inline.go (view raw)
1//
2// Blackfriday Markdown Processor
3// Available at http://github.com/russross/blackfriday
4//
5// Copyright © 2011 Russ Ross <russ@russross.com>.
6// Distributed under the Simplified BSD License.
7// See README.md for details.
8//
9
10//
11// Functions to parse inline elements.
12//
13
14package blackfriday
15
16import (
17 "bytes"
18 "regexp"
19 "strconv"
20)
21
22var (
23 urlRe = `((https?|ftp):\/\/|\/)[-A-Za-z0-9+&@#\/%?=~_|!:,.;\(\)]+`
24 anchorRe = regexp.MustCompile(`^(<a\shref="` + urlRe + `"(\stitle="[^"<>]+")?\s?>` + urlRe + `<\/a>)`)
25)
26
27// Functions to parse text within a block
28// Each function returns the number of chars taken care of
29// data is the complete block being rendered
30// offset is the number of valid chars before the current cursor
31
32func (p *parser) inline(out *bytes.Buffer, data []byte) {
33 // this is called recursively: enforce a maximum depth
34 if p.nesting >= p.maxNesting {
35 return
36 }
37 p.nesting++
38
39 i, end := 0, 0
40 for i < len(data) {
41 // copy inactive chars into the output
42 for end < len(data) && p.inlineCallback[data[end]] == nil {
43 end++
44 }
45
46 p.r.NormalText(out, data[i:end])
47
48 if end >= len(data) {
49 break
50 }
51 i = end
52
53 // call the trigger
54 handler := p.inlineCallback[data[end]]
55 if consumed := handler(p, out, data, i); consumed == 0 {
56 // no action from the callback; buffer the byte for later
57 end = i + 1
58 } else {
59 // skip past whatever the callback used
60 i += consumed
61 end = i
62 }
63 }
64
65 p.nesting--
66}
67
68// single and double emphasis parsing
69func emphasis(p *parser, out *bytes.Buffer, data []byte, offset int) int {
70 data = data[offset:]
71 c := data[0]
72 ret := 0
73
74 if len(data) > 2 && data[1] != c {
75 // whitespace cannot follow an opening emphasis;
76 // strikethrough only takes two characters '~~'
77 if c == '~' || isspace(data[1]) {
78 return 0
79 }
80 if ret = helperEmphasis(p, out, data[1:], c); ret == 0 {
81 return 0
82 }
83
84 return ret + 1
85 }
86
87 if len(data) > 3 && data[1] == c && data[2] != c {
88 if isspace(data[2]) {
89 return 0
90 }
91 if ret = helperDoubleEmphasis(p, out, data[2:], c); ret == 0 {
92 return 0
93 }
94
95 return ret + 2
96 }
97
98 if len(data) > 4 && data[1] == c && data[2] == c && data[3] != c {
99 if c == '~' || isspace(data[3]) {
100 return 0
101 }
102 if ret = helperTripleEmphasis(p, out, data, 3, c); ret == 0 {
103 return 0
104 }
105
106 return ret + 3
107 }
108
109 return 0
110}
111
112func codeSpan(p *parser, out *bytes.Buffer, data []byte, offset int) int {
113 data = data[offset:]
114
115 nb := 0
116
117 // count the number of backticks in the delimiter
118 for nb < len(data) && data[nb] == '`' {
119 nb++
120 }
121
122 // find the next delimiter
123 i, end := 0, 0
124 for end = nb; end < len(data) && i < nb; end++ {
125 if data[end] == '`' {
126 i++
127 } else {
128 i = 0
129 }
130 }
131
132 // no matching delimiter?
