Update Blackfriday dependency (closes #522) (#532)

- Fixup Telegram bridge implementation to support updated dependency.

1 files changed, 443 insertions, 344 deletions

diff --git a/vendor/github.com/russross/blackfriday/block.go b/vendor/github.com/russross/blackfriday/block.go
index 7fc731d5..d7da33f2 100644
--- a/vendor/github.com/russross/blackfriday/block.go
+++ b/vendor/github.com/russross/blackfriday/block.go
@@ -15,17 +15,26 @@ package blackfriday
 
 import (
 	"bytes"
-	"unicode"
+	"html"
+	"regexp"
+
+	"github.com/shurcooL/sanitized_anchor_name"
+)
+
+const (
+	charEntity = "&(?:#x[a-f0-9]{1,8}|#[0-9]{1,8}|[a-z][a-z0-9]{1,31});"
+	escapable  = "[!\"#$%&'()*+,./:;<=>?@[\\\\\\]^_`{|}~-]"
+)
+
+var (
+	reBackslashOrAmp      = regexp.MustCompile("[\\&]")
+	reEntityOrEscapedChar = regexp.MustCompile("(?i)\\\\" + escapable + "|" + charEntity)
 )
 
 // Parse block-level data.
 // Note: this function and many that it calls assume that
 // the input buffer ends with a newline.
-func (p *parser) block(out *bytes.Buffer, data []byte) {
-	if len(data) == 0 || data[len(data)-1] != '\n' {
-		panic("block input is missing terminating newline")
-	}
-
+func (p *Markdown) block(data []byte) {
 	// this is called recursively: enforce a maximum depth
 	if p.nesting >= p.maxNesting {
 		return
@@ -34,14 +43,14 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 
 	// parse out one block-level construct at a time
 	for len(data) > 0 {
-		// prefixed header:
+		// prefixed heading:
 		//
-		// # Header 1
-		// ## Header 2
+		// # Heading 1
+		// ## Heading 2
 		// ...
-		// ###### Header 6
-		if p.isPrefixHeader(data) {
-			data = data[p.prefixHeader(out, data):]
+		// ###### Heading 6
+		if p.isPrefixHeading(data) {
+			data = data[p.prefixHeading(data):]
 			continue
 		}
 
@@ -51,7 +60,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//     ...
 		// </div>
 		if data[0] == '<' {
-			if i := p.html(out, data, true); i > 0 {
+			if i := p.html(data, true); i > 0 {
 				data = data[i:]
 				continue
 			}
@@ -62,9 +71,9 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// % stuff
 		// % more stuff
 		// % even more stuff
-		if p.flags&EXTENSION_TITLEBLOCK != 0 {
+		if p.extensions&Titleblock != 0 {
 			if data[0] == '%' {
-				if i := p.titleBlock(out, data, true); i > 0 {
+				if i := p.titleBlock(data, true); i > 0 {
 					data = data[i:]
 					continue
 				}
@@ -86,7 +95,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//         return b
 		//      }
 		if p.codePrefix(data) > 0 {
-			data = data[p.code(out, data):]
+			data = data[p.code(data):]
 			continue
 		}
 
@@ -100,8 +109,8 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//     return n * fact(n-1)
 		// }
 		// ```
-		if p.flags&EXTENSION_FENCED_CODE != 0 {
-			if i := p.fencedCodeBlock(out, data, true); i > 0 {
+		if p.extensions&FencedCode != 0 {
+			if i := p.fencedCodeBlock(data, true); i > 0 {
 				data = data[i:]
 				continue
 			}
@@ -115,9 +124,9 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// or
 		// ______
 		if p.isHRule(data) {
-			p.r.HRule(out)
+			p.addBlock(HorizontalRule, nil)
 			var i int
-			for i = 0; data[i] != '\n'; i++ {
+			for i = 0; i < len(data) && data[i] != '\n'; i++ {
 			}
 			data = data[i:]
 			continue
@@ -128,7 +137,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// > A big quote I found somewhere
 		// > on the web
 		if p.quotePrefix(data) > 0 {
-			data = data[p.quote(out, data):]
+			data = data[p.quote(data):]
 			continue
 		}
 
@@ -138,8 +147,8 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// ------|-----|---------
 		// Bob   | 31  | 555-1234
 		// Alice | 27  | 555-4321
-		if p.flags&EXTENSION_TABLES != 0 {
-			if i := p.table(out, data); i > 0 {
+		if p.extensions&Tables != 0 {
+			if i := p.table(data); i > 0 {
 				data = data[i:]
 				continue
 			}
@@ -152,7 +161,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//
 		// also works with + or -
 		if p.uliPrefix(data) > 0 {
-			data = data[p.list(out, data, 0):]
+			data = data[p.list(data, 0):]
 			continue
 		}
 
@@ -161,7 +170,7 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		// 1. Item 1
 		// 2. Item 2
 		if p.oliPrefix(data) > 0 {
-			data = data[p.list(out, data, LIST_TYPE_ORDERED):]
+			data = data[p.list(data, ListTypeOrdered):]
 			continue
 		}
 
@@ -173,55 +182,62 @@ func (p *parser) block(out *bytes.Buffer, data []byte) {
 		//
 		// Term 2
 		// :   Definition c
-		if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
+		if p.extensions&DefinitionLists != 0 {
 			if p.dliPrefix(data) > 0 {
-				data = data[p.list(out, data, LIST_TYPE_DEFINITION):]
+				data = data[p.list(data, ListTypeDefinition):]
 				continue
 			}
 		}
 
 		// anything else must look like a normal paragraph
-		// note: this finds underlined headers, too
-		data = data[p.paragraph(out, data):]
+		// note: this finds underlined headings, too
+		data = data[p.paragraph(data):]
 	}
 
 	p.nesting--
 }
 
-func (p *parser) isPrefixHeader(data []byte) bool {
+func (p *Markdown) addBlock(typ NodeType, content []byte) *Node {
+	p.closeUnmatchedBlocks()
+	container := p.addChild(typ, 0)
+	container.content = content
+	return container
+}
+
+func (p *Markdown) isPrefixHeading(data []byte) bool {
 	if data[0] != '#' {
 		return false
 	}
 
-	if p.flags&EXTENSION_SPACE_HEADERS != 0 {
+	if p.extensions&SpaceHeadings != 0 {
 		level := 0
-		for level < 6 && data[level] == '#' {
+		for level < 6 && level < len(data) && data[level] == '#' {
 			level++
 		}
-		if data[level] != ' ' {
+		if level == len(data) || data[level] != ' ' {
 			return false
 		}
 	}
 	return true
 }
 
