/*

  Copyright (c) 2008, Adobe Systems Incorporated

  All rights reserved.



  Redistribution and use in source and binary forms, with or without 

  modification, are permitted provided that the following conditions are

  met:



  * Redistributions of source code must retain the above copyright notice, 

    this list of conditions and the following disclaimer.

  

  * Redistributions in binary form must reproduce the above copyright

    notice, this list of conditions and the following disclaimer in the 

    documentation and/or other materials provided with the distribution.

  

  * Neither the name of Adobe Systems Incorporated nor the names of its 

    contributors may be used to endorse or promote products derived from 

    this software without specific prior written permission.



  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 

  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/



//http://code.google.com/p/as3corelib/

//package com.adobe.serialization.json

package com.google.maps.extras.arcgislink.json

{

	

	public class JSONDecoder

	{	

	

		/** 

		 * Flag indicating if the parser should be strict about the format

		 * of the JSON string it is attempting to decode.

		 */

		private var strict:Boolean;

		

		/** The value that will get parsed from the JSON string */

		private var value:*;

		

		/** The tokenizer designated to read the JSON string */

		private var tokenizer:JSONTokenizer;

		

		/** The current token from the tokenizer */

		private var token:JSONToken;

		

		/**

		 * Constructs a new JSONDecoder to parse a JSON string 

		 * into a native object.

		 *

		 * @param s The JSON string to be converted

		 *		into a native object

		 * @param strict Flag indicating if the JSON string needs to

		 * 		strictly match the JSON standard or not.

		 * @langversion ActionScript 3.0

		 * @playerversion Flash 9.0

		 * @tiptext

		 */

		public function JSONDecoder( s:String, strict:Boolean )

		{	

			this.strict = strict;

			tokenizer = new JSONTokenizer( s, strict );

			

			nextToken();

			value = parseValue();

			

			// Make sure the input stream is empty

			if ( strict && nextToken() != null )

			{

				tokenizer.parseError( "Unexpected characters left in input stream" );

			}

		}

		

		/**

		 * Gets the internal object that was created by parsing

		 * the JSON string passed to the constructor.

		 *

		 * @return The internal object representation of the JSON

		 * 		string that was passed to the constructor

		 * @langversion ActionScript 3.0

		 * @playerversion Flash 9.0

		 * @tiptext

		 */

		public function getValue():*

		{

			return value;

		}

		

		/**

		 * Returns the next token from the tokenzier reading

		 * the JSON string

		 */

		private function nextToken():JSONToken

		{

			return token = tokenizer.getNextToken();

		}

		

		/**

		 * Attempt to parse an array.

		 */

		private function parseArray():Array

		{

			// create an array internally that we're going to attempt

			// to parse from the tokenizer

			var a:Array = new Array();

			

			// grab the next token from the tokenizer to move

			// past the opening [

			nextToken();

			

			// check to see if we have an empty array

			if ( token.type == JSONTokenType.RIGHT_BRACKET )

			{

				// we're done reading the array, so return it

				return a;

			}

			// in non-strict mode an empty array is also a comma

			// followed by a right bracket

			else if ( !strict && token.type == JSONTokenType.COMMA )

			{

				// move past the comma

				nextToken();

				

				// check to see if we're reached the end of the array

				if ( token.type == JSONTokenType.RIGHT_BRACKET )

				{

					return a;	

				}

				else

				{

					tokenizer.parseError( "Leading commas are not supported.  Expecting ']' but found " + token.value );

				}

			}

			

			// deal with elements of the array, and use an "infinite"

			// loop because we could have any amount of elements

			while ( true )

			{

				// read in the value and add it to the array

				a.push( parseValue() );

			

				// after the value there should be a ] or a ,

				nextToken();

				

				if ( token.type == JSONTokenType.RIGHT_BRACKET )

				{

					// we're done reading the array, so return it

					return a;

				}

				else if ( token.type == JSONTokenType.COMMA )

				{

					// move past the comma and read another value

					nextToken();

					

					// Allow arrays to have a comma after the last element

					// if the decoder is not in strict mode

					if ( !strict )

					{

						// Reached ",]" as the end of the array, so return it

						if ( token.type == JSONTokenType.RIGHT_BRACKET )

						{

							return a;

						}

					}

				}

				else

				{

					tokenizer.parseError( "Expecting ] or , but found " + token.value );

				}

			}

            return null;

		}

		

		/**

		 * Attempt to parse an object.

