Description:
------------
json_decode() fails completely on the following code:

Reproduce code:
---------------
var_dump(json_decode('[{0:"tan","model":"sedan"},{"0":"red",model:"sports"}]'));
var_dump(json_decode('{"1":"one",2:"two","5":\'fi"ve\'}'));

Expected result:
----------------
array(2) {
  [0]=>
  object(stdClass)(2) {
    [0]=>
    string(3) "tan"
    ["model"]=>
    string(5) "sedan"
  }
  [1]=>
  object(stdClass)(2) {
    [0]=>
    string(3) "red"
    ["model"]=>
    string(6) "sports"
  }
}
object(stdClass)(3) {
  [1]=>
  string(3) "one"
  [2]=>
  string(3) "two"
  [5]=>
  string(5) "fi"ve"
}


Actual result:
--------------
NULL
NULL