Disabled formatting in URLs

README.md

@@ -51,9 +51,9 @@ coverage: 100.0% of statements
 ## Benchmarks
 
 ```
-BenchmarkSmall-12        6202569               190.9 ns/op            32 B/op          1 allocs/op
+BenchmarkSmall-12        5933677               190.8 ns/op            32 B/op          1 allocs/op
-BenchmarkMedium-12       1000000              1080 ns/op             512 B/op          1 allocs/op
+BenchmarkMedium-12        971929              1085 ns/op             512 B/op          1 allocs/op
-BenchmarkLarge-12         271048              4115 ns/op            2560 B/op          2 allocs/op
+BenchmarkLarge-12         277028              4075 ns/op            2560 B/op          2 allocs/op
 ```
 
 ## License

Render.go

@@ -253,14 +253,13 @@ func (r *renderer) writeText(markdown string) {
 		searchStart   = 0
 		linkTextStart = -1
 		linkTextEnd   = -1
-		urlStart      = -1
 		codeStart     = -1
 		emStart       = -1
 		strongStart   = -1
 		strikeStart   = -1
-		parentheses   = 0
 	)
 
+begin:
 	for {
 		i := strings.IndexAny(markdown[searchStart:], "[]()`*_~")
 
@@ -282,18 +281,31 @@ func (r *renderer) writeText(markdown string) {
 			linkTextEnd = i
 
 		case '(':
-			if parentheses == 0 {
+			if linkTextStart == -1 || linkTextEnd == -1 {
-				urlStart = i
+				continue
 			}
 
-			parentheses++
+			level := 1
 
+			for {
+				pos := strings.IndexAny(markdown[searchStart:], "()")
+
+				if pos == -1 {
+					goto begin
+				}
+
+				switch markdown[searchStart+pos] {
+				case '(':
+					level++
 				case ')':
-			parentheses--
+					level--
+
+					if level == 0 {
+						urlEnd := searchStart + pos
+						searchStart = urlEnd + 1
 
-			if parentheses == 0 && linkTextStart >= 0 && linkTextEnd >= 0 && urlStart >= 0 {
 						linkText := markdown[linkTextStart+1 : linkTextEnd]
-				linkURL := markdown[urlStart+1 : i]
+						linkURL := markdown[i+1 : urlEnd]
 
 						r.WriteString("<a href=\"")
 						r.WriteString(sanitizeURL(linkURL))
@@ -303,9 +315,12 @@ func (r *renderer) writeText(markdown string) {
 
 						linkTextStart = -1
 						linkTextEnd = -1
-				urlStart = -1
+						tokenStart = urlEnd + 1
+						goto begin
+					}
+				}
 
-				tokenStart = i + 1
+				searchStart += pos + 1
 			}
 
 		case '`':

Render_test.go

@@ -50,6 +50,7 @@ func TestLink(t *testing.T) {
 	assert.Equal(t, markdown.Render("[text]https://example.com/)"), "<p>[text]https://example.com/)</p>")
 	assert.Equal(t, markdown.Render("[text(https://example.com/)"), "<p>[text(https://example.com/)</p>")
 	assert.Equal(t, markdown.Render("text](https://example.com/)"), "<p>text](https://example.com/)</p>")
+	assert.Equal(t, markdown.Render("[text](https://example.com/_test_)"), "<p><a href=\"https://example.com/_test_\">text</a></p>")
 	assert.Equal(t, markdown.Render("Prefix [text](https://example.com/) suffix."), "<p>Prefix <a href=\"https://example.com/\">text</a> suffix.</p>")
 }