-func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) prefixHeading(data []byte) int {
 	level := 0
-	for level < 6 && data[level] == '#' {
+	for level < 6 && level < len(data) && data[level] == '#' {
 		level++
 	}
 	i := skipChar(data, level, ' ')
 	end := skipUntilChar(data, i, '\n')
 	skip := end
 	id := ""
-	if p.flags&EXTENSION_HEADER_IDS != 0 {
+	if p.extensions&HeadingIDs != 0 {
 		j, k := 0, 0
-		// find start/end of header id
+		// find start/end of heading id
 		for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ {
 		}
 		for k = j + 1; k < end && data[k] != '}'; k++ {
 		}
-		// extract header id iff found
+		// extract heading id iff found
 		if j < end && k < end {
 			id = string(data[j+2 : k])
 			end = j
@@ -241,45 +257,41 @@ func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
 		end--
 	}
 	if end > i {
-		if id == "" && p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
-			id = SanitizedAnchorName(string(data[i:end]))
+		if id == "" && p.extensions&AutoHeadingIDs != 0 {
+			id = sanitized_anchor_name.Create(string(data[i:end]))
 		}
-		work := func() bool {
-			p.inline(out, data[i:end])
-			return true
-		}
-		p.r.Header(out, work, level, id)
+		block := p.addBlock(Heading, data[i:end])
+		block.HeadingID = id
+		block.Level = level
 	}
 	return skip
 }
 
-func (p *parser) isUnderlinedHeader(data []byte) int {
-	// test of level 1 header
+func (p *Markdown) isUnderlinedHeading(data []byte) int {
+	// test of level 1 heading
 	if data[0] == '=' {
 		i := skipChar(data, 1, '=')
 		i = skipChar(data, i, ' ')
-		if data[i] == '\n' {
+		if i < len(data) && data[i] == '\n' {
 			return 1
-		} else {
-			return 0
 		}
+		return 0
 	}
 
-	// test of level 2 header
+	// test of level 2 heading
 	if data[0] == '-' {
 		i := skipChar(data, 1, '-')
 		i = skipChar(data, i, ' ')
-		if data[i] == '\n' {
+		if i < len(data) && data[i] == '\n' {
 			return 2
-		} else {
-			return 0
 		}
+		return 0
 	}
 
 	return 0
 }
 
-func (p *parser) titleBlock(out *bytes.Buffer, data []byte, doRender bool) int {
+func (p *Markdown) titleBlock(data []byte, doRender bool) int {
 	if data[0] != '%' {
 		return 0
 	}
@@ -293,12 +305,17 @@ func (p *parser) titleBlock(out *bytes.Buffer, data []byte, doRender bool) int {
 	}
 
 	data = bytes.Join(splitData[0:i], []byte("\n"))
-	p.r.TitleBlock(out, data)
-
-	return len(data)
+	consumed := len(data)
+	data = bytes.TrimPrefix(data, []byte("% "))
+	data = bytes.Replace(data, []byte("\n% "), []byte("\n"), -1)
+	block := p.addBlock(Heading, data)
+	block.Level = 1
+	block.IsTitleblock = true
+
+	return consumed
 }
 
-func (p *parser) html(out *bytes.Buffer, data []byte, doRender bool) int {
+func (p *Markdown) html(data []byte, doRender bool) int {
 	var i, j int
 
 	// identify the opening tag
@@ -310,17 +327,12 @@ func (p *parser) html(out *bytes.Buffer, data []byte, doRender bool) int {
 	// handle special cases
 	if !tagfound {
 		// check for an HTML comment
-		if size := p.htmlComment(out, data, doRender); size > 0 {
+		if size := p.htmlComment(data, doRender); size > 0 {
 			return size
 		}
 
 		// check for an <hr> tag
-		if size := p.htmlHr(out, data, doRender); size > 0 {
-			return size
-		}
-
-		// check for HTML CDATA
-		if size := p.htmlCDATA(out, data, doRender); size > 0 {
+		if size := p.htmlHr(data, doRender); size > 0 {
 			return size
 		}
 
@@ -395,60 +407,42 @@ func (p *parser) html(out *bytes.Buffer, data []byte, doRender bool) int {
 		for end > 0 && data[end-1] == '\n' {
 			end--
 		}
-		p.r.BlockHtml(out, data[:end])
+		finalizeHTMLBlock(p.addBlock(HTMLBlock, data[:end]))
 	}
 
 	return i
 }
 
-func (p *parser) renderHTMLBlock(out *bytes.Buffer, data []byte, start int, doRender bool) int {
-	// html block needs to end with a blank line
-	if i := p.isEmpty(data[start:]); i > 0 {
-		size := start + i
+func finalizeHTMLBlock(block *Node) {
+	block.Literal = block.content
+	block.content = nil
+}
+
+// HTML comment, lax form
+func (p *Markdown) htmlComment(data []byte, doRender bool) int {
+	i := p.inlineHTMLComment(data)
+	// needs to end with a blank line
+	if j := p.isEmpty(data[i:]); j > 0 {
+		size := i + j
 		if doRender {
 			// trim trailing newlines
 			end := size
 			for end > 0 && data[end-1] == '\n' {
 				end--
 			}
-			p.r.BlockHtml(out, data[:end])
+			block := p.addBlock(HTMLBlock, data[:end])
+			finalizeHTMLBlock(block)
 		}
 		return size
 	}
 	return 0
 }
 
