jsonpack.js

/*
 Copyright (c) 2013, Rodrigo González, Sapienlab All Rights Reserved.
 Available via MIT LICENSE. See https://github.com/roro89/jsonpack/blob/master/LICENSE.md for details.
 */
(function(define) {

	define([], function() {

		var TOKEN_TRUE = -1;
		var TOKEN_FALSE = -2;
		var TOKEN_NULL = -3;
		var TOKEN_EMPTY_STRING = -4;
		var TOKEN_UNDEFINED = -5;

		var pack = function(json, options) {

			// Canonizes the options
			options = options || {};

			// A shorthand for debugging
			var verbose = options.verbose || false;

			verbose && console.log('Normalize the JSON Object');

			// JSON as Javascript Object (Not string representation)
			json = typeof json === 'string' ? this.JSON.parse(json) : json;

			verbose && console.log('Creating a empty dictionary');

			// The dictionary
			var dictionary = {
				strings : [],
				integers : [],
				floats : []
			};

			verbose && console.log('Creating the AST');

			// The AST
			var ast = (function recursiveAstBuilder(item) {

				verbose && console.log('Calling recursiveAstBuilder with ' + this.JSON.stringify(item));

				// The type of the item
				var type = typeof item;

				// Case 7: The item is null
				if (item === null) {
					return {
						type : 'null',
						index : TOKEN_NULL
					};
				}
				
				//add undefined 
				if (typeof item === 'undefined') {
					return {
						type : 'undefined',
						index : TOKEN_UNDEFINED
					};
				}

				// Case 1: The item is Array Object
				if ( item instanceof Array) {

					// Create a new sub-AST of type Array (@)
					var ast = ['@'];

					// Add each items
					for (var i in item) {
						
						if (!item.hasOwnProperty(i)) continue;

						ast.push(recursiveAstBuilder(item[i]));
					}

					// And return
					return ast;

				}

				// Case 2: The item is Object
				if (type === 'object') {

					// Create a new sub-AST of type Object ($)
					var ast = ['$'];

					// Add each items
					for (var key in item) {

						if (!item.hasOwnProperty(key))
							continue;

						ast.push(recursiveAstBuilder(key));
						ast.push(recursiveAstBuilder(item[key]));
					}

					// And return
					return ast;

				}

				// Case 3: The item empty string
				if (item === '') {
					return {
						type : 'empty',
						index : TOKEN_EMPTY_STRING
					};
				}

				// Case 4: The item is String
				if (type === 'string') {

					// The index of that word in the dictionary
					var index = _indexOf.call(dictionary.strings, item);

					// If not, add to the dictionary and actualize the index
					if (index == -1) {
						dictionary.strings.push(_encode(item));
						index = dictionary.strings.length - 1;
					}

					// Return the token
					return {
						type : 'strings',
						index : index
					};
				}

				// Case 5: The item is integer
				if (type === 'number' && item % 1 === 0) {

					// The index of that number in the dictionary
					var index = _indexOf.call(dictionary.integers, item);

					// If not, add to the dictionary and actualize the index
					if (index == -1) {
						dictionary.integers.push(_base10To36(item));
						index = dictionary.integers.length - 1;
					}

					// Return the token
					return {
						type : 'integers',
						index : index
					};
				}

				// Case 6: The item is float
				if (type === 'number') {
					// The index of that number in the dictionary
					var index = _indexOf.call(dictionary.floats, item);

					// If not, add to the dictionary and actualize the index
					if (index == -1) {
						// Float not use base 36
						dictionary.floats.push(item);
						index = dictionary.floats.length - 1;
					}

					// Return the token
					return {
						type : 'floats',
						index : index
					};
				}

				// Case 7: The item is boolean
				if (type === 'boolean') {
					return {
						type : 'boolean',
						index : item ? TOKEN_TRUE : TOKEN_FALSE
					};
				}

				// Default
				throw new Error('Unexpected argument of type ' + typeof (item));

			})(json);

			// A set of shorthands proxies for the length of the dictionaries
			var stringLength = dictionary.strings.length;
			var integerLength = dictionary.integers.length;
			var floatLength = dictionary.floats.length;

			verbose && console.log('Parsing the dictionary');

			// Create a raw dictionary
			var packed = dictionary.strings.join('|');
			packed += '^' + dictionary.integers.join('|');
			packed += '^' + dictionary.floats.join('|');

			verbose && console.log('Parsing the structure');

			// And add the structure
			packed += '^' + (function recursiveParser(item) {

				verbose && console.log('Calling a recursiveParser with ' + this.JSON.stringify(item));

