1/*
2*******************************************************************************
3* Copyright (C) 2012-2014, International Business Machines
4* Corporation and others.  All Rights Reserved.
5*******************************************************************************
6* utf8collationiterator.cpp
7*
8* created on: 2012nov12 (from utf16collationiterator.cpp & uitercollationiterator.cpp)
9* created by: Markus W. Scherer
10*/
11
12#include "unicode/utypes.h"
13
14#if !UCONFIG_NO_COLLATION
15
16#include "unicode/utf8.h"
17#include "charstr.h"
18#include "cmemory.h"
19#include "collation.h"
20#include "collationdata.h"
21#include "collationfcd.h"
22#include "collationiterator.h"
23#include "normalizer2impl.h"
24#include "uassert.h"
25#include "utf8collationiterator.h"
26
27U_NAMESPACE_BEGIN
28
29UTF8CollationIterator::~UTF8CollationIterator() {}
30
31void
32UTF8CollationIterator::resetToOffset(int32_t newOffset) {
33    reset();
34    pos = newOffset;
35}
36
37int32_t
38UTF8CollationIterator::getOffset() const {
39    return pos;
40}
41
42uint32_t
43UTF8CollationIterator::handleNextCE32(UChar32 &c, UErrorCode & /*errorCode*/) {
44    if(pos == length) {
45        c = U_SENTINEL;
46        return Collation::FALLBACK_CE32;
47    }
48    // Optimized combination of U8_NEXT_OR_FFFD() and UTRIE2_U8_NEXT32().
49    c = u8[pos++];
50    if(c < 0xc0) {
51        // ASCII 00..7F; trail bytes 80..BF map to error values.
52        return trie->data32[c];
53    }
54    uint8_t t1, t2;
55    if(c < 0xe0 && pos != length && (t1 = (u8[pos] - 0x80)) <= 0x3f) {
56        // U+0080..U+07FF; 00..7F map to error values.
57        uint32_t ce32 = trie->data32[trie->index[(UTRIE2_UTF8_2B_INDEX_2_OFFSET - 0xc0) + c] + t1];
58        c = ((c & 0x1f) << 6) | t1;
59        ++pos;
60        return ce32;
61    } else if(c <= 0xef &&
62              ((pos + 1) < length || length < 0) &&
63              (t1 = (u8[pos] - 0x80)) <= 0x3f && (c != 0xe0 || t1 >= 0x20) &&
64              (t2 = (u8[pos + 1] - 0x80)) <= 0x3f
65    ) {
66        // U+0800..U+FFFF; caller maps surrogates to error values.
67        c = (UChar)((c << 12) | (t1 << 6) | t2);
68        pos += 2;
69        return UTRIE2_GET32_FROM_U16_SINGLE_LEAD(trie, c);
70    } else {
71        // Function call for supplementary code points and error cases.
72        // Illegal byte sequences yield U+FFFD.
