577 lines
13 KiB
JavaScript
577 lines
13 KiB
JavaScript
//
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// list
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// ┌──────┐
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// ┌──────────────┼─head │
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// │ │ tail─┼──────────────┐
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// │ └──────┘ │
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// ▼ ▼
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// item item item item
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// ┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐
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// null ◀──┼─prev │◀───┼─prev │◀───┼─prev │◀───┼─prev │
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// │ next─┼───▶│ next─┼───▶│ next─┼───▶│ next─┼──▶ null
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// ├──────┤ ├──────┤ ├──────┤ ├──────┤
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// │ data │ │ data │ │ data │ │ data │
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// └──────┘ └──────┘ └──────┘ └──────┘
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//
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function createItem(data) {
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return {
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prev: null,
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next: null,
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data: data
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};
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}
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function allocateCursor(node, prev, next) {
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var cursor;
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if (cursors !== null) {
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cursor = cursors;
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cursors = cursors.cursor;
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cursor.prev = prev;
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cursor.next = next;
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cursor.cursor = node.cursor;
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} else {
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cursor = {
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prev: prev,
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next: next,
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cursor: node.cursor
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};
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}
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node.cursor = cursor;
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return cursor;
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}
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function releaseCursor(node) {
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var cursor = node.cursor;
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node.cursor = cursor.cursor;
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cursor.prev = null;
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cursor.next = null;
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cursor.cursor = cursors;
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cursors = cursor;
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}
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var cursors = null;
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var List = function() {
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this.cursor = null;
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this.head = null;
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this.tail = null;
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};
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List.createItem = createItem;
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List.prototype.createItem = createItem;
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List.prototype.updateCursors = function(prevOld, prevNew, nextOld, nextNew) {
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var cursor = this.cursor;
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while (cursor !== null) {
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if (cursor.prev === prevOld) {
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cursor.prev = prevNew;
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}
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if (cursor.next === nextOld) {
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cursor.next = nextNew;
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}
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cursor = cursor.cursor;
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}
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};
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List.prototype.getSize = function() {
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var size = 0;
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var cursor = this.head;
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while (cursor) {
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size++;
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cursor = cursor.next;
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}
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return size;
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};
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List.prototype.fromArray = function(array) {
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var cursor = null;
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this.head = null;
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for (var i = 0; i < array.length; i++) {
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var item = createItem(array[i]);
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if (cursor !== null) {
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cursor.next = item;
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} else {
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this.head = item;
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}
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item.prev = cursor;
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cursor = item;
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}
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this.tail = cursor;
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return this;
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};
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List.prototype.toArray = function() {
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var cursor = this.head;
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var result = [];
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while (cursor) {
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result.push(cursor.data);
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cursor = cursor.next;
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}
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return result;
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};
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List.prototype.toJSON = List.prototype.toArray;
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List.prototype.isEmpty = function() {
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return this.head === null;
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};
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List.prototype.first = function() {
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return this.head && this.head.data;
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};
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List.prototype.last = function() {
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return this.tail && this.tail.data;
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};
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List.prototype.each = function(fn, context) {
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var item;
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if (context === undefined) {
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context = this;
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}
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// push cursor
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var cursor = allocateCursor(this, null, this.head);
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while (cursor.next !== null) {
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item = cursor.next;
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cursor.next = item.next;
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fn.call(context, item.data, item, this);
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}
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// pop cursor
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releaseCursor(this);
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};
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List.prototype.forEach = List.prototype.each;
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List.prototype.eachRight = function(fn, context) {
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var item;
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if (context === undefined) {
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context = this;
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}
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// push cursor
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var cursor = allocateCursor(this, this.tail, null);
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while (cursor.prev !== null) {
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item = cursor.prev;
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cursor.prev = item.prev;
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fn.call(context, item.data, item, this);
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}
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// pop cursor
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releaseCursor(this);
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};
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List.prototype.forEachRight = List.prototype.eachRight;
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List.prototype.reduce = function(fn, initialValue, context) {
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var item;
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if (context === undefined) {
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context = this;
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}
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// push cursor
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var cursor = allocateCursor(this, null, this.head);
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var acc = initialValue;
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while (cursor.next !== null) {
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item = cursor.next;
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cursor.next = item.next;
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acc = fn.call(context, acc, item.data, item, this);
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}
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// pop cursor
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releaseCursor(this);
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return acc;
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};
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List.prototype.reduceRight = function(fn, initialValue, context) {
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var item;
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if (context === undefined) {
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context = this;
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}
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// push cursor
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var cursor = allocateCursor(this, this.tail, null);
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var acc = initialValue;
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while (cursor.prev !== null) {
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item = cursor.prev;
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cursor.prev = item.prev;
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acc = fn.call(context, acc, item.data, item, this);
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}
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// pop cursor
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releaseCursor(this);
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return acc;
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};
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List.prototype.nextUntil = function(start, fn, context) {
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if (start === null) {
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return;
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}
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var item;
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if (context === undefined) {
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context = this;
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}
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// push cursor
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var cursor = allocateCursor(this, null, start);
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while (cursor.next !== null) {
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item = cursor.next;
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cursor.next = item.next;
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if (fn.call(context, item.data, item, this)) {
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break;
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}
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}
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// pop cursor
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releaseCursor(this);
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};
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List.prototype.prevUntil = function(start, fn, context) {
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if (start === null) {
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return;
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}
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var item;
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if (context === undefined) {
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context = this;
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}
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// push cursor
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var cursor = allocateCursor(this, start, null);
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while (cursor.prev !== null) {
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item = cursor.prev;
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cursor.prev = item.prev;
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if (fn.call(context, item.data, item, this)) {
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break;
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}
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}
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// pop cursor
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releaseCursor(this);
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};
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List.prototype.some = function(fn, context) {
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var cursor = this.head;
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if (context === undefined) {
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context = this;
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}
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while (cursor !== null) {