				// If the item is Array, then is a object of
				// type [object Object] or [object Array]
				if ( item instanceof Array) {

					// The packed resulting
					var packed = item.shift();

					for (var i in item) {
						
						if (!item.hasOwnProperty(i)) 
							continue;
						
						packed += recursiveParser(item[i]) + '|';
					}

					return (packed[packed.length - 1] === '|' ? packed.slice(0, -1) : packed) + ']';

				}

				// A shorthand proxies
				var type = item.type, index = item.index;

				if (type === 'strings') {
					// Just return the base 36 of index
					return _base10To36(index);
				}

				if (type === 'integers') {
					// Return a base 36 of index plus stringLength offset
					return _base10To36(stringLength + index);
				}

				if (type === 'floats') {
					// Return a base 36 of index plus stringLength and integerLength offset
					return _base10To36(stringLength + integerLength + index);
				}

				if (type === 'boolean') {
					return item.index;
				}

				if (type === 'null') {
					return TOKEN_NULL;
				}

				if (type === 'undefined') {
					return TOKEN_UNDEFINED;
				}

				if (type === 'empty') {
					return TOKEN_EMPTY_STRING;
				}

				throw new TypeError('The item is alien!');

			})(ast);

			verbose && console.log('Ending parser');

			// If debug, return a internal representation of dictionary and stuff
			if (options.debug)
				return {
					dictionary : dictionary,
					ast : ast,
					packed : packed
				};

			return packed;

		};

		var unpack = function(packed, options) {

			// Canonizes the options
			options = options || {};

			// A raw buffer
			var rawBuffers = packed.split('^');

			// Create a dictionary
			options.verbose && console.log('Building dictionary');
			var dictionary = [];

			// Add the strings values
			var buffer = rawBuffers[0];
			if (buffer !== '') {
				buffer = buffer.split('|');
				options.verbose && console.log('Parse the strings dictionary');
				for (var i=0, n=buffer.length; i<n; i++){
					dictionary.push(_decode(buffer[i]));
				}
			}

			// Add the integers values
			buffer = rawBuffers[1];
			if (buffer !== '') {
				buffer = buffer.split('|');
				options.verbose && console.log('Parse the integers dictionary');
				for (var i=0, n=buffer.length; i<n; i++){
					dictionary.push(_base36To10(buffer[i]));
				}
			}

			// Add the floats values
			buffer = rawBuffers[2];
			if (buffer !== '') {
				buffer = buffer.split('|')
				options.verbose && console.log('Parse the floats dictionary');
				for (var i=0, n=buffer.length; i<n; i++){
					dictionary.push(parseFloat(buffer[i]));
				}
			}
			// Free memory
			delete buffer;

			options.verbose && console.log('Tokenizing the structure');

			// Tokenizer the structure
			var number36 = '';
			var tokens = [];
			var len=rawBuffers[3].length;
			for (var i = 0; i < len; i++) {
				var symbol = rawBuffers[3].charAt(i);
				if (symbol === '|' || symbol === '$' || symbol === '@' || symbol === ']') {
					if (number36) {
						tokens.push(_base36To10(number36));
						number36 = '';
					}
					symbol !== '|' && tokens.push(symbol);
				} else {
					number36 += symbol;
				}
			}

			// A shorthand proxy for tokens.length
			var tokensLength = tokens.length;

			// The index of the next token to read
			var tokensIndex = 0;

			options.verbose && console.log('Starting recursive parser');

			return (function recursiveUnpackerParser() {

				// Maybe '$' (object) or '@' (array)
				var type = tokens[tokensIndex++];

				options.verbose && console.log('Reading collection type ' + (type === '$' ? 'object' : 'Array'));

				// Parse an array
				if (type === '@') {

					var node = [];

					for (; tokensIndex < tokensLength; tokensIndex++) {
						var value = tokens[tokensIndex];
						options.verbose && console.log('Read ' + value + ' symbol');
						if (value === ']')
							return node;
						if (value === '@' || value === '$') {
							node.push(recursiveUnpackerParser());
						} else {
							switch(value) {
								case TOKEN_TRUE:
									node.push(true);
									break;
								case TOKEN_FALSE:
									node.push(false);
									break;
								case TOKEN_NULL:
									node.push(null);
									break;
								case TOKEN_UNDEFINED:
									node.push(undefined);
									break;
								case TOKEN_EMPTY_STRING:
									node.push('');
									break;
								default:
									node.push(dictionary[value]);
							}

