -- _NORM_INDEX_TOP=32, see enum in this file
*
* UTrie normTrie;                              -- size in bytes=indexes[_NORM_INDEX_TRIE_SIZE]
* 
* uint16_t extraData[extraDataTop];            -- extraDataTop=indexes[_NORM_INDEX_UCHAR_COUNT]
*                                                 extraData[0] contains the number of units for
*                                                 FC_NFKC_Closure (formatVersion>=2.1)
*
* uint16_t combiningTable[combiningTableTop];  -- combiningTableTop=indexes[_NORM_INDEX_COMBINE_DATA_COUNT]
*                                                 combiningTableTop may include one 16-bit padding unit
*                                                 to make sure that fcdTrie is 32-bit-aligned
*
* UTrie fcdTrie;                               -- size in bytes=indexes[_NORM_INDEX_FCD_TRIE_SIZE]
*
* UTrie auxTrie;                               -- size in bytes=indexes[_NORM_INDEX_AUX_TRIE_SIZE]
*
* uint16_t canonStartSets[canonStartSetsTop]   -- canonStartSetsTop=indexes[_NORM_INDEX_CANON_SET_COUNT]
*                                                 serialized USets and binary search tables, see below
*
*
* The indexes array contains lengths and sizes of the following arrays and structures
* as well as the following values:
*  indexes[_NORM_INDEX_COMBINE_FWD_COUNT]=combineFwdTop
*      -- one more than the highest combining index computed for forward-only-combining characters
*  indexes[_NORM_INDEX_COMBINE_BOTH_COUNT]=combineBothTop-combineFwdTop
*      -- number of combining indexes computed for both-ways-combining characters
*  indexes[_NORM_INDEX_COMBINE_BACK_COUNT]=combineBackTop-combineBothTop
*      -- number of combining indexes computed for backward-only-combining characters
*
*  indexes[_NORM_INDEX_MIN_NF*_NO_MAYBE] (where *={ C, D, KC, KD })
*      -- first code point with a quick check NF* value of NO/MAYBE
*
*
* - Tries
*
* The main structures are two UTrie tables ("compact arrays"),
* each with one index array and one data array.
* See utrie.h and utrie.c.
*
*
* - Tries in unorm.dat
*
* The first trie (normTrie above)
* provides data for the NF* quick checks and normalization.
* The second trie (fcdTrie above) provides data just for FCD checks.
*
*
* - norm32 data words from the first trie
*
* The norm32Table contains one 32-bit word "norm32" per code point.
* It contains the following bit fields:
* 31..16   extra data index, _NORM_EXTRA_SHIFT is used to shift this field down
*          if this index is <_NORM_EXTRA_INDEX_TOP then it is an index into
*              extraData[] where variable-length normalization data for this
*              code point is found
*          if this index is <_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
*              then this is a norm32 for a leading surrogate, and the index
*              value is used together with the following trailing surrogate
*              code unit in the second trie access
*          if this index is >=_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
*              then this is a norm32 for a "special" character,
*              i.e., the character is a Hangul syllable or a Jamo
*              see _NORM_EXTRA_HANGUL etc.
*          generally, instead of extracting this index from the norm32 and
*              comparing it with the above constants,
*              the normalization code compares the entire norm32 value
*              with _NORM_MIN_SPECIAL, _NORM_SURROGATES_TOP, _NORM_MIN_HANGUL etc.
*
* 15..8    combining class (cc) according to UnicodeData.txt
*
*  7..6    _NORM_COMBINES_ANY flags, used in composition to see if a character
*              combines with any following or preceding character(s)
*              at all
*     7    _NORM_COMBINES_BACK
*     6    _NORM_COMBINES_FWD
*
*  5..0    quick check flags, set for "no" or "maybe", with separate flags for
*              each normalization form
*              the higher bits are "maybe" flags; for NF*D there are no such flags
*              the lower bits are "no" flags for all forms, in the same order
*              as the "maybe" flags,
*              which is (MSB to LSB): NFKD NFD NFKC NFC
*  5..4    _NORM_QC_ANY_MAYBE
*  3..0    _NORM_QC_ANY_NO
*              see further related constants
*
*
* - Extra data per code point
*
* "Extra data" is referenced by the index in norm32.
* It is variable-length data. It is only present, and only those parts
* of it are, as needed for a given character.