-// HTML comment, lax form
-func (p *parser) htmlComment(out *bytes.Buffer, data []byte, doRender bool) int {
-	i := p.inlineHTMLComment(out, data)
-	return p.renderHTMLBlock(out, data, i, doRender)
-}
-
-// HTML CDATA section
-func (p *parser) htmlCDATA(out *bytes.Buffer, data []byte, doRender bool) int {
-	const cdataTag = "<![cdata["
-	const cdataTagLen = len(cdataTag)
-	if len(data) < cdataTagLen+1 {
-		return 0
-	}
-	if !bytes.Equal(bytes.ToLower(data[:cdataTagLen]), []byte(cdataTag)) {
-		return 0
-	}
-	i := cdataTagLen
-	// scan for an end-of-comment marker, across lines if necessary
-	for i < len(data) && !(data[i-2] == ']' && data[i-1] == ']' && data[i] == '>') {
-		i++
-	}
-	i++
-	// no end-of-comment marker
-	if i >= len(data) {
+// HR, which is the only self-closing block tag considered
+func (p *Markdown) htmlHr(data []byte, doRender bool) int {
+	if len(data) < 4 {
 		return 0
 	}
-	return p.renderHTMLBlock(out, data, i, doRender)
-}
-
-// HR, which is the only self-closing block tag considered
-func (p *parser) htmlHr(out *bytes.Buffer, data []byte, doRender bool) int {
 	if data[0] != '<' || (data[1] != 'h' && data[1] != 'H') || (data[2] != 'r' && data[2] != 'R') {
 		return 0
 	}
@@ -456,22 +450,31 @@ func (p *parser) htmlHr(out *bytes.Buffer, data []byte, doRender bool) int {
 		// not an <hr> tag after all; at least not a valid one
 		return 0
 	}
-
 	i := 3
-	for data[i] != '>' && data[i] != '\n' {
+	for i < len(data) && data[i] != '>' && data[i] != '\n' {
 		i++
 	}
-
-	if data[i] == '>' {
-		return p.renderHTMLBlock(out, data, i+1, doRender)
+	if i < len(data) && data[i] == '>' {
+		i++
+		if j := p.isEmpty(data[i:]); j > 0 {
+			size := i + j
+			if doRender {
+				// trim newlines
+				end := size
+				for end > 0 && data[end-1] == '\n' {
+					end--
+				}
+				finalizeHTMLBlock(p.addBlock(HTMLBlock, data[:end]))
+			}
+			return size
+		}
 	}
-
 	return 0
 }
 
-func (p *parser) htmlFindTag(data []byte) (string, bool) {
+func (p *Markdown) htmlFindTag(data []byte) (string, bool) {
 	i := 0
-	for isalnum(data[i]) {
+	for i < len(data) && isalnum(data[i]) {
 		i++
 	}
 	key := string(data[:i])
@@ -481,9 +484,11 @@ func (p *parser) htmlFindTag(data []byte) (string, bool) {
 	return "", false
 }
 
-func (p *parser) htmlFindEnd(tag string, data []byte) int {
+func (p *Markdown) htmlFindEnd(tag string, data []byte) int {
 	// assume data[0] == '<' && data[1] == '/' already tested
-
+	if tag == "hr" {
+		return 2
+	}
 	// check if tag is a match
 	closetag := []byte("</" + tag + ">")
 	if !bytes.HasPrefix(data, closetag) {
@@ -503,7 +508,7 @@ func (p *parser) htmlFindEnd(tag string, data []byte) int {
 		return i
 	}
 
-	if p.flags&EXTENSION_LAX_HTML_BLOCKS != 0 {
+	if p.extensions&LaxHTMLBlocks != 0 {
 		return i
 	}
 	if skip = p.isEmpty(data[i:]); skip == 0 {
@@ -514,7 +519,7 @@ func (p *parser) htmlFindEnd(tag string, data []byte) int {
 	return i + skip
 }
 
-func (*parser) isEmpty(data []byte) int {
+func (*Markdown) isEmpty(data []byte) int {
 	// it is okay to call isEmpty on an empty buffer
 	if len(data) == 0 {
 		return 0
@@ -526,10 +531,13 @@ func (*parser) isEmpty(data []byte) int {
 			return 0
 		}
 	}
-	return i + 1
+	if i < len(data) && data[i] == '\n' {
+		i++
+	}
+	return i
 }
 
-func (*parser) isHRule(data []byte) bool {
+func (*Markdown) isHRule(data []byte) bool {
 	i := 0
 
 	// skip up to three spaces
@@ -545,7 +553,7 @@ func (*parser) isHRule(data []byte) bool {
 
 	// the whole line must be the char or whitespace
 	n := 0
-	for data[i] != '\n' {
+	for i < len(data) && data[i] != '\n' {
 		switch {
 		case data[i] == c:
 			n++
@@ -561,8 +569,7 @@ func (*parser) isHRule(data []byte) bool {
 // isFenceLine checks if there's a fence line (e.g., ``` or ``` go) at the beginning of data,
 // and returns the end index if so, or 0 otherwise. It also returns the marker found.
 // If syntax is not nil, it gets set to the syntax specified in the fence line.
-// A final newline is mandatory to recognize the fence line, unless newlineOptional is true.
-func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional bool) (end int, marker string) {
+func isFenceLine(data []byte, syntax *string, oldmarker string) (end int, marker string) {
 	i, size := 0, 0
 
 	// skip up to three spaces
@@ -604,7 +611,7 @@ func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional
 		i = skipChar(data, i, ' ')
 
 		if i >= len(data) {
-			if newlineOptional && i == len(data) {
+			if i == len(data) {
 				return i, marker
 			}
 			return 0, ""
@@ -649,33 +656,33 @@ func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional
 
 	i = skipChar(data, i, ' ')
 	if i >= len(data) || data[i] != '\n' {
-		if newlineOptional && i == len(data) {
+		if i == len(data) {
 			return i, marker
 		}
 		return 0, ""
 	}
-
 	return i + 1, marker // Take newline into account.
 }
 
 // fencedCodeBlock returns the end index if data contains a fenced code block at the beginning,
 // or 0 otherwise. It writes to out if doRender is true, otherwise it has no side effects.
 // If doRender is true, a final newline is mandatory to recognize the fenced code block.
-func (p *parser) fencedCodeBlock(out *bytes.Buffer, data []byte, doRender bool) int {
+func (p *Markdown) fencedCodeBlock(data []byte, doRender bool) int {
 	var syntax string
-	beg, marker := isFenceLine(data, &syntax, "", false)
+	beg, marker := isFenceLine(data, &syntax, "")
 	if beg == 0 || beg >= len(data) {
 		return 0
 	}
 
 	var work bytes.Buffer
+	work.Write([]byte(syntax))
+	work.WriteByte('\n')
 
 	for {
 		// safe to assume beg < len(data)
 
