add arraylist

arraylist/arraylist.go

@@ -0,0 +1,249 @@
+package arraylist
+
+const defaultSize = 1024
+
+var none interface{}
+
+type Element struct {
+	Value interface{}
+
+	prev int
+	next int
+
+	index int
+
+	list *List
+}
+
+func (e *Element) Next() *Element {
+	if e.next == 0 || e.Value == none || e.list == nil {
+		return nil
+	}
+
+	return e.list.elems[e.next]
+}
+
+func (e *Element) Prev() *Element {
+	if e.prev == 0 || e.Value == none || e.list == nil {
+		return nil
+	}
+
+	return e.list.elems[e.prev]
+}
+
+type List struct {
+	elems []*Element
+
+	num int
+
+	root *Element
+
+	free int
+}
+
+func New() *List {
+	return NewSize(defaultSize)
+}
+
+func NewSize(size int) *List {
+	if size < defaultSize {
+		size = defaultSize
+	}
+
+	l := new(List)
+
+	l.elems = make([]*Element, size)
+	for i := range l.elems {
+		e := new(Element)
+
+		e.list = l
+		e.index = i
+		e.next = i + 1
+		if i+1 == len(l.elems) {
+			e.next = -1
+		}
+
+		l.elems[i] = e
+	}
+
+	//use first for root
+	l.root = l.elems[0]
+	l.root.next = 0
+	l.root.prev = 0
+
+	l.free = 1
+	l.num = 0
+
+	return l
+}
+
+func (l *List) Len() int {
+	return l.num
+}
+
+func (l *List) Front() *Element {
+	if l.root.next == 0 {
+		return nil
+	} else {
+		return l.elems[l.root.next]
+	}
+}
+
+func (l *List) Back() *Element {
+	if l.root.prev == 0 {
+		return nil
+	} else {
+		return l.elems[l.root.prev]
+	}
+}
+
+func (l *List) remove(e *Element) *Element {
+	next := e.next
+	prev := e.prev
+
+	l.elems[prev].next = next
+	l.elems[next].prev = prev
+
+	e.next = -1
+	e.prev = -1
+
+	l.num--
+
+	return e
+}
+
+func (l *List) Remove(e *Element) interface{} {
+	if e.list != l {
+		return nil
+	}
+
+	if e.next == -1 || e.prev == -1 {
+		return e.Value
+	}
+
+	l.remove(e)
+
+	v := e.Value
+	e.Value = none
+
+	e.next = l.free
+	l.free = e.index
+
+	return v
+}
+
+func (l *List) getFreeElem() *Element {
+	if l.free == -1 {
+		//no free elements, create
+		num := len(l.elems)
+
+		newElems := make([]*Element, 2*num)
+		for i := num; i < 2*num; i++ {
+			e := new(Element)
+			e.list = l
+			e.index = i
+			e.next = i + 1
+			if i+1 == 2*num {
+				e.next = -1
+			}
+
+			newElems[i] = e
+		}
+
+		l.free = num
+
+		copy(newElems, l.elems)
+
+		l.elems = newElems
+	}
+
+	n := l.free
+	l.free = l.elems[n].next
+
+	return l.elems[n]
+}
+
+func (l *List) insert(e *Element, index int) *Element {
+	at := l.elems[index]
+	n := at.next
+	at.next = e.index
+	e.prev = at.index
+	e.next = n
+	l.elems[n].prev = e.index
+	e.list = l
+	l.num++
+	return e
+}
+
+func (l *List) insertValue(v interface{}, index int) *Element {
+	e := l.getFreeElem()
+	e.Value = v
+
+	return l.insert(e, index)
+}
+
+func (l *List) PushFront(v interface{}) *Element {
+	return l.insertValue(v, l.root.index)
+}
+
+func (l *List) PushBack(v interface{}) *Element {
+	return l.insertValue(v, l.root.prev)
+}
+
+func (l *List) InsertBefore(v interface{}, mark *Element) *Element {
+	if mark.list != l {
+		return nil
+	}
+
+	return l.insertValue(v, mark.prev)
+}
+
+func (l *List) InsertAfter(v interface{}, mark *Element) *Element {
+	if mark.list != l {
+		return nil
+	}
+
+	return l.insertValue(v, mark.index)
+}
+
+func (l *List) MoveToFront(e *Element) {
+	if e.list != l || l.root.next == e.index {
+		return
+	}
+
+	l.insert(l.remove(e), l.root.index)
+}
+
+func (l *List) MoveToBack(e *Element) {
+	if e.list != l || l.root.prev == e.index {
+		return
+	}
+	l.insert(l.remove(e), l.root.prev)
+}
+
+func (l *List) MoveBefore(e, mark *Element) {
+	if e.list != l || e == mark {
+		return
+	}
+
+	l.insert(l.remove(e), mark.prev)
+}
+
+func (l *List) MoveAfter(e, mark *Element) {
+	if e.list != l || e == mark {
+		return
+	}
+	l.insert(l.remove(e), mark.index)
+}
+
+func (l *List) PushBackList(other *List) {
+	for i, e := other.Len(), other.Front(); i > 0; i, e = i-1, e.Next() {
+		l.insertValue(e.Value, l.root.prev)
+	}
+}
+
