diff options
Diffstat (limited to 'vendor/golang.org/x/text/unicode/norm/normalize.go')
-rw-r--r-- | vendor/golang.org/x/text/unicode/norm/normalize.go | 609 |
1 files changed, 609 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/unicode/norm/normalize.go b/vendor/golang.org/x/text/unicode/norm/normalize.go new file mode 100644 index 0000000..e28ac64 --- /dev/null +++ b/vendor/golang.org/x/text/unicode/norm/normalize.go | |||
@@ -0,0 +1,609 @@ | |||
1 | // Copyright 2011 The Go Authors. All rights reserved. | ||
2 | // Use of this source code is governed by a BSD-style | ||
3 | // license that can be found in the LICENSE file. | ||
4 | |||
5 | // Note: the file data_test.go that is generated should not be checked in. | ||
6 | //go:generate go run maketables.go triegen.go | ||
7 | //go:generate go test -tags test | ||
8 | |||
9 | // Package norm contains types and functions for normalizing Unicode strings. | ||
10 | package norm // import "golang.org/x/text/unicode/norm" | ||
11 | |||
12 | import ( | ||
13 | "unicode/utf8" | ||
14 | |||
15 | "golang.org/x/text/transform" | ||
16 | ) | ||
17 | |||
18 | // A Form denotes a canonical representation of Unicode code points. | ||
19 | // The Unicode-defined normalization and equivalence forms are: | ||
20 | // | ||
21 | // NFC Unicode Normalization Form C | ||
22 | // NFD Unicode Normalization Form D | ||
23 | // NFKC Unicode Normalization Form KC | ||
24 | // NFKD Unicode Normalization Form KD | ||
25 | // | ||
26 | // For a Form f, this documentation uses the notation f(x) to mean | ||
27 | // the bytes or string x converted to the given form. | ||
28 | // A position n in x is called a boundary if conversion to the form can | ||
29 | // proceed independently on both sides: | ||
30 | // f(x) == append(f(x[0:n]), f(x[n:])...) | ||
31 | // | ||
32 | // References: http://unicode.org/reports/tr15/ and | ||
33 | // http://unicode.org/notes/tn5/. | ||
34 | type Form int | ||
35 | |||
36 | const ( | ||
37 | NFC Form = iota | ||
38 | NFD | ||
39 | NFKC | ||
40 | NFKD | ||
41 | ) | ||
42 | |||
43 | // Bytes returns f(b). May return b if f(b) = b. | ||
44 | func (f Form) Bytes(b []byte) []byte { | ||
45 | src := inputBytes(b) | ||
46 | ft := formTable[f] | ||
47 | n, ok := ft.quickSpan(src, 0, len(b), true) | ||
48 | if ok { | ||
49 | return b | ||
50 | } | ||
51 | out := make([]byte, n, len(b)) | ||
52 | copy(out, b[0:n]) | ||
53 | rb := reorderBuffer{f: *ft, src: src, nsrc: len(b), out: out, flushF: appendFlush} | ||
54 | return doAppendInner(&rb, n) | ||
55 | } | ||
56 | |||
57 | // String returns f(s). | ||
58 | func (f Form) String(s string) string { | ||
59 | src := inputString(s) | ||
60 | ft := formTable[f] | ||
61 | n, ok := ft.quickSpan(src, 0, len(s), true) | ||
62 | if ok { | ||
63 | return s | ||
64 | } | ||
65 | out := make([]byte, n, len(s)) | ||
66 | copy(out, s[0:n]) | ||
67 | rb := reorderBuffer{f: *ft, src: src, nsrc: len(s), out: out, flushF: appendFlush} | ||
68 | return string(doAppendInner(&rb, n)) | ||
69 | } | ||
70 | |||
