/*
* Copyright (C) 2013 Glyptodon LLC
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
var Guacamole = Guacamole || {};
/**
* Simple Guacamole protocol parser that invokes an oninstruction event when
* full instructions are available from data received via receive().
*
* @constructor
*/
Guacamole.Parser = function() {
/**
* Reference to this parser.
* @private
*/
var parser = this;
/**
* Current buffer of received data. This buffer grows until a full
* element is available. After a full element is available, that element
* is flushed into the element buffer.
*
* @private
*/
var buffer = "";
/**
* Buffer of all received, complete elements. After an entire instruction
* is read, this buffer is flushed, and a new instruction begins.
*
* @private
*/
var element_buffer = [];
// The location of the last element's terminator
var element_end = -1;
// Where to start the next length search or the next element
var start_index = 0;
/**
* Appends the given instruction data packet to the internal buffer of
* this Guacamole.Parser, executing all completed instructions at
* the beginning of this buffer, if any.
*
* @param {String} packet The instruction data to receive.
*/
this.receive = function(packet) {
// Truncate buffer as necessary
if (start_index > 4096 && element_end >= start_index) {
buffer = buffer.substring(start_index);
// Reset parse relative to truncation
element_end -= start_index;
start_index = 0;
}
// Append data to buffer
buffer += packet;
// While search is within currently received data
while (element_end < buffer.length) {
// If we are waiting for element data
if (element_end >= start_index) {
// We now have enough data for the element. Parse.
var element = buffer.substring(start_index, element_end);
var terminator = buffer.substring(element_end, element_end+1);
// Add element to array
element_buffer.push(element);
// If last element, handle instruction
if (terminator == ";") {
// Get opcode
var opcode = element_buffer.shift();
// Call instruction handler.
if (parser.oninstruction != null)
parser.oninstruction(opcode, element_buffer);
// Clear elements
element_buffer.length = 0;
}
else if (terminator != ',')
throw new Error("Illegal terminator.");
// Start searching for length at character after
// element terminator
start_index = element_end + 1;
}
// Search for end of length
var length_end = buffer.indexOf(".", start_index);
if (length_end != -1) {
// Parse length
var length = parseInt(buffer.substring(element_end+1, length_end));
if (length == NaN)
throw new Error("Non-numeric character in element length.");
// Calculate start of element
start_index = length_end + 1;
// Calculate location of element terminator
element_end = start_index + length;
}
// If no period yet, continue search when more data
// is received
else {
start_index = buffer.length;
break;
}
} // end parse loop
};
/**
* Fired once for every complete Guacamole instruction received, in order.
*
* @event
* @param {String} opcode The Guacamole instruction opcode.
* @param {Array} parameters The parameters provided for the instruction,
* if any.
*/
this.oninstruction = null;
};