Check in the pristine copy of ICU 4.6...

icu46/source/common/unormimp.h

+/*
+*******************************************************************************
+*
+*   Copyright (C) 2001-2010, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+*******************************************************************************
+*   file name:  unormimp.h
+*   encoding:   US-ASCII
+*   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. @draft ICU 2.6 */
+enum {
+    /** Options bit 0, do not decompose Hangul syllables. @draft ICU 2.6 */
+    UNORM_NX_HANGUL=1,
+    /** Options bit 1, do not decompose CJK compatibility characters. @draft ICU 2.6 */
+    UNORM_NX_CJK_COMPAT=2
+};
+
+/**
+ * Swap unorm.icu. See udataswp.h.
+ * @internal
+ */
+U_CAPI int32_t U_EXPORT2
+unorm_swap(const UDataSwapper *ds,
+           const void *inData, int32_t length, void *outData,
+           UErrorCode *pErrorCode);
+
+/**
+ * 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