 		// check for the end of the code block
-		newlineOptional := !doRender
-		fenceEnd, _ := isFenceLine(data[beg:], nil, marker, newlineOptional)
+		fenceEnd, _ := isFenceLine(data[beg:], nil, marker)
 		if fenceEnd != 0 {
 			beg += fenceEnd
 			break
@@ -697,24 +704,55 @@ func (p *parser) fencedCodeBlock(out *bytes.Buffer, data []byte, doRender bool)
 	}
 
 	if doRender {
-		p.r.BlockCode(out, work.Bytes(), syntax)
+		block := p.addBlock(CodeBlock, work.Bytes()) // TODO: get rid of temp buffer
+		block.IsFenced = true
+		finalizeCodeBlock(block)
 	}
 
 	return beg
 }
 
-func (p *parser) table(out *bytes.Buffer, data []byte) int {
-	var header bytes.Buffer
-	i, columns := p.tableHeader(&header, data)
+func unescapeChar(str []byte) []byte {
+	if str[0] == '\\' {
+		return []byte{str[1]}
+	}
+	return []byte(html.UnescapeString(string(str)))
+}
+
+func unescapeString(str []byte) []byte {
+	if reBackslashOrAmp.Match(str) {
+		return reEntityOrEscapedChar.ReplaceAllFunc(str, unescapeChar)
+	}
+	return str
+}
+
+func finalizeCodeBlock(block *Node) {
+	if block.IsFenced {
+		newlinePos := bytes.IndexByte(block.content, '\n')
+		firstLine := block.content[:newlinePos]
+		rest := block.content[newlinePos+1:]
+		block.Info = unescapeString(bytes.Trim(firstLine, "\n"))
+		block.Literal = rest
+	} else {
+		block.Literal = block.content
+	}
+	block.content = nil
+}
+
+func (p *Markdown) table(data []byte) int {
+	table := p.addBlock(Table, nil)
+	i, columns := p.tableHeader(data)
 	if i == 0 {
+		p.tip = table.Parent
+		table.Unlink()
 		return 0
 	}
 
-	var body bytes.Buffer
+	p.addBlock(TableBody, nil)
 
 	for i < len(data) {
 		pipes, rowStart := 0, i
-		for ; data[i] != '\n'; i++ {
+		for ; i < len(data) && data[i] != '\n'; i++ {
 			if data[i] == '|' {
 				pipes++
 			}
@@ -726,12 +764,12 @@ func (p *parser) table(out *bytes.Buffer, data []byte) int {
 		}
 
 		// include the newline in data sent to tableRow
-		i++
-		p.tableRow(&body, data[rowStart:i], columns, false)
+		if i < len(data) && data[i] == '\n' {
+			i++
+		}
+		p.tableRow(data[rowStart:i], columns, false)
 	}
 
-	p.r.Table(out, header.Bytes(), body.Bytes(), columns)
-
 	return i
 }
 
@@ -744,10 +782,10 @@ func isBackslashEscaped(data []byte, i int) bool {
 	return backslashes&1 == 1
 }
 
-func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns []int) {
+func (p *Markdown) tableHeader(data []byte) (size int, columns []CellAlignFlags) {
 	i := 0
 	colCount := 1
-	for i = 0; data[i] != '\n'; i++ {
+	for i = 0; i < len(data) && data[i] != '\n'; i++ {
 		if data[i] == '|' && !isBackslashEscaped(data, i) {
 			colCount++
 		}
@@ -759,7 +797,11 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 	}
 
 	// include the newline in the data sent to tableRow
-	header := data[:i+1]
+	j := i
+	if j < len(data) && data[j] == '\n' {
+		j++
+	}
+	header := data[:j]
 
 	// column count ignores pipes at beginning or end of line
 	if data[0] == '|' {
@@ -769,7 +811,7 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 		colCount--
 	}
 
-	columns = make([]int, colCount)
+	columns = make([]CellAlignFlags, colCount)
 
 	// move on to the header underline
 	i++
@@ -785,27 +827,29 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 	// each column header is of form: / *:?-+:? *|/ with # dashes + # colons >= 3
 	// and trailing | optional on last column
 	col := 0
-	for data[i] != '\n' {
+	for i < len(data) && data[i] != '\n' {
 		dashes := 0
 
 		if data[i] == ':' {
 			i++
-			columns[col] |= TABLE_ALIGNMENT_LEFT
+			columns[col] |= TableAlignmentLeft
 			dashes++
 		}
-		for data[i] == '-' {
+		for i < len(data) && data[i] == '-' {
 			i++
 			dashes++
 		}
-		if data[i] == ':' {
+		if i < len(data) && data[i] == ':' {
 			i++
-			columns[col] |= TABLE_ALIGNMENT_RIGHT
+			columns[col] |= TableAlignmentRight
 			dashes++
 		}
-		for data[i] == ' ' {
+		for i < len(data) && data[i] == ' ' {
 			i++
 		}
-
+		if i == len(data) {
+			return
+		}
 		// end of column test is messy
 		switch {
 		case dashes < 3:
@@ -816,12 +860,12 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 			// marker found, now skip past trailing whitespace
 			col++
 			i++
-			for data[i] == ' ' {
+			for i < len(data) && data[i] == ' ' {
 				i++
 			}
 
 			// trailing junk found after last column
-			if col >= colCount && data[i] != '\n' {
+			if col >= colCount && i < len(data) && data[i] != '\n' {
 				return
 			}
 
@@ -842,27 +886,31 @@ func (p *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns
 		return
 	}
 
-	p.tableRow(out, header, columns, true)
-	size = i + 1
+	p.addBlock(TableHead, nil)
+	p.tableRow(header, columns, true)
+	size = i
+	if size < len(data) && data[size] == '\n' {
+		size++
+	}
 	return
 }
 
-func (p *parser) tableRow(out *bytes.Buffer, data []byte, columns []int, header bool) {
+func (p *Markdown) tableRow(data []byte, columns []CellAlignFlags, header bool) {
+	p.addBlock(TableRow, nil)
 	i, col := 0, 0
-	var rowWork bytes.Buffer
 
 	if data[i] == '|' && !isBackslashEscaped(data, i) {
 		i++
 	}
 
 	for col = 0; col < len(columns) && i < len(data); col++ {
-		for data[i] == ' ' {
+		for i < len(data) && data[i] == ' ' {
 			i++
 		}
 
 		cellStart := i
 
-		for (data[i] != '|' || isBackslashEscaped(data, i)) && data[i] != '\n' {
+		for i < len(data) && (data[i] != '|' || isBackslashEscaped(data, i)) && data[i] != '\n' {
 			i++
 		}
 
@@ -871,42 +919,33 @@ func (p *parser) tableRow(out *bytes.Buffer, data []byte, columns []int, header
 		// skip the end-of-cell marker, possibly taking us past end of buffer
 		i++
 
