github.com/slspeek/camlistore_namedsearch@v0.0.0-20140519202248-ed6f70f7721a/lib/python/simplejson/scanner.py (about)

     1  """JSON token scanner
     2  """
     3  import re
     4  def _import_c_make_scanner():
     5      try:
     6          from simplejson._speedups import make_scanner
     7          return make_scanner
     8      except ImportError:
     9          return None
    10  c_make_scanner = _import_c_make_scanner()
    11  
    12  __all__ = ['make_scanner']
    13  
    14  NUMBER_RE = re.compile(
    15      r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?',
    16      (re.VERBOSE | re.MULTILINE | re.DOTALL))
    17  
    18  def py_make_scanner(context):
    19      parse_object = context.parse_object
    20      parse_array = context.parse_array
    21      parse_string = context.parse_string
    22      match_number = NUMBER_RE.match
    23      encoding = context.encoding
    24      strict = context.strict
    25      parse_float = context.parse_float
    26      parse_int = context.parse_int
    27      parse_constant = context.parse_constant
    28      object_hook = context.object_hook
    29      object_pairs_hook = context.object_pairs_hook
    30      memo = context.memo
    31  
    32      def _scan_once(string, idx):
    33          try:
    34              nextchar = string[idx]
    35          except IndexError:
    36              raise StopIteration
    37  
    38          if nextchar == '"':
    39              return parse_string(string, idx + 1, encoding, strict)
    40          elif nextchar == '{':
    41              return parse_object((string, idx + 1), encoding, strict,
    42                  _scan_once, object_hook, object_pairs_hook, memo)
    43          elif nextchar == '[':
    44              return parse_array((string, idx + 1), _scan_once)
    45          elif nextchar == 'n' and string[idx:idx + 4] == 'null':
    46              return None, idx + 4
    47          elif nextchar == 't' and string[idx:idx + 4] == 'true':
    48              return True, idx + 4
    49          elif nextchar == 'f' and string[idx:idx + 5] == 'false':
    50              return False, idx + 5
    51  
    52          m = match_number(string, idx)
    53          if m is not None:
    54              integer, frac, exp = m.groups()
    55              if frac or exp:
    56                  res = parse_float(integer + (frac or '') + (exp or ''))
    57              else:
    58                  res = parse_int(integer)
    59              return res, m.end()
    60          elif nextchar == 'N' and string[idx:idx + 3] == 'NaN':
    61              return parse_constant('NaN'), idx + 3
    62          elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity':
    63              return parse_constant('Infinity'), idx + 8
    64          elif nextchar == '-' and string[idx:idx + 9] == '-Infinity':
    65              return parse_constant('-Infinity'), idx + 9
    66          else:
    67              raise StopIteration
    68  
    69      def scan_once(string, idx):
    70          try:
    71              return _scan_once(string, idx)
    72          finally:
    73              memo.clear()
    74  
    75      return scan_once
    76  
    77  make_scanner = c_make_scanner or py_make_scanner