133 if i < nb && end >= len(data) {
134 return 0
135 }
136
137 // trim outside whitespace
138 fBegin := nb
139 for fBegin < end && data[fBegin] == ' ' {
140 fBegin++
141 }
142
143 fEnd := end - nb
144 for fEnd > fBegin && data[fEnd-1] == ' ' {
145 fEnd--
146 }
147
148 // render the code span
149 if fBegin != fEnd {
150 p.r.CodeSpan(out, data[fBegin:fEnd])
151 }
152
153 return end
154
155}
156
157// newline preceded by two spaces becomes <br>
158// newline without two spaces works when EXTENSION_HARD_LINE_BREAK is enabled
159func lineBreak(p *parser, out *bytes.Buffer, data []byte, offset int) int {
160 // remove trailing spaces from out
161 outBytes := out.Bytes()
162 end := len(outBytes)
163 eol := end
164 for eol > 0 && outBytes[eol-1] == ' ' {
165 eol--
166 }
167 out.Truncate(eol)
168
169 precededByTwoSpaces := offset >= 2 && data[offset-2] == ' ' && data[offset-1] == ' '
170 precededByBackslash := offset >= 1 && data[offset-1] == '\\' // see http://spec.commonmark.org/0.18/#example-527
171 precededByBackslash = precededByBackslash && p.flags&EXTENSION_BACKSLASH_LINE_BREAK != 0
172
173 // should there be a hard line break here?
174 if p.flags&EXTENSION_HARD_LINE_BREAK == 0 && !precededByTwoSpaces && !precededByBackslash {
175 return 0
176 }
177
178 if precededByBackslash && eol > 0 {
179 out.Truncate(eol - 1)
180 }
181 p.r.LineBreak(out)
182 return 1
183}
184
185type linkType int
186
187const (
188 linkNormal linkType = iota
189 linkImg
190 linkDeferredFootnote
191 linkInlineFootnote
192)
193
194// '[': parse a link or an image or a footnote
195func link(p *parser, out *bytes.Buffer, data []byte, offset int) int {
196 // no links allowed inside regular links, footnote, and deferred footnotes
197 if p.insideLink && (offset > 0 && data[offset-1] == '[' || len(data)-1 > offset && data[offset+1] == '^') {
198 return 0
199 }
200
201 // [text] == regular link
202 // ![alt] == image
203 // ^[text] == inline footnote
204 // [^refId] == deferred footnote
205 var t linkType
206 if offset > 0 && data[offset-1] == '!' {
207 t = linkImg
208 } else if p.flags&EXTENSION_FOOTNOTES != 0 {
209 if offset > 0 && data[offset-1] == '^' {
210 t = linkInlineFootnote
211 } else if len(data)-1 > offset && data[offset+1] == '^' {
212 t = linkDeferredFootnote
213 }
214 }
215
216 data = data[offset:]
217
218 var (
219 i = 1
220 noteId int
221 title, link []byte
222 textHasNl = false
223 )
224
225 if t == linkDeferredFootnote {
226 i++
227 }
228
229 // look for the matching closing bracket
230 for level := 1; level > 0 && i < len(data); i++ {
231 switch {
232 case data[i] == '\n':
233 textHasNl = true
234
235 case data[i-1] == '\\':
236 continue
237
238 case data[i] == '[':
239 level++
240
241 case data[i] == ']':
242 level--
243 if level <= 0 {
244 i-- // compensate for extra i++ in for loop
245 }
246 }
247 }
248
249 if i >= len(data) {
250 return 0
251 }
252
253 txtE := i
254 i++
255
256 // skip any amount of whitespace or newline
257 // (this is much more lax than original markdown syntax)
258 for i < len(data) && isspace(data[i]) {
259 i++
260 }
261
262 // inline style link
263 switch {
264 case i < len(data) && data[i] == '(':
265 // skip initial whitespace
266 i++
267
268 for i < len(data) && isspace(data[i]) {