71 | // IsNormal returns true if b == f(b). | ||
72 | func (f Form) IsNormal(b []byte) bool { | ||
73 | src := inputBytes(b) | ||
74 | ft := formTable[f] | ||
75 | bp, ok := ft.quickSpan(src, 0, len(b), true) | ||
76 | if ok { | ||
77 | return true | ||
78 | } | ||
79 | rb := reorderBuffer{f: *ft, src: src, nsrc: len(b)} | ||
80 | rb.setFlusher(nil, cmpNormalBytes) | ||
81 | for bp < len(b) { | ||
82 | rb.out = b[bp:] | ||
83 | if bp = decomposeSegment(&rb, bp, true); bp < 0 { | ||
84 | return false | ||
85 | } | ||
86 | bp, _ = rb.f.quickSpan(rb.src, bp, len(b), true) | ||
87 | } | ||
88 | return true | ||
89 | } | ||
90 | |||
91 | func cmpNormalBytes(rb *reorderBuffer) bool { | ||
92 | b := rb.out | ||
93 | for i := 0; i < rb.nrune; i++ { | ||
94 | info := rb.rune[i] | ||
95 | if int(info.size) > len(b) { | ||
96 | return false | ||
97 | } | ||
98 | p := info.pos | ||
99 | pe := p + info.size | ||
100 | for ; p < pe; p++ { | ||
101 | if b[0] != rb.byte[p] { | ||
102 | return false | ||
103 | } | ||
104 | b = b[1:] | ||
105 | } | ||
106 | } | ||
107 | return true | ||
108 | } | ||
109 | |||
110 | // IsNormalString returns true if s == f(s). | ||
111 | func (f Form) IsNormalString(s string) bool { | ||
112 | src := inputString(s) | ||
113 | ft := formTable[f] | ||
114 | bp, ok := ft.quickSpan(src, 0, len(s), true) | ||
115 | if ok { | ||
116 | return true | ||
117 | } | ||
118 | rb := reorderBuffer{f: *ft, src: src, nsrc: len(s)} | ||
119 | rb.setFlusher(nil, func(rb *reorderBuffer) bool { | ||
120 | for i := 0; i < rb.nrune; i++ { | ||
121 | info := rb.rune[i] | ||
122 | if bp+int(info.size) > len(s) { | ||
123 | return false | ||
124 | } | ||
125 | p := info.pos | ||
126 | pe := p + info.size | ||
127 | for ; p < pe; p++ { | ||
128 | if s[bp] != rb.byte[p] { | ||
129 | return false | ||
130 | } | ||
131 | bp++ | ||
132 | } | ||
133 | } | ||
134 | return true | ||
135 | }) | ||
136 | for bp < len(s) { | ||
137 | if bp = decomposeSegment(&rb, bp, true); bp < 0 { | ||
138 | return false | ||
139 | } | ||
140 | bp, _ = rb.f.quickSpan(rb.src, bp, len(s), true) | ||
141 | } | ||
142 | return true | ||
143 | } | ||
144 | |||
145 | // patchTail fixes a case where a rune may be incorrectly normalized | ||
146 | // if it is followed by illegal continuation bytes. It returns the | ||
147 | // patched buffer and whether the decomposition is still in progress. | ||
148 | func patchTail(rb *reorderBuffer) bool { | ||
149 | info, p := lastRuneStart(&rb.f, rb.out) | ||
150 | if p == -1 || info.size == 0 { | ||
151 | return true | ||
152 | } | ||
153 | end := p + int(info.size) | ||
154 | extra := len(rb.out) - end | ||
155 | if extra > 0 { | ||
156 | // Potentially allocating memory. However, this only | ||
157 | // happens with ill-formed UTF-8. | ||
158 | x := make([]byte, 0) | ||
159 | x = append(x, rb.out[len(rb.out)-extra:]...) | ||
160 | rb.out = rb.out[:end] | ||
161 | decomposeToLastBoundary(rb) | ||
162 | rb.doFlush() | ||
163 | rb.out = append(rb.out, x...) | ||
164 | return false | ||
165 | } | ||
166 | buf := rb.out[p:] | ||
