64 lines
1.7 KiB
JavaScript
64 lines
1.7 KiB
JavaScript
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/*!
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* ws: a node.js websocket client
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* Copyright(c) 2011 Einar Otto Stangvik <einaros@gmail.com>
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* MIT Licensed
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*/
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var util = require('util');
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function BufferPool(initialSize, growStrategy, shrinkStrategy) {
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if (this instanceof BufferPool === false) {
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throw new TypeError("Classes can't be function-called");
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}
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if (typeof initialSize === 'function') {
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shrinkStrategy = growStrategy;
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growStrategy = initialSize;
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initialSize = 0;
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}
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else if (typeof initialSize === 'undefined') {
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initialSize = 0;
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}
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this._growStrategy = (growStrategy || function(db, size) {
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return db.used + size;
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}).bind(null, this);
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this._shrinkStrategy = (shrinkStrategy || function(db) {
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return initialSize;
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}).bind(null, this);
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this._buffer = initialSize ? new Buffer(initialSize) : null;
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this._offset = 0;
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this._used = 0;
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this._changeFactor = 0;
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this.__defineGetter__('size', function(){
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return this._buffer == null ? 0 : this._buffer.length;
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});
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this.__defineGetter__('used', function(){
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return this._used;
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});
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}
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BufferPool.prototype.get = function(length) {
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if (this._buffer == null || this._offset + length > this._buffer.length) {
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var newBuf = new Buffer(this._growStrategy(length));
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this._buffer = newBuf;
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this._offset = 0;
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}
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this._used += length;
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var buf = this._buffer.slice(this._offset, this._offset + length);
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this._offset += length;
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return buf;
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}
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BufferPool.prototype.reset = function(forceNewBuffer) {
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var len = this._shrinkStrategy();
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if (len < this.size) this._changeFactor -= 1;
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if (forceNewBuffer || this._changeFactor < -2) {
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this._changeFactor = 0;
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this._buffer = len ? new Buffer(len) : null;
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}
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this._offset = 0;
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this._used = 0;
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}
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module.exports = BufferPool;
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