88 lines
2.3 KiB
JavaScript
88 lines
2.3 KiB
JavaScript
|
"use strict";
|
||
|
|
|
||
|
|
Object.defineProperty(exports, "__esModule", {
|
||
|
|
value: true
|
||
|
|
});
|
||
|
|
exports.default = DLL;
|
||
|
|
// Simple doubly linked list (https://en.wikipedia.org/wiki/Doubly_linked_list) implementation
|
||
|
|
// used for queues. This implementation assumes that the node provided by the user can be modified
|
||
|
|
// to adjust the next and last properties. We implement only the minimal functionality
|
||
|
|
// for queue support.
|
||
|
|
function DLL() {
|
||
|
|
this.head = this.tail = null;
|
||
|
|
this.length = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
function setInitial(dll, node) {
|
||
|
|
dll.length = 1;
|
||
|
|
dll.head = dll.tail = node;
|
||
|
|
}
|
||
|
|
|
||
|
|
DLL.prototype.removeLink = function (node) {
|
||
|
|
if (node.prev) node.prev.next = node.next;else this.head = node.next;
|
||
|
|
if (node.next) node.next.prev = node.prev;else this.tail = node.prev;
|
||
|
|
|
||
|
|
node.prev = node.next = null;
|
||
|
|
this.length -= 1;
|
||
|
|
return node;
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.empty = function () {
|
||
|
|
while (this.head) this.shift();
|
||
|
|
return this;
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.insertAfter = function (node, newNode) {
|
||
|
|
newNode.prev = node;
|
||
|
|
newNode.next = node.next;
|
||
|
|
if (node.next) node.next.prev = newNode;else this.tail = newNode;
|
||
|
|
node.next = newNode;
|
||
|
|
this.length += 1;
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.insertBefore = function (node, newNode) {
|
||
|
|
newNode.prev = node.prev;
|
||
|
|
newNode.next = node;
|
||
|
|
if (node.prev) node.prev.next = newNode;else this.head = newNode;
|
||
|
|
node.prev = newNode;
|
||
|
|
this.length += 1;
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.unshift = function (node) {
|
||
|
|
if (this.head) this.insertBefore(this.head, node);else setInitial(this, node);
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.push = function (node) {
|
||
|
|
if (this.tail) this.insertAfter(this.tail, node);else setInitial(this, node);
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.shift = function () {
|
||
|
|
return this.head && this.removeLink(this.head);
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.pop = function () {
|
||
|
|
return this.tail && this.removeLink(this.tail);
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.toArray = function () {
|
||
|
|
var arr = Array(this.length);
|
||
|
|
var curr = this.head;
|
||
|
|
for (var idx = 0; idx < this.length; idx++) {
|
||
|
|
arr[idx] = curr.data;
|
||
|
|
curr = curr.next;
|
||
|
|
}
|
||
|
|
return arr;
|
||
|
|
};
|
||
|
|
|
||
|
|
DLL.prototype.remove = function (testFn) {
|
||
|
|
var curr = this.head;
|
||
|
|
while (!!curr) {
|
||
|
|
var next = curr.next;
|
||
|
|
if (testFn(curr)) {
|
||
|
|
this.removeLink(curr);
|
||
|
|
}
|
||
|
|
curr = next;
|
||
|
|
}
|
||
|
|
return this;
|
||
|
|
};
|
||
|
|
module.exports = exports["default"];
|