453 lines
18 KiB
C
453 lines
18 KiB
C
/*
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*******************************************************************************
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*
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* Copyright (C) 2001, International Business Machines
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* Corporation and others. All Rights Reserved.
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*
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*******************************************************************************
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* file name: unormimp.h
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* encoding: US-ASCII
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* tab size: 8 (not used)
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* indentation:4
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*
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* created on: 2001may25
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* created by: Markus W. Scherer
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*/
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#ifndef __UNORMIMP_H__
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#define __UNORMIMP_H__
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#include "unicode/utypes.h"
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#include "unicode/uiter.h"
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#include "unicode/unorm.h"
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#include "utrie.h"
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#include "ustr_imp.h"
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/*
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* This new implementation of the normalization code loads its data from
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* unorm.dat, which is generated with the gennorm tool.
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* The format of that file is described at the end of this file.
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*/
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/* norm32 value constants */
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enum {
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/* quick check flags 0..3 set mean "no" for their forms */
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_NORM_QC_NFC=0x11, /* no|maybe */
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_NORM_QC_NFKC=0x22, /* no|maybe */
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_NORM_QC_NFD=4, /* no */
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_NORM_QC_NFKD=8, /* no */
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_NORM_QC_ANY_NO=0xf,
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/* quick check flags 4..5 mean "maybe" for their forms; test flags>=_NORM_QC_MAYBE */
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_NORM_QC_MAYBE=0x10,
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_NORM_QC_ANY_MAYBE=0x30,
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_NORM_QC_MASK=0x3f,
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_NORM_COMBINES_FWD=0x40,
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_NORM_COMBINES_BACK=0x80,
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_NORM_COMBINES_ANY=0xc0,
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_NORM_CC_SHIFT=8, /* UnicodeData.txt combining class in bits 15..8 */
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_NORM_CC_MASK=0xff00,
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_NORM_EXTRA_SHIFT=16, /* 16 bits for the index to UChars and other extra data */
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_NORM_EXTRA_INDEX_TOP=0xfc00, /* start of surrogate specials after shift */
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_NORM_EXTRA_SURROGATE_MASK=0x3ff,
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_NORM_EXTRA_SURROGATE_TOP=0x3f0, /* hangul etc. */
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_NORM_EXTRA_HANGUL=_NORM_EXTRA_SURROGATE_TOP,
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_NORM_EXTRA_JAMO_L, /* ### not used */
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_NORM_EXTRA_JAMO_V,
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_NORM_EXTRA_JAMO_T
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};
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/* norm32 value constants using >16 bits */
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#define _NORM_MIN_SPECIAL 0xfc000000
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#define _NORM_SURROGATES_TOP 0xfff00000
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#define _NORM_MIN_HANGUL 0xfff00000
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#define _NORM_MIN_JAMO_V 0xfff20000
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#define _NORM_JAMO_V_TOP 0xfff30000
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/* indexes[] value names */
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enum {
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_NORM_INDEX_TRIE_SIZE, /* number of bytes in normalization trie */
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_NORM_INDEX_UCHAR_COUNT, /* number of UChars in extra data */
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_NORM_INDEX_COMBINE_DATA_COUNT, /* number of uint16_t words for combining data */
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_NORM_INDEX_COMBINE_FWD_COUNT, /* number of code points that combine forward */
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_NORM_INDEX_COMBINE_BOTH_COUNT, /* number of code points that combine forward and backward */
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_NORM_INDEX_COMBINE_BACK_COUNT, /* number of code points that combine backward */
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_NORM_INDEX_MIN_NFC_NO_MAYBE, /* first code point with quick check NFC NO/MAYBE */
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_NORM_INDEX_MIN_NFKC_NO_MAYBE, /* first code point with quick check NFKC NO/MAYBE */
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_NORM_INDEX_MIN_NFD_NO_MAYBE, /* first code point with quick check NFD NO/MAYBE */
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_NORM_INDEX_MIN_NFKD_NO_MAYBE, /* first code point with quick check NFKD NO/MAYBE */
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_NORM_INDEX_FCD_TRIE_SIZE, /* number of bytes in FCD trie */
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_NORM_INDEX_TOP=32 /* changing this requires a new formatVersion */
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};
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enum {
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/* FCD check: everything below this code point is known to have a 0 lead combining class */
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_NORM_MIN_WITH_LEAD_CC=0x300
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};
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enum {
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/**
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* Bit 7 of the length byte for a decomposition string in extra data is
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* a flag indicating whether the decomposition string is
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* preceded by a 16-bit word with the leading and trailing cc
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* of the decomposition (like for A-umlaut);
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* if not, then both cc's are zero (like for compatibility ideographs).
