CasperSecurity
//
// 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;