source: code/trunk/vendor/github.com/andybalholm/brotli/transform.go@ 145

Last change on this file since 145 was 145, checked in by Izuru Yakumo, 22 months ago

Updated the Makefile and vendored depedencies

Signed-off-by: Izuru Yakumo <yakumo.izuru@…>
File size: 10.0 KB
Line 
1package brotli
2
3const (
4 transformIdentity = 0
5 transformOmitLast1 = 1
6 transformOmitLast2 = 2
7 transformOmitLast3 = 3
8 transformOmitLast4 = 4
9 transformOmitLast5 = 5
10 transformOmitLast6 = 6
11 transformOmitLast7 = 7
12 transformOmitLast8 = 8
13 transformOmitLast9 = 9
14 transformUppercaseFirst = 10
15 transformUppercaseAll = 11
16 transformOmitFirst1 = 12
17 transformOmitFirst2 = 13
18 transformOmitFirst3 = 14
19 transformOmitFirst4 = 15
20 transformOmitFirst5 = 16
21 transformOmitFirst6 = 17
22 transformOmitFirst7 = 18
23 transformOmitFirst8 = 19
24 transformOmitFirst9 = 20
25 transformShiftFirst = 21
26 transformShiftAll = 22 + iota - 22
27 numTransformTypes
28)
29
30const transformsMaxCutOff = transformOmitLast9
31
32type transforms struct {
33 prefix_suffix_size uint16
34 prefix_suffix []byte
35 prefix_suffix_map []uint16
36 num_transforms uint32
37 transforms []byte
38 params []byte
39 cutOffTransforms [transformsMaxCutOff + 1]int16
40}
41
42func transformPrefixId(t *transforms, I int) byte {
43 return t.transforms[(I*3)+0]
44}
45
46func transformType(t *transforms, I int) byte {
47 return t.transforms[(I*3)+1]
48}
49
50func transformSuffixId(t *transforms, I int) byte {
51 return t.transforms[(I*3)+2]
52}
53
54func transformPrefix(t *transforms, I int) []byte {
55 return t.prefix_suffix[t.prefix_suffix_map[transformPrefixId(t, I)]:]
56}
57
58func transformSuffix(t *transforms, I int) []byte {
59 return t.prefix_suffix[t.prefix_suffix_map[transformSuffixId(t, I)]:]
60}
61
62/* RFC 7932 transforms string data */
63const kPrefixSuffix string = "\001 \002, \010 of the \004 of \002s \001.\005 and \004 " + "in \001\"\004 to \002\">\001\n\002. \001]\005 for \003 a \006 " + "that \001'\006 with \006 from \004 by \001(\006. T" + "he \004 on \004 as \004 is \004ing \002\n\t\001:\003ed " + "\002=\"\004 at \003ly \001,\002='\005.com/\007. This \005" + " not \003er \003al \004ful \004ive \005less \004es" + "t \004ize \002\xc2\xa0\004ous \005 the \002e \000"
64
65var kPrefixSuffixMap = [50]uint16{
66 0x00,
67 0x02,
68 0x05,
69 0x0E,
70 0x13,
71 0x16,
72 0x18,
73 0x1E,
74 0x23,
75 0x25,
76 0x2A,
77 0x2D,
78 0x2F,
79 0x32,
80 0x34,
81 0x3A,
82 0x3E,
83 0x45,
84 0x47,
85 0x4E,
86 0x55,
87 0x5A,
88 0x5C,
89 0x63,
90 0x68,
91 0x6D,
92 0x72,
93 0x77,
94 0x7A,
95 0x7C,
96 0x80,
97 0x83,
98 0x88,
99 0x8C,
100 0x8E,
101 0x91,
102 0x97,
103 0x9F,
104 0xA5,
105 0xA9,
106 0xAD,
107 0xB2,
108 0xB7,
109 0xBD,
110 0xC2,
111 0xC7,
112 0xCA,
113 0xCF,
114 0xD5,
115 0xD8,
116}
117
118/* RFC 7932 transforms */
119var kTransformsData = []byte{
120 49,
121 transformIdentity,
122 49,
123 49,
124 transformIdentity,
125 0,
126 0,
127 transformIdentity,
128 0,
129 49,
130 transformOmitFirst1,
131 49,
132 49,
133 transformUppercaseFirst,