* The norm32 extra data index is added to the beginning of extraData[]
* to get to a vector of 16-bit words with data at the following offsets:
*
* [-1]     Combining index for composition.
*              Stored only if norm32&_NORM_COMBINES_ANY .
* [0]      Lengths of the canonical and compatibility decomposition strings.
*              Stored only if there are decompositions, i.e.,
*              if norm32&(_NORM_QC_NFD|_NORM_QC_NFKD)
*          High byte: length of NFKD, or 0 if none
*          Low byte: length of NFD, or 0 if none
*          Each length byte also has another flag:
*              Bit 7 of a length byte is set if there are non-zero
*              combining classes (cc's) associated with the respective
*              decomposition. If this flag is set, then the decomposition
*              is preceded by a 16-bit word that contains the
*              leading and trailing cc's.
*              Bits 6..0 of a length byte are the length of the
*              decomposition string, not counting the cc word.
* [1..n]   NFD
* [n+1..]  NFKD
*
* Each of the two decompositions consists of up to two parts:
* - The 16-bit words with the leading and trailing cc's.
*   This is only stored if bit 7 of the corresponding length byte
*   is set. In this case, at least one of the cc's is not zero.
*   High byte: leading cc==cc of the first code point in the decomposition string
*   Low byte: trailing cc==cc of the last code point in the decomposition string
* - The decomposition string in UTF-16, with length code units.
*
*
* - Combining indexes and combiningTable[]
*
* Combining indexes are stored at the [-1] offset of the extra data
* if the character combines forward or backward with any other characters.
* They are used for (re)composition in NF*C.
* Values of combining indexes are arranged according to whether a character
* combines forward, backward, or both ways:
*    forward-only < both ways < backward-only
*
* The index values for forward-only and both-ways combining characters
* are indexes into the combiningTable[].
* The index values for backward-only combining characters are simply
* incremented from the preceding index values to be unique.
*
* In the combiningTable[], a variable-length list
* of variable-length (back-index, code point) pair entries is stored
* for each forward-combining character.
*
* These back-indexes are the combining indexes of both-ways or backward-only
* combining characters that the forward-combining character combines with.
*
* Each list is sorted in ascending order of back-indexes.
* Each list is terminated with the last back-index having bit 15 set.
*
* Each pair (back-index, code point) takes up either 2 or 3
* 16-bit words.
* The first word of a list entry is the back-index, with its bit 15 set if
* this is the last pair in the list.
*
* The second word contains flags in bits 15..13 that determine
* if there is a third word and how the combined character is encoded:
* 15   set if there is a third word in this list entry
* 14   set if the result is a supplementary character
* 13   set if the result itself combines forward
*
* According to these bits 15..14 of the second word,
* the result character is encoded as follows:
* 00 or 01 The result is <=0x1fff and stored in bits 12..0 of
*          the second word.
* 10       The result is 0x2000..0xffff and stored in the third word.
*          Bits 12..0 of the second word are not used.
* 11       The result is a supplementary character.
*          Bits 9..0 of the leading surrogate are in bits 9..0 of
*          the second word.
*          Add 0xd800 to these bits to get the complete surrogate.
*          Bits 12..10 of the second word are not used.
*          The trailing surrogate is stored in the third word.
*
*
* - FCD trie
*
* The FCD trie is very simple.
* It is a folded trie with 16-bit data words.
* In each word, the high byte contains the leading cc of the character,
* and the low byte contains the trailing cc of the character.
* These cc's are the cc's of the first and last code points in the
* canonical decomposition of the character.
*
* Since all 16 bits are used for cc's, lead surrogates must be tested
* by checking the code unit instead of the trie data.
* This is done only if the 16-bit data word is not zero.
* If the code unit is a leading surrogate and the data word is not zero,
* then instead of cc's it contains the offset for the second trie lookup.
*
*
* - Auxiliary trie and data
*
* The auxiliary 16-bit trie contains data for additional properties.
* Bits
* 15..13   reserved
*     12   not NFC_Skippable (f) (formatVersion>=2.2)
*     11   flag: not a safe starter for canonical closure
*     10   composition exclusion
*  9.. 0   index into extraData[] to FC_NFKC_Closure string
*          (not for lead surrogate),
*          or lead surrogate offset (for lead surrogate, if 9..0 not zero)
*
* - FC_NFKC_Closure strings in extraData[]
*
* Strings are either stored as a single code unit or as the length
* followed by that many units.