167 | rb.out = rb.out[:p] | ||
168 | decomposeToLastBoundary(rb) | ||
169 | if s := rb.ss.next(info); s == ssStarter { | ||
170 | rb.doFlush() | ||
171 | rb.ss.first(info) | ||
172 | } else if s == ssOverflow { | ||
173 | rb.doFlush() | ||
174 | rb.insertCGJ() | ||
175 | rb.ss = 0 | ||
176 | } | ||
177 | rb.insertUnsafe(inputBytes(buf), 0, info) | ||
178 | return true | ||
179 | } | ||
180 | |||
181 | func appendQuick(rb *reorderBuffer, i int) int { | ||
182 | if rb.nsrc == i { | ||
183 | return i | ||
184 | } | ||
185 | end, _ := rb.f.quickSpan(rb.src, i, rb.nsrc, true) | ||
186 | rb.out = rb.src.appendSlice(rb.out, i, end) | ||
187 | return end | ||
188 | } | ||
189 | |||
190 | // Append returns f(append(out, b...)). | ||
191 | // The buffer out must be nil, empty, or equal to f(out). | ||
192 | func (f Form) Append(out []byte, src ...byte) []byte { | ||
193 | return f.doAppend(out, inputBytes(src), len(src)) | ||
194 | } | ||
195 | |||
196 | func (f Form) doAppend(out []byte, src input, n int) []byte { | ||
197 | if n == 0 { | ||
198 | return out | ||
199 | } | ||
200 | ft := formTable[f] | ||
201 | // Attempt to do a quickSpan first so we can avoid initializing the reorderBuffer. | ||
202 | if len(out) == 0 { | ||
203 | p, _ := ft.quickSpan(src, 0, n, true) | ||
204 | out = src.appendSlice(out, 0, p) | ||
205 | if p == n { | ||
206 | return out | ||
207 | } | ||
208 | rb := reorderBuffer{f: *ft, src: src, nsrc: n, out: out, flushF: appendFlush} | ||
209 | return doAppendInner(&rb, p) | ||
210 | } | ||
211 | rb := reorderBuffer{f: *ft, src: src, nsrc: n} | ||
212 | return doAppend(&rb, out, 0) | ||
213 | } | ||
214 | |||
215 | func doAppend(rb *reorderBuffer, out []byte, p int) []byte { | ||
216 | rb.setFlusher(out, appendFlush) | ||
217 | src, n := rb.src, rb.nsrc | ||
218 | doMerge := len(out) > 0 | ||
219 | if q := src.skipContinuationBytes(p); q > p { | ||
220 | // Move leading non-starters to destination. | ||
221 | rb.out = src.appendSlice(rb.out, p, q) | ||
222 | p = q | ||
223 | doMerge = patchTail(rb) | ||
224 | } | ||
225 | fd := &rb.f | ||
226 | if doMerge { | ||
227 | var info Properties | ||
228 | if p < n { | ||
229 | info = fd.info(src, p) | ||
230 | if !info.BoundaryBefore() || info.nLeadingNonStarters() > 0 { | ||
231 | if p == 0 { | ||
232 | decomposeToLastBoundary(rb) | ||
233 | } | ||
234 | p = decomposeSegment(rb, p, true) | ||
235 | } | ||
236 | } | ||
237 | if info.size == 0 { | ||
238 | rb.doFlush() | ||
239 | // Append incomplete UTF-8 encoding. | ||
240 | return src.appendSlice(rb.out, p, n) | ||
241 | } | ||
242 | if rb.nrune > 0 { | ||
243 | return doAppendInner(rb, p) | ||
244 | } | ||
245 | } | ||
246 | p = appendQuick(rb, p) | ||
247 | return doAppendInner(rb, p) | ||
248 | } | ||
249 | |||
250 | func doAppendInner(rb *reorderBuffer, p int) []byte { | ||
251 | for n := rb.nsrc; p < n; { | ||
252 | p = decomposeSegment(rb, p, true) | ||
253 | p = appendQuick(rb, p) | ||
254 | } | ||
255 | return rb.out | ||
256 | } | ||
257 | |||