-		for cellEnd > cellStart && data[cellEnd-1] == ' ' {
+		for cellEnd > cellStart && cellEnd-1 < len(data) && data[cellEnd-1] == ' ' {
 			cellEnd--
 		}
 
-		var cellWork bytes.Buffer
-		p.inline(&cellWork, data[cellStart:cellEnd])
-
-		if header {
-			p.r.TableHeaderCell(&rowWork, cellWork.Bytes(), columns[col])
-		} else {
-			p.r.TableCell(&rowWork, cellWork.Bytes(), columns[col])
-		}
+		cell := p.addBlock(TableCell, data[cellStart:cellEnd])
+		cell.IsHeader = header
+		cell.Align = columns[col]
 	}
 
 	// pad it out with empty columns to get the right number
 	for ; col < len(columns); col++ {
-		if header {
-			p.r.TableHeaderCell(&rowWork, nil, columns[col])
-		} else {
-			p.r.TableCell(&rowWork, nil, columns[col])
-		}
+		cell := p.addBlock(TableCell, nil)
+		cell.IsHeader = header
+		cell.Align = columns[col]
 	}
 
 	// silently ignore rows with too many cells
-
-	p.r.TableRow(out, rowWork.Bytes())
 }
 
 // returns blockquote prefix length
-func (p *parser) quotePrefix(data []byte) int {
+func (p *Markdown) quotePrefix(data []byte) int {
 	i := 0
-	for i < 3 && data[i] == ' ' {
+	for i < 3 && i < len(data) && data[i] == ' ' {
 		i++
 	}
-	if data[i] == '>' {
-		if data[i+1] == ' ' {
+	if i < len(data) && data[i] == '>' {
+		if i+1 < len(data) && data[i+1] == ' ' {
 			return i + 2
 		}
 		return i + 1
@@ -916,7 +955,7 @@ func (p *parser) quotePrefix(data []byte) int {
 
 // blockquote ends with at least one blank line
 // followed by something without a blockquote prefix
-func (p *parser) terminateBlockquote(data []byte, beg, end int) bool {
+func (p *Markdown) terminateBlockquote(data []byte, beg, end int) bool {
 	if p.isEmpty(data[beg:]) <= 0 {
 		return false
 	}
@@ -927,7 +966,8 @@ func (p *parser) terminateBlockquote(data []byte, beg, end int) bool {
 }
 
 // parse a blockquote fragment
-func (p *parser) quote(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) quote(data []byte) int {
+	block := p.addBlock(BlockQuote, nil)
 	var raw bytes.Buffer
 	beg, end := 0, 0
 	for beg < len(data) {
@@ -935,9 +975,9 @@ func (p *parser) quote(out *bytes.Buffer, data []byte) int {
 		// Step over whole lines, collecting them. While doing that, check for
 		// fenced code and if one's found, incorporate it altogether,
 		// irregardless of any contents inside it
-		for data[end] != '\n' {
-			if p.flags&EXTENSION_FENCED_CODE != 0 {
-				if i := p.fencedCodeBlock(out, data[end:], false); i > 0 {
+		for end < len(data) && data[end] != '\n' {
+			if p.extensions&FencedCode != 0 {
+				if i := p.fencedCodeBlock(data[end:], false); i > 0 {
 					// -1 to compensate for the extra end++ after the loop:
 					end += i - 1
 					break
@@ -945,44 +985,47 @@ func (p *parser) quote(out *bytes.Buffer, data []byte) int {
 			}
 			end++
 		}
-		end++
-
+		if end < len(data) && data[end] == '\n' {
+			end++
+		}
 		if pre := p.quotePrefix(data[beg:]); pre > 0 {
 			// skip the prefix
 			beg += pre
 		} else if p.terminateBlockquote(data, beg, end) {
 			break
 		}
-
 		// this line is part of the blockquote
 		raw.Write(data[beg:end])
 		beg = end
 	}
-
-	var cooked bytes.Buffer
-	p.block(&cooked, raw.Bytes())
-	p.r.BlockQuote(out, cooked.Bytes())
+	p.block(raw.Bytes())
+	p.finalize(block)
 	return end
 }
 
 // returns prefix length for block code
-func (p *parser) codePrefix(data []byte) int {
-	if data[0] == ' ' && data[1] == ' ' && data[2] == ' ' && data[3] == ' ' {
+func (p *Markdown) codePrefix(data []byte) int {
+	if len(data) >= 1 && data[0] == '\t' {
+		return 1
+	}
+	if len(data) >= 4 && data[0] == ' ' && data[1] == ' ' && data[2] == ' ' && data[3] == ' ' {
 		return 4
 	}
 	return 0
 }
 
-func (p *parser) code(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) code(data []byte) int {
 	var work bytes.Buffer
 
 	i := 0
 	for i < len(data) {
 		beg := i
-		for data[i] != '\n' {
+		for i < len(data) && data[i] != '\n' {
+			i++
+		}
+		if i < len(data) && data[i] == '\n' {
 			i++
 		}
-		i++
 
 		blankline := p.isEmpty(data[beg:i]) > 0
 		if pre := p.codePrefix(data[beg:i]); pre > 0 {
@@ -993,7 +1036,7 @@ func (p *parser) code(out *bytes.Buffer, data []byte) int {
 			break
 		}
 
-		// verbatim copy to the working buffeu
+		// verbatim copy to the working buffer
 		if blankline {
 			work.WriteByte('\n')
 		} else {
@@ -1013,122 +1056,183 @@ func (p *parser) code(out *bytes.Buffer, data []byte) int {
 
 	work.WriteByte('\n')
 
-	p.r.BlockCode(out, work.Bytes(), "")
+	block := p.addBlock(CodeBlock, work.Bytes()) // TODO: get rid of temp buffer
+	block.IsFenced = false
+	finalizeCodeBlock(block)
 
 	return i
 }
 
 // returns unordered list item prefix
-func (p *parser) uliPrefix(data []byte) int {
+func (p *Markdown) uliPrefix(data []byte) int {
 	i := 0
-
 	// start with up to 3 spaces
-	for i < 3 && data[i] == ' ' {
+	for i < len(data) && i < 3 && data[i] == ' ' {
 		i++
 	}
-
-	// need a *, +, or - followed by a space
+	if i >= len(data)-1 {
+		return 0
+	}
+	// need one of {'*', '+', '-'} followed by a space or a tab
 	if (data[i] != '*' && data[i] != '+' && data[i] != '-') ||
-		data[i+1] != ' ' {
+		(data[i+1] != ' ' && data[i+1] != '\t') {
 		return 0
 	}
 	return i + 2
 }
 