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*/
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_NORM_DECOMP_FLAG_LENGTH_HAS_CC=0x80,
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/**
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* Bits 6..0 of the length byte contain the actual length.
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*/
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_NORM_DECOMP_LENGTH_MASK=0x7f
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};
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/**
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* Is the normalizer data loaded?
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* This is used internally before other internal normalizer functions
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* are called.
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* It saves this check in each of many normalization calls that
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* are made for, e.g., collation.
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*
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* @param pErrorCode as usual
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* @return boolean value for whether the normalization data is loaded
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*
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* @internal
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*/
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U_CAPI UBool U_EXPORT2
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unorm_haveData(UErrorCode *pErrorCode);
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/**
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* Internal API for normalizing.
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* Does not check for bad input.
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* @internal
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*/
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U_CAPI int32_t U_EXPORT2
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unorm_internalNormalize(UChar *dest, int32_t destCapacity,
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const UChar *src, int32_t srcLength,
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UNormalizationMode mode, UBool ignoreHangul,
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UErrorCode *pErrorCode);
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/**
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* internal API, used by normlzr.cpp
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* @internal
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*/
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U_CAPI int32_t U_EXPORT2
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unorm_decompose(UChar *dest, int32_t destCapacity,
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const UChar *src, int32_t srcLength,
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UBool compat, UBool ignoreHangul,
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UErrorCode *pErrorCode);
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/**
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* internal API, used by normlzr.cpp
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* @internal
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*/
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U_CAPI int32_t U_EXPORT2
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unorm_compose(UChar *dest, int32_t destCapacity,
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const UChar *src, int32_t srcLength,
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UBool compat, UBool ignoreHangul,
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UErrorCode *pErrorCode);
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/**
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* Internal API, used by collation code.
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* Get access to the internal FCD trie table to be able to perform
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* incremental, per-code unit, FCD checks in collation.
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* One pointer is sufficient because the trie index values are offset
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* by the index size, so that the same pointer is used to access the trie data.
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* @internal
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*/
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U_CAPI const uint16_t * U_EXPORT2
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unorm_getFCDTrie(UErrorCode *pErrorCode);
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#ifdef XP_CPLUSPLUS
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U_NAMESPACE_BEGIN
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/**
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* Internal API, used by collation code.
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* Get the FCD value for a code unit, with
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* bits 15..8 lead combining class
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* bits 7..0 trail combining class
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*
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* If c is a lead surrogate and the value is not 0,
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* then instead of combining classes the value
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* is used in unorm_getFCD16FromSurrogatePair() to get the real value
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* of the supplementary code point.
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*
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* @internal
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*/
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inline uint16_t
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unorm_getFCD16(const uint16_t *fcdTrieIndex, UChar c) {
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return
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fcdTrieIndex[
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(fcdTrieIndex[
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c>>UTRIE_SHIFT
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]<<UTRIE_INDEX_SHIFT)+
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(c&UTRIE_MASK)
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];
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}
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/**
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* Internal API, used by collation code.
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* Get the FCD value for a supplementary code point, with
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* bits 15..8 lead combining class
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* bits 7..0 trail combining class
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*
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* @param fcd16 The FCD value for the lead surrogate, not 0.
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* @param c2 The trail surrogate code unit.
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*
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* @internal
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*/
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inline uint16_t
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unorm_getFCD16FromSurrogatePair(const uint16_t *fcdTrieIndex, uint16_t fcd16, UChar c2) {
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return
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fcdTrieIndex[
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(fcdTrieIndex[
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(int32_t)fcd16+((c2&0x3ff)>>UTRIE_SHIFT)
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]<<UTRIE_INDEX_SHIFT)+
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(c2&UTRIE_MASK)
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];
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}
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U_NAMESPACE_END
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#endif
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/**
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* Description of the format of unorm.dat. ### TODO describe 2.0 with UTrie
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*
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* For more details of how to use the data structures see the code
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* in unorm.cpp (runtime normalization code) and
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* in gennorm.c and gennorm/store.c (build-time data generation).
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*
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*
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* - Overall partition
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*
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* unorm.dat customarily begins with a UDataInfo structure, see udata.h and .c.