258 | // AppendString returns f(append(out, []byte(s))). | ||
259 | // The buffer out must be nil, empty, or equal to f(out). | ||
260 | func (f Form) AppendString(out []byte, src string) []byte { | ||
261 | return f.doAppend(out, inputString(src), len(src)) | ||
262 | } | ||
263 | |||
264 | // QuickSpan returns a boundary n such that b[0:n] == f(b[0:n]). | ||
265 | // It is not guaranteed to return the largest such n. | ||
266 | func (f Form) QuickSpan(b []byte) int { | ||
267 | n, _ := formTable[f].quickSpan(inputBytes(b), 0, len(b), true) | ||
268 | return n | ||
269 | } | ||
270 | |||
271 | // Span implements transform.SpanningTransformer. It returns a boundary n such | ||
272 | // that b[0:n] == f(b[0:n]). It is not guaranteed to return the largest such n. | ||
273 | func (f Form) Span(b []byte, atEOF bool) (n int, err error) { | ||
274 | n, ok := formTable[f].quickSpan(inputBytes(b), 0, len(b), atEOF) | ||
275 | if n < len(b) { | ||
276 | if !ok { | ||
277 | err = transform.ErrEndOfSpan | ||
278 | } else { | ||
279 | err = transform.ErrShortSrc | ||
280 | } | ||
281 | } | ||
282 | return n, err | ||
283 | } | ||
284 | |||
285 | // SpanString returns a boundary n such that s[0:n] == f(s[0:n]). | ||
286 | // It is not guaranteed to return the largest such n. | ||
287 | func (f Form) SpanString(s string, atEOF bool) (n int, err error) { | ||
288 | n, ok := formTable[f].quickSpan(inputString(s), 0, len(s), atEOF) | ||
289 | if n < len(s) { | ||
290 | if !ok { | ||
291 | err = transform.ErrEndOfSpan | ||
292 | } else { | ||
293 | err = transform.ErrShortSrc | ||
294 | } | ||
295 | } | ||
296 | return n, err | ||
297 | } | ||
298 | |||
299 | // quickSpan returns a boundary n such that src[0:n] == f(src[0:n]) and | ||
300 | // whether any non-normalized parts were found. If atEOF is false, n will | ||
301 | // not point past the last segment if this segment might be become | ||
302 | // non-normalized by appending other runes. | ||
303 | func (f *formInfo) quickSpan(src input, i, end int, atEOF bool) (n int, ok bool) { | ||
304 | var lastCC uint8 | ||
305 | ss := streamSafe(0) | ||
306 | lastSegStart := i | ||
307 | for n = end; i < n; { | ||
308 | if j := src.skipASCII(i, n); i != j { | ||
309 | i = j | ||
310 | lastSegStart = i - 1 | ||
311 | lastCC = 0 | ||
312 | ss = 0 | ||
313 | continue | ||
314 | } | ||
315 | info := f.info(src, i) | ||
316 | if info.size == 0 { | ||
317 | if atEOF { | ||
318 | // include incomplete runes | ||
319 | return n, true | ||
320 | } | ||
321 | return lastSegStart, true | ||
322 | } | ||
323 | // This block needs to be before the next, because it is possible to | ||
324 | // have an overflow for runes that are starters (e.g. with U+FF9E). | ||
325 | switch ss.next(info) { | ||
326 | case ssStarter: | ||
327 | lastSegStart = i | ||
328 | case ssOverflow: | ||
329 | return lastSegStart, false | ||
330 | case ssSuccess: | ||
331 | if lastCC > info.ccc { | ||
332 | return lastSegStart, false | ||
333 | } | ||
334 | } | ||
335 | if f.composing { | ||
336 | if !info.isYesC() { | ||
337 | break | ||
