add vendor data

vendor/github.com/dunglas/httpsfv/list.go

@@ -0,0 +1,99 @@
+package httpsfv
+
+import (
+	"errors"
+	"strings"
+)
+
+// ErrInvalidListFormat is returned when the format of a list is invalid.
+var ErrInvalidListFormat = errors.New("invalid list format")
+
+// List contains items an inner lists.
+//
+// See https://httpwg.org/specs/rfc9651.html#list
+type List []Member
+
+// marshalSFV serializes as defined in
+// https://httpwg.org/specs/rfc9651.html#ser-list.
+func (l List) marshalSFV(b *strings.Builder) error {
+	s := len(l)
+	for i := 0; i < s; i++ {
+		if err := l[i].marshalSFV(b); err != nil {
+			return err
+		}
+
+		if i != s-1 {
+			if _, err := b.WriteString(", "); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// UnmarshalList parses a list as defined in
+// https://httpwg.org/specs/rfc9651.html#parse-list.
+func UnmarshalList(v []string) (List, error) {
+	s := &scanner{
+		data: strings.Join(v, ","),
+	}
+
+	s.scanWhileSp()
+
+	sfv, err := parseList(s)
+	if err != nil {
+		return List{}, err
+	}
+
+	return sfv, nil
+}
+
+// parseList parses as defined in
+// https://httpwg.org/specs/rfc9651.html#parse-list.
+func parseList(s *scanner) (List, error) {
+	var l List
+
+	for !s.eof() {
+		m, err := parseItemOrInnerList(s)
+		if err != nil {
+			return nil, err
+		}
+
+		l = append(l, m)
+
+		s.scanWhileOWS()
+
+		if s.eof() {
+			return l, nil
+		}
+
+		if s.data[s.off] != ',' {
+			return nil, &UnmarshalError{s.off, ErrInvalidListFormat}
+		}
+		s.off++
+
+		s.scanWhileOWS()
+
+		if s.eof() {
+			// there is a trailing comma
+			return nil, &UnmarshalError{s.off, ErrInvalidListFormat}
+		}
+	}
+
+	return l, nil
+}
+
+// parseItemOrInnerList parses as defined in
+// https://httpwg.org/specs/rfc9651.html#parse-item-or-list.
+func parseItemOrInnerList(s *scanner) (Member, error) {
+	if s.eof() {
+		return nil, &UnmarshalError{s.off, ErrInvalidInnerListFormat}
+	}
+
+	if s.data[s.off] == '(' {
+		return parseInnerList(s)
+	}
+
+	return parseItem(s)
+}