73        c = utf8_nextCharSafeBody(u8, &pos, length, c, -3);
74        return data->getCE32(c);
75    }
76}
77
78UBool
79UTF8CollationIterator::foundNULTerminator() {
80    if(length < 0) {
81        length = --pos;
82        return TRUE;
83    } else {
84        return FALSE;
85    }
86}
87
88UBool
89UTF8CollationIterator::forbidSurrogateCodePoints() const {
90    return TRUE;
91}
92
93UChar32
94UTF8CollationIterator::nextCodePoint(UErrorCode & /*errorCode*/) {
95    if(pos == length) {
96        return U_SENTINEL;
97    }
98    if(u8[pos] == 0 && length < 0) {
99        length = pos;
100        return U_SENTINEL;
101    }
102    UChar32 c;
103    U8_NEXT_OR_FFFD(u8, pos, length, c);
104    return c;
105}
106
107UChar32
108UTF8CollationIterator::previousCodePoint(UErrorCode & /*errorCode*/) {
109    if(pos == 0) {
110        return U_SENTINEL;
111    }
112    UChar32 c;
113    U8_PREV_OR_FFFD(u8, 0, pos, c);
114    return c;
115}
116
117void
118UTF8CollationIterator::forwardNumCodePoints(int32_t num, UErrorCode & /*errorCode*/) {
119    U8_FWD_N(u8, pos, length, num);
120}
121
122void
123UTF8CollationIterator::backwardNumCodePoints(int32_t num, UErrorCode & /*errorCode*/) {
124    U8_BACK_N(u8, 0, pos, num);
125}
126
127// FCDUTF8CollationIterator ------------------------------------------------ ***
128
129FCDUTF8CollationIterator::~FCDUTF8CollationIterator() {}
130
131void
132FCDUTF8CollationIterator::resetToOffset(int32_t newOffset) {
133    reset();
134    start = pos = newOffset;
135    state = CHECK_FWD;
136}
137
138int32_t
139FCDUTF8CollationIterator::getOffset() const {
140    if(state != IN_NORMALIZED) {
141        return pos;
142    } else if(pos == 0) {
143        return start;
144    } else {
145        return limit;
146    }
147}
148
149uint32_t
150FCDUTF8CollationIterator::handleNextCE32(UChar32 &c, UErrorCode &errorCode) {
151    for(;;) {
152        if(state == CHECK_FWD) {
153            // Combination of UTF8CollationIterator::handleNextCE32() with FCD check fastpath.
154            if(pos == length) {
155                c = U_SENTINEL;
156                return Collation::FALLBACK_CE32;
157            }
158            c = u8[pos++];
159            if(c < 0xc0) {
160                // ASCII 00..7F; trail bytes 80..BF map to error values.
161                return trie->data32[c];
162            }
163            uint8_t t1, t2;
164            if(c < 0xe0 && pos != length && (t1 = (u8[pos] - 0x80)) <= 0x3f) {
165                // U+0080..U+07FF; 00..7F map to error values.
166                uint32_t ce32 = trie->data32[trie->index[(UTRIE2_UTF8_2B_INDEX_2_OFFSET - 0xc0) + c] + t1];
167                c = ((c & 0x1f) << 6) | t1;
168                ++pos;
169                if(CollationFCD::hasTccc(c) && pos != length && nextHasLccc()) {
170                    pos -= 2;
171                } else {
172                    return ce32;
173                }
174            } else if(c <= 0xef &&
175                      ((pos + 1) < length || length < 0) &&
176                      (t1 = (u8[pos] - 0x80)) <= 0x3f && (c != 0xe0 || t1 >= 0x20) &&
177                      (t2 = (u8[pos + 1] - 0x80)) <= 0x3f
178            ) {
179                // U+0800..U+FFFF; caller maps surrogates to error values.
180                c = (UChar)((c << 12) | (t1 << 6) | t2);
181                pos += 2;
182                if(CollationFCD::hasTccc(c) &&
183                        (CollationFCD::maybeTibetanCompositeVowel(c) ||
184                            (pos != length && nextHasLccc()))) {
185                    pos -= 3;
186                } else {
187                    break;  // return CE32(BMP)
188                }
189            } else {
190                // Function call for supplementary code points and error cases.
191                // Illegal byte sequences yield U+FFFD.
192                c = utf8_nextCharSafeBody(u8, &pos, length, c, -3);
193                if(c == 0xfffd) {
194                    return Collation::FFFD_CE32;
195                } else {
196                    U_ASSERT(c > 0xffff);
197                    if(CollationFCD::hasTccc(U16_LEAD(c)) && pos != length && nextHasLccc()) {
198                        pos -= 4;
199                    } else {
200                        return data->getCE32FromSupplementary(c);
201                    }
202                }
203            }
204            if(!nextSegment(errorCode)) {
205                c = U_SENTINEL;
206                return Collation::FALLBACK_CE32;
207            }
208            continue;
209        } else if(state == IN_FCD_SEGMENT && pos != limit) {
210            return UTF8CollationIterator::handleNextCE32(c, errorCode);
211        } else if(state == IN_NORMALIZED && pos != normalized.length()) {
212            c = normalized[pos++];
213            break;
214        } else {
215            switchToForward();
216        }
217    }
218    return UTRIE2_GET32_FROM_U16_SINGLE_LEAD(trie, c);
219}
220
221UBool
222FCDUTF8CollationIterator::nextHasLccc() const {
223    U_ASSERT(state == CHECK_FWD && pos != length);
224    // The lowest code point with ccc!=0 is U+0300 which is CC 80 in UTF-8.
