1 files changed, 254 insertions, 0 deletions
diff --git a/src/cmd/vendor/rsc.io/markdown/table.go b/src/cmd/vendor/rsc.io/markdown/table.go
new file mode 100644
index 0000000000..95f41c834c
--- /dev/null
+++ b/src/cmd/vendor/rsc.io/markdown/table.go
@@ -0,0 +1,254 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package markdown
+
+import (
+	"bytes"
+	"strings"
+)
+
+type tableTrimmed string
+
+func isTableSpace(c byte) bool {
+	return c == ' ' || c == '\t' || c == '\v' || c == '\f'
+}
+
+func tableTrimSpace(s string) string {
+	i := 0
+	for i < len(s) && isTableSpace(s[i]) {
+		i++
+	}
+	j := len(s)
+	for j > i && isTableSpace(s[j-1]) {
+		j--
+	}
+	return s[i:j]
+}
+
+func tableTrimOuter(row string) tableTrimmed {
+	row = tableTrimSpace(row)
+	if len(row) > 0 && row[0] == '|' {
+		row = row[1:]
+	}
+	if len(row) > 0 && row[len(row)-1] == '|' {
+		row = row[:len(row)-1]
+	}
+	return tableTrimmed(row)
+}
+
+func isTableStart(hdr1, delim1 string) bool {
+	// Scan potential delimiter string, counting columns.
+	// This happens on every line of text,
+	// so make it relatively quick - nothing expensive.
+	col := 0
+	delim := tableTrimOuter(delim1)
+	i := 0
+	for ; ; col++ {
+		for i < len(delim) && isTableSpace(delim[i]) {
+			i++
+		}
+		if i >= len(delim) {
+			break
+		}
+		if i < len(delim) && delim[i] == ':' {
+			i++
+		}
+		if i >= len(delim) || delim[i] != '-' {
+			return false
+		}
+		i++
+		for i < len(delim) && delim[i] == '-' {
+			i++
+		}
+		if i < len(delim) && delim[i] == ':' {
+			i++
+		}
+		for i < len(delim) && isTableSpace(delim[i]) {
+			i++
+		}
+		if i < len(delim) && delim[i] == '|' {
+			i++
+		}
+	}
+
+	if strings.TrimSpace(hdr1) == "|" {
+		// https://github.com/github/cmark-gfm/pull/127 and
+		// https://github.com/github/cmark-gfm/pull/128
+		// fixed a buffer overread by rejecting | by itself as a table line.
+		// That seems to violate the spec, but we will play along.
+		return false
+	}
+
+	return col == tableCount(tableTrimOuter(hdr1))
+}
+
+func tableCount(row tableTrimmed) int {
+	col := 1
+	prev := byte(0)
+	for i := 0; i < len(row); i++ {
+		c := row[i]
+		if c == '|' && prev != '\\' {
+			col++
+		}
+		prev = c
+	}
+	return col
+}
+
+type tableBuilder struct {
+	hdr   tableTrimmed
+	delim tableTrimmed
+	rows  []tableTrimmed
+}
+
+func (b *tableBuilder) start(hdr, delim string) {
+	b.hdr = tableTrimOuter(hdr)
+	b.delim = tableTrimOuter(delim)
+}
+
+func (b *tableBuilder) addRow(row string) {
+	b.rows = append(b.rows, tableTrimOuter(row))
+}
+
+type Table struct {
+	Position
+	Header []*Text
+	Align  []string // 'l', 'c', 'r' for left, center, right; 0 for unset
+	Rows   [][]*Text
+}
+
+func (t *Table) PrintHTML(buf *bytes.Buffer) {
+	buf.WriteString("<table>\n")
+	buf.WriteString("<thead>\n")
+	buf.WriteString("<tr>\n")
+	for i, hdr := range t.Header {
+		buf.WriteString("<th")
+		if t.Align[i] != "" {
+			buf.WriteString(" align=\"")
+			buf.WriteString(t.Align[i])
