github.com/TeaOSLab/EdgeNode@v1.3.8/internal/utils/linkedlist/list.go (about)

     1  // Copyright 2022 Liuxiangchao iwind.liu@gmail.com. All rights reserved.
     2  
     3  package linkedlist
     4  
     5  type List[T any] struct {
     6  	head  *Item[T]
     7  	end   *Item[T]
     8  	count int
     9  }
    10  
    11  func NewList[T any]() *List[T] {
    12  	return &List[T]{}
    13  }
    14  
    15  func (this *List[T]) Head() *Item[T] {
    16  	return this.head
    17  }
    18  
    19  func (this *List[T]) End() *Item[T] {
    20  	return this.end
    21  }
    22  
    23  func (this *List[T]) Push(item *Item[T]) {
    24  	if item == nil {
    25  		return
    26  	}
    27  
    28  	// 如果已经在末尾了，则do nothing
    29  	if this.end == item {
    30  		return
    31  	}
    32  
    33  	if item.prev != nil || item.next != nil || this.head == item {
    34  		this.Remove(item)
    35  	}
    36  	this.add(item)
    37  }
    38  
    39  func (this *List[T]) Shift() *Item[T] {
    40  	if this.head != nil {
    41  		var old = this.head
    42  		this.Remove(this.head)
    43  		return old
    44  	}
    45  	return nil
    46  }
    47  
    48  func (this *List[T]) Remove(item *Item[T]) {
    49  	if item == nil {
    50  		return
    51  	}
    52  	if item.prev != nil {
    53  		item.prev.next = item.next
    54  	}
    55  	if item.next != nil {
    56  		item.next.prev = item.prev
    57  	}
    58  	if item == this.head {
    59  		this.head = item.next
    60  	}
    61  	if item == this.end {
    62  		this.end = item.prev
    63  	}
    64  
    65  	item.prev = nil
    66  	item.next = nil
    67  	this.count--
    68  }
    69  
    70  func (this *List[T]) Len() int {
    71  	return this.count
    72  }
    73  
    74  func (this *List[T]) Range(f func(item *Item[T]) (goNext bool)) {
    75  	for e := this.head; e != nil; e = e.next {
    76  		goNext := f(e)
    77  		if !goNext {
    78  			break
    79  		}
    80  	}
    81  }
    82  
    83  func (this *List[T]) RangeReverse(f func(item *Item[T]) (goNext bool)) {
    84  	for e := this.end; e != nil; e = e.prev {
    85  		goNext := f(e)
    86  		if !goNext {
    87  			break
    88  		}
    89  	}
    90  }
    91  
    92  func (this *List[T]) Reset() {
    93  	this.head = nil
    94  	this.end = nil
    95  }
    96  
    97  func (this *List[T]) add(item *Item[T]) {
    98  	if item == nil {
    99  		return
   100  	}
   101  	if this.end != nil {
   102  		this.end.next = item
   103  		item.prev = this.end
   104  		item.next = nil
   105  	}
   106  	this.end = item
   107  	if this.head == nil {
   108  		this.head = item
   109  	}
   110  	this.count++
   111  }