From 325be0d6a1b49f6bc6c47a2f72a34b552a5ab8ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=87=95=E5=BD=92=E6=9D=A5?= <yguilai@foxmail.com>
Date: Mon, 6 Feb 2023 09:46:25 +0800
Subject: [PATCH] feat: add func Iterator, ForEach, RetainAll and DeleteAll for
 List structure (#71)

---
 datastructure/list/list.go      | 44 +++++++++++++++++++++
 datastructure/list/list_test.go | 68 +++++++++++++++++++++++++++++++++
 2 files changed, 112 insertions(+)

diff --git a/datastructure/list/list.go b/datastructure/list/list.go
index 31687bd..ef77b0f 100644
--- a/datastructure/list/list.go
+++ b/datastructure/list/list.go
@@ -5,6 +5,7 @@
 package datastructure
 
 import (
+	"github.com/duke-git/lancet/v2/iterator"
 	"reflect"
 )
 
@@ -323,3 +324,46 @@ func (l *List[T]) SubList(fromIndex, toIndex int) *List[T] {
 	copy(subList, data)
 	return NewList(subList)
 }
+
+// ForEach performs the given action for each element of the list.
+func (l *List[T]) ForEach(consumer func(T)) {
+	for _, it := range l.data {
+		consumer(it)
+	}
+}
+
+// RetainAll retains only the elements in this list that are contained in the given list.
+func (l *List[T]) RetainAll(list *List[T]) bool {
+	return l.batchRemove(list, true)
+}
+
+// DeleteAll removes from this list all of its elements that are contained in the given list.
+func (l *List[T]) DeleteAll(list *List[T]) bool {
+	return l.batchRemove(list, false)
+}
+
+func (l *List[T]) batchRemove(list *List[T], complement bool) bool {
+	var (
+		w    = 0
+		data = l.data
+		size = len(data)
+	)
+
+	for i := 0; i < size; i++ {
+		if list.Contain(data[i]) == complement {
+			data[w] = data[i]
+			w++
+		}
+	}
+
+	if w != size {
+		l.data = data[:w]
+		return true
+	}
+	return false
+}
+
+// Iterator returns an iterator over the elements in this list in proper sequence.
+func (l *List[T]) Iterator() iterator.Iterator[T] {
+	return iterator.FromSlice(l.data)
+}
diff --git a/datastructure/list/list_test.go b/datastructure/list/list_test.go
index 33a5c27..0ce58ba 100644
--- a/datastructure/list/list_test.go
+++ b/datastructure/list/list_test.go
@@ -357,3 +357,71 @@ func TestDeleteIf(t *testing.T) {
 	assert.Equal([]int{2, 3, 4}, list.Data())
 	assert.Equal(0, count)
 }
+
+func TestForEach(t *testing.T) {
+	assert := internal.NewAssert(t, "TestForEach")
+
+	list := NewList([]int{1, 2, 3, 4})
+
+	rs := make([]int, 0)
+	list.ForEach(func(i int) {
+		rs = append(rs, i)
+	})
+
+	assert.Equal([]int{1, 2, 3, 4}, rs)
+}
+
+func TestRetainAll(t *testing.T) {
+	assert := internal.NewAssert(t, "TestRetainAll")
+
+	list := NewList([]int{1, 2, 3, 4})
+	list1 := NewList([]int{1, 2, 3, 4})
+	list2 := NewList([]int{1, 2, 3, 4})
+
+	retain := NewList([]int{1, 2})
+	retain1 := NewList([]int{2, 3})
+	retain2 := NewList([]int{1, 2, 5})
+
+	list.RetainAll(retain)
+	list1.RetainAll(retain1)
+	list2.RetainAll(retain2)
+
+	assert.Equal([]int{1, 2}, list.Data())
+	assert.Equal([]int{2, 3}, list1.Data())
+	assert.Equal([]int{1, 2}, list2.Data())
+}
+
+func TestDeleteAll(t *testing.T) {
+	assert := internal.NewAssert(t, "TestDeleteAll")
+
+	list := NewList([]int{1, 2, 3, 4})
+	list1 := NewList([]int{1, 2, 3, 4})
+	list2 := NewList([]int{1, 2, 3, 4})
+
+	del := NewList([]int{1})
+	del1 := NewList([]int{2, 3})
+	del2 := NewList([]int{1, 2, 5})
+
+	list.DeleteAll(del)
+	list1.DeleteAll(del1)
+	list2.DeleteAll(del2)
+	assert.Equal([]int{2, 3, 4}, list.Data())
+	assert.Equal([]int{1, 4}, list1.Data())
+	assert.Equal([]int{3, 4}, list2.Data())
+}
+
+func TestIterator(t *testing.T) {
+	assert := internal.NewAssert(t, "TestIterator")
+
+	list := NewList([]int{1, 2, 3, 4})
+
+	iterator := list.Iterator()
+
+	rs := make([]int, 0)
+	for iterator.HasNext() {
+		item, _ := iterator.Next()
+		rs = append(rs, item)
+	}
+
+	assert.Equal([]int{1, 2, 3, 4}, rs)
+}