row_id.go RawHistoryFolder

1package vt
2
3// RowID identifies one physical terminal row for the lifetime of a Screen.
4// Row IDs are never zero and are never reused by their owning Screen.
5type RowID uint64
6
7func (s *Screen) nextRowIDValue() RowID {
8	if s.nextRowID >= ^RowID(0)-2 {
9		panic("vt: row ID space exhausted")
10	}
11	s.nextRowID++
12	return s.nextRowID
13}
14
15func (s *Screen) newBuffer(width, height int) *buffer {
16	b := newBuffer(width, height)
17	for i := range b.rowIDs {
18		b.rowIDs[i] = s.nextRowIDValue()
19	}
20	return b
21}
22
23func (s *Screen) fillMissingRowIDs(b *buffer) {
24	if b == nil {
25		return
26	}
27	for i := range b.rowIDs {
28		if b.rowIDs[i] == 0 {
29			b.rowIDs[i] = s.nextRowIDValue()
30		}
31	}
32}
33
34// RowIDs returns an owned copy of the active live grid's row identities.
35func (s *Screen) RowIDs() []RowID {
36	if s == nil || s.buffer == nil {
37		return nil
38	}
39	return append([]RowID(nil), s.buffer.rowIDs...)
40}
41
42// RowID returns the identity of active live row y, or zero when y is out of
43// range.
44func (s *Screen) RowID(y int) RowID {
45	if s == nil || s.buffer == nil || y < 0 || y >= len(s.buffer.rowIDs) {
46		return 0
47	}
48	return s.buffer.rowIDs[y]
49}