269 i++
270 }
271
272 linkB := i
273
274 // look for link end: ' " )
275 findlinkend:
276 for i < len(data) {
277 switch {
278 case data[i] == '\\':
279 i += 2
280
281 case data[i] == ')' || data[i] == '\'' || data[i] == '"':
282 break findlinkend
283
284 default:
285 i++
286 }
287 }
288
289 if i >= len(data) {
290 return 0
291 }
292 linkE := i
293
294 // look for title end if present
295 titleB, titleE := 0, 0
296 if data[i] == '\'' || data[i] == '"' {
297 i++
298 titleB = i
299
300 findtitleend:
301 for i < len(data) {
302 switch {
303 case data[i] == '\\':
304 i += 2
305
306 case data[i] == ')':
307 break findtitleend
308
309 default:
310 i++
311 }
312 }
313
314 if i >= len(data) {
315 return 0
316 }
317
318 // skip whitespace after title
319 titleE = i - 1
320 for titleE > titleB && isspace(data[titleE]) {
321 titleE--
322 }
323
324 // check for closing quote presence
325 if data[titleE] != '\'' && data[titleE] != '"' {
326 titleB, titleE = 0, 0
327 linkE = i
328 }
329 }
330
331 // remove whitespace at the end of the link
332 for linkE > linkB && isspace(data[linkE-1]) {
333 linkE--
334 }
335
336 // remove optional angle brackets around the link
337 if data[linkB] == '<' {
338 linkB++
339 }
340 if data[linkE-1] == '>' {
341 linkE--
342 }
343
344 // build escaped link and title
345 if linkE > linkB {
346 link = data[linkB:linkE]
347 }
348
349 if titleE > titleB {
350 title = data[titleB:titleE]
351 }
352
353 i++
354
355 // reference style link
356 case i < len(data)-1 && data[i] == '[' && data[i+1] != '^':
357 var id []byte
358
359 // look for the id
360 i++
361 linkB := i
362 for i < len(data) && data[i] != ']' {
363 i++
364 }
365 if i >= len(data) {
366 return 0
367 }
368 linkE := i
369
370 // find the reference
371 if linkB == linkE {
372 if textHasNl {
373 var b bytes.Buffer
374
375 for j := 1; j < txtE; j++ {
376 switch {
377 case data[j] != '\n':
378 b.WriteByte(data[j])
379 case data[j-1] != ' ':
380 b.WriteByte(' ')
381 }
382 }
383
384 id = b.Bytes()
385 } else {
386 id = data[1:txtE]
387 }
388 } else {
389 id = data[linkB:linkE]
390 }
391
392 // find the reference with matching id (ids are case-insensitive)
393 key := string(bytes.ToLower(id))
394 lr, ok := p.refs[key]
395 if !ok {
396 return 0
397
398 }
399
400 // keep link and title from reference
401 link = lr.link
402 title = lr.title
403 i++
404
405 // shortcut reference style link or reference or inline footnote
406 default:
407 var id []byte
408
409 // craft the id
410 if textHasNl {
411 var b bytes.Buffer
412
413 for j := 1; j < txtE; j++ {
414 switch {
415 case data[j] != '\n':
416 b.WriteByte(data[j])
417 case data[j-1] != ' ':
418 b.WriteByte(' ')
419 }
420 }
421
422 id = b.Bytes()
423 } else {
424 if t == linkDeferredFootnote {
425 id = data[2:txtE] // get rid of the ^
426 } else {
427 id = data[1:txtE]
428 }
429 }
430
431 key := string(bytes.ToLower(id))
432 if t == linkInlineFootnote {
433 // create a new reference
434 noteId = len(p.notes) + 1
435
436 var fragment []byte
437 if len(id) > 0 {
438 if len(id) < 16 {
439 fragment = make([]byte, len(id))
440 } else {
441 fragment = make([]byte, 16)
442 }
443 copy(fragment, slugify(id))
444 } else {
445 fragment = append([]byte("footnote-"), []byte(strconv.Itoa(noteId))...)