+func (l *List) PushFrontList(other *List) {
+	for i, e := other.Len(), other.Back(); i > 0; i, e = i-1, e.Prev() {
+		l.insertValue(e.Value, l.root.index)
+	}
+}

arraylist/arraylist_test.go

@@ -0,0 +1,307 @@
+package arraylist
+
+import (
+	"reflect"
+	"testing"
+)
+
+func checkListLen(t *testing.T, l *List, len int) bool {
+	if n := l.Len(); n != len {
+		t.Errorf("l.Len() = %d, want %d", n, len)
+		return false
+	}
+	return true
+}
+
+func checkListPointers(t *testing.T, l *List, es []*Element) {
+
+	root := l.root
+
+	if !checkListLen(t, l, len(es)) {
+		return
+	}
+
+	// zero length lists must be the zero value or properly initialized (sentinel circle)
+	if len(es) == 0 {
+		if l.root.next != 0 && l.root.next != root.index || l.root.prev != 0 && l.root.prev != root.index {
+			t.Errorf("l.root.next = %d, l.root.prev = %d; both should both be 0 or %d", l.root.next, l.root.prev, root.index)
+		}
+		return
+	}
+	// len(es) > 0
+
+	e1 := []*Element{}
+	for e := l.Front(); e != nil; e = e.Next() {
+		e1 = append(e1, e)
+	}
+
+	if !reflect.DeepEqual(e1, es) {
+		t.Fatal("front not equal")
+	}
+
+	e2 := []*Element{}
+	for e := l.Back(); e != nil; e = e.Prev() {
+		e2 = append([]*Element{e}, e2...)
+	}
+
+	if !reflect.DeepEqual(e2, es) {
+		t.Fatal("front not equal")
+	}
+
+	// check internal and external prev/next connections
+	for i, e := range es {
+		prev := root
+		Prev := (*Element)(nil)
+		if i > 0 {
+			prev = es[i-1]
+			Prev = prev
+		}
+		if p := e.prev; p != prev.index {
+			t.Errorf("elt[%d](%p).prev = %p, want %p", i, e, p, prev)
+		}
+		if p := e.Prev(); p != Prev {
+			t.Errorf("elt[%d](%p).Prev() = %p, want %p", i, e, p, Prev)
+		}
+
+		next := root
+		Next := (*Element)(nil)
+		if i < len(es)-1 {
+			next = es[i+1]
+			Next = next
+		}
+		if n := e.next; n != next.index {
+			t.Errorf("elt[%d](%p).next = %p, want %p", i, e, n, next)
+		}
+		if n := e.Next(); n != Next {
+			t.Errorf("elt[%d](%p).Next() = %p, want %p", i, e, n, Next)
+		}
+	}
+}
+
+func TestList(t *testing.T) {
+	l := New()
+	checkListPointers(t, l, []*Element{})
+
+	// Single element list
+	e := l.PushFront("a")
+	checkListPointers(t, l, []*Element{e})
+	l.MoveToFront(e)
+	checkListPointers(t, l, []*Element{e})
+	l.MoveToBack(e)
+	checkListPointers(t, l, []*Element{e})
+	l.Remove(e)
+	checkListPointers(t, l, []*Element{})
+
+	// Bigger list
+	e2 := l.PushFront(2)
+	e1 := l.PushFront(1)
+	e3 := l.PushBack(3)
+	e4 := l.PushBack("banana")
+	checkListPointers(t, l, []*Element{e1, e2, e3, e4})
+
+	l.Remove(e2)
+	checkListPointers(t, l, []*Element{e1, e3, e4})
+
+	l.MoveToFront(e3) // move from middle
+	checkListPointers(t, l, []*Element{e3, e1, e4})
+
+	l.MoveToFront(e1)
+	l.MoveToBack(e3) // move from middle
+	checkListPointers(t, l, []*Element{e1, e4, e3})
+
+	l.MoveToFront(e3) // move from back
+	checkListPointers(t, l, []*Element{e3, e1, e4})
+	l.MoveToFront(e3) // should be no-op
+	checkListPointers(t, l, []*Element{e3, e1, e4})
+
+	l.MoveToBack(e3) // move from front
+	checkListPointers(t, l, []*Element{e1, e4, e3})
+	l.MoveToBack(e3) // should be no-op
+	checkListPointers(t, l, []*Element{e1, e4, e3})
+
+	e2 = l.InsertBefore(2, e1) // insert before front
+	checkListPointers(t, l, []*Element{e2, e1, e4, e3})
+	l.Remove(e2)
+	e2 = l.InsertBefore(2, e4) // insert before middle
+	checkListPointers(t, l, []*Element{e1, e2, e4, e3})
+	l.Remove(e2)
+	e2 = l.InsertBefore(2, e3) // insert before back
+	checkListPointers(t, l, []*Element{e1, e4, e2, e3})
+	l.Remove(e2)
+
+	e2 = l.InsertAfter(2, e1) // insert after front
+	checkListPointers(t, l, []*Element{e1, e2, e4, e3})
+	l.Remove(e2)
+	e2 = l.InsertAfter(2, e4) // insert after middle
+	checkListPointers(t, l, []*Element{e1, e4, e2, e3})
+	l.Remove(e2)
+	e2 = l.InsertAfter(2, e3) // insert after back
+	checkListPointers(t, l, []*Element{e1, e4, e3, e2})
+	l.Remove(e2)
+
+	// Check standard iteration.