225    // CJK U+4000..U+DFFF except U+Axxx are also FCD-inert. (Lead bytes E4..ED except EA.)
226    UChar32 c = u8[pos];
227    if(c < 0xcc || (0xe4 <= c && c <= 0xed && c != 0xea)) { return FALSE; }
228    int32_t i = pos;
229    U8_NEXT_OR_FFFD(u8, i, length, c);
230    if(c > 0xffff) { c = U16_LEAD(c); }
231    return CollationFCD::hasLccc(c);
232}
233
234UBool
235FCDUTF8CollationIterator::previousHasTccc() const {
236    U_ASSERT(state == CHECK_BWD && pos != 0);
237    UChar32 c = u8[pos - 1];
238    if(c < 0x80) { return FALSE; }
239    int32_t i = pos;
240    U8_PREV_OR_FFFD(u8, 0, i, c);
241    if(c > 0xffff) { c = U16_LEAD(c); }
242    return CollationFCD::hasTccc(c);
243}
244
245UChar
246FCDUTF8CollationIterator::handleGetTrailSurrogate() {
247    if(state != IN_NORMALIZED) { return 0; }
248    U_ASSERT(pos < normalized.length());
249    UChar trail;
250    if(U16_IS_TRAIL(trail = normalized[pos])) { ++pos; }
251    return trail;
252}
253
254UBool
255FCDUTF8CollationIterator::foundNULTerminator() {
256    if(state == CHECK_FWD && length < 0) {
257        length = --pos;
258        return TRUE;
259    } else {
260        return FALSE;
261    }
262}
263
264UChar32
265FCDUTF8CollationIterator::nextCodePoint(UErrorCode &errorCode) {
266    UChar32 c;
267    for(;;) {
268        if(state == CHECK_FWD) {
269            if(pos == length || ((c = u8[pos]) == 0 && length < 0)) {
270                return U_SENTINEL;
271            }
272            if(c < 0x80) {
273                ++pos;
274                return c;
275            }
276            U8_NEXT_OR_FFFD(u8, pos, length, c);
277            if(CollationFCD::hasTccc(c <= 0xffff ? c : U16_LEAD(c)) &&
278                    (CollationFCD::maybeTibetanCompositeVowel(c) ||
279                        (pos != length && nextHasLccc()))) {
280                // c is not FCD-inert, therefore it is not U+FFFD and it has a valid byte sequence
281                // and we can use U8_LENGTH() rather than a previous-position variable.
282                pos -= U8_LENGTH(c);
283                if(!nextSegment(errorCode)) {
284                    return U_SENTINEL;
285                }
286                continue;
287            }
288            return c;
289        } else if(state == IN_FCD_SEGMENT && pos != limit) {
290            U8_NEXT_OR_FFFD(u8, pos, length, c);
291            return c;
292        } else if(state == IN_NORMALIZED && pos != normalized.length()) {
293            c = normalized.char32At(pos);
294            pos += U16_LENGTH(c);
295            return c;
296        } else {
297            switchToForward();
298        }
299    }
300}
301
302UChar32
303FCDUTF8CollationIterator::previousCodePoint(UErrorCode &errorCode) {
304    UChar32 c;
305    for(;;) {
306        if(state == CHECK_BWD) {
307            if(pos == 0) {
308                return U_SENTINEL;
309            }
310            if((c = u8[pos - 1]) < 0x80) {
311                --pos;
312                return c;
313            }
314            U8_PREV_OR_FFFD(u8, 0, pos, c);
315            if(CollationFCD::hasLccc(c <= 0xffff ? c : U16_LEAD(c)) &&
316                    (CollationFCD::maybeTibetanCompositeVowel(c) ||
317                        (pos != 0 && previousHasTccc()))) {
318                // c is not FCD-inert, therefore it is not U+FFFD and it has a valid byte sequence
319                // and we can use U8_LENGTH() rather than a previous-position variable.