 // returns ordered list item prefix
-func (p *parser) oliPrefix(data []byte) int {
+func (p *Markdown) oliPrefix(data []byte) int {
 	i := 0
 
 	// start with up to 3 spaces
-	for i < 3 && data[i] == ' ' {
+	for i < 3 && i < len(data) && data[i] == ' ' {
 		i++
 	}
 
 	// count the digits
 	start := i
-	for data[i] >= '0' && data[i] <= '9' {
+	for i < len(data) && data[i] >= '0' && data[i] <= '9' {
 		i++
 	}
+	if start == i || i >= len(data)-1 {
+		return 0
+	}
 
-	// we need >= 1 digits followed by a dot and a space
-	if start == i || data[i] != '.' || data[i+1] != ' ' {
+	// we need >= 1 digits followed by a dot and a space or a tab
+	if data[i] != '.' || !(data[i+1] == ' ' || data[i+1] == '\t') {
 		return 0
 	}
 	return i + 2
 }
 
 // returns definition list item prefix
-func (p *parser) dliPrefix(data []byte) int {
+func (p *Markdown) dliPrefix(data []byte) int {
+	if len(data) < 2 {
+		return 0
+	}
 	i := 0
-
-	// need a : followed by a spaces
-	if data[i] != ':' || data[i+1] != ' ' {
+	// need a ':' followed by a space or a tab
+	if data[i] != ':' || !(data[i+1] == ' ' || data[i+1] == '\t') {
 		return 0
 	}
-	for data[i] == ' ' {
+	for i < len(data) && data[i] == ' ' {
 		i++
 	}
 	return i + 2
 }
 
 // parse ordered or unordered list block
-func (p *parser) list(out *bytes.Buffer, data []byte, flags int) int {
+func (p *Markdown) list(data []byte, flags ListType) int {
 	i := 0
-	flags |= LIST_ITEM_BEGINNING_OF_LIST
-	work := func() bool {
-		for i < len(data) {
-			skip := p.listItem(out, data[i:], &flags)
-			i += skip
+	flags |= ListItemBeginningOfList
+	block := p.addBlock(List, nil)
+	block.ListFlags = flags
+	block.Tight = true
 
-			if skip == 0 || flags&LIST_ITEM_END_OF_LIST != 0 {
-				break
-			}
-			flags &= ^LIST_ITEM_BEGINNING_OF_LIST
+	for i < len(data) {
+		skip := p.listItem(data[i:], &flags)
+		if flags&ListItemContainsBlock != 0 {
+			block.ListData.Tight = false
 		}
-		return true
+		i += skip
+		if skip == 0 || flags&ListItemEndOfList != 0 {
+			break
+		}
+		flags &= ^ListItemBeginningOfList
 	}
 
-	p.r.List(out, work, flags)
+	above := block.Parent
+	finalizeList(block)
+	p.tip = above
 	return i
 }
 
+// Returns true if block ends with a blank line, descending if needed
+// into lists and sublists.
+func endsWithBlankLine(block *Node) bool {
+	// TODO: figure this out. Always false now.
+	for block != nil {
+		//if block.lastLineBlank {
+		//return true
+		//}
+		t := block.Type
+		if t == List || t == Item {
+			block = block.LastChild
+		} else {
+			break
+		}
+	}
+	return false
+}
+
+func finalizeList(block *Node) {
+	block.open = false
+	item := block.FirstChild
+	for item != nil {
+		// check for non-final list item ending with blank line:
+		if endsWithBlankLine(item) && item.Next != nil {
+			block.ListData.Tight = false
+			break
+		}
+		// recurse into children of list item, to see if there are spaces
+		// between any of them:
+		subItem := item.FirstChild
+		for subItem != nil {
+			if endsWithBlankLine(subItem) && (item.Next != nil || subItem.Next != nil) {
+				block.ListData.Tight = false
+				break
+			}
+			subItem = subItem.Next
+		}
+		item = item.Next
+	}
+}
+
 // Parse a single list item.
 // Assumes initial prefix is already removed if this is a sublist.
-func (p *parser) listItem(out *bytes.Buffer, data []byte, flags *int) int {
+func (p *Markdown) listItem(data []byte, flags *ListType) int {
 	// keep track of the indentation of the first line
 	itemIndent := 0
-	for itemIndent < 3 && data[itemIndent] == ' ' {
-		itemIndent++
+	if data[0] == '\t' {
+		itemIndent += 4
+	} else {
+		for itemIndent < 3 && data[itemIndent] == ' ' {
+			itemIndent++
+		}
 	}
 
+	var bulletChar byte = '*'
 	i := p.uliPrefix(data)
 	if i == 0 {
 		i = p.oliPrefix(data)
+	} else {
+		bulletChar = data[i-2]
 	}
 	if i == 0 {
 		i = p.dliPrefix(data)
 		// reset definition term flag
 		if i > 0 {
-			*flags &= ^LIST_TYPE_TERM
+			*flags &= ^ListTypeTerm
 		}
 	}
 	if i == 0 {
-		// if in defnition list, set term flag and continue
-		if *flags&LIST_TYPE_DEFINITION != 0 {
-			*flags |= LIST_TYPE_TERM
+		// if in definition list, set term flag and continue
+		if *flags&ListTypeDefinition != 0 {
+			*flags |= ListTypeTerm
 		} else {
 			return 0
 		}
 	}
 
 	// skip leading whitespace on first line
-	for data[i] == ' ' {
+	for i < len(data) && data[i] == ' ' {
 		i++
 	}
 
 	// find the end of the line
 	line := i
-	for i > 0 && data[i-1] != '\n' {
+	for i > 0 && i < len(data) && data[i-1] != '\n' {
 		i++
 	}
 
@@ -1148,7 +1252,7 @@ gatherlines:
 		i++
 
 		// find the end of this line
-		for data[i-1] != '\n' {
+		for i < len(data) && data[i-1] != '\n' {
 			i++
 		}
 
@@ -1156,18 +1260,24 @@ gatherlines:
 		// and move on to the next line
 		if p.isEmpty(data[line:i]) > 0 {
 			containsBlankLine = true
-			raw.Write(data[line:i])
 			line = i
 			continue
 		}
 
