Source code for simplejson.scanner

"""JSON token scanner
"""
import re
def _import_c_make_scanner():
    try:
        from simplejson._speedups import make_scanner
        return make_scanner
    except ImportError:
        return None
c_make_scanner = _import_c_make_scanner()

__all__ = ['make_scanner', 'JSONDecodeError']

NUMBER_RE = re.compile(
    r'(-?(?:0|[1-9]\d*))(\.\d+)?([eE][-+]?\d+)?',
    (re.VERBOSE | re.MULTILINE | re.DOTALL))

[docs]class JSONDecodeError(ValueError): """Subclass of ValueError with the following additional properties: msg: The unformatted error message doc: The JSON document being parsed pos: The start index of doc where parsing failed end: The end index of doc where parsing failed (may be None) lineno: The line corresponding to pos colno: The column corresponding to pos endlineno: The line corresponding to end (may be None) endcolno: The column corresponding to end (may be None) """ # Note that this exception is used from _speedups def __init__(self, msg, doc, pos, end=None): ValueError.__init__(self, errmsg(msg, doc, pos, end=end)) self.msg = msg self.doc = doc self.pos = pos self.end = end self.lineno, self.colno = linecol(doc, pos) if end is not None: self.endlineno, self.endcolno = linecol(doc, end) else: self.endlineno, self.endcolno = None, None def __reduce__(self): return self.__class__, (self.msg, self.doc, self.pos, self.end)
def linecol(doc, pos): lineno = doc.count('\n', 0, pos) + 1 if lineno == 1: colno = pos + 1 else: colno = pos - doc.rindex('\n', 0, pos) return lineno, colno def errmsg(msg, doc, pos, end=None): lineno, colno = linecol(doc, pos) msg = msg.replace('%r', repr(doc[pos:pos + 1])) if end is None: fmt = '%s: line %d column %d (char %d)' return fmt % (msg, lineno, colno, pos) endlineno, endcolno = linecol(doc, end) fmt = '%s: line %d column %d - line %d column %d (char %d - %d)' return fmt % (msg, lineno, colno, endlineno, endcolno, pos, end) def py_make_scanner(context): parse_object = context.parse_object parse_array = context.parse_array parse_string = context.parse_string match_number = NUMBER_RE.match encoding = context.encoding strict = context.strict parse_float = context.parse_float parse_int = context.parse_int parse_constant = context.parse_constant object_hook = context.object_hook object_pairs_hook = context.object_pairs_hook memo = context.memo def _scan_once(string, idx): errmsg = 'Expecting value' try: nextchar = string[idx] except IndexError: raise JSONDecodeError(errmsg, string, idx) if nextchar == '"': return parse_string(string, idx + 1, encoding, strict) elif nextchar == '{': return parse_object((string, idx + 1), encoding, strict, _scan_once, object_hook, object_pairs_hook, memo) elif nextchar == '[': return parse_array((string, idx + 1), _scan_once) elif nextchar == 'n' and string[idx:idx + 4] == 'null': return None, idx + 4 elif nextchar == 't' and string[idx:idx + 4] == 'true': return True, idx + 4 elif nextchar == 'f' and string[idx:idx + 5] == 'false': return False, idx + 5 m = match_number(string, idx) if m is not None: integer, frac, exp = m.groups() if frac or exp: res = parse_float(integer + (frac or '') + (exp or '')) else: res = parse_int(integer) return res, m.end() elif nextchar == 'N' and string[idx:idx + 3] == 'NaN': return parse_constant('NaN'), idx + 3 elif nextchar == 'I' and string[idx:idx + 8] == 'Infinity': return parse_constant('Infinity'), idx + 8 elif nextchar == '-' and string[idx:idx + 9] == '-Infinity': return parse_constant('-Infinity'), idx + 9 else: raise JSONDecodeError(errmsg, string, idx) def scan_once(string, idx): if idx < 0: # Ensure the same behavior as the C speedup, otherwise # this would work for *some* negative string indices due # to the behavior of __getitem__ for strings. #98 raise JSONDecodeError('Expecting value', string, idx) try: return _scan_once(string, idx) finally: memo.clear() return scan_once make_scanner = c_make_scanner or py_make_scanner