2 files changed, 420 insertions, 0 deletions
diff --git a/libgo/go/container/list/list.go b/libgo/go/container/list/list.go
new file mode 100755
index 000000000..c1ebcddaa
--- /dev/null
+++ b/libgo/go/container/list/list.go
@@ -0,0 +1,211 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The list package implements a doubly linked list.
+//
+// To iterate over a list (where l is a *List):
+//	for e := l.Front(); e != nil; e = e.Next() {
+//		// do something with e.Value
+//	}
+//
+package list
+
+// Element is an element in the linked list.
+type Element struct {
+	// Next and previous pointers in the doubly-linked list of elements.
+	// The front of the list has prev = nil, and the back has next = nil.
+	next, prev *Element
+
+	// The list to which this element belongs.
+	list *List
+
+	// The contents of this list element.
+	Value interface{}
+}
+
+// Next returns the next list element or nil.
+func (e *Element) Next() *Element { return e.next }
+
+// Prev returns the previous list element or nil.
+func (e *Element) Prev() *Element { return e.prev }
+
+// List represents a doubly linked list.
+// The zero value for List is an empty list ready to use.
+type List struct {
+	front, back *Element
+	len         int
+}
+
+// Init initializes or clears a List.
+func (l *List) Init() *List {
+	l.front = nil
+	l.back = nil
+	l.len = 0
+	return l
+}
+
+// New returns an initialized list.
+func New() *List { return new(List) }
+
+// Front returns the first element in the list.
+func (l *List) Front() *Element { return l.front }
+
+// Back returns the last element in the list.
+func (l *List) Back() *Element { return l.back }
+
+// Remove removes the element from the list
+// and returns its Value.
+func (l *List) Remove(e *Element) interface{} {
+	l.remove(e)
+	e.list = nil // do what remove does not
+	return e.Value
+}
+
+// remove the element from the list, but do not clear the Element's list field.
+// This is so that other List methods may use remove when relocating Elements
+// without needing to restore the list field.
+func (l *List) remove(e *Element) {
+	if e.list != l {
+		return
+	}
+	if e.prev == nil {
+		l.front = e.next
+	} else {
+		e.prev.next = e.next
+	}
+	if e.next == nil {
+		l.back = e.prev
+	} else {
+		e.next.prev = e.prev
+	}
+
+	e.prev = nil
+	e.next = nil
+	l.len--
+}
+
+func (l *List) insertBefore(e *Element, mark *Element) {
+	if mark.prev == nil {
+		// new front of the list
+		l.front = e
+	} else {
+		mark.prev.next = e
+	}
+	e.prev = mark.prev
+	mark.prev = e
+	e.next = mark
+	l.len++
+}
+
+func (l *List) insertAfter(e *Element, mark *Element) {
+	if mark.next == nil {
+		// new back of the list
+		l.back = e
+	} else {
+		mark.next.prev = e
+	}
+	e.next = mark.next
+	mark.next = e
+	e.prev = mark
+	l.len++
+}
+
+func (l *List) insertFront(e *Element) {
+	if l.front == nil {
+		// empty list
+		l.front, l.back = e, e
+		e.prev, e.next = nil, nil
+		l.len = 1
+		return
+	}
+	l.insertBefore(e, l.front)
+}
+
+func (l *List) insertBack(e *Element) {
+	if l.back == nil {
+		// empty list
+		l.front, l.back = e, e
+		e.prev, e.next = nil, nil
+		l.len = 1
+		return
+	}
+	l.insertAfter(e, l.back)
+}
+
+// PushFront inserts the value at the front of the list and returns a new Element containing the value.
+func (l *List) PushFront(value interface{}) *Element {
+	e := &Element{nil, nil, l, value}
+	l.insertFront(e)
+	return e
+}
+
+// PushBack inserts the value at the back of the list and returns a new Element containing the value.
+func (l *List) PushBack(value interface{}) *Element {
+	e := &Element{nil, nil, l, value}
+	l.insertBack(e)
+	return e
+}
+
+// InsertBefore inserts the value immediately before mark and returns a new Element containing the value.
+func (l *List) InsertBefore(value interface{}, mark *Element) *Element {
+	if mark.list != l {
+		return nil
+	}
+	e := &Element{nil, nil, l, value}
+	l.insertBefore(e, mark)
+	return e
+}
+
+// InsertAfter inserts the value immediately after mark and returns a new Element containing the value.