134 0,
135 49,
136 transformIdentity,
137 47,
138 0,
139 transformIdentity,
140 49,
141 4,
142 transformIdentity,
143 0,
144 49,
145 transformIdentity,
146 3,
147 49,
148 transformUppercaseFirst,
149 49,
150 49,
151 transformIdentity,
152 6,
153 49,
154 transformOmitFirst2,
155 49,
156 49,
157 transformOmitLast1,
158 49,
159 1,
160 transformIdentity,
161 0,
162 49,
163 transformIdentity,
164 1,
165 0,
166 transformUppercaseFirst,
167 0,
168 49,
169 transformIdentity,
170 7,
171 49,
172 transformIdentity,
173 9,
174 48,
175 transformIdentity,
176 0,
177 49,
178 transformIdentity,
179 8,
180 49,
181 transformIdentity,
182 5,
183 49,
184 transformIdentity,
185 10,
186 49,
187 transformIdentity,
188 11,
189 49,
190 transformOmitLast3,
191 49,
192 49,
193 transformIdentity,
194 13,
195 49,
196 transformIdentity,
197 14,
198 49,
199 transformOmitFirst3,
200 49,
201 49,
202 transformOmitLast2,
203 49,
204 49,
205 transformIdentity,
206 15,
207 49,
208 transformIdentity,
209 16,
210 0,
211 transformUppercaseFirst,
212 49,
213 49,
214 transformIdentity,
215 12,
216 5,
217 transformIdentity,
218 49,
219 0,
220 transformIdentity,
221 1,
222 49,
223 transformOmitFirst4,
224 49,
225 49,
226 transformIdentity,
227 18,
228 49,
229 transformIdentity,
230 17,
231 49,
232 transformIdentity,
233 19,
234 49,
235 transformIdentity,
236 20,
237 49,
238 transformOmitFirst5,
239 49,
240 49,
241 transformOmitFirst6,
242 49,
243 47,
244 transformIdentity,
245 49,
246 49,
247 transformOmitLast4,
248 49,
249 49,
250 transformIdentity,
251 22,
252 49,
253 transformUppercaseAll,
254 49,
255 49,
256 transformIdentity,
257 23,
258 49,
259 transformIdentity,
260 24,
261 49,
262 transformIdentity,
263 25,
264 49,
265 transformOmitLast7,
266 49,
267 49,
268 transformOmitLast1,
269 26,
270 49,
271 transformIdentity,
272 27,
273 49,
274 transformIdentity,
275 28,
276 0,
277 transformIdentity,
278 12,
279 49,
280 transformIdentity,
281 29,
282 49,
283 transformOmitFirst9,
284 49,
285 49,
286 transformOmitFirst7,
287 49,
288 49,
289 transformOmitLast6,
290 49,
291 49,
292 transformIdentity,
293 21,
294 49,
295 transformUppercaseFirst,
296 1,
297 49,
298 transformOmitLast8,
299 49,
300 49,
301 transformIdentity,
302 31,
303 49,
304 transformIdentity,
305 32,
306 47,
307 transformIdentity,
308 3,
309 49,
310 transformOmitLast5,
311 49,
312 49,
313 transformOmitLast9,
314 49,
315 0,
316 transformUppercaseFirst,
317 1,
318 49,
319 transformUppercaseFirst,
320 8,
321 5,
322 transformIdentity,
323 21,
324 49,
325 transformUppercaseAll,
326 0,
327 49,
328 transformUppercaseFirst,
329 10,
330 49,
331 transformIdentity,
332 30,
333 0,
334 transformIdentity,
335 5,
336 35,
337 transformIdentity,
338 49,
339 47,
340 transformIdentity,
341 2,
342 49,
343 transformUppercaseFirst,
344 17,
345 49,
346 transformIdentity,
347 36,
348 49,
349 transformIdentity,
350 33,
351 5,
352 transformIdentity,
353 0,
354 49,
355 transformUppercaseFirst,
356 21,
357 49,
358 transformUppercaseFirst,
359 5,
360 49,
361 transformIdentity,