446 }
447
448 ref := &reference{
449 noteId: noteId,
450 hasBlock: false,
451 link: fragment,
452 title: id,
453 }
454
455 p.notes = append(p.notes, ref)
456
457 link = ref.link
458 title = ref.title
459 } else {
460 // find the reference with matching id
461 lr, ok := p.refs[key]
462 if !ok {
463 return 0
464 }
465
466 if t == linkDeferredFootnote {
467 lr.noteId = len(p.notes) + 1
468 p.notes = append(p.notes, lr)
469 }
470
471 // keep link and title from reference
472 link = lr.link
473 // if inline footnote, title == footnote contents
474 title = lr.title
475 noteId = lr.noteId
476 }
477
478 // rewind the whitespace
479 i = txtE + 1
480 }
481
482 // build content: img alt is escaped, link content is parsed
483 var content bytes.Buffer
484 if txtE > 1 {
485 if t == linkImg {
486 content.Write(data[1:txtE])
487 } else {
488 // links cannot contain other links, so turn off link parsing temporarily
489 insideLink := p.insideLink
490 p.insideLink = true
491 p.inline(&content, data[1:txtE])
492 p.insideLink = insideLink
493 }
494 }
495
496 var uLink []byte
497 if t == linkNormal || t == linkImg {
498 if len(link) > 0 {
499 var uLinkBuf bytes.Buffer
500 unescapeText(&uLinkBuf, link)
501 uLink = uLinkBuf.Bytes()
502 }
503
504 // links need something to click on and somewhere to go
505 if len(uLink) == 0 || (t == linkNormal && content.Len() == 0) {
506 return 0
507 }
508 }
509
510 // call the relevant rendering function
511 switch t {
512 case linkNormal:
513 p.r.Link(out, uLink, title, content.Bytes())
514
515 case linkImg:
516 outSize := out.Len()
517 outBytes := out.Bytes()
518 if outSize > 0 && outBytes[outSize-1] == '!' {
519 out.Truncate(outSize - 1)
520 }
521
522 p.r.Image(out, uLink, title, content.Bytes())
523
524 case linkInlineFootnote:
525 outSize := out.Len()
526 outBytes := out.Bytes()
527 if outSize > 0 && outBytes[outSize-1] == '^' {
528 out.Truncate(outSize - 1)
529 }
530
531 p.r.FootnoteRef(out, link, noteId)
532
533 case linkDeferredFootnote:
534 p.r.FootnoteRef(out, link, noteId)
535
536 default:
537 return 0
538 }
539
540 return i
541}
542
543// '<' when tags or autolinks are allowed
544func leftAngle(p *parser, out *bytes.Buffer, data []byte, offset int) int {
545 data = data[offset:]
546 altype := LINK_TYPE_NOT_AUTOLINK
547 end := tagLength(data, &altype)
548
549 if end > 2 {
550 if altype != LINK_TYPE_NOT_AUTOLINK {
551 var uLink bytes.Buffer
552 unescapeText(&uLink, data[1:end+1-2])
553 if uLink.Len() > 0 {
554 p.r.AutoLink(out, uLink.Bytes(), altype)
555 }
556 } else {
557 p.r.RawHtmlTag(out, data[:end])
558 }
559 }
560
561 return end
562}
563
564// '\\' backslash escape
565var escapeChars = []byte("\\`*_{}[]()#+-.!:|&<>~")
566
567func escape(p *parser, out *bytes.Buffer, data []byte, offset int) int {
568 data = data[offset:]
569
570 if len(data) > 1 {
571 if bytes.IndexByte(escapeChars, data[1]) < 0 {
572 return 0
573 }
574
575 p.r.NormalText(out, data[1:2])
576 }
577
578 return 2
579}
580
581func unescapeText(ob *bytes.Buffer, src []byte) {
582 i := 0
583 for i < len(src) {
584 org := i
585 for i < len(src) && src[i] != '\\' {
586 i++
587 }
588
589 if i > org {
590 ob.Write(src[org:i])
591 }
592
593 if i+1 >= len(src) {
594 break
595 }
596
597 ob.WriteByte(src[i+1])
598 i += 2
599 }
600}
601
602// '&' escaped when it doesn't belong to an entity
603// valid entities are assumed to be anything matching &#?[A-Za-z0-9]+;
604func entity(p *parser, out *bytes.Buffer, data []byte, offset int) int {
605 data = data[offset:]
606
607 end := 1
608
609 if end < len(data) && data[end] == '#' {
610 end++
611 }
612