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if (fn.call(context, cursor.data, cursor, this)) {
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return true;
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}
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cursor = cursor.next;
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}
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return false;
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};
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List.prototype.map = function(fn, context) {
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var result = new List();
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var cursor = this.head;
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if (context === undefined) {
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context = this;
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}
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while (cursor !== null) {
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result.appendData(fn.call(context, cursor.data, cursor, this));
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cursor = cursor.next;
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}
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return result;
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};
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List.prototype.filter = function(fn, context) {
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var result = new List();
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var cursor = this.head;
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if (context === undefined) {
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context = this;
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}
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while (cursor !== null) {
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if (fn.call(context, cursor.data, cursor, this)) {
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result.appendData(cursor.data);
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}
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cursor = cursor.next;
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}
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return result;
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};
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List.prototype.clear = function() {
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this.head = null;
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this.tail = null;
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};
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List.prototype.copy = function() {
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var result = new List();
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var cursor = this.head;
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while (cursor !== null) {
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result.insert(createItem(cursor.data));
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cursor = cursor.next;
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}
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return result;
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};
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List.prototype.prepend = function(item) {
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// head
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// ^
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// item
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this.updateCursors(null, item, this.head, item);
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// insert to the beginning of the list
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if (this.head !== null) {
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// new item <- first item
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this.head.prev = item;
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// new item -> first item
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item.next = this.head;
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} else {
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// if list has no head, then it also has no tail
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// in this case tail points to the new item
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this.tail = item;
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}
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// head always points to new item
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this.head = item;
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return this;
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};
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List.prototype.prependData = function(data) {
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return this.prepend(createItem(data));
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};
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List.prototype.append = function(item) {
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return this.insert(item);
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};
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List.prototype.appendData = function(data) {
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return this.insert(createItem(data));
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};
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List.prototype.insert = function(item, before) {
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if (before !== undefined && before !== null) {
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// prev before
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// ^
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// item
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this.updateCursors(before.prev, item, before, item);
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if (before.prev === null) {
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// insert to the beginning of list
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if (this.head !== before) {
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throw new Error('before doesn\'t belong to list');
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}
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// since head points to before therefore list doesn't empty
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// no need to check tail
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this.head = item;
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before.prev = item;
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item.next = before;
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this.updateCursors(null, item);
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} else {
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// insert between two items
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before.prev.next = item;
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item.prev = before.prev;
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before.prev = item;
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item.next = before;
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}
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} else {
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// tail
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// ^
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// item
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this.updateCursors(this.tail, item, null, item);
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// insert to the ending of the list
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if (this.tail !== null) {
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// last item -> new item
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this.tail.next = item;
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// last item <- new item
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item.prev = this.tail;
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} else {
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// if list has no tail, then it also has no head
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// in this case head points to new item
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this.head = item;
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}
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// tail always points to new item
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this.tail = item;
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}
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return this;
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};
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List.prototype.insertData = function(data, before) {
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return this.insert(createItem(data), before);
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};
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List.prototype.remove = function(item) {
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// item
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// ^
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// prev next
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this.updateCursors(item, item.prev, item, item.next);
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if (item.prev !== null) {
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item.prev.next = item.next;
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} else {
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if (this.head !== item) {
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throw new Error('item doesn\'t belong to list');
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}
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this.head = item.next;
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}
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if (item.next !== null) {
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item.next.prev = item.prev;
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} else {
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if (this.tail !== item) {
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throw new Error('item doesn\'t belong to list');
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}
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this.tail = item.prev;
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}
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item.prev = null;
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item.next = null;
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return item;
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};
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List.prototype.push = function(data) {
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this.insert(createItem(data));
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};
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List.prototype.pop = function() {
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if (this.tail !== null) {
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return this.remove(this.tail);
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}
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};
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List.prototype.unshift = function(data) {
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this.prepend(createItem(data));
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};
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List.prototype.shift = function() {
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if (this.head !== null) {
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return this.remove(this.head);
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}
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};
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List.prototype.prependList = function(list) {
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return this.insertList(list, this.head);
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};
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List.prototype.appendList = function(list) {
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return this.insertList(list);
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};
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List.prototype.insertList = function(list, before) {
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// ignore empty lists
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if (list.head === null) {
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return this;
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}
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if (before !== undefined && before !== null) {
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this.updateCursors(before.prev, list.tail, before, list.head);
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// insert in the middle of dist list
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if (before.prev !== null) {
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// before.prev <-> list.head
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before.prev.next = list.head;
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list.head.prev = before.prev;
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} else {
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this.head = list.head;
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}
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before.prev = list.tail;
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list.tail.next = before;
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} else {
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this.updateCursors(this.tail, list.tail, null, list.head);
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// insert to end of the list
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if (this.tail !== null) {
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// if destination list has a tail, then it also has a head,
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// but head doesn't change
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// dest tail -> source head
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this.tail.next = list.head;
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// dest tail <- source head
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list.head.prev = this.tail;
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} else {
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// if list has no a tail, then it also has no a head
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// in this case points head to new item
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this.head = list.head;
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}
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// tail always start point to new item
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this.tail = list.tail;
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}
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list.head = null;
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list.tail = null;
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return this;
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};
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List.prototype.replace = function(oldItem, newItemOrList) {
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if ('head' in newItemOrList) {
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this.insertList(newItemOrList, oldItem);
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} else {
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this.insert(newItemOrList, oldItem);
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}
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this.remove(oldItem);
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};
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module.exports = List;
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