json_parseMore.js

// Adapted from Crockford's JSON.parse (see https://github.com/douglascrockford/JSON-js)
// This version adds support for NaN, -Infinity and Infinity.

(function(){
	var at,	 // The index of the current character
		ch,	 // The current character
		escapee = {
			'"':  '"',
			'\\': '\\',
			'/':  '/',
			b:	'\b',
			f:	'\f',
			n:	'\n',
			r:	'\r',
			t:	'\t'
		},
		text,
		error = function (m) {
			throw {
				name: 'SyntaxError',
				message: m,
				at:	at,
				text: text
			};
		},
		next = function (c) {
			return ch = text.charAt(at++);
		},
		check = function (c) {
			if (c !== ch) {
				error("Expected '" + c + "' instead of '" + ch + "'");
			}
			ch = text.charAt(at++);
		},
		number = function () {
			var string = '';
			if (ch === '-') {
				string = '-';
				check('-');
			}
			if (ch === 'I') {
				check('I');
				check('n');
				check('f');
				check('i');
				check('n');
				check('i');
				check('t');
				check('y');
				return -Infinity;
			}
			while (ch >= '0' && ch <= '9') {
				string += ch;
				next();
			}
			if (ch === '.') {
				string += '.';
				while (next() && ch >= '0' && ch <= '9') {
					string += ch;
				}
			}
			if (ch === 'e' || ch === 'E') {
				string += ch;
				next();
				if (ch === '-' || ch === '+') {
					string += ch;
					next();
				}
				while (ch >= '0' && ch <= '9') {
					string += ch;
					next();
				}
			}
			return +string;
		},
		string = function () {
			var hex,
				i,
				string = '',
				uffff;
			if (ch === '"') {
				while (next()) {
					if (ch === '"') {
						next();
						return string;
					}
					if (ch === '\\') {
						next();
						if (ch === 'u') {
							uffff = 0;
							for (i = 0; i < 4; i ++) {
								hex = parseInt(next(), 16);
								if (!isFinite(hex)) {
									break;
								}
								uffff = uffff * 16 + hex;
							}
							string += String.fromCharCode(uffff);
						} else if (escapee[ch]) {
							string += escapee[ch];
						} else {
							break;
						}
					} else {
						string += ch;
					}
				}
			}
			error("Bad string");
		},
		white = function () { // Skip whitespace.
			while (ch && ch <= ' ') {
				next();
			}
		},
		word = function () {
			switch (ch) {
			case 't':
				check('t');
				check('r');
				check('u');
				check('e');
				return true;
			case 'f':
				check('f');
				check('a');
				check('l');
				check('s');
				check('e');
				return false;
			case 'n':
				check('n');
				check('u');
				check('l');
				check('l');
				return null;
			case 'N':
				check('N');
				check('a');
				check('N');
				return NaN;
			case 'I':
				check('I');
				check('n');
				check('f');
				check('i');
				check('n');
				check('i');
				check('t');
				check('y');
				return Infinity;
			}
			error("Unexpected '" + ch + "'");
		},
		array = function () {
			var array = [];
			if (ch === '[') {
				check('[');
				white();
				if (ch === ']') {
					check(']');
					return array;   // empty array
				}
				while (ch) {
					array.push(value());
					white();
					if (ch === ']') {
						check(']');
						return array;
					}
					check(',');
					white();
				}
			}
			error("Bad array");
		},
		object = function () {
			var key, object = {};
			if (ch === '{') {
				check('{');
				white();
				if (ch === '}') {
					check('}');
					return object;   // empty object
				}
				while (ch) {
					key = string();
					white();
					check(':');
					if (Object.hasOwnProperty.call(object, key)) {
						error('Duplicate key "' + key + '"');
					}
					object[key] = value();
					white();
					if (ch === '}') {
						check('}');
						return object;
					}
					check(',');
					white();
				}
			}
			error("Bad object");
		};
	var value = function () {
		white();
		switch (ch) {
		case '{':
			return object();
		case '[':
			return array();
		case '"':
			return string();
		case '-':
			return number();
		default:
			return ch >= '0' && ch <= '9' ? number() : word();
		}
	};
	
	JSON.parseMore = function(source, reviver){
		var result;
		text = source;
		at = 0;
		ch = ' ';
		result = value();
		white();
		if (ch) {
			error("Syntax error");
		}	
		return typeof reviver === 'function'
		? (function walk(holder, key) {
			var k, v, value = holder[key];
			if (value && typeof value === 'object') {
				for (k in value) {
					if (Object.prototype.hasOwnProperty.call(value, k)) {
						v = walk(value, k);
						if (v !== undefined) {
							value[k] = v;
						} else {
							delete value[k];
						}
					}
				}
			}
			return reviver.call(holder, key, value);
		}({'': result}, ''))
		: result;
	}
	
})();