mirror of https://github.com/nodejs/node.git
91 lines
2.1 KiB
JavaScript
91 lines
2.1 KiB
JavaScript
;(function() { // closure for web browsers
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function Item (data, prev, next) {
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this.next = next
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if (next) next.prev = this
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this.prev = prev
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if (prev) prev.next = this
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this.data = data
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}
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function FastList () {
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if (!(this instanceof FastList)) return new FastList
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this._head = null
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this._tail = null
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this.length = 0
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}
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FastList.prototype =
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{ push: function (data) {
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this._tail = new Item(data, this._tail, null)
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if (!this._head) this._head = this._tail
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this.length ++
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}
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, pop: function () {
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if (this.length === 0) return undefined
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var t = this._tail
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this._tail = t.prev
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if (t.prev) {
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t.prev = this._tail.next = null
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}
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this.length --
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if (this.length === 1) this._head = this._tail
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else if (this.length === 0) this._head = this._tail = null
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return t.data
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}
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, unshift: function (data) {
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this._head = new Item(data, null, this._head)
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if (!this._tail) this._tail = this._head
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this.length ++
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}
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, shift: function () {
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if (this.length === 0) return undefined
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var h = this._head
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this._head = h.next
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if (h.next) {
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h.next = this._head.prev = null
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}
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this.length --
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if (this.length === 1) this._tail = this._head
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else if (this.length === 0) this._head = this._tail = null
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return h.data
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}
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, item: function (n) {
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if (n < 0) n = this.length + n
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var h = this._head
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while (n-- > 0 && h) h = h.next
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return h ? h.data : undefined
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}
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, slice: function (n, m) {
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if (!n) n = 0
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if (!m) m = this.length
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if (m < 0) m = this.length + m
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if (n < 0) n = this.length + n
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if (m <= n) {
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throw new Error("invalid offset: "+n+","+m)
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}
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var len = m - n
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, ret = new Array(len)
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, i = 0
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, h = this._head
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while (n-- > 0 && h) h = h.next
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while (i < len && h) {
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ret[i++] = h.data
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h = h.next
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}
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return ret
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}
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, drop: function () {
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FastList.call(this)
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}
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}
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if ("undefined" !== typeof(exports)) module.exports = FastList
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else if ("function" === typeof(define) && define.amd) {
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define("FastList", function() { return FastList })
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} else (function () { return this })().FastList = FastList
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})()
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