1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4*******************************************************************************
5* Copyright (C) 2013-2015, International Business Machines
6* Corporation and others. All Rights Reserved.
7*******************************************************************************
8* collationfastlatin.h
9*
10* created on: 2013aug09
11* created by: Markus W. Scherer
12*/
13
14#ifndef __COLLATIONFASTLATIN_H__
15#define __COLLATIONFASTLATIN_H__
16
17#include "unicode/utypes.h"
18
19#if !UCONFIG_NO_COLLATION
20
21U_NAMESPACE_BEGIN
22
23struct CollationData;
24struct CollationSettings;
25
26class U_I18N_API CollationFastLatin /* all static */ {
27public:
28 /**
29 * Fast Latin format version (one byte 1..FF).
30 * Must be incremented for any runtime-incompatible changes,
31 * in particular, for changes to any of the following constants.
32 *
33 * When the major version number of the main data format changes,
34 * we can reset this fast Latin version to 1.
35 */
36 static const uint16_t VERSION = 2;
37
38 static const int32_t LATIN_MAX = 0x17f;
39 static const int32_t LATIN_LIMIT = LATIN_MAX + 1;
40
41 static const int32_t LATIN_MAX_UTF8_LEAD = 0xc5; // UTF-8 lead byte of LATIN_MAX
42
43 static const int32_t PUNCT_START = 0x2000;
44 static const int32_t PUNCT_LIMIT = 0x2040;
45
46 // excludes U+FFFE & U+FFFF
47 static const int32_t NUM_FAST_CHARS = LATIN_LIMIT + (PUNCT_LIMIT - PUNCT_START);
48
49 // Note on the supported weight ranges:
50 // Analysis of UCA 6.3 and CLDR 23 non-search tailorings shows that
51 // the CEs for characters in the above ranges, excluding expansions with length >2,
52 // excluding contractions of >2 characters, and other restrictions
53 // (see the builder's getCEsFromCE32()),
54 // use at most about 150 primary weights,
55 // where about 94 primary weights are possibly-variable (space/punct/symbol/currency),
56 // at most 4 secondary before-common weights,
57 // at most 4 secondary after-common weights,
58 // at most 16 secondary high weights (in secondary CEs), and
59 // at most 4 tertiary after-common weights.
60 // The following ranges are designed to support slightly more weights than that.
61 // (en_US_POSIX is unusual: It creates about 64 variable + 116 Latin primaries.)
62
63 // Digits may use long primaries (preserving more short ones)
64 // or short primaries (faster) without changing this data structure.
65 // (If we supported numeric collation, then digits would have to have long primaries
66 // so that special handling does not affect the fast path.)
67
68 static const uint32_t SHORT_PRIMARY_MASK = 0xfc00; // bits 15..10
69 static const uint32_t INDEX_MASK = 0x3ff; // bits 9..0 for expansions & contractions
70 static const uint32_t SECONDARY_MASK = 0x3e0; // bits 9..5
71 static const uint32_t CASE_MASK = 0x18; // bits 4..3
72 static const uint32_t LONG_PRIMARY_MASK = 0xfff8; // bits 15..3
73 static const uint32_t TERTIARY_MASK = 7; // bits 2..0
74 static const uint32_t CASE_AND_TERTIARY_MASK = CASE_MASK | TERTIARY_MASK;
75
76 static const uint32_t TWO_SHORT_PRIMARIES_MASK =
77 (SHORT_PRIMARY_MASK << 16) | SHORT_PRIMARY_MASK; // 0xfc00fc00
78 static const uint32_t TWO_LONG_PRIMARIES_MASK =
79 (LONG_PRIMARY_MASK << 16) | LONG_PRIMARY_MASK; // 0xfff8fff8
80 static const uint32_t TWO_SECONDARIES_MASK =
81 (SECONDARY_MASK << 16) | SECONDARY_MASK; // 0x3e003e0
82 static const uint32_t TWO_CASES_MASK =
83 (CASE_MASK << 16) | CASE_MASK; // 0x180018
84 static const uint32_t TWO_TERTIARIES_MASK =
85 (TERTIARY_MASK << 16) | TERTIARY_MASK; // 0x70007
86
87 /**
88 * Contraction with one fast Latin character.
