-import collections
-
-VOID = 0x00
-TRUE = 0x01
-FALSE = 0x02
-BOOL = (TRUE, FALSE)
-INT8 = 0x10
-INT16 = 0x11
-INT32 = 0x12
-INT64 = 0x13
-# These are to be supported in the future
-# FLOAT = 0x20
-# DOUBLE = 0x21
-BINARY = 0x30
-UTF8 = 0x31
-UTF16 = 0x32
-UTF32 = 0x33
-LIST = 0x40
-DICTIONARY = 0x41
-
-STRING_TAGS = set([UTF8, UTF16, UTF32])
-
-DEFAULT_INTEGER_ENCODING = INT32
-DEFAULT_STRING_ENCODING = UTF8
-
-TaggedObject = collections.namedtuple('TaggedObject', ['tag', 'value'])
-
-_TYPES_TO_TAGS = {
- int: DEFAULT_INTEGER_ENCODING,
- bytes: BINARY,
- str: DEFAULT_STRING_ENCODING,
- list: LIST,
- dict: DICTIONARY,
- collections.OrderedDict: DICTIONARY,
-}
-
-def _tag(o):
- if isinstance(o, TaggedObject):
- return o
-
- if o is None:
- return TaggedObject(tag = VOID, value = o)
-
- if o is True:
- return TaggedObject(tag = TRUE, value = o)
-
- if o is False:
- return TaggedObject(tag = FALSE, value = o)
-
- return TaggedObject(tag = _TYPES_TO_TAGS[type(o)], value = o)
-
-_NONE = TaggedObject(tag = VOID, value = None)
-_TRUE = TaggedObject(tag = TRUE, value = True)
-_FALSE = TaggedObject(tag = FALSE, value = False)
-
-_TAGS_TO_IN_RANGE_PREDICATES = collections.OrderedDict([
- (INT8, lambda i: -128 <= i and i <= 127),
- (INT16, lambda i: -32768 <= i and i <= 32767),
- (INT32, lambda i: -2147483648 <= i and i <= 2147483647),
- (INT64, lambda i: -9223372036854775808 <= i and i <= 9223372036854775807),
-])
-
-class TooWideError(Exception):
- pass
-
-SMALLEST = object()
-
-def autotag(o, **kwargs):
- preferred_integer_tag = kwargs.pop('preferred_integer_tag', DEFAULT_INTEGER_ENCODING)
- preferred_string_tag = kwargs.pop('preferred_string_tag', DEFAULT_STRING_ENCODING)
-
- if kwargs:
- raise TypeError("autotag() got an unexpected keyword argument '{}'".format(
- list(kwargs.keys())[0],
- ))
-
- if isinstance(o, TaggedObject):
- return o
-
- if o is None:
- return _NONE
-
- if o is True:
- return _TRUE
-
- if o is False:
- return _FALSE
-
- if isinstance(o, int):
- if preferred_integer_tag is not SMALLEST and _TAGS_TO_IN_RANGE_PREDICATES[preferred_integer_tag](o):
- return TaggedObject(tag = preferred_integer_tag, value = o)
-
- else:
- for tag, in_range_predicate in _TAGS_TO_IN_RANGE_PREDICATES.items():
- if in_range_predicate(o):
- return TaggedObject(tag = tag, value = o)
-
- raise TooWideError("Integer {} is too wide to be serialized")
-
- if isinstance(o, str):
- # TODO Support SMALLEST for preferred string tag
- return TaggedObject(tag = preferred_string_tag, value = o)
-
- if isinstance(o, bytes):
- return TaggedObject(tag = BINARY, value = o)
-
- if isinstance(o, list):
- return TaggedObject(
- tag = LIST,
- value = [
- autotag(
- i,
- preferred_integer_tag = preferred_integer_tag,
- preferred_string_tag = preferred_string_tag,
- ) for i in o
- ],
- )
-
- if isinstance(o, dict):
- return TaggedObject(
- tag = DICTIONARY,
- value = collections.OrderedDict([
- (
- autotag(
- key,
- preferred_integer_tag = preferred_integer_tag,
- preferred_string_tag = preferred_string_tag,
- ),
- autotag(
- value,
- preferred_integer_tag = preferred_integer_tag,
- preferred_string_tag = preferred_string_tag,
- ),
- ) for key, value in o.items()
- ]),
- )
-
- raise Exception('Unsupported type {}'.format(type(o)))