338 | } | ||
339 | } else { | ||
340 | if !info.isYesD() { | ||
341 | break | ||
342 | } | ||
343 | } | ||
344 | lastCC = info.ccc | ||
345 | i += int(info.size) | ||
346 | } | ||
347 | if i == n { | ||
348 | if !atEOF { | ||
349 | n = lastSegStart | ||
350 | } | ||
351 | return n, true | ||
352 | } | ||
353 | return lastSegStart, false | ||
354 | } | ||
355 | |||
356 | // QuickSpanString returns a boundary n such that s[0:n] == f(s[0:n]). | ||
357 | // It is not guaranteed to return the largest such n. | ||
358 | func (f Form) QuickSpanString(s string) int { | ||
359 | n, _ := formTable[f].quickSpan(inputString(s), 0, len(s), true) | ||
360 | return n | ||
361 | } | ||
362 | |||
363 | // FirstBoundary returns the position i of the first boundary in b | ||
364 | // or -1 if b contains no boundary. | ||
365 | func (f Form) FirstBoundary(b []byte) int { | ||
366 | return f.firstBoundary(inputBytes(b), len(b)) | ||
367 | } | ||
368 | |||
369 | func (f Form) firstBoundary(src input, nsrc int) int { | ||
370 | i := src.skipContinuationBytes(0) | ||
371 | if i >= nsrc { | ||
372 | return -1 | ||
373 | } | ||
374 | fd := formTable[f] | ||
375 | ss := streamSafe(0) | ||
376 | // We should call ss.first here, but we can't as the first rune is | ||
377 | // skipped already. This means FirstBoundary can't really determine | ||
378 | // CGJ insertion points correctly. Luckily it doesn't have to. | ||
379 | for { | ||
380 | info := fd.info(src, i) | ||
381 | if info.size == 0 { | ||
382 | return -1 | ||
383 | } | ||
384 | if s := ss.next(info); s != ssSuccess { | ||
385 | return i | ||
386 | } | ||
387 | i += int(info.size) | ||
388 | if i >= nsrc { | ||
389 | if !info.BoundaryAfter() && !ss.isMax() { | ||
390 | return -1 | ||
391 | } | ||
392 | return nsrc | ||
393 | } | ||
394 | } | ||
395 | } | ||
396 | |||
397 | // FirstBoundaryInString returns the position i of the first boundary in s | ||
398 | // or -1 if s contains no boundary. | ||
399 | func (f Form) FirstBoundaryInString(s string) int { | ||
400 | return f.firstBoundary(inputString(s), len(s)) | ||
401 | } | ||
402 | |||
403 | // NextBoundary reports the index of the boundary between the first and next | ||
404 | // segment in b or -1 if atEOF is false and there are not enough bytes to | ||
405 | // determine this boundary. | ||
406 | func (f Form) NextBoundary(b []byte, atEOF bool) int { | ||
407 | return f.nextBoundary(inputBytes(b), len(b), atEOF) | ||
408 | } | ||
409 | |||
410 | // NextBoundaryInString reports the index of the boundary between the first and | ||
411 | // next segment in b or -1 if atEOF is false and there are not enough bytes to | ||
412 | // determine this boundary. | ||
413 | func (f Form) NextBoundaryInString(s string, atEOF bool) int { | ||
414 | return f.nextBoundary(inputString(s), len(s), atEOF) | ||
415 | } | ||
416 | |||
417 | func (f Form) nextBoundary(src input, nsrc int, atEOF bool) int { | ||
418 | if nsrc == 0 { | ||
419 | if atEOF { | ||
420 | return 0 | ||
421 | } | ||
422 | return -1 | ||
423 | } | ||
424 | fd := formTable[f] | ||