+	sum := 0
+	for e := l.Front(); e != nil; e = e.Next() {
+		if i, ok := e.Value.(int); ok {
+			sum += i
+		}
+	}
+	if sum != 4 {
+		t.Errorf("sum over l = %d, want 4", sum)
+	}
+
+	// Clear all elements by iterating
+	var next *Element
+	for e := l.Front(); e != nil; e = next {
+		next = e.Next()
+		l.Remove(e)
+	}
+	checkListPointers(t, l, []*Element{})
+}
+
+func checkList(t *testing.T, l *List, es []interface{}) {
+	if !checkListLen(t, l, len(es)) {
+		return
+	}
+
+	i := 0
+	for e := l.Front(); e != nil; e = e.Next() {
+		le := e.Value.(int)
+		if le != es[i] {
+			t.Errorf("elt[%d].Value = %v, want %v", i, le, es[i])
+		}
+		i++
+	}
+}
+
+func TestExtending(t *testing.T) {
+	l1 := New()
+	l2 := New()
+
+	l1.PushBack(1)
+	l1.PushBack(2)
+	l1.PushBack(3)
+
+	l2.PushBack(4)
+	l2.PushBack(5)
+
+	l3 := New()
+	l3.PushBackList(l1)
+	checkList(t, l3, []interface{}{1, 2, 3})
+	l3.PushBackList(l2)
+	checkList(t, l3, []interface{}{1, 2, 3, 4, 5})
+
+	l3 = New()
+	l3.PushFrontList(l2)
+	checkList(t, l3, []interface{}{4, 5})
+	l3.PushFrontList(l1)
+	checkList(t, l3, []interface{}{1, 2, 3, 4, 5})
+
+	checkList(t, l1, []interface{}{1, 2, 3})
+	checkList(t, l2, []interface{}{4, 5})
+
+	l3 = New()
+	l3.PushBackList(l1)
+	checkList(t, l3, []interface{}{1, 2, 3})
+	l3.PushBackList(l3)
+	checkList(t, l3, []interface{}{1, 2, 3, 1, 2, 3})
+
+	l3 = New()
+	l3.PushFrontList(l1)
+	checkList(t, l3, []interface{}{1, 2, 3})
+	l3.PushFrontList(l3)
+	checkList(t, l3, []interface{}{1, 2, 3, 1, 2, 3})
+
+	l3 = New()
+	l1.PushBackList(l3)
+	checkList(t, l1, []interface{}{1, 2, 3})
+	l1.PushFrontList(l3)
+	checkList(t, l1, []interface{}{1, 2, 3})
+}
+
+func TestRemove(t *testing.T) {
+	l := New()
+	e1 := l.PushBack(1)
+	e2 := l.PushBack(2)
+	checkListPointers(t, l, []*Element{e1, e2})
+	e := l.Front()
+	l.Remove(e)
+	checkListPointers(t, l, []*Element{e2})
+	l.Remove(e)
+	checkListPointers(t, l, []*Element{e2})
+}
+
+func TestIssue4103(t *testing.T) {
+	l1 := New()
+	l1.PushBack(1)
+	l1.PushBack(2)
+
+	l2 := New()
+	l2.PushBack(3)
+	l2.PushBack(4)
+
+	e := l1.Front()
+	l2.Remove(e) // l2 should not change because e is not an element of l2
+	if n := l2.Len(); n != 2 {
+		t.Errorf("l2.Len() = %d, want 2", n)
+	}
+
+	l1.InsertBefore(8, e)
+	if n := l1.Len(); n != 3 {
+		t.Errorf("l1.Len() = %d, want 3", n)
+	}
+}
+
+func TestIssue6349(t *testing.T) {
+	l := New()
+	l.PushBack(1)
+	l.PushBack(2)
+
+	e := l.Front()
+	v := l.Remove(e)
+
+	if v != 1 {
+		t.Errorf("e.value = %d, want 1", e.Value)
+	}
+
+	if e.Next() != nil {
+		t.Errorf("e.Next() != nil")
+	}
+	if e.Prev() != nil {
+		t.Errorf("e.Prev() != nil")
+	}
+}
+
+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
+}