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