425 | info := fd.info(src, 0) | ||
426 | if info.size == 0 { | ||
427 | if atEOF { | ||
428 | return 1 | ||
429 | } | ||
430 | return -1 | ||
431 | } | ||
432 | ss := streamSafe(0) | ||
433 | ss.first(info) | ||
434 | |||
435 | for i := int(info.size); i < nsrc; i += int(info.size) { | ||
436 | info = fd.info(src, i) | ||
437 | if info.size == 0 { | ||
438 | if atEOF { | ||
439 | return i | ||
440 | } | ||
441 | return -1 | ||
442 | } | ||
443 | // TODO: Using streamSafe to determine the boundary isn't the same as | ||
444 | // using BoundaryBefore. Determine which should be used. | ||
445 | if s := ss.next(info); s != ssSuccess { | ||
446 | return i | ||
447 | } | ||
448 | } | ||
449 | if !atEOF && !info.BoundaryAfter() && !ss.isMax() { | ||
450 | return -1 | ||
451 | } | ||
452 | return nsrc | ||
453 | } | ||
454 | |||
455 | // LastBoundary returns the position i of the last boundary in b | ||
456 | // or -1 if b contains no boundary. | ||
457 | func (f Form) LastBoundary(b []byte) int { | ||
458 | return lastBoundary(formTable[f], b) | ||
459 | } | ||
460 | |||
461 | func lastBoundary(fd *formInfo, b []byte) int { | ||
462 | i := len(b) | ||
463 | info, p := lastRuneStart(fd, b) | ||
464 | if p == -1 { | ||
465 | return -1 | ||
466 | } | ||
467 | if info.size == 0 { // ends with incomplete rune | ||
468 | if p == 0 { // starts with incomplete rune | ||
469 | return -1 | ||
470 | } | ||
471 | i = p | ||
472 | info, p = lastRuneStart(fd, b[:i]) | ||
473 | if p == -1 { // incomplete UTF-8 encoding or non-starter bytes without a starter | ||
474 | return i | ||
475 | } | ||
476 | } | ||
477 | if p+int(info.size) != i { // trailing non-starter bytes: illegal UTF-8 | ||
478 | return i | ||
479 | } | ||
480 | if info.BoundaryAfter() { | ||
481 | return i | ||
482 | } | ||
483 | ss := streamSafe(0) | ||
484 | v := ss.backwards(info) | ||
485 | for i = p; i >= 0 && v != ssStarter; i = p { | ||
486 | info, p = lastRuneStart(fd, b[:i]) | ||
487 | if v = ss.backwards(info); v == ssOverflow { | ||
488 | break | ||
489 | } | ||
490 | if p+int(info.size) != i { | ||
491 | if p == -1 { // no boundary found | ||
492 | return -1 | ||
493 | } | ||
494 | return i // boundary after an illegal UTF-8 encoding | ||
495 | } | ||
496 | } | ||
497 | return i | ||
498 | } | ||
499 | |||
500 | // decomposeSegment scans the first segment in src into rb. It inserts 0x034f | ||
501 | // (Grapheme Joiner) when it encounters a sequence of more than 30 non-starters | ||
502 | // and returns the number of bytes consumed from src or iShortDst or iShortSrc. | ||
503 | func decomposeSegment(rb *reorderBuffer, sp int, atEOF bool) int { | ||
504 | // Force one character to be consumed. | ||
505 | info := rb.f.info(rb.src, sp) | ||
506 | if info.size == 0 { | ||
507 | return 0 | ||
508 | } | ||
509 | if s := rb.ss.next(info); s == ssStarter { | ||
510 | // TODO: this could be removed if we don't support merging. | ||
511 | if rb.nrune > 0 { | ||
512 | goto end | ||
513 | } | ||
514 | } else if s == ssOverflow { | ||