		 */

		private function parseObject():Object

		{

			// create the object internally that we're going to

			// attempt to parse from the tokenizer

			var o:Object = new OrderedObject();//NL: changed  new Object();

						

			// store the string part of an object member so

			// that we can assign it a value in the object

			var key:String

			

			// grab the next token from the tokenizer

			nextToken();

			

			// check to see if we have an empty object

			if ( token.type == JSONTokenType.RIGHT_BRACE )

			{

				// we're done reading the object, so return it

				return o;

			}

			// in non-strict mode an empty object is also a comma

			// followed by a right bracket

			else if ( !strict && token.type == JSONTokenType.COMMA )

			{

				// move past the comma

				nextToken();

				

				// check to see if we're reached the end of the object

				if ( token.type == JSONTokenType.RIGHT_BRACE )

				{

					return o;

				}

				else

				{

					tokenizer.parseError( "Leading commas are not supported.  Expecting '}' but found " + token.value );

				}

			}

			

			// deal with members of the object, and use an "infinite"

			// loop because we could have any amount of members

			while ( true )

			{

				if ( token.type == JSONTokenType.STRING )

				{

					// the string value we read is the key for the object

					key = String( token.value );

					

					// move past the string to see what's next

					nextToken();

					

					// after the string there should be a :

					if ( token.type == JSONTokenType.COLON )

					{	

						// move past the : and read/assign a value for the key

						nextToken();

						o[key] = parseValue();	

						

						// move past the value to see what's next

						nextToken();

						

						// after the value there's either a } or a ,

						if ( token.type == JSONTokenType.RIGHT_BRACE )

						{

							// we're done reading the object, so return it

							return o;	

						}

						else if ( token.type == JSONTokenType.COMMA )

						{

							// skip past the comma and read another member

							nextToken();

							

							// Allow objects to have a comma after the last member

							// if the decoder is not in strict mode

							if ( !strict )

							{

								// Reached ",}" as the end of the object, so return it

								if ( token.type == JSONTokenType.RIGHT_BRACE )

								{

									return o;

								}

							}

						}

						else

						{

							tokenizer.parseError( "Expecting } or , but found " + token.value );

						}

					}

					else

					{

						tokenizer.parseError( "Expecting : but found " + token.value );

					}

				}

				else

				{	

					tokenizer.parseError( "Expecting string but found " + token.value );

				}

			}

            return null;

		}

		

		/**

		 * Attempt to parse a value

		 */

		private function parseValue():Object

		{

			// Catch errors when the input stream ends abruptly

			if ( token == null )

			{

				tokenizer.parseError( "Unexpected end of input" );

			}

					

			switch ( token.type )

			{

				case JSONTokenType.LEFT_BRACE:

					return parseObject();

					

				case JSONTokenType.LEFT_BRACKET:

					return parseArray();

					

				case JSONTokenType.STRING:

				case JSONTokenType.NUMBER:

				case JSONTokenType.TRUE:

				case JSONTokenType.FALSE:

				case JSONTokenType.NULL:

					return token.value;

					

				case JSONTokenType.NAN:

					if ( !strict )

					{

						return token.value;

					}

					else

					{

						tokenizer.parseError( "Unexpected " + token.value );

					}



				default:

					tokenizer.parseError( "Unexpected " + token.value );

					

			}

			

            return null;

		}

	}

}