// 包 ilist 提供了侵入式链表的实现 package ilist type Linker interface { Next() Element Prev() Element SetNext(Element) SetPrev(Element) } type Element interface { Linker } // ElementMapper 默认提供身份映射。 // 如果它们不相同,则可以替换它以提供将元素映射到链接器对象的结构。 // 在以下情况下通常不需要 ElementMapper:Linker 保持原样,Element 保持原样, // 或者 Linker 和 Element 是相同类型 type ElementMapper struct{} // linkerFor maps an Element to a Linker. // This default implementation should be inline 1d func (ElementMapper) linkerFor(elem Element) Linker { return elem } type List struct { head Element tail Element } func (l *List) Reset() { l.head = nil l.tail = nil } func (l *List) Empty() bool { return l.head == nil } func (l *List) Front() Element { return l.head } func (l *List) Back() Element { return l.tail } func (l *List) PushFront(e Element) { ElementMapper{}.linkerFor(e).SetPrev(nil) ElementMapper{}.linkerFor(e).SetNext(l.head) //当前头部作为新头部的下一个节点 if l.head != nil { ElementMapper{}.linkerFor(l.head).SetPrev(e) } else { l.tail = e } l.head = e } func (l *List) PushBack(e Element) { ElementMapper{}.linkerFor(e).SetPrev(l.tail) // 当前尾部作为新尾部的上一个节点 ElementMapper{}.linkerFor(e).SetNext(nil) if l.tail != nil { ElementMapper{}.linkerFor(l.tail).SetNext(e) } else { l.head = e } l.tail = e } // 将m尾插到l,然后清除m func (l *List) PushBackList(m *List) { // 如果没有 if l.head == nil { l.head = m.head l.tail = m.tail } else { ElementMapper{}.linkerFor(l.tail).SetNext(m.head) ElementMapper{}.linkerFor(m.head).SetPrev(l.tail) l.tail = m.tail } m.head = nil m.tail = nil } func (l *List) InsertAfter(b, e Element) { a := ElementMapper{}.linkerFor(b).Next() ElementMapper{}.linkerFor(e).SetNext(a) ElementMapper{}.linkerFor(e).SetPrev(b) ElementMapper{}.linkerFor(b).SetNext(e) if a != nil { ElementMapper{}.linkerFor(a).SetPrev(e) } else { l.tail = e } } func (l *List) InsertBefore(a, e Element) { b := ElementMapper{}.linkerFor(a).Prev() ElementMapper{}.linkerFor(e).SetPrev(b) ElementMapper{}.linkerFor(e).SetNext(a) ElementMapper{}.linkerFor(a).SetPrev(e) if b != nil { ElementMapper{}.linkerFor(b).SetNext(e) } else { l.head = e } } func (l *List) Remove(e Element) { prev := ElementMapper{}.linkerFor(e).Prev() next := ElementMapper{}.linkerFor(e).Next() if prev != nil { ElementMapper{}.linkerFor(prev).SetNext(next) } else { l.tail = next } if next != nil { ElementMapper{}.linkerFor(next).SetPrev(prev) } else { l.tail = prev } } type Entry struct { next Element prev Element } func (e *Entry) Next() Element { return e.next } func (e *Entry) Prev() Element { return e.prev } func (e *Entry) SetNext(elem Element) { e.next = elem } func (e *Entry) SetPrev(elem Element) { e.prev = elem }