515 | rb.insertCGJ() | ||
516 | goto end | ||
517 | } | ||
518 | if err := rb.insertFlush(rb.src, sp, info); err != iSuccess { | ||
519 | return int(err) | ||
520 | } | ||
521 | for { | ||
522 | sp += int(info.size) | ||
523 | if sp >= rb.nsrc { | ||
524 | if !atEOF && !info.BoundaryAfter() { | ||
525 | return int(iShortSrc) | ||
526 | } | ||
527 | break | ||
528 | } | ||
529 | info = rb.f.info(rb.src, sp) | ||
530 | if info.size == 0 { | ||
531 | if !atEOF { | ||
532 | return int(iShortSrc) | ||
533 | } | ||
534 | break | ||
535 | } | ||
536 | if s := rb.ss.next(info); s == ssStarter { | ||
537 | break | ||
538 | } else if s == ssOverflow { | ||
539 | rb.insertCGJ() | ||
540 | break | ||
541 | } | ||
542 | if err := rb.insertFlush(rb.src, sp, info); err != iSuccess { | ||
543 | return int(err) | ||
544 | } | ||
545 | } | ||
546 | end: | ||
547 | if !rb.doFlush() { | ||
548 | return int(iShortDst) | ||
549 | } | ||
550 | return sp | ||
551 | } | ||
552 | |||
553 | // lastRuneStart returns the runeInfo and position of the last | ||
554 | // rune in buf or the zero runeInfo and -1 if no rune was found. | ||
555 | func lastRuneStart(fd *formInfo, buf []byte) (Properties, int) { | ||
556 | p := len(buf) - 1 | ||
557 | for ; p >= 0 && !utf8.RuneStart(buf[p]); p-- { | ||
558 | } | ||
559 | if p < 0 { | ||
560 | return Properties{}, -1 | ||
561 | } | ||
562 | return fd.info(inputBytes(buf), p), p | ||
563 | } | ||
564 | |||
565 | // decomposeToLastBoundary finds an open segment at the end of the buffer | ||
566 | // and scans it into rb. Returns the buffer minus the last segment. | ||
567 | func decomposeToLastBoundary(rb *reorderBuffer) { | ||
568 | fd := &rb.f | ||
569 | info, i := lastRuneStart(fd, rb.out) | ||
570 | if int(info.size) != len(rb.out)-i { | ||
571 | // illegal trailing continuation bytes | ||
572 | return | ||
573 | } | ||
574 | if info.BoundaryAfter() { | ||
575 | return | ||
576 | } | ||
577 | var add [maxNonStarters + 1]Properties // stores runeInfo in reverse order | ||
578 | padd := 0 | ||
579 | ss := streamSafe(0) | ||
580 | p := len(rb.out) | ||
581 | for { | ||
582 | add[padd] = info | ||
583 | v := ss.backwards(info) | ||
584 | if v == ssOverflow { | ||
585 | // Note that if we have an overflow, it the string we are appending to | ||
586 | // is not correctly normalized. In this case the behavior is undefined. | ||
587 | break | ||
588 | } | ||
589 | padd++ | ||
590 | p -= int(info.size) | ||
591 | if v == ssStarter || p < 0 { | ||
592 | break | ||
593 | } | ||
594 | info, i = lastRuneStart(fd, rb.out[:p]) | ||
595 | if int(info.size) != p-i { | ||
596 | break | ||
597 | } | ||
598 | } | ||
599 | rb.ss = ss | ||
600 | // Copy bytes for insertion as we may need to overwrite rb.out. | ||
601 | var buf [maxBufferSize * utf8.UTFMax]byte | ||
602 | cp := buf[:copy(buf[:], rb.out[p:])] | ||
603 | rb.out = rb.out[:p] | ||
604 | for padd--; padd >= 0; padd-- { | ||
605 | info = add[padd] | ||
606 | rb.insertUnsafe(inputBytes(cp), 0, info) | ||
607 | cp = cp[info.size:] | ||
608 | } | ||
609 | } | ||