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shrine-medco/shrine-webclient/src/main/html/node_modules/ws/lib/PerMessageDeflate.js
f422d9cc2cdfrelease/1.22.1

PerMessageDeflate.js
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			var zlib = require('zlib');

			var AVAILABLE_WINDOW_BITS = [8, 9, 10, 11, 12, 13, 14, 15];
			var DEFAULT_WINDOW_BITS = 15;
			var DEFAULT_MEM_LEVEL = 8;

			PerMessageDeflate.extensionName = 'permessage-deflate';

			/**
			* Per-message Compression Extensions implementation
			*/

			function PerMessageDeflate(options, isServer,maxPayload) {
			if (this instanceof PerMessageDeflate === false) {
			throw new TypeError("Classes can't be function-called");
			}

			this._options = options \|\| {};
			this._isServer = !!isServer;
			this._inflate = null;
			this._deflate = null;
			this.params = null;
			this._maxPayload = maxPayload \|\| 0;
			}

			/**
			* Create extension parameters offer
			*
			* @api public
			*/

			PerMessageDeflate.prototype.offer = function() {
			var params = {};
			if (this._options.serverNoContextTakeover) {
			params.server_no_context_takeover = true;
			}
			if (this._options.clientNoContextTakeover) {
			params.client_no_context_takeover = true;
			}
			if (this._options.serverMaxWindowBits) {
			params.server_max_window_bits = this._options.serverMaxWindowBits;
			}
			if (this._options.clientMaxWindowBits) {
			params.client_max_window_bits = this._options.clientMaxWindowBits;
			} else if (this._options.clientMaxWindowBits == null) {
			params.client_max_window_bits = true;
			}
			return params;
			};

			/**
			* Accept extension offer
			*
			* @api public
			*/

			PerMessageDeflate.prototype.accept = function(paramsList) {
			paramsList = this.normalizeParams(paramsList);

			var params;
			if (this._isServer) {
			params = this.acceptAsServer(paramsList);
			} else {
			params = this.acceptAsClient(paramsList);
			}

			this.params = params;
			return params;
			};

			/**
			* Releases all resources used by the extension
			*
			* @api public
			*/

			PerMessageDeflate.prototype.cleanup = function() {
			if (this._inflate) {
			if (this._inflate.writeInProgress) {
			this._inflate.pendingClose = true;
			} else {
			if (this._inflate.close) this._inflate.close();
			this._inflate = null;
			}
			}
			if (this._deflate) {
			if (this._deflate.writeInProgress) {
			this._deflate.pendingClose = true;
			} else {
			if (this._deflate.close) this._deflate.close();
			this._deflate = null;
			}
			}
			};

			/**
			* Accept extension offer from client
			*
			* @api private
			*/

			PerMessageDeflate.prototype.acceptAsServer = function(paramsList) {
			var accepted = {};
			var result = paramsList.some(function(params) {
			accepted = {};
			if (this._options.serverNoContextTakeover === false && params.server_no_context_takeover) {
			return;
			}
			if (this._options.serverMaxWindowBits === false && params.server_max_window_bits) {
			return;
			}
			if (typeof this._options.serverMaxWindowBits === 'number' &&
			typeof params.server_max_window_bits === 'number' &&
			this._options.serverMaxWindowBits > params.server_max_window_bits) {
			return;
			}
			if (typeof this._options.clientMaxWindowBits === 'number' && !params.client_max_window_bits) {
			return;
			}

			if (this._options.serverNoContextTakeover \|\| params.server_no_context_takeover) {
			accepted.server_no_context_takeover = true;
			}
			if (this._options.clientNoContextTakeover) {
			accepted.client_no_context_takeover = true;
			}
			if (this._options.clientNoContextTakeover !== false && params.client_no_context_takeover) {
			accepted.client_no_context_takeover = true;
			}
			if (typeof this._options.serverMaxWindowBits === 'number') {
			accepted.server_max_window_bits = this._options.serverMaxWindowBits;
			} else if (typeof params.server_max_window_bits === 'number') {
			accepted.server_max_window_bits = params.server_max_window_bits;
			}
			if (typeof this._options.clientMaxWindowBits === 'number') {
			accepted.client_max_window_bits = this._options.clientMaxWindowBits;
			} else if (this._options.clientMaxWindowBits !== false && typeof params.client_max_window_bits === 'number') {
			accepted.client_max_window_bits = params.client_max_window_bits;
			}
			return true;
			}, this);

			if (!result) {
			throw new Error('Doesn\'t support the offered configuration');
			}

			return accepted;
			};