						}
					}

					options.verbose && console.log('Parsed ' + this.JSON.stringify(node));

					return node;

				}

				// Parse a object
				if (type === '$') {
					var node = {};

					for (; tokensIndex < tokensLength; tokensIndex++) {

						var key = tokens[tokensIndex];

						if (key === ']')
							return node;

						if (key === TOKEN_EMPTY_STRING)
							key = '';
						else
							key = dictionary[key];

						var value = tokens[++tokensIndex];

						if (value === '@' || value === '$') {
							node[key] = recursiveUnpackerParser();
						} else {
							switch(value) {
								case TOKEN_TRUE:
									node[key] = true;
									break;
								case TOKEN_FALSE:
									node[key] = false;
									break;
								case TOKEN_NULL:
									node[key] = null;
									break;
								case TOKEN_UNDEFINED:
									node[key] = undefined;
									break;
								case TOKEN_EMPTY_STRING:
									node[key] = '';
									break;
								default:
									node[key] = dictionary[value];
							}

						}
					}

					options.verbose && console.log('Parsed ' + this.JSON.stringify(node));

					return node;
				}

				throw new TypeError('Bad token ' + type + ' isn\'t a type');

			})();

		}
		/**
		 * Get the index value of the dictionary
		 * @param {Object} dictionary a object that have two array attributes: 'string' and 'number'
		 * @param {Object} data
		 */
		var _indexOfDictionary = function(dictionary, value) {

			// The type of the value
			var type = typeof value;

			// If is boolean, return a boolean token
			if (type === 'boolean')
				return value ? TOKEN_TRUE : TOKEN_FALSE;

			// If is null, return a... yes! the null token
			if (value === null)
				return TOKEN_NULL;

			//add undefined
			if (typeof value === 'undefined')
				return TOKEN_UNDEFINED;


			if (value === '') {
				return TOKEN_EMPTY_STRING;
			}

			if (type === 'string') {
				value = _encode(value);
				var index = _indexOf.call(dictionary.strings, value);
				if (index === -1) {
					dictionary.strings.push(value);
					index = dictionary.strings.length - 1;
				}
			}

			// If has an invalid JSON type (example a function)
			if (type !== 'string' && type !== 'number') {
				throw new Error('The type is not a JSON type');
			};

			if (type === 'string') {// string
				value = _encode(value);
			} else if (value % 1 === 0) {// integer
				value = _base10To36(value);
			} else {// float

			}

			// If is number, "serialize" the value
			value = type === 'number' ? _base10To36(value) : _encode(value);

			// Retrieve the index of that value in the dictionary
			var index = _indexOf.call(dictionary[type], value);

			// If that value is not in the dictionary
			if (index === -1) {
				// Push the value
				dictionary[type].push(value);
				// And return their index
				index = dictionary[type].length - 1;
			}

			// If the type is a number, then add the '+'  prefix character
			// to differentiate that they is a number index. If not, then
			// just return a 36-based representation of the index
			return type === 'number' ? '+' + index : index;

		};

		var _encode = function(str) {
			if ( typeof str !== 'string')
				return str;

			return str.replace(/[\+ \|\^\%]/g, function(a) {
				return ({
				' ' : '+',
				'+' : '%2B',
				'|' : '%7C',
				'^' : '%5E',
				'%' : '%25'
				})[a]
			});
		};

		var _decode = function(str) {
			if ( typeof str !== 'string')
				return str;

			return str.replace(/\+|%2B|%7C|%5E|%25/g, function(a) {
				return ({
				'+' : ' ',
				'%2B' : '+',
				'%7C' : '|',
				'%5E' : '^',
				'%25' : '%'
				})[a]
			})
		};

		var _base10To36 = function(number) {
			return Number.prototype.toString.call(number, 36).toUpperCase();
		};

		var _base36To10 = function(number) {
			return parseInt(number, 36);
		};

		var _indexOf = Array.prototype.indexOf ||
		function(obj, start) {
			for (var i = (start || 0), j = this.length; i < j; i++) {
				if (this[i] === obj) {
					return i;
				}
			}
			return -1;
		};

		return {
			JSON : JSON,
			pack : pack,
			unpack : unpack
		};

	});

})( typeof define == 'undefined' || !define.amd ? function(deps, factory) {
	var jsonpack = factory();
	if ( typeof exports != 'undefined')
		for (var key in jsonpack)
		exports[key] = jsonpack[key];
	else
		window.jsonpack = jsonpack;
} : define);