89 * Use INDEX_MASK to find the start of the contraction list after the fixed table.
90 * The first entry contains the default mapping.
91 * Otherwise use CONTR_CHAR_MASK for the contraction character index
92 * (in ascending order).
93 * Use CONTR_LENGTH_SHIFT for the length of the entry
94 * (1=BAIL_OUT, 2=one CE, 3=two CEs).
95 *
96 * Also, U+0000 maps to a contraction entry, so that the fast path need not
97 * check for NUL termination.
98 * It usually maps to a contraction list with only the completely ignorable default value.
99 */
100 static const uint32_t CONTRACTION = 0x400;
101 /**
102 * An expansion encodes two CEs.
103 * Use INDEX_MASK to find the pair of CEs after the fixed table.
104 *
105 * The higher a mini CE value, the easier it is to process.
106 * For expansions and higher, no context needs to be considered.
107 */
108 static const uint32_t EXPANSION = 0x800;
109 /**
110 * Encodes one CE with a long/low mini primary (there are 128).
111 * All potentially-variable primaries must be in this range,
112 * to make the short-primary path as fast as possible.
113 */
114 static const uint32_t MIN_LONG = 0xc00;
115 static const uint32_t LONG_INC = 8;
116 static const uint32_t MAX_LONG = 0xff8;
117 /**
118 * Encodes one CE with a short/high primary (there are 60),
119 * plus a secondary CE if the secondary weight is high.
120 * Fast handling: At least all letter primaries should be in this range.
121 */
122 static const uint32_t MIN_SHORT = 0x1000;
123 static const uint32_t SHORT_INC = 0x400;
124 /** The highest primary weight is reserved for U+FFFF. */
125 static const uint32_t MAX_SHORT = SHORT_PRIMARY_MASK;
126
127 static const uint32_t MIN_SEC_BEFORE = 0; // must add SEC_OFFSET
128 static const uint32_t SEC_INC = 0x20;
129 static const uint32_t MAX_SEC_BEFORE = MIN_SEC_BEFORE + 4 * SEC_INC; // 5 before common
130 static const uint32_t COMMON_SEC = MAX_SEC_BEFORE + SEC_INC;
131 static const uint32_t MIN_SEC_AFTER = COMMON_SEC + SEC_INC;
132 static const uint32_t MAX_SEC_AFTER = MIN_SEC_AFTER + 5 * SEC_INC; // 6 after common
133 static const uint32_t MIN_SEC_HIGH = MAX_SEC_AFTER + SEC_INC; // 20 high secondaries
134 static const uint32_t MAX_SEC_HIGH = SECONDARY_MASK;
135
136 /**
137 * Lookup: Add this offset to secondary weights, except for completely ignorable CEs.
138 * Must be greater than any special value, e.g., MERGE_WEIGHT.
139 * The exact value is not relevant for the format version.
140 */
141 static const uint32_t SEC_OFFSET = SEC_INC;
142 static const uint32_t COMMON_SEC_PLUS_OFFSET = COMMON_SEC + SEC_OFFSET;
143
144 static const uint32_t TWO_SEC_OFFSETS =
145 (SEC_OFFSET << 16) | SEC_OFFSET; // 0x200020
146 static const uint32_t TWO_COMMON_SEC_PLUS_OFFSET =
147 (COMMON_SEC_PLUS_OFFSET << 16) | COMMON_SEC_PLUS_OFFSET;
148
149 static const uint32_t LOWER_CASE = 8; // case bits include this offset
150 static const uint32_t TWO_LOWER_CASES = (LOWER_CASE << 16) | LOWER_CASE; // 0x80008
151
152 static const uint32_t COMMON_TER = 0; // must add TER_OFFSET
153 static const uint32_t MAX_TER_AFTER = 7; // 7 after common
154
155 /**
156 * Lookup: Add this offset to tertiary weights, except for completely ignorable CEs.