 		// calculate the indentation
 		indent := 0
-		for indent < 4 && line+indent < i && data[line+indent] == ' ' {
-			indent++
+		indentIndex := 0
+		if data[line] == '\t' {
+			indentIndex++
+			indent += 4
+		} else {
+			for indent < 4 && line+indent < i && data[line+indent] == ' ' {
+				indent++
+				indentIndex++
+			}
 		}
 
-		chunk := data[line+indent : i]
+		chunk := data[line+indentIndex : i]
 
 		// evaluate how this line fits in
 		switch {
@@ -1177,15 +1287,7 @@ gatherlines:
 			p.dliPrefix(chunk) > 0:
 
 			if containsBlankLine {
-				// end the list if the type changed after a blank line
-				if indent <= itemIndent &&
-					((*flags&LIST_TYPE_ORDERED != 0 && p.uliPrefix(chunk) > 0) ||
-						(*flags&LIST_TYPE_ORDERED == 0 && p.oliPrefix(chunk) > 0)) {
-
-					*flags |= LIST_ITEM_END_OF_LIST
-					break gatherlines
-				}
-				*flags |= LIST_ITEM_CONTAINS_BLOCK
+				*flags |= ListItemContainsBlock
 			}
 
 			// to be a nested list, it must be indented more
@@ -1199,93 +1301,89 @@ gatherlines:
 				sublist = raw.Len()
 			}
 
-		// is this a nested prefix header?
-		case p.isPrefixHeader(chunk):
-			// if the header is not indented, it is not nested in the list
+		// is this a nested prefix heading?
+		case p.isPrefixHeading(chunk):
+			// if the heading is not indented, it is not nested in the list
 			// and thus ends the list
 			if containsBlankLine && indent < 4 {
-				*flags |= LIST_ITEM_END_OF_LIST
+				*flags |= ListItemEndOfList
 				break gatherlines
 			}
-			*flags |= LIST_ITEM_CONTAINS_BLOCK
+			*flags |= ListItemContainsBlock
 
 		// anything following an empty line is only part
 		// of this item if it is indented 4 spaces
 		// (regardless of the indentation of the beginning of the item)
 		case containsBlankLine && indent < 4:
-			if *flags&LIST_TYPE_DEFINITION != 0 && i < len(data)-1 {
+			if *flags&ListTypeDefinition != 0 && i < len(data)-1 {
 				// is the next item still a part of this list?
 				next := i
-				for data[next] != '\n' {
+				for next < len(data) && data[next] != '\n' {
 					next++
 				}
 				for next < len(data)-1 && data[next] == '\n' {
 					next++
 				}
 				if i < len(data)-1 && data[i] != ':' && data[next] != ':' {
-					*flags |= LIST_ITEM_END_OF_LIST
+					*flags |= ListItemEndOfList
 				}
 			} else {
-				*flags |= LIST_ITEM_END_OF_LIST
+				*flags |= ListItemEndOfList
 			}
 			break gatherlines
 
 		// a blank line means this should be parsed as a block
 		case containsBlankLine:
-			*flags |= LIST_ITEM_CONTAINS_BLOCK
+			raw.WriteByte('\n')
+			*flags |= ListItemContainsBlock
 		}
 
-		containsBlankLine = false
+		// if this line was preceded by one or more blanks,
+		// re-introduce the blank into the buffer
+		if containsBlankLine {
+			containsBlankLine = false
+			raw.WriteByte('\n')
+		}
 
 		// add the line into the working buffer without prefix
-		raw.Write(data[line+indent : i])
+		raw.Write(data[line+indentIndex : i])
 
 		line = i
 	}
 
-	// If reached end of data, the Renderer.ListItem call we're going to make below
-	// is definitely the last in the list.
-	if line >= len(data) {
-		*flags |= LIST_ITEM_END_OF_LIST
-	}
-
 	rawBytes := raw.Bytes()
 
+	block := p.addBlock(Item, nil)
+	block.ListFlags = *flags
+	block.Tight = false
+	block.BulletChar = bulletChar
+	block.Delimiter = '.' // Only '.' is possible in Markdown, but ')' will also be possible in CommonMark
+
 	// render the contents of the list item
-	var cooked bytes.Buffer
-	if *flags&LIST_ITEM_CONTAINS_BLOCK != 0 && *flags&LIST_TYPE_TERM == 0 {
+	if *flags&ListItemContainsBlock != 0 && *flags&ListTypeTerm == 0 {
 		// intermediate render of block item, except for definition term
 		if sublist > 0 {
-			p.block(&cooked, rawBytes[:sublist])
-			p.block(&cooked, rawBytes[sublist:])
+			p.block(rawBytes[:sublist])
+			p.block(rawBytes[sublist:])
 		} else {
-			p.block(&cooked, rawBytes)
+			p.block(rawBytes)
 		}
 	} else {
 		// intermediate render of inline item
 		if sublist > 0 {
-			p.inline(&cooked, rawBytes[:sublist])
-			p.block(&cooked, rawBytes[sublist:])
+			child := p.addChild(Paragraph, 0)
+			child.content = rawBytes[:sublist]
+			p.block(rawBytes[sublist:])
 		} else {
-			p.inline(&cooked, rawBytes)
+			child := p.addChild(Paragraph, 0)
+			child.content = rawBytes
 		}
 	}
-
-	// render the actual list item
-	cookedBytes := cooked.Bytes()
-	parsedEnd := len(cookedBytes)
-
-	// strip trailing newlines
-	for parsedEnd > 0 && cookedBytes[parsedEnd-1] == '\n' {
-		parsedEnd--
-	}
-	p.r.ListItem(out, cookedBytes[:parsedEnd], *flags)
-
 	return line
 }
 
 // render a single paragraph that has already been parsed out
-func (p *parser) renderParagraph(out *bytes.Buffer, data []byte) {
+func (p *Markdown) renderParagraph(data []byte) {
 	if len(data) == 0 {
 		return
 	}
@@ -1296,27 +1394,29 @@ func (p *parser) renderParagraph(out *bytes.Buffer, data []byte) {
 		beg++
 	}
 
+	end := len(data)
 	// trim trailing newline
-	end := len(data) - 1
+	if data[len(data)-1] == '\n' {
+		end--
+	}
 
 	// trim trailing spaces
 	for end > beg && data[end-1] == ' ' {
 		end--
 	}
 
-	work := func() bool {
-		p.inline(out, data[beg:end])
-		return true
-	}
-	p.r.Paragraph(out, work)
+	p.addBlock(Paragraph, data[beg:end])
 }
 
