1
0
mirror of https://github.com/golang/go synced 2024-11-25 22:17:58 -07:00

container/list: added MoveBefore and MoveAfter

Fixes #4940.

R=golang-dev, bradfitz, gri
CC=golang-dev
https://golang.org/cl/12021044
This commit is contained in:
Pieter Droogendijk 2013-07-31 14:11:25 -07:00 committed by Robert Griesemer
parent 9f75dd7f25
commit fbcc24bb9d
2 changed files with 52 additions and 0 deletions

View File

@ -179,6 +179,24 @@ func (l *List) MoveToBack(e *Element) {
l.insert(l.remove(e), l.root.prev)
}
// MoveBefore moves element e to its new position before mark.
// If e is not an element of l, or e == mark, the list is not modified.
func (l *List) MoveBefore(e, mark *Element) {
if e.list != l || e == mark {
return
}
l.insert(l.remove(e), mark.prev)
}
// MoveAfter moves element e to its new position after mark.
// If e is not an element of l, or e == mark, the list is not modified.
func (l *List) MoveAfter(e, mark *Element) {
if e.list != l || e == mark {
return
}
l.insert(l.remove(e), mark)
}
// PushBackList inserts a copy of an other list at the back of list l.
// The lists l and other may be the same.
func (l *List) PushBackList(other *List) {

View File

@ -233,3 +233,37 @@ func TestIssue4103(t *testing.T) {
t.Errorf("l1.Len() = %d, want 3", n)
}
}
func TestMove(t *testing.T) {
l := New()
e1 := l.PushBack(1)
e2 := l.PushBack(2)
e3 := l.PushBack(3)
e4 := l.PushBack(4)
l.MoveAfter(e3, e3)
checkListPointers(t, l, []*Element{e1, e2, e3, e4})
l.MoveBefore(e2, e2)
checkListPointers(t, l, []*Element{e1, e2, e3, e4})
l.MoveAfter(e3, e2)
checkListPointers(t, l, []*Element{e1, e2, e3, e4})
l.MoveBefore(e2, e3)
checkListPointers(t, l, []*Element{e1, e2, e3, e4})
l.MoveBefore(e2, e4)
checkListPointers(t, l, []*Element{e1, e3, e2, e4})
e1, e2, e3, e4 = e1, e3, e2, e4
l.MoveBefore(e4, e1)
checkListPointers(t, l, []*Element{e4, e1, e2, e3})
e1, e2, e3, e4 = e4, e1, e2, e3
l.MoveAfter(e4, e1)
checkListPointers(t, l, []*Element{e1, e4, e2, e3})
e1, e2, e3, e4 = e1, e4, e2, e3
l.MoveAfter(e2, e3)
checkListPointers(t, l, []*Element{e1, e3, e2, e4})
e1, e2, e3, e4 = e1, e3, e2, e4
}