157 * Must be greater than any special value, e.g., MERGE_WEIGHT.
158 * Must be greater than case bits as well, so that with combined case+tertiary weights
159 * plus the offset the tertiary bits does not spill over into the case bits.
160 * The exact value is not relevant for the format version.
161 */
162 static const uint32_t TER_OFFSET = SEC_OFFSET;
163 static const uint32_t COMMON_TER_PLUS_OFFSET = COMMON_TER + TER_OFFSET;
164
165 static const uint32_t TWO_TER_OFFSETS = (TER_OFFSET << 16) | TER_OFFSET;
166 static const uint32_t TWO_COMMON_TER_PLUS_OFFSET =
167 (COMMON_TER_PLUS_OFFSET << 16) | COMMON_TER_PLUS_OFFSET;
168
169 static const uint32_t MERGE_WEIGHT = 3;
170 static const uint32_t EOS = 2; // end of string
171 static const uint32_t BAIL_OUT = 1;
172
173 /**
174 * Contraction result first word bits 8..0 contain the
175 * second contraction character, as a char index 0..NUM_FAST_CHARS-1.
176 * Each contraction list is terminated with a word containing CONTR_CHAR_MASK.
177 */
178 static const uint32_t CONTR_CHAR_MASK = 0x1ff;
179 /**
180 * Contraction result first word bits 10..9 contain the result length:
181 * 1=bail out, 2=one mini CE, 3=two mini CEs
182 */
183 static const uint32_t CONTR_LENGTH_SHIFT = 9;
184
185 /**
186 * Comparison return value when the regular comparison must be used.
187 * The exact value is not relevant for the format version.
188 */
189 static const int32_t BAIL_OUT_RESULT = -2;
190
191 static inline int32_t getCharIndex(UChar c) {
192 if(c <= LATIN_MAX) {
193 return c;
194 } else if(PUNCT_START <= c && c < PUNCT_LIMIT) {
195 return c - (PUNCT_START - LATIN_LIMIT);
196 } else {
197 // Not a fast Latin character.
198 // Note: U+FFFE & U+FFFF are forbidden in tailorings
199 // and thus do not occur in any contractions.
200 return -1;
201 }
202 }
203
204 /**
205 * Computes the options value for the compare functions
206 * and writes the precomputed primary weights.
207 * Returns -1 if the Latin fastpath is not supported for the data and settings.
208 * The capacity must be LATIN_LIMIT.
209 */
210 static int32_t getOptions(const CollationData *data, const CollationSettings &settings,
211 uint16_t *primaries, int32_t capacity);
212
213 static int32_t compareUTF16(const uint16_t *table, const uint16_t *primaries, int32_t options,
214 const UChar *left, int32_t leftLength,
215 const UChar *right, int32_t rightLength);
216
217 static int32_t compareUTF8(const uint16_t *table, const uint16_t *primaries, int32_t options,
218 const uint8_t *left, int32_t leftLength,
219 const uint8_t *right, int32_t rightLength);
220
221private:
222 static uint32_t lookup(const uint16_t *table, UChar32 c);
223 static uint32_t lookupUTF8(const uint16_t *table, UChar32 c,
224 const uint8_t *s8, int32_t &sIndex, int32_t sLength);
225 static uint32_t lookupUTF8Unsafe(const uint16_t *table, UChar32 c,
226 const uint8_t *s8, int32_t &sIndex);
227
228 static uint32_t nextPair(const uint16_t *table, UChar32 c, uint32_t ce,
229 const UChar *s16, const uint8_t *s8, int32_t &sIndex, int32_t &sLength);
230
231 static inline uint32_t getPrimaries(uint32_t variableTop, uint32_t pair) {
232 uint32_t ce = pair & 0xffff;
233 if(ce >= MIN_SHORT) { return pair & TWO_SHORT_PRIMARIES_MASK; }
234 if(ce > variableTop) { return pair & TWO_LONG_PRIMARIES_MASK; }
235 if(ce >= MIN_LONG) { return 0; } // variable
236 return pair; // special mini CE
237 }
238 static inline uint32_t getSecondariesFromOneShortCE(uint32_t ce) {
239 ce &= SECONDARY_MASK;
240 if(ce < MIN_SEC_HIGH) {
241 return ce + SEC_OFFSET;
242 } else {
243 return ((ce + SEC_OFFSET) << 16) | COMMON_SEC_PLUS_OFFSET;
244 }
245 }
246 static uint32_t getSecondaries(uint32_t variableTop, uint32_t pair);
247 static uint32_t getCases(uint32_t variableTop, UBool strengthIsPrimary, uint32_t pair);
248 static uint32_t getTertiaries(uint32_t variableTop, UBool withCaseBits, uint32_t pair);
249 static uint32_t getQuaternaries(uint32_t variableTop, uint32_t pair);
250
251private:
252 CollationFastLatin(); // no constructor
253};
254
255/*
256 * Format of the CollationFastLatin data table.