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* After that there are the following arrays:
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*
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* uint16_t indexes[_NORM_INDEX_TOP]; -- _NORM_INDEX_TOP=indexes[0]=indexes[_NORM_INDEX_COUNT]
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*
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* uint16_t stage1[stage1Top]; -- stage1Top=indexes[_NORM_INDEX_TRIE_INDEX_COUNT]
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* uint32_t norm32Table[norm32TableTop]; -- norm32TableTop=indexes[_NORM_INDEX_TRIE_DATA_COUNT]
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*
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* uint16_t extraData[extraDataTop]; -- extraDataTop=indexes[_NORM_INDEX_UCHAR_COUNT]
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* uint16_t combiningTable[combiningTableTop]; -- combiningTableTop=indexes[_NORM_INDEX_COMBINE_DATA_COUNT]
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*
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* uint16_t fcdStage1[fcdStage1Top]; -- fcdStage1Top=indexes[_NORM_INDEX_FCD_TRIE_INDEX_COUNT]
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* uint16_t fcdTable[fcdTableTop]; -- fcdTableTop=indexes[_NORM_INDEX_FCD_TRIE_DATA_COUNT]
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*
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*
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* The indexes array contains lengths of the following arrays (and its own length)
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* as well as the following values:
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* indexes[_NORM_INDEX_COUNT]=_NORM_INDEX_TOP
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* -- length of indexes[]
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* indexes[_NORM_INDEX_TRIE_SHIFT]=_NORM_TRIE_SHIFT
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* -- for trie indexes: shift UChars by this much
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* indexes[_NORM_INDEX_COMBINE_FWD_COUNT]=combineFwdTop
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* -- one more than the highest combining index computed for forward-only-combining characters
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* indexes[_NORM_INDEX_COMBINE_BOTH_COUNT]=combineBothTop-combineFwdTop
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* -- number of combining indexes computed for both-ways-combining characters
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* indexes[_NORM_INDEX_COMBINE_BACK_COUNT]=combineBackTop-combineBothTop
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* -- number of combining indexes computed for backward-only-combining characters
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*
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*
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* - Tries
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*
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* The main structures are two trie tables ("compact arrays"),
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* each with one index array and one data array.
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* Generally, tries use the upper bits of an input value to access the index array,
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* which results in an index to the data array where a block of values is stored.
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* The lower bits of the same input value are then used to index inside that data
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* block to get to the specific data element for the input value.
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*
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* In order to use each trie with a single base pointer, the index values in
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* the index array are offset by the length of the index array.
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* With this, a base pointer to the trie index array is also directly used
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* with the index value to access the trie data array.
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* For example, if trieIndex[n] refers to offset m in trieData[] then
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* the actual value is q=trieIndex[n]=lengthof(trieIndex)+m
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* and you access trieIndex[q] instead of trieData[m].
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*
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*
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* - Folded tries
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*
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* The tries here are extended to work for lookups on UTF-16 strings with
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* supplementary characters encoded with surrogate pairs.
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* They are called "folded tries".
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*
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* Each 16-bit code unit (UChar, not code point UChar32) is looked up this way.
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* If there is relevant data for any given code unit, then the data or the code unit
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* must be checked for whether it is a leading surrogate.
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* If so, then the data contains an offset that is used together with the following
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* trailing surrogate code unit value for a second trie access.
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* This uses a portion of the index array beyond what is accessible with 16-bit units,
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* i.e., it uses the part of the trie index array starting at its index
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* 0x10000>>_NORM_TRIE_SHIFT.
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*
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* Such folded tries are useful when processing UTF-16 strings, especially if
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* many code points do not have relevant data, so that the check for
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* surrogates and the second trie lookup are rarely performed.
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* It avoids the overhead of a double-index trie that is necessary if the input
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* is always with 21-bit code points.
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*
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*
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* - Tries in unorm.dat
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*
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* The first trie consists of the stage1 and the norm32Table arrays.
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* It provides data for the NF* quick checks and normalization.
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* The second trie consists of the fcdStage1 and the fcdTable arrays
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* and provides data just for FCD checks.
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*
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*
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* - norm32 data words from the first trie
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*
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* The norm32Table contains one 32-bit word "norm32" per code point.
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* It contains the following bit fields:
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* 31..16 extra data index, _NORM_EXTRA_SHIFT is used to shift this field down
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* if this index is <_NORM_EXTRA_INDEX_TOP then it is an index into
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* extraData[] where variable-length normalization data for this
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* code point is found
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* if this index is <_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
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* then this is a norm32 for a leading surrogate, and the index
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* value is used together with the following trailing surrogate
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* code unit in the second trie access
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* if this index is >=_NORM_EXTRA_INDEX_TOP+_NORM_EXTRA_SURROGATE_TOP
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* then this is a norm32 for a "special" character,
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* i.e., the character is a Hangul syllable or a Jamo
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* see _NORM_EXTRA_HANGUL etc.
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* generally, instead of extracting this index from the norm32 and
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* comparing it with the above constants,
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* the normalization code compares the entire norm32 value
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* with _NORM_MIN_SPECIAL, _NORM_SURROGATES_TOP, _NORM_MIN_HANGUL etc.