-func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
+func (p *Markdown) paragraph(data []byte) int {
 	// prev: index of 1st char of previous line
 	// line: index of 1st char of current line
 	// i: index of cursor/end of current line
 	var prev, line, i int
-
+	tabSize := TabSizeDefault
+	if p.extensions&TabSizeEight != 0 {
+		tabSize = TabSizeDouble
+	}
 	// keep going until we find something to mark the end of the paragraph
 	for i < len(data) {
 		// mark the beginning of the current line
@@ -1324,24 +1424,32 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 		current := data[i:]
 		line = i
 
+		// did we find a reference or a footnote? If so, end a paragraph
+		// preceding it and report that we have consumed up to the end of that
+		// reference:
+		if refEnd := isReference(p, current, tabSize); refEnd > 0 {
+			p.renderParagraph(data[:i])
+			return i + refEnd
+		}
+
 		// did we find a blank line marking the end of the paragraph?
 		if n := p.isEmpty(current); n > 0 {
 			// did this blank line followed by a definition list item?
-			if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
+			if p.extensions&DefinitionLists != 0 {
 				if i < len(data)-1 && data[i+1] == ':' {
-					return p.list(out, data[prev:], LIST_TYPE_DEFINITION)
+					return p.list(data[prev:], ListTypeDefinition)
 				}
 			}
 
-			p.renderParagraph(out, data[:i])
+			p.renderParagraph(data[:i])
 			return i + n
 		}
 
-		// an underline under some text marks a header, so our paragraph ended on prev line
+		// an underline under some text marks a heading, so our paragraph ended on prev line
 		if i > 0 {
-			if level := p.isUnderlinedHeader(current); level > 0 {
+			if level := p.isUnderlinedHeading(current); level > 0 {
 				// render the paragraph
-				p.renderParagraph(out, data[:prev])
+				p.renderParagraph(data[:prev])
 
 				// ignore leading and trailing whitespace
 				eol := i - 1
@@ -1352,24 +1460,17 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 					eol--
 				}
 
-				// render the header
-				// this ugly double closure avoids forcing variables onto the heap
-				work := func(o *bytes.Buffer, pp *parser, d []byte) func() bool {
-					return func() bool {
-						pp.inline(o, d)
-						return true
-					}
-				}(out, p, data[prev:eol])
-
 				id := ""
-				if p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
-					id = SanitizedAnchorName(string(data[prev:eol]))
+				if p.extensions&AutoHeadingIDs != 0 {
+					id = sanitized_anchor_name.Create(string(data[prev:eol]))
 				}
 
-				p.r.Header(out, work, level, id)
+				block := p.addBlock(Heading, data[prev:eol])
+				block.Level = level
+				block.HeadingID = id
 
 				// find the end of the underline
-				for data[i] != '\n' {
+				for i < len(data) && data[i] != '\n' {
 					i++
 				}
 				return i
@@ -1377,74 +1478,72 @@ func (p *parser) paragraph(out *bytes.Buffer, data []byte) int {
 		}
 
 		// if the next line starts a block of HTML, then the paragraph ends here
-		if p.flags&EXTENSION_LAX_HTML_BLOCKS != 0 {
-			if data[i] == '<' && p.html(out, current, false) > 0 {
+		if p.extensions&LaxHTMLBlocks != 0 {
+			if data[i] == '<' && p.html(current, false) > 0 {
 				// rewind to before the HTML block
-				p.renderParagraph(out, data[:i])
+				p.renderParagraph(data[:i])
 				return i
 			}
 		}
 
-		// if there's a prefixed header or a horizontal rule after this, paragraph is over
-		if p.isPrefixHeader(current) || p.isHRule(current) {
-			p.renderParagraph(out, data[:i])
+		// if there's a prefixed heading or a horizontal rule after this, paragraph is over
+		if p.isPrefixHeading(current) || p.isHRule(current) {
+			p.renderParagraph(data[:i])
 			return i
 		}
 
 		// if there's a fenced code block, paragraph is over
-		if p.flags&EXTENSION_FENCED_CODE != 0 {
-			if p.fencedCodeBlock(out, current, false) > 0 {
-				p.renderParagraph(out, data[:i])
+		if p.extensions&FencedCode != 0 {
+			if p.fencedCodeBlock(current, false) > 0 {
+				p.renderParagraph(data[:i])
 				return i
 			}
 		}
 
 		// if there's a definition list item, prev line is a definition term
-		if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
+		if p.extensions&DefinitionLists != 0 {
 			if p.dliPrefix(current) != 0 {
-				return p.list(out, data[prev:], LIST_TYPE_DEFINITION)
+				ret := p.list(data[prev:], ListTypeDefinition)
+				return ret
 			}
 		}
 
 		// if there's a list after this, paragraph is over
-		if p.flags&EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK != 0 {
+		if p.extensions&NoEmptyLineBeforeBlock != 0 {
 			if p.uliPrefix(current) != 0 ||
 				p.oliPrefix(current) != 0 ||
 				p.quotePrefix(current) != 0 ||
 				p.codePrefix(current) != 0 {
-				p.renderParagraph(out, data[:i])
+				p.renderParagraph(data[:i])
 				return i
 			}
 		}
 
 		// otherwise, scan to the beginning of the next line
-		for data[i] != '\n' {
-			i++
+		nl := bytes.IndexByte(data[i:], '\n')
+		if nl >= 0 {
+			i += nl + 1
+		} else {
+			i += len(data[i:])
 		}
-		i++
 	}
 
-	p.renderParagraph(out, data[:i])
+	p.renderParagraph(data[:i])
 	return i
 }
 
-// SanitizedAnchorName returns a sanitized anchor name for the given text.
-//
-// It implements the algorithm specified in the package comment.
-func SanitizedAnchorName(text string) string {
-	var anchorName []rune
-	futureDash := false
-	for _, r := range text {
-		switch {
-		case unicode.IsLetter(r) || unicode.IsNumber(r):
-			if futureDash && len(anchorName) > 0 {
-				anchorName = append(anchorName, '-')
-			}
-			futureDash = false
-			anchorName = append(anchorName, unicode.ToLower(r))
-		default:
-			futureDash = true
-		}
+func skipChar(data []byte, start int, char byte) int {
+	i := start
+	for i < len(data) && data[i] == char {
+		i++
+	}
+	return i
+}
+
+func skipUntilChar(text []byte, start int, char byte) int {
+	i := start
+	for i < len(text) && text[i] != char {
+		i++
 	}
-	return string(anchorName)
+	return i
 }