362 37,
363 0,
364 transformIdentity,
365 30,
366 49,
367 transformIdentity,
368 38,
369 0,
370 transformUppercaseAll,
371 0,
372 49,
373 transformIdentity,
374 39,
375 0,
376 transformUppercaseAll,
377 49,
378 49,
379 transformIdentity,
380 34,
381 49,
382 transformUppercaseAll,
383 8,
384 49,
385 transformUppercaseFirst,
386 12,
387 0,
388 transformIdentity,
389 21,
390 49,
391 transformIdentity,
392 40,
393 0,
394 transformUppercaseFirst,
395 12,
396 49,
397 transformIdentity,
398 41,
399 49,
400 transformIdentity,
401 42,
402 49,
403 transformUppercaseAll,
404 17,
405 49,
406 transformIdentity,
407 43,
408 0,
409 transformUppercaseFirst,
410 5,
411 49,
412 transformUppercaseAll,
413 10,
414 0,
415 transformIdentity,
416 34,
417 49,
418 transformUppercaseFirst,
419 33,
420 49,
421 transformIdentity,
422 44,
423 49,
424 transformUppercaseAll,
425 5,
426 45,
427 transformIdentity,
428 49,
429 0,
430 transformIdentity,
431 33,
432 49,
433 transformUppercaseFirst,
434 30,
435 49,
436 transformUppercaseAll,
437 30,
438 49,
439 transformIdentity,
440 46,
441 49,
442 transformUppercaseAll,
443 1,
444 49,
445 transformUppercaseFirst,
446 34,
447 0,
448 transformUppercaseFirst,
449 33,
450 0,
451 transformUppercaseAll,
452 30,
453 0,
454 transformUppercaseAll,
455 1,
456 49,
457 transformUppercaseAll,
458 33,
459 49,
460 transformUppercaseAll,
461 21,
462 49,
463 transformUppercaseAll,
464 12,
465 0,
466 transformUppercaseAll,
467 5,
468 49,
469 transformUppercaseAll,
470 34,
471 0,
472 transformUppercaseAll,
473 12,
474 0,
475 transformUppercaseFirst,
476 30,
477 0,
478 transformUppercaseAll,
479 34,
480 0,
481 transformUppercaseFirst,
482 34,
483}
484
485var kBrotliTransforms = transforms{
486 217,
487 []byte(kPrefixSuffix),
488 kPrefixSuffixMap[:],
489 121,
490 kTransformsData,
491 nil, /* no extra parameters */
492 [transformsMaxCutOff + 1]int16{0, 12, 27, 23, 42, 63, 56, 48, 59, 64},
493}
494
495func getTransforms() *transforms {
496 return &kBrotliTransforms
497}
498
499func toUpperCase(p []byte) int {
500 if p[0] < 0xC0 {
501 if p[0] >= 'a' && p[0] <= 'z' {
502 p[0] ^= 32
503 }
504
505 return 1
506 }
507
508 /* An overly simplified uppercasing model for UTF-8. */
509 if p[0] < 0xE0 {
510 p[1] ^= 32
511 return 2
512 }
513
514 /* An arbitrary transform for three byte characters. */
515 p[2] ^= 5
516
517 return 3
518}
519
520func shiftTransform(word []byte, word_len int, parameter uint16) int {
521 /* Limited sign extension: scalar < (1 << 24). */
522 var scalar uint32 = (uint32(parameter) & 0x7FFF) + (0x1000000 - (uint32(parameter) & 0x8000))
523 if word[0] < 0x80 {
524 /* 1-byte rune / 0sssssss / 7 bit scalar (ASCII). */
525 scalar += uint32(word[0])
526
527 word[0] = byte(scalar & 0x7F)
528 return 1
529 } else if word[0] < 0xC0 {
530 /* Continuation / 10AAAAAA. */
531 return 1
532 } else if word[0] < 0xE0 {
533 /* 2-byte rune / 110sssss AAssssss / 11 bit scalar. */
534 if word_len < 2 {
535 return 1
536 }
537 scalar += uint32(word[1]&0x3F | (word[0]&0x1F)<<6)
538 word[0] = byte(0xC0 | (scalar>>6)&0x1F)