*   const char16_t *s=extraData+(index from auxTrie data bits 9..0);
*   int32_t length;
*   if(*s<0xff00) {
*     // s points to the single-unit string
*     length=1;
*   } else {
*     length=*s&0xff;
*     ++s;
*   }
*
* Conditions for "NF* Skippable" from Mark Davis' com.ibm.text.UCD.NFSkippable:
* (used in NormalizerTransliterator)
*
* A skippable character is
* a) unassigned, or ALL of the following:
* b) of combining class 0.
* c) not decomposed by this normalization form.
* AND if NFC or NFKC,
* d) can never compose with a previous character.
* e) can never compose with a following character.
* f) can never change if another character is added.
*    Example: a-breve might satisfy all but f, but if you
*    add an ogonek it changes to a-ogonek + breve
*
* a)..e) must be tested from norm32.
* Since f) is more complicated, the (not-)NFC_Skippable flag (f) is built
* into the auxiliary trie.
* The same bit is used for NFC and NFKC; (c) differs for them.
* As usual, we build the "not skippable" flags so that unassigned
* code points get a 0 bit.
* This bit is only valid after (a)..(e) test false; test NFD_NO before (f) as well.
* Test Hangul LV syllables entirely in code.
*
*
* - structure inside canonStartSets[]
*
* This array maps from code points c to sets of code points (USerializedSet).
* The result sets are the code points whose canonical decompositions start
* with c.
*
* canonStartSets[] contains the following sub-arrays:
*
* indexes[_NORM_SET_INDEX_TOP]
*   - contains lengths of sub-arrays etc.
*
* startSets[indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH]-_NORM_SET_INDEX_TOP]
*   - contains serialized sets (USerializedSet) of canonical starters for
*     enumerating canonically equivalent strings
*     indexes[_NORM_SET_INDEX_CANON_SETS_LENGTH] includes _NORM_SET_INDEX_TOP
*     for details about the structure see uset.c
*
* bmpTable[indexes[_NORM_SET_INDEX_CANON_BMP_TABLE_LENGTH]]
*   - a sorted search table for BMP code points whose results are
*     either indexes to USerializedSets or single code points for
*     single-code point sets;
*     each entry is a pair of { code point, result } with result=(binary) yy xxxxxx xxxxxxxx
*     if yy==01 then there is a USerializedSet at canonStartSets+x
*     else build a USerializedSet with result as the single code point
*
* suppTable[indexes[_NORM_SET_INDEX_CANON_SUPP_TABLE_LENGTH]]
*   - a sorted search table for supplementary code points whose results are
*     either indexes to USerializedSets or single code points for
*     single-code point sets;
*     each entry is a triplet of { high16(cp), low16(cp), result }
*     each code point's high-word may contain extra data in bits 15..5:
*     if the high word has bit 15 set, then build a set with a single code point
*     which is (((high16(cp)&0x1f00)<<8)|result;
*     else there is a USerializedSet at canonStartSets+result
*
* FormatVersion 2.3 adds 2 serialized sets for normalization exclusions.
* They are stored in the data file so that the runtime normalization code need
* not depend on other properties and their data and implementation files.
* The _NORM_SET_INDEX_NX_..._OFFSET offsets in the canonStartSets index table
* give the location for each set.
* There is no set stored for UNORM_NX_HANGUL because it's trivial to create
* without using properties.
*
* Set contents:
*
* _NORM_SET_INDEX_NX_CJK_COMPAT_OFFSET (for UNORM_NX_CJK_COMPAT)
*     [[:Ideographic:]&[:NFD_QC=No:]]
*     =[CJK Ideographs]&[has canonical decomposition]
*
* _NORM_SET_INDEX_NX_UNICODE32_OFFSET (for UNORM_UNICODE_3_2)
*     [:^Age=3.2:]
*     =set with all code points that were not designated by the specified Unicode version
*
* _NORM_SET_INDEX_NX_RESERVED_OFFSET
*     This is an offset that points to where the next, future set would start.
*     Currently it indicates where the previous set ends, and thus its length.
*     The name for this enum constant may in the future be applied to different
*     index slots. In order to get the limit of a set, use its index slot and
*     the immediately following one regardless of that one's enum name.
*/

#endif /* #if !UCONFIG_NO_NORMALIZATION */

#endif