613 for end < len(data) && isalnum(data[end]) {
614 end++
615 }
616
617 if end < len(data) && data[end] == ';' {
618 end++ // real entity
619 } else {
620 return 0 // lone '&'
621 }
622
623 p.r.Entity(out, data[:end])
624
625 return end
626}
627
628func linkEndsWithEntity(data []byte, linkEnd int) bool {
629 entityRanges := htmlEntity.FindAllIndex(data[:linkEnd], -1)
630 if entityRanges != nil && entityRanges[len(entityRanges)-1][1] == linkEnd {
631 return true
632 }
633 return false
634}
635
636func autoLink(p *parser, out *bytes.Buffer, data []byte, offset int) int {
637 // quick check to rule out most false hits on ':'
638 if p.insideLink || len(data) < offset+3 || data[offset+1] != '/' || data[offset+2] != '/' {
639 return 0
640 }
641
642 // Now a more expensive check to see if we're not inside an anchor element
643 anchorStart := offset
644 offsetFromAnchor := 0
645 for anchorStart > 0 && data[anchorStart] != '<' {
646 anchorStart--
647 offsetFromAnchor++
648 }
649
650 anchorStr := anchorRe.Find(data[anchorStart:])
651 if anchorStr != nil {
652 out.Write(anchorStr[offsetFromAnchor:])
653 return len(anchorStr) - offsetFromAnchor
654 }
655
656 // scan backward for a word boundary
657 rewind := 0
658 for offset-rewind > 0 && rewind <= 7 && isletter(data[offset-rewind-1]) {
659 rewind++
660 }
661 if rewind > 6 { // longest supported protocol is "mailto" which has 6 letters
662 return 0
663 }
664
665 origData := data
666 data = data[offset-rewind:]
667
668 if !isSafeLink(data) {
669 return 0
670 }
671
672 linkEnd := 0
673 for linkEnd < len(data) && !isEndOfLink(data[linkEnd]) {
674 linkEnd++
675 }
676
677 // Skip punctuation at the end of the link
678 if (data[linkEnd-1] == '.' || data[linkEnd-1] == ',') && data[linkEnd-2] != '\\' {
679 linkEnd--
680 }
681
682 // But don't skip semicolon if it's a part of escaped entity:
683 if data[linkEnd-1] == ';' && data[linkEnd-2] != '\\' && !linkEndsWithEntity(data, linkEnd) {
684 linkEnd--
685 }
686
687 // See if the link finishes with a punctuation sign that can be closed.
688 var copen byte
689 switch data[linkEnd-1] {
690 case '"':
691 copen = '"'
692 case '\'':
693 copen = '\''
694 case ')':
695 copen = '('
696 case ']':
697 copen = '['
698 case '}':
699 copen = '{'
700 default:
701 copen = 0
702 }
703
704 if copen != 0 {
705 bufEnd := offset - rewind + linkEnd - 2
706
707 openDelim := 1
708
709 /* Try to close the final punctuation sign in this same line;
710 * if we managed to close it outside of the URL, that means that it's
711 * not part of the URL. If it closes inside the URL, that means it
712 * is part of the URL.
713 *
714 * Examples:
715 *
716 * foo http://www.pokemon.com/Pikachu_(Electric) bar
717 * => http://www.pokemon.com/Pikachu_(Electric)
718 *
719 * foo (http://www.pokemon.com/Pikachu_(Electric)) bar
720 * => http://www.pokemon.com/Pikachu_(Electric)
721 *
722 * foo http://www.pokemon.com/Pikachu_(Electric)) bar
723 * => http://www.pokemon.com/Pikachu_(Electric))
724 *
725 * (foo http://www.pokemon.com/Pikachu_(Electric)) bar
726 * => foo http://www.pokemon.com/Pikachu_(Electric)
727 */
728
729 for bufEnd >= 0 && origData[bufEnd] != '\n' && openDelim != 0 {
730 if origData[bufEnd] == data[linkEnd-1] {
731 openDelim++
732 }
733
734 if origData[bufEnd] == copen {
735 openDelim--
736 }
737
738 bufEnd--
739 }
740
741 if openDelim == 0 {
742 linkEnd--
743 }
744 }
745
746 // we were triggered on the ':', so we need to rewind the output a bit
747 if out.Len() >= rewind {
748 out.Truncate(len(out.Bytes()) - rewind)
749 }
750
751 var uLink bytes.Buffer
752 unescapeText(&uLink, data[:linkEnd])
753