			/**
			* Accept extension response from server
			*
			* @api privaye
			*/

			PerMessageDeflate.prototype.acceptAsClient = function(paramsList) {
			var params = paramsList[0];
			if (this._options.clientNoContextTakeover != null) {
			if (this._options.clientNoContextTakeover === false && params.client_no_context_takeover) {
			throw new Error('Invalid value for "client_no_context_takeover"');
			}
			}
			if (this._options.clientMaxWindowBits != null) {
			if (this._options.clientMaxWindowBits === false && params.client_max_window_bits) {
			throw new Error('Invalid value for "client_max_window_bits"');
			}
			if (typeof this._options.clientMaxWindowBits === 'number' &&
			(!params.client_max_window_bits \|\| params.client_max_window_bits > this._options.clientMaxWindowBits)) {
			throw new Error('Invalid value for "client_max_window_bits"');
			}
			}
			return params;
			};

			/**
			* Normalize extensions parameters
			*
			* @api private
			*/

			PerMessageDeflate.prototype.normalizeParams = function(paramsList) {
			return paramsList.map(function(params) {
			Object.keys(params).forEach(function(key) {
			var value = params[key];
			if (value.length > 1) {
			throw new Error('Multiple extension parameters for ' + key);
			}

			value = value[0];

			switch (key) {
			case 'server_no_context_takeover':
			case 'client_no_context_takeover':
			if (value !== true) {
			throw new Error('invalid extension parameter value for ' + key + ' (' + value + ')');
			}
			params[key] = true;
			break;
			case 'server_max_window_bits':
			case 'client_max_window_bits':
			if (typeof value === 'string') {
			value = parseInt(value, 10);
			if (!~AVAILABLE_WINDOW_BITS.indexOf(value)) {
			throw new Error('invalid extension parameter value for ' + key + ' (' + value + ')');
			}
			}
			if (!this._isServer && value === true) {
			throw new Error('Missing extension parameter value for ' + key);
			}
			params[key] = value;
			break;
			default:
			throw new Error('Not defined extension parameter (' + key + ')');
			}
			}, this);
			return params;
			}, this);
			};

			/**
			* Decompress message
			*
			* @api public
			*/

			PerMessageDeflate.prototype.decompress = function (data, fin, callback) {
			var endpoint = this._isServer ? 'client' : 'server';

			if (!this._inflate) {
			var maxWindowBits = this.params[endpoint + '_max_window_bits'];
			this._inflate = zlib.createInflateRaw({
			windowBits: 'number' === typeof maxWindowBits ? maxWindowBits : DEFAULT_WINDOW_BITS
			});
			}
			this._inflate.writeInProgress = true;

			var self = this;
			var buffers = [];
			var cumulativeBufferLength=0;

			this._inflate.on('error', onError).on('data', onData);
			this._inflate.write(data);
			if (fin) {
			this._inflate.write(new Buffer([0x00, 0x00, 0xff, 0xff]));
			}
			this._inflate.flush(function() {
			cleanup();
			callback(null, Buffer.concat(buffers));
			});

			function onError(err) {
			cleanup();
			callback(err);
			}

			function onData(data) {
			if(self._maxPayload!==undefined && self._maxPayload!==null && self._maxPayload>0){
			cumulativeBufferLength+=data.length;
			if(cumulativeBufferLength>self._maxPayload){
			buffers=[];
			cleanup();
			var err={type:1009};
			callback(err);
			return;
			}
			}
			buffers.push(data);
			}

			function cleanup() {
			if (!self._inflate) return;
			self._inflate.removeListener('error', onError);
			self._inflate.removeListener('data', onData);
			self._inflate.writeInProgress = false;
			if ((fin && self.params[endpoint + '_no_context_takeover']) \|\| self._inflate.pendingClose) {
			if (self._inflate.close) self._inflate.close();
			self._inflate = null;
			}
			}
			};

			/**
			* Compress message
			*
			* @api public
			*/

			PerMessageDeflate.prototype.compress = function (data, fin, callback) {
			var endpoint = this._isServer ? 'server' : 'client';

			if (!this._deflate) {
			var maxWindowBits = this.params[endpoint + '_max_window_bits'];
			this._deflate = zlib.createDeflateRaw({
			flush: zlib.Z_SYNC_FLUSH,
			windowBits: 'number' === typeof maxWindowBits ? maxWindowBits : DEFAULT_WINDOW_BITS,
			memLevel: this._options.memLevel \|\| DEFAULT_MEM_LEVEL
			});
			}
			this._deflate.writeInProgress = true;

			var self = this;
			var buffers = [];

			this._deflate.on('error', onError).on('data', onData);
			this._deflate.write(data);
			this._deflate.flush(function() {
			cleanup();
			var data = Buffer.concat(buffers);
			if (fin) {
			data = data.slice(0, data.length - 4);
			}
			callback(null, data);
			});

			function onError(err) {
			cleanup();
			callback(err);
			}

			function onData(data) {
			buffers.push(data);
			}

			function cleanup() {
			if (!self._deflate) return;
			self._deflate.removeListener('error', onError);
			self._deflate.removeListener('data', onData);
			self._deflate.writeInProgress = false;
			if ((fin && self.params[endpoint + '_no_context_takeover']) \|\| self._deflate.pendingClose) {
			if (self._deflate.close) self._deflate.close();
			self._deflate = null;
			}
			}
			};

			module.exports = PerMessageDeflate;