320                pos += U8_LENGTH(c);
321                if(!previousSegment(errorCode)) {
322                    return U_SENTINEL;
323                }
324                continue;
325            }
326            return c;
327        } else if(state == IN_FCD_SEGMENT && pos != start) {
328            U8_PREV_OR_FFFD(u8, 0, pos, c);
329            return c;
330        } else if(state >= IN_NORMALIZED && pos != 0) {
331            c = normalized.char32At(pos - 1);
332            pos -= U16_LENGTH(c);
333            return c;
334        } else {
335            switchToBackward();
336        }
337    }
338}
339
340void
341FCDUTF8CollationIterator::forwardNumCodePoints(int32_t num, UErrorCode &errorCode) {
342    // Specify the class to avoid a virtual-function indirection.
343    // In Java, we would declare this class final.
344    while(num > 0 && FCDUTF8CollationIterator::nextCodePoint(errorCode) >= 0) {
345        --num;
346    }
347}
348
349void
350FCDUTF8CollationIterator::backwardNumCodePoints(int32_t num, UErrorCode &errorCode) {
351    // Specify the class to avoid a virtual-function indirection.
352    // In Java, we would declare this class final.
353    while(num > 0 && FCDUTF8CollationIterator::previousCodePoint(errorCode) >= 0) {
354        --num;
355    }
356}
357
358void
359FCDUTF8CollationIterator::switchToForward() {
360    U_ASSERT(state == CHECK_BWD ||
361             (state == IN_FCD_SEGMENT && pos == limit) ||
362             (state == IN_NORMALIZED && pos == normalized.length()));
363    if(state == CHECK_BWD) {
364        // Turn around from backward checking.
365        start = pos;
366        if(pos == limit) {
367            state = CHECK_FWD;  // Check forward.
368        } else {  // pos < limit
369            state = IN_FCD_SEGMENT;  // Stay in FCD segment.
370        }
371    } else {
372        // Reached the end of the FCD segment.
373        if(state == IN_FCD_SEGMENT) {
374            // The input text segment is FCD, extend it forward.
375        } else {
376            // The input text segment needed to be normalized.
377            // Switch to checking forward from it.
378            start = pos = limit;
379        }
380        state = CHECK_FWD;
381    }
382}
383
384UBool
385FCDUTF8CollationIterator::nextSegment(UErrorCode &errorCode) {
386    if(U_FAILURE(errorCode)) { return FALSE; }
387    U_ASSERT(state == CHECK_FWD && pos != length);
388    // The input text [start..pos[ passes the FCD check.
389    int32_t segmentStart = pos;
390    // Collect the characters being checked, in case they need to be normalized.
391    UnicodeString s;
392    uint8_t prevCC = 0;
393    for(;;) {
394        // Fetch the next character and its fcd16 value.
395        int32_t cpStart = pos;
396        UChar32 c;
397        U8_NEXT_OR_FFFD(u8, pos, length, c);
398        uint16_t fcd16 = nfcImpl.getFCD16(c);
399        uint8_t leadCC = (uint8_t)(fcd16 >> 8);
400        if(leadCC == 0 && cpStart != segmentStart) {
401            // FCD boundary before this character.
402            pos = cpStart;
403            break;
404        }
405        s.append(c);
406        if(leadCC != 0 && (prevCC > leadCC || CollationFCD::isFCD16OfTibetanCompositeVowel(fcd16))) {
407            // Fails FCD check. Find the next FCD boundary and normalize.
408            while(pos != length) {
409                cpStart = pos;
410                U8_NEXT_OR_FFFD(u8, pos, length, c);
411                if(nfcImpl.getFCD16(c) <= 0xff) {
412                    pos = cpStart;
413                    break;
414                }
415                s.append(c);
416            }
417            if(!normalize(s, errorCode)) { return FALSE; }
418            start = segmentStart;
419            limit = pos;
420            state = IN_NORMALIZED;
421            pos = 0;
422            return TRUE;
423        }
424        prevCC = (uint8_t)fcd16;
425        if(pos == length || prevCC == 0) {
426            // FCD boundary after the last character.