754 if uLink.Len() > 0 {
755 p.r.AutoLink(out, uLink.Bytes(), LINK_TYPE_NORMAL)
756 }
757
758 return linkEnd - rewind
759}
760
761func isEndOfLink(char byte) bool {
762 return isspace(char) || char == '<'
763}
764
765var validUris = [][]byte{[]byte("http://"), []byte("https://"), []byte("ftp://"), []byte("mailto://")}
766var validPaths = [][]byte{[]byte("/"), []byte("./"), []byte("../")}
767
768func isSafeLink(link []byte) bool {
769 for _, path := range validPaths {
770 if len(link) >= len(path) && bytes.Equal(link[:len(path)], path) {
771 if len(link) == len(path) {
772 return true
773 } else if isalnum(link[len(path)]) {
774 return true
775 }
776 }
777 }
778
779 for _, prefix := range validUris {
780 // TODO: handle unicode here
781 // case-insensitive prefix test
782 if len(link) > len(prefix) && bytes.Equal(bytes.ToLower(link[:len(prefix)]), prefix) && isalnum(link[len(prefix)]) {
783 return true
784 }
785 }
786
787 return false
788}
789
790// return the length of the given tag, or 0 is it's not valid
791func tagLength(data []byte, autolink *int) int {
792 var i, j int
793
794 // a valid tag can't be shorter than 3 chars
795 if len(data) < 3 {
796 return 0
797 }
798
799 // begins with a '<' optionally followed by '/', followed by letter or number
800 if data[0] != '<' {
801 return 0
802 }
803 if data[1] == '/' {
804 i = 2
805 } else {
806 i = 1
807 }
808
809 if !isalnum(data[i]) {
810 return 0
811 }
812
813 // scheme test
814 *autolink = LINK_TYPE_NOT_AUTOLINK
815
816 // try to find the beginning of an URI
817 for i < len(data) && (isalnum(data[i]) || data[i] == '.' || data[i] == '+' || data[i] == '-') {
818 i++
819 }
820
821 if i > 1 && i < len(data) && data[i] == '@' {
822 if j = isMailtoAutoLink(data[i:]); j != 0 {
823 *autolink = LINK_TYPE_EMAIL
824 return i + j
825 }
826 }
827
828 if i > 2 && i < len(data) && data[i] == ':' {
829 *autolink = LINK_TYPE_NORMAL
830 i++
831 }
832
833 // complete autolink test: no whitespace or ' or "
834 switch {
835 case i >= len(data):
836 *autolink = LINK_TYPE_NOT_AUTOLINK
837 case *autolink != 0:
838 j = i
839
840 for i < len(data) {
841 if data[i] == '\\' {
842 i += 2
843 } else if data[i] == '>' || data[i] == '\'' || data[i] == '"' || isspace(data[i]) {
844 break
845 } else {
846 i++
847 }
848
849 }
850
851 if i >= len(data) {
852 return 0
853 }
854 if i > j && data[i] == '>' {
855 return i + 1
856 }
857
858 // one of the forbidden chars has been found
859 *autolink = LINK_TYPE_NOT_AUTOLINK
860 }
861
862 // look for something looking like a tag end
863 for i < len(data) && data[i] != '>' {
864 i++
865 }
866 if i >= len(data) {
867 return 0
868 }
869 return i + 1
870}
871
872// look for the address part of a mail autolink and '>'
873// this is less strict than the original markdown e-mail address matching
874func isMailtoAutoLink(data []byte) int {
875 nb := 0
876
877 // address is assumed to be: [-@._a-zA-Z0-9]+ with exactly one '@'
878 for i := 0; i < len(data); i++ {
879 if isalnum(data[i]) {
880 continue
881 }
882
883 switch data[i] {
884 case '@':
885 nb++
886
887 case '-', '.', '_':
888 break
889
890 case '>':
891 if nb == 1 {
892 return i + 1
893 } else {
894 return 0
895 }
896 default:
897 return 0
898 }
899 }
900
901 return 0
902}
903
904// look for the next emph char, skipping other constructs
905func helperFindEmphChar(data []byte, c byte) int {
906 i := 1
907
908 for i < len(data) {
909 for i < len(data) && data[i] != c && data[i] != '`' && data[i] != '[' {
910 i++
911 }
912 if i >= len(data) {
913 return 0
914 }
915 if data[i] == c {
916 return i
917 }
918
919 // do not count escaped chars