+func (l *List) InsertAfter(value interface{}, mark *Element) *Element {
+	if mark.list != l {
+		return nil
+	}
+	e := &Element{nil, nil, l, value}
+	l.insertAfter(e, mark)
+	return e
+}
+
+// MoveToFront moves the element to the front of the list.
+func (l *List) MoveToFront(e *Element) {
+	if e.list != l || l.front == e {
+		return
+	}
+	l.remove(e)
+	l.insertFront(e)
+}
+
+// MoveToBack moves the element to the back of the list.
+func (l *List) MoveToBack(e *Element) {
+	if e.list != l || l.back == e {
+		return
+	}
+	l.remove(e)
+	l.insertBack(e)
+}
+
+// Len returns the number of elements in the list.
+func (l *List) Len() int { return l.len }
+
+// PushBackList inserts each element of ol at the back of the list.
+func (l *List) PushBackList(ol *List) {
+	last := ol.Back()
+	for e := ol.Front(); e != nil; e = e.Next() {
+		l.PushBack(e.Value)
+		if e == last {
+			break
+		}
+	}
+}
+
+// PushFrontList inserts each element of ol at the front of the list. The ordering of the passed list is preserved.
+func (l *List) PushFrontList(ol *List) {
+	first := ol.Front()
+	for e := ol.Back(); e != nil; e = e.Prev() {
+		l.PushFront(e.Value)
+		if e == first {
+			break
+		}
+	}
+}
diff --git a/libgo/go/container/list/list_test.go b/libgo/go/container/list/list_test.go
new file mode 100755
index 000000000..1d44ff84e
--- /dev/null
+++ b/libgo/go/container/list/list_test.go
@@ -0,0 +1,209 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package list
+
+import (
+	"testing"
+)
+
+func checkListPointers(t *testing.T, l *List, es []*Element) {
+	if len(es) == 0 {
+		if l.front != nil || l.back != nil {
+			t.Errorf("l.front/l.back = %v/%v should be nil/nil", l.front, l.back)
+		}
+		return
+	}
+
+	if l.front != es[0] {
+		t.Errorf("l.front = %v, want %v", l.front, es[0])
+	}
+	if last := es[len(es)-1]; l.back != last {
+		t.Errorf("l.back = %v, want %v", l.back, last)
+	}
+
+	for i, e := range es {
+		var e_prev, e_next *Element = nil, nil
+		if i > 0 {
+			e_prev = es[i-1]
+		}
+		if i < len(es)-1 {
+			e_next = es[i+1]
+		}
+		if e.prev != e_prev {
+			t.Errorf("elt #%d (%v) has prev=%v, want %v", i, e, e.prev, e_prev)
+		}
+		if e.next != e_next {
+			t.Errorf("elt #%d (%v) has next=%v, want %v", i, e, e.next, e_next)
+		}
+	}
+}
+
+func checkListLen(t *testing.T, l *List, n int) {
+	if an := l.Len(); an != n {
+		t.Errorf("l.Len() = %d, want %d", an, n)
+	}
+}
+
+func TestList(t *testing.T) {
+	l := New()
+	checkListPointers(t, l, []*Element{})
+	checkListLen(t, l, 0)
+
+	// Single element list
+	e := l.PushFront("a")
+	checkListLen(t, l, 1)
+	checkListPointers(t, l, []*Element{e})
+	l.MoveToFront(e)
+	checkListPointers(t, l, []*Element{e})
+	l.MoveToBack(e)
+	checkListPointers(t, l, []*Element{e})
+	checkListLen(t, l, 1)
+	l.Remove(e)
+	checkListPointers(t, l, []*Element{})
+	checkListLen(t, l, 0)
+
+	// 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})
+	checkListLen(t, l, 4)
+
+	l.Remove(e2)
+	checkListPointers(t, l, []*Element{e1, e3, e4})
+	checkListLen(t, l, 3)
+
+	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.Iter() = %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{})
+	checkListLen(t, l, 0)
+}
+
+func checkList(t *testing.T, l *List, es []interface{}) {
+	if l.Len() != len(es) {
+		t.Errorf("list has len=%v, want %v", l.Len(), 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 has 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})
+	checkListLen(t, l, 1)
+	l.Remove(e)
+	checkListPointers(t, l, []*Element{e2})
+	checkListLen(t, l, 1)
+}