Fix replaceEntities

common.go

@@ -317,9 +317,13 @@ func replaceEntities(b []byte, i int, entitiesMap map[string][]byte, revEntities
 		}
 	} else {
 		for ; j < len(b) && j-i-1 <= MaxEntityLength && b[j] != ';'; j++ {
+			if !(b[j] >= '0' && b[j] <= '9' || b[j] >= 'a' && b[j] <= 'z' || b[j] >= 'A' && b[j] <= 'Z') {
+				// invalid character reference character
+				break
+			}
 		}
-		if j <= i+1 || len(b) <= j {
-			return b, j - 1
+		if len(b) <= j || j == i+1 || b[j] != ';' {
+			return b, i
 		}
 
 		var ok bool
@@ -399,7 +403,7 @@ func ReplaceMultipleWhitespaceAndEntities(b []byte, entitiesMap map[string][]byt
 	if j == 0 {
 		return b
 	} else if j == 1 { // only if starts with whitespace
-		b[k-1] = b[0]
+		b[k-1] = b[0] // move newline to end of whitespace
 		return b[k-1:]
 	} else if k < len(b) {
 		j += copy(b[j:], b[k:])

common_test.go

@@ -243,6 +243,10 @@ func TestReplaceMultipleWhitespaceAndEntities(t *testing.T) {
 		entity   string
 		expected string
 	}{
+		{"  ", " "},
+		{" & a   ", " & a "},
+		{" &acute a   ", " &acute a "},
+		{"\n    Lorem & ipsum\n    dolor sid amet\n", "\nLorem & ipsum\ndolor sid amet\n"},
 		{"  ϕ  " \n ", " ϕ \"\n"},
 	}
 	for _, tt := range entityTests {