427            break;
428        }
429    }
430    limit = pos;
431    pos = segmentStart;
432    U_ASSERT(pos != limit);
433    state = IN_FCD_SEGMENT;
434    return TRUE;
435}
436
437void
438FCDUTF8CollationIterator::switchToBackward() {
439    U_ASSERT(state == CHECK_FWD ||
440             (state == IN_FCD_SEGMENT && pos == start) ||
441             (state >= IN_NORMALIZED && pos == 0));
442    if(state == CHECK_FWD) {
443        // Turn around from forward checking.
444        limit = pos;
445        if(pos == start) {
446            state = CHECK_BWD;  // Check backward.
447        } else {  // pos > start
448            state = IN_FCD_SEGMENT;  // Stay in FCD segment.
449        }
450    } else {
451        // Reached the start of the FCD segment.
452        if(state == IN_FCD_SEGMENT) {
453            // The input text segment is FCD, extend it backward.
454        } else {
455            // The input text segment needed to be normalized.
456            // Switch to checking backward from it.
457            limit = pos = start;
458        }
459        state = CHECK_BWD;
460    }
461}
462
463UBool
464FCDUTF8CollationIterator::previousSegment(UErrorCode &errorCode) {
465    if(U_FAILURE(errorCode)) { return FALSE; }
466    U_ASSERT(state == CHECK_BWD && pos != 0);
467    // The input text [pos..limit[ passes the FCD check.
468    int32_t segmentLimit = pos;
469    // Collect the characters being checked, in case they need to be normalized.
470    UnicodeString s;
471    uint8_t nextCC = 0;
472    for(;;) {
473        // Fetch the previous character and its fcd16 value.
474        int32_t cpLimit = pos;
475        UChar32 c;
476        U8_PREV_OR_FFFD(u8, 0, pos, c);
477        uint16_t fcd16 = nfcImpl.getFCD16(c);
478        uint8_t trailCC = (uint8_t)fcd16;
479        if(trailCC == 0 && cpLimit != segmentLimit) {
480            // FCD boundary after this character.
481            pos = cpLimit;
482            break;
483        }
484        s.append(c);
485        if(trailCC != 0 && ((nextCC != 0 && trailCC > nextCC) ||
486                            CollationFCD::isFCD16OfTibetanCompositeVowel(fcd16))) {
487            // Fails FCD check. Find the previous FCD boundary and normalize.
488            while(fcd16 > 0xff && pos != 0) {
489                cpLimit = pos;
490                U8_PREV_OR_FFFD(u8, 0, pos, c);
491                fcd16 = nfcImpl.getFCD16(c);
492                if(fcd16 == 0) {
493                    pos = cpLimit;
494                    break;
495                }
496                s.append(c);
497            }
498            s.reverse();
499            if(!normalize(s, errorCode)) { return FALSE; }
500            limit = segmentLimit;
501            start = pos;
502            state = IN_NORMALIZED;
503            pos = normalized.length();
504            return TRUE;
505        }
506        nextCC = (uint8_t)(fcd16 >> 8);
507        if(pos == 0 || nextCC == 0) {
508            // FCD boundary before the following character.
509            break;
510        }
511    }
512    start = pos;
513    pos = segmentLimit;
514    U_ASSERT(pos != start);
515    state = IN_FCD_SEGMENT;
516    return TRUE;
517}
518
519UBool
520FCDUTF8CollationIterator::normalize(const UnicodeString &s, UErrorCode &errorCode) {
521    // NFD without argument checking.
522    U_ASSERT(U_SUCCESS(errorCode));
523    nfcImpl.decompose(s, normalized, errorCode);
524    return U_SUCCESS(errorCode);
525}
526
527U_NAMESPACE_END
528
529#endif  // !UCONFIG_NO_COLLATION
530