+			buf.WriteString("\"")
+		}
+		buf.WriteString(">")
+		hdr.PrintHTML(buf)
+		buf.WriteString("</th>\n")
+	}
+	buf.WriteString("</tr>\n")
+	buf.WriteString("</thead>\n")
+	if len(t.Rows) > 0 {
+		buf.WriteString("<tbody>\n")
+		for _, row := range t.Rows {
+			buf.WriteString("<tr>\n")
+			for i, cell := range row {
+				buf.WriteString("<td")
+				if i < len(t.Align) && t.Align[i] != "" {
+					buf.WriteString(" align=\"")
+					buf.WriteString(t.Align[i])
+					buf.WriteString("\"")
+				}
+				buf.WriteString(">")
+				cell.PrintHTML(buf)
+				buf.WriteString("</td>\n")
+			}
+			buf.WriteString("</tr>\n")
+		}
+		buf.WriteString("</tbody>\n")
+	}
+	buf.WriteString("</table>\n")
+}
+
+func (t *Table) printMarkdown(buf *bytes.Buffer, s mdState) {
+}
+
+func (b *tableBuilder) build(p buildState) Block {
+	pos := p.pos()
+	pos.StartLine-- // builder does not count header
+	pos.EndLine = pos.StartLine + 1 + len(b.rows)
+	t := &Table{
+		Position: pos,
+	}
+	width := tableCount(b.hdr)
+	t.Header = b.parseRow(p, b.hdr, pos.StartLine, width)
+	t.Align = b.parseAlign(b.delim, width)
+	t.Rows = make([][]*Text, len(b.rows))
+	for i, row := range b.rows {
+		t.Rows[i] = b.parseRow(p, row, pos.StartLine+2+i, width)
+	}
+	return t
+}
+
+func (b *tableBuilder) parseRow(p buildState, row tableTrimmed, line int, width int) []*Text {
+	out := make([]*Text, 0, width)
+	pos := Position{StartLine: line, EndLine: line}
+	start := 0
+	unesc := nop
+	for i := 0; i < len(row); i++ {
+		c := row[i]
+		if c == '\\' && i+1 < len(row) && row[i+1] == '|' {
+			unesc = tableUnescape
+			i++
+			continue
+		}
+		if c == '|' {
+			out = append(out, p.newText(pos, unesc(strings.Trim(string(row[start:i]), " \t\v\f"))))
+			if len(out) == width {
+				// Extra cells are discarded!
+				return out
+			}
+			start = i + 1
+			unesc = nop
+		}
+	}
+	out = append(out, p.newText(pos, unesc(strings.Trim(string(row[start:]), " \t\v\f"))))
+	for len(out) < width {
+		// Missing cells are considered empty.
+		out = append(out, p.newText(pos, ""))
+	}
+	return out
+}
+
+func nop(text string) string {
+	return text
+}
+
+func tableUnescape(text string) string {
+	out := make([]byte, 0, len(text))
+	for i := 0; i < len(text); i++ {
+		c := text[i]
+		if c == '\\' && i+1 < len(text) && text[i+1] == '|' {
+			i++
+			c = '|'
+		}
+		out = append(out, c)
+	}
+	return string(out)
+}
+
+func (b *tableBuilder) parseAlign(delim tableTrimmed, n int) []string {
+	align := make([]string, 0, tableCount(delim))
+	start := 0
+	for i := 0; i < len(delim); i++ {
+		if delim[i] == '|' {
+			align = append(align, tableAlign(string(delim[start:i])))
+			start = i + 1
+		}
+	}
+	align = append(align, tableAlign(string(delim[start:])))
+	return align
+}
+
+func tableAlign(cell string) string {
+	cell = tableTrimSpace(cell)
+	l := cell[0] == ':'
+	r := cell[len(cell)-1] == ':'
+	switch {
+	case l && r:
+		return "center"
+	case l:
+		return "left"
+	case r:
+		return "right"
+	}
+	return ""
+}