920 if i != 0 && data[i-1] == '\\' {
921 i++
922 continue
923 }
924
925 if data[i] == '`' {
926 // skip a code span
927 tmpI := 0
928 i++
929 for i < len(data) && data[i] != '`' {
930 if tmpI == 0 && data[i] == c {
931 tmpI = i
932 }
933 i++
934 }
935 if i >= len(data) {
936 return tmpI
937 }
938 i++
939 } else if data[i] == '[' {
940 // skip a link
941 tmpI := 0
942 i++
943 for i < len(data) && data[i] != ']' {
944 if tmpI == 0 && data[i] == c {
945 tmpI = i
946 }
947 i++
948 }
949 i++
950 for i < len(data) && (data[i] == ' ' || data[i] == '\n') {
951 i++
952 }
953 if i >= len(data) {
954 return tmpI
955 }
956 if data[i] != '[' && data[i] != '(' { // not a link
957 if tmpI > 0 {
958 return tmpI
959 } else {
960 continue
961 }
962 }
963 cc := data[i]
964 i++
965 for i < len(data) && data[i] != cc {
966 if tmpI == 0 && data[i] == c {
967 return i
968 }
969 i++
970 }
971 if i >= len(data) {
972 return tmpI
973 }
974 i++
975 }
976 }
977 return 0
978}
979
980func helperEmphasis(p *parser, out *bytes.Buffer, data []byte, c byte) int {
981 i := 0
982
983 // skip one symbol if coming from emph3
984 if len(data) > 1 && data[0] == c && data[1] == c {
985 i = 1
986 }
987
988 for i < len(data) {
989 length := helperFindEmphChar(data[i:], c)
990 if length == 0 {
991 return 0
992 }
993 i += length
994 if i >= len(data) {
995 return 0
996 }
997
998 if i+1 < len(data) && data[i+1] == c {
999 i++
1000 continue
1001 }
1002
1003 if data[i] == c && !isspace(data[i-1]) {
1004
1005 if p.flags&EXTENSION_NO_INTRA_EMPHASIS != 0 {
1006 if !(i+1 == len(data) || isspace(data[i+1]) || ispunct(data[i+1])) {
1007 continue
1008 }
1009 }
1010
1011 var work bytes.Buffer
1012 p.inline(&work, data[:i])
1013 p.r.Emphasis(out, work.Bytes())
1014 return i + 1
1015 }
1016 }
1017
1018 return 0
1019}
1020
1021func helperDoubleEmphasis(p *parser, out *bytes.Buffer, data []byte, c byte) int {
1022 i := 0
1023
1024 for i < len(data) {
1025 length := helperFindEmphChar(data[i:], c)
1026 if length == 0 {
1027 return 0
1028 }
1029 i += length
1030
1031 if i+1 < len(data) && data[i] == c && data[i+1] == c && i > 0 && !isspace(data[i-1]) {
1032 var work bytes.Buffer
1033 p.inline(&work, data[:i])
1034
1035 if work.Len() > 0 {
1036 // pick the right renderer
1037 if c == '~' {
1038 p.r.StrikeThrough(out, work.Bytes())
1039 } else {
1040 p.r.DoubleEmphasis(out, work.Bytes())
1041 }
1042 }
1043 return i + 2
1044 }
1045 i++
1046 }
1047 return 0
1048}
1049
1050func helperTripleEmphasis(p *parser, out *bytes.Buffer, data []byte, offset int, c byte) int {
1051 i := 0
1052 origData := data
1053 data = data[offset:]
1054
1055 for i < len(data) {
1056 length := helperFindEmphChar(data[i:], c)
1057 if length == 0 {
1058 return 0
1059 }
1060 i += length
1061
1062 // skip whitespace preceded symbols
1063 if data[i] != c || isspace(data[i-1]) {
1064 continue
1065 }
1066
1067 switch {
1068 case i+2 < len(data) && data[i+1] == c && data[i+2] == c:
1069 // triple symbol found
1070 var work bytes.Buffer
1071
1072 p.inline(&work, data[:i])
1073 if work.Len() > 0 {
1074 p.r.TripleEmphasis(out, work.Bytes())
1075 }
1076 return i + 3
1077 case (i+1 < len(data) && data[i+1] == c):
1078 // double symbol found, hand over to emph1
1079 length = helperEmphasis(p, out, origData[offset-2:], c)
1080 if length == 0 {
1081 return 0
1082 } else {
1083 return length - 2
1084 }
1085 default:
1086 // single symbol found, hand over to emph2
1087 length = helperDoubleEmphasis(p, out, origData[offset-1:], c)
1088 if length == 0 {
1089 return 0
1090 } else {
1091 return length - 1
1092 }
1093 }
1094 }
1095 return 0
1096}