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*
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* 15..8 combining class (cc) according to UnicodeData.txt
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*
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* 7..6 _NORM_COMBINES_ANY flags, used in composition to see if a character
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* combines with any following or preceding character(s)
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* at all
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* 7 _NORM_COMBINES_BACK
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* 6 _NORM_COMBINES_FWD
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*
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* 5..0 quick check flags, set for "no" or "maybe", with separate flags for
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* each normalization form
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* the higher bits are "maybe" flags; for NF*D there are no such flags
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* the lower bits are "no" flags for all forms, in the same order
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* as the "maybe" flags,
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* which is (MSB to LSB): NFKD NFD NFKC NFC
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* 5..4 _NORM_QC_ANY_MAYBE
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* 3..0 _NORM_QC_ANY_NO
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* see further related constants
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*
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*
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* - Extra data per code point
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*
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* "Extra data" is referenced by the index in norm32.
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* It is variable-length data. It is only present, and only those parts
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* of it are, as needed for a given character.
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* The norm32 extra data index is added to the beginning of extraData[]
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* to get to a vector of 16-bit words with data at the following offsets:
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*
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* [-1] Combining index for composition.
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* Stored only if norm32&_NORM_COMBINES_ANY .
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* [0] Lengths of the canonical and compatibility decomposition strings.
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* Stored only if there are decompositions, i.e.,
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* if norm32&(_NORM_QC_NFD|_NORM_QC_NFKD)
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* High byte: length of NFKD, or 0 if none
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* Low byte: length of NFD, or 0 if none
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* Each length byte also has another flag:
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* Bit 7 of a length byte is set if there are non-zero
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* combining classes (cc's) associated with the respective
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* decomposition. If this flag is set, then the decomposition
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* is preceded by a 16-bit word that contains the
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* leading and trailing cc's.
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* Bits 6..0 of a length byte are the length of the
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* decomposition string, not counting the cc word.
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* [1..n] NFD
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* [n+1..] NFKD
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*
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* Each of the two decompositions consists of up to two parts:
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* - The 16-bit words with the leading and trailing cc's.
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* This is only stored if bit 7 of the corresponding length byte
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* is set. In this case, at least one of the cc's is not zero.
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* High byte: leading cc==cc of the first code point in the decomposition string
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* Low byte: trailing cc==cc of the last code point in the decomposition string
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* - The decomposition string in UTF-16, with length code units.
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*
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*
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* - Combining indexes and combiningTable[]
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*
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* Combining indexes are stored at the [-1] offset of the extra data
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* if the character combines forward or backward with any other characters.
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* They are used for (re)composition in NF*C.
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* Values of combining indexes are arranged according to whether a character
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* combines forward, backward, or both ways:
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* forward-only < both ways < backward-only
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*
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* The index values for forward-only and both-ways combining characters
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* are indexes into the combiningTable[].
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* The index values for backward-only combining characters are simply
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* incremented from the preceding index values to be unique.
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*
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* In the combiningTable[], a variable-length list
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* of variable-length (back-index, code point) pair entries is stored
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* for each forward-combining character.
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*
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* These back-indexes are the combining indexes of both-ways or backward-only
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* combining characters that the forward-combining character combines with.
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*
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* Each list is sorted in ascending order of back-indexes.
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* Each list is terminated with the last back-index having bit 15 set.
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*
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* Each pair (back-index, code point) takes up either 2 or 3
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* 16-bit words.
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* The first word of a list entry is the back-index, with its bit 15 set if
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* this is the last pair in the list.
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*
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* The second word contains flags in bits 15..13 that determine
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* if there is a third word and how the combined character is encoded:
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* 15 set if there is a third word in this list entry
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* 14 set if the result is a supplementary character
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* 13 set if the result itself combines forward
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*
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* According to these bits 15..14 of the second word,
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* the result character is encoded as follows:
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* 00 or 01 The result is <=0x1fff and stored in bits 12..0 of
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* the second word.
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* 10 The result is 0x2000..0xffff and stored in the third word.
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* Bits 12..0 of the second word are not used.
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* 11 The result is a supplementary character.
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* Bits 9..0 of the leading surrogate are in bits 9..0 of
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* the second word.
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* Add 0xd800 to these bits to get the complete surrogate.
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* Bits 12..10 of the second word are not used.
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* The trailing surrogate is stored in the third word.
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*
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*
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* - FCD trie
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*
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* The FCD trie is very simple.
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* It is a folded trie with 16-bit data words.
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* In each word, the high byte contains the leading cc of the character,
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* and the low byte contains the trailing cc of the character.
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* These cc's are the cc's of the first and last code points in the
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* canonical decomposition of the character.
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*
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* Since all 16 bits are used for cc's, lead surrogates must be tested
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* by checking the code unit instead of the trie data.
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* This is done only if the 16-bit data word is not zero.
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* If the code unit is a leading surrogate and the data word is not zero,
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* then instead of cc's it contains the offset for the second trie lookup.
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*/
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#endif
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