257 * CollationFastLatin::VERSION = 2.
258 *
259 * This table contains data for a Latin-text collation fastpath.
260 * The data is stored as an array of uint16_t which contains the following parts.
261 *
262 * uint16_t -- version & header length
263 * Bits 15..8: version, must match the VERSION
264 * 7..0: length of the header
265 *
266 * uint16_t varTops[header length - 1]
267 * Version 2:
268 * varTops[m] is the highest CollationFastLatin long-primary weight
269 * of supported maxVariable group m
270 * (special reorder group space, punct, symbol, currency).
271 *
272 * Version 1:
273 * Each of these values maps the variable top lead byte of a supported maxVariable group
274 * to the highest CollationFastLatin long-primary weight.
275 * The values are stored in ascending order.
276 * Bits 15..7: max fast-Latin long-primary weight (bits 11..3 shifted left by 4 bits)
277 * 6..0: regular primary lead byte
278 *
279 * uint16_t miniCEs[0x1c0]
280 * A mini collation element for each character U+0000..U+017F and U+2000..U+203F.
281 * Each value encodes one or two mini CEs (two are possible if the first one
282 * has a short mini primary and the second one is a secondary CE, i.e., primary == 0),
283 * or points to an expansion or to a contraction table.
284 * U+0000 always has a contraction entry,
285 * so that NUL-termination need not be tested in the fastpath.
286 * If the collation elements for a character or contraction cannot be encoded in this format,
287 * then the BAIL_OUT value is stored.
288 * For details see the comments for the class constants.
289 *
290 * uint16_t expansions[variable length];
291 * Expansion mini CEs contain an offset relative to just after the miniCEs table.
292 * An expansions contains exactly 2 mini CEs.
293 *
294 * uint16_t contractions[variable length];
295 * Contraction mini CEs contain an offset relative to just after the miniCEs table.
296 * It points to a list of tuples which map from a contraction suffix character to a result.
297 * First uint16_t of each tuple:
298 * Bits 10..9: Length of the result (1..3), see comments on CONTR_LENGTH_SHIFT.
299 * Bits 8..0: Contraction character, see comments on CONTR_CHAR_MASK.
300 * This is followed by 0, 1, or 2 uint16_t according to the length.
301 * Each list is terminated by an entry with CONTR_CHAR_MASK.
302 * Each list starts with such an entry which also contains the default result
303 * for when there is no contraction match.
304 *
305 * -----------------
306 * Changes for version 2 (ICU 55)
307 *
308 * Special reorder groups do not necessarily start on whole primary lead bytes any more.
309 * Therefore, the varTops data has a new format:
310 * Version 1 stored the lead bytes of the highest root primaries for
311 * the maxVariable-supported special reorder groups.
312 * Now the top 16 bits would need to be stored,
313 * and it is simpler to store only the fast-Latin weights.
314 */
315
316U_NAMESPACE_END
317
318#endif // !UCONFIG_NO_COLLATION
319#endif // __COLLATIONFASTLATIN_H__
320