539 word[1] = byte(uint32(word[1]&0xC0) | scalar&0x3F)
540 return 2
541 } else if word[0] < 0xF0 {
542 /* 3-byte rune / 1110ssss AAssssss BBssssss / 16 bit scalar. */
543 if word_len < 3 {
544 return word_len
545 }
546 scalar += uint32(word[2])&0x3F | uint32(word[1]&0x3F)<<6 | uint32(word[0]&0x0F)<<12
547 word[0] = byte(0xE0 | (scalar>>12)&0x0F)
548 word[1] = byte(uint32(word[1]&0xC0) | (scalar>>6)&0x3F)
549 word[2] = byte(uint32(word[2]&0xC0) | scalar&0x3F)
550 return 3
551 } else if word[0] < 0xF8 {
552 /* 4-byte rune / 11110sss AAssssss BBssssss CCssssss / 21 bit scalar. */
553 if word_len < 4 {
554 return word_len
555 }
556 scalar += uint32(word[3])&0x3F | uint32(word[2]&0x3F)<<6 | uint32(word[1]&0x3F)<<12 | uint32(word[0]&0x07)<<18
557 word[0] = byte(0xF0 | (scalar>>18)&0x07)
558 word[1] = byte(uint32(word[1]&0xC0) | (scalar>>12)&0x3F)
559 word[2] = byte(uint32(word[2]&0xC0) | (scalar>>6)&0x3F)
560 word[3] = byte(uint32(word[3]&0xC0) | scalar&0x3F)
561 return 4
562 }
563
564 return 1
565}
566
567func transformDictionaryWord(dst []byte, word []byte, len int, trans *transforms, transform_idx int) int {
568 var idx int = 0
569 var prefix []byte = transformPrefix(trans, transform_idx)
570 var type_ byte = transformType(trans, transform_idx)
571 var suffix []byte = transformSuffix(trans, transform_idx)
572 {
573 var prefix_len int = int(prefix[0])
574 prefix = prefix[1:]
575 for {
576 tmp1 := prefix_len
577 prefix_len--
578 if tmp1 == 0 {
579 break
580 }
581 dst[idx] = prefix[0]
582 idx++
583 prefix = prefix[1:]
584 }
585 }
586 {
587 var t int = int(type_)
588 var i int = 0
589 if t <= transformOmitLast9 {
590 len -= t
591 } else if t >= transformOmitFirst1 && t <= transformOmitFirst9 {
592 var skip int = t - (transformOmitFirst1 - 1)
593 word = word[skip:]
594 len -= skip
595 }
596
597 for i < len {
598 dst[idx] = word[i]
599 idx++
600 i++
601 }
602 if t == transformUppercaseFirst {
603 toUpperCase(dst[idx-len:])
604 } else if t == transformUppercaseAll {
605 var uppercase []byte = dst
606 uppercase = uppercase[idx-len:]
607 for len > 0 {
608 var step int = toUpperCase(uppercase)
609 uppercase = uppercase[step:]
610 len -= step
611 }
612 } else if t == transformShiftFirst {
613 var param uint16 = uint16(trans.params[transform_idx*2]) + uint16(trans.params[transform_idx*2+1])<<8
614 shiftTransform(dst[idx-len:], int(len), param)
615 } else if t == transformShiftAll {
616 var param uint16 = uint16(trans.params[transform_idx*2]) + uint16(trans.params[transform_idx*2+1])<<8
617 var shift []byte = dst
618 shift = shift[idx-len:]
619 for len > 0 {
620 var step int = shiftTransform(shift, int(len), param)
621 shift = shift[step:]
622 len -= step
623 }
624 }
625 }
626 {
627 var suffix_len int = int(suffix[0])
628 suffix = suffix[1:]
629 for {
630 tmp2 := suffix_len
631 suffix_len--
632 if tmp2 == 0 {
633 break
634 }
635 dst[idx] = suffix[0]
636 idx++
637 suffix = suffix[1:]
638 }
639 return idx
640 }
641}
Note: See TracBrowser for help on using the repository browser.