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scuffed-code/icu4c/source/common/unormimp.h
Andy Heninger 04448b004f ICU-12764 UTF-8 source files, update file encoding comments. 
X-SVN-Rev: 39641
2017-02-03 18:57:23 +00:00

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// © 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 UChar *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
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