1 """JSON token scanner

     2 """

     3 import re

     4 try:

     5     from simplejson._speedups import make_scanner as c_make_scanner

     6 except ImportError:

     7     c_make_scanner = None

     8 

     9 __all__ = ['make_scanner']

    10 

    11 NUMBER_RE = re.compile(

    12     r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?',

    13     (re.VERBOSE | re.MULTILINE | re.DOTALL))

    14 

    15 def py_make_scanner(context):

    16     parse_object = context.parse_object

    17     parse_array = context.parse_array

    18     parse_string = context.parse_string

    19     match_number = NUMBER_RE.match

    20     encoding = context.encoding

    21     strict = context.strict

    22     parse_float = context.parse_float

    23     parse_int = context.parse_int

    24     parse_constant = context.parse_constant

    25     object_hook = context.object_hook

    26 

    27     def _scan_once(string, idx):

    28         try:

    29             nextchar = string[idx]

    30         except IndexError:

    31             raise StopIteration

    32 

    33         if nextchar == '"':

    34             return parse_string(string, idx + 1, encoding, strict)

    35         elif nextchar == '{':

    36             return parse_object((string, idx + 1), encoding, strict, _scan_once, object_hook)

    37         elif nextchar == '[':

    38             return parse_array((string, idx + 1), _scan_once)

    39         elif nextchar == 'n' and string[idx:idx + 4] == 'null':

    40             return None, idx + 4

    41         elif nextchar == 't' and string[idx:idx + 4] == 'true':

    42             return True, idx + 4

    43         elif nextchar == 'f' and string[idx:idx + 5] == 'false':

    44             return False, idx + 5

    45 

    46         m = match_number(string, idx)

    47         if m is not None:

    48             integer, frac, exp = m.groups()

    49             if frac or exp:

    50                 res = parse_float(integer + (frac or '') + (exp or ''))

    51             else:

    52                 res = parse_int(integer)

    53             return res, m.end()

    54         elif nextchar == 'N' and string[idx:idx + 3] == 'NaN':

    55             return parse_constant('NaN'), idx + 3

    56         elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity':

    57             return parse_constant('Infinity'), idx + 8

    58         elif nextchar == '-' and string[idx:idx + 9] == '-Infinity':

    59             return parse_constant('-Infinity'), idx + 9

    60         else:

    61             raise StopIteration

    62 

    63     return _scan_once

    64 

    65 make_scanner = c_make_scanner or py_make_scanner