code.kerkeslager.com Git - ton/blob - don/string.py

   1 import binascii
   2 import collections
   3 import functools
   4 import re
   5
   6 from don import tags, _shared
   7
   8 def _integer_size_to_string_serializer(integer_size):
   9     minimum = -(2 ** (integer_size - 1))
  10     maximum = 2 ** (integer_size - 1) - 1
  11
  12     def serializer(integer):
  13         assert minimum <= integer and integer <= maximum
  14         return '{}i{}'.format(integer, integer_size)
  15
  16     return serializer
  17
  18 def _serialize_float(f):
  19     return '{}f'.format(f)
  20
  21 def _serialize_double(d):
  22     return '{}d'.format(d)
  23
  24 def _serialize_binary(b):
  25     return '"{}"b'.format(binascii.hexlify(b).decode('ascii'))
  26
  27 def _utf_encoding_to_serializer(utf_encoding):
  28     def serializer(s):
  29         return '"{}"{}'.format(s, utf_encoding)
  30
  31     return serializer
  32
  33 def _string_serialize_list(l):
  34     return '[{}]'.format(', '.join(map(serialize, l)))
  35
  36 def _string_serialize_dictionary(d):
  37     def serialize_kvp(kvp):
  38         return serialize(kvp[0]) + ': ' + serialize(kvp[1])
  39     return '{ ' + ', '.join(map(serialize_kvp, d.items())) + ' }'
  40
  41 _STRING_SERIALIZERS = {
  42     tags.VOID: lambda o: 'null',
  43     tags.TRUE: lambda o: 'true',
  44     tags.FALSE: lambda o: 'false',
  45     tags.INT8: _integer_size_to_string_serializer(8),
  46     tags.INT16: _integer_size_to_string_serializer(16),
  47     tags.INT32: _integer_size_to_string_serializer(32),
  48     tags.INT64: _integer_size_to_string_serializer(64),
  49     tags.FLOAT: _serialize_float,
  50     tags.DOUBLE: _serialize_double,
  51     tags.BINARY: _serialize_binary,
  52     tags.UTF8: _utf_encoding_to_serializer('utf8'),
  53     tags.UTF16: _utf_encoding_to_serializer('utf16'),
  54     tags.UTF32: _utf_encoding_to_serializer('utf32'),
  55     tags.LIST: _string_serialize_list,
  56     tags.DICTIONARY: _string_serialize_dictionary,
  57 }
  58
  59 def serialize(o):
  60     o = tags._tag(o)
  61
  62     return _STRING_SERIALIZERS[o.tag](o.value)
  63
  64 def _consume_leading_whitespace(wrapped_parser):
  65     @functools.wraps(wrapped_parser)
  66     def parser(s):
  67         s = s.lstrip()
  68         return wrapped_parser(s)
  69
  70     return parser
  71
  72 def _make_constant_parser(constant, value):
  73     @_consume_leading_whitespace
  74     def constant_parser(s):
  75         if s.startswith(constant):
  76             result = _shared.ParseResult(
  77                 success = True,
  78                 value = value,
  79                 remaining = s[len(constant):],
  80             )
  81             return result
  82
  83         return _shared._FAILED_PARSE_RESULT
  84
  85     return constant_parser
  86
  87 def _make_integer_parser(width):
  88     matcher = re.compile(r'(-?\d+)i' + str(width))
  89
  90     @_consume_leading_whitespace
  91     def integer_parser(s):
  92         match = matcher.match(s)
  93
  94         if match:
  95             # TODO Validate that the integer is in range
  96             return _shared.ParseResult(
  97                 success = True,
  98                 value = int(match.group(1)),
  99                 remaining = s[match.end():],
 100             )
 101
 102         return _shared._FAILED_PARSE_RESULT
 103
 104     return integer_parser
 105
 106 _BINARY32_MATCHER = re.compile(r'(-?\d+\.\d+)f')
 107 _BINARY64_MATCHER = re.compile(r'(-?\d+\.\d+)d')
 108
 109 @_consume_leading_whitespace
 110 def _binary32_parser(s):
 111     match = _BINARY32_MATCHER.match(s)
 112
 113     if match:
 114         # TODO Validate that the float is in range
 115         return _shared.ParseResult(
 116             success = True,
 117             value = float(match.group(1)),
 118             remaining = s[match.end():],
 119         )
 120
 121     return _shared._FAILED_PARSE_RESULT
 122
 123 @_consume_leading_whitespace
 124 def _binary64_parser(s):
 125     match = _BINARY64_MATCHER.match(s)
 126
 127     if match:
 128         # TODO Validate that the double is in range
 129         return _shared.ParseResult(
 130             success = True,
 131             value = float(match.group(1)),
 132             remaining = s[match.end():],
 133         )
 134
 135     return _shared._FAILED_PARSE_RESULT
 136
 137 _BINARY_MATCHER = re.compile(r'"([\da-f]*)"b')
 138
 139 def _binary_parser(s):
 140     match = _BINARY_MATCHER.match(s)
 141
 142     if match:
 143         return _shared.ParseResult(
 144             success = True,
 145             value = binascii.unhexlify(match.group(1)),
 146             remaining = s[match.end():],
 147         )
 148
 149     return _shared._FAILED_PARSE_RESULT
 150
 151 def _make_utf_parser(encoding):
 152     matcher = re.compile(r'"(.*?)"' + encoding)
 153
 154     def parser(s):
 155         match = matcher.match(s)
 156
 157         if match:
 158             return _shared.ParseResult(
 159                 success = True,
 160                 value = match.group(1),
 161                 remaining = s[match.end():],
 162             )
 163
 164         return _shared._FAILED_PARSE_RESULT
 165
 166     return parser
 167
 168 def _prefix_with_comma(parser):
 169     def wrapped(s):
 170         if s.startswith(','):
 171             s = s[1:]
 172
 173             result = parser(s)
 174             if not result.success:
 175                 raise Exception('Trailing comma before "{}"'.format(s))
 176
 177             return result
 178
 179         return _shared._FAILED_PARSE_RESULT
 180
 181     return wrapped
 182
 183 def _comma_separate_and_wrap(wrapped_parser, start_wrap, end_wrap, typecaster):
 184     parser_prefixed_with_comma = _prefix_with_comma(wrapped_parser)
 185
 186     def parser(s):
 187         if s.startswith(start_wrap):
 188             s = s[1:]
 189         else:
 190             return _shared._FAILED_PARSE_RESULT
 191
 192         value = []
 193         first = True
 194
 195         parse_result = wrapped_parser(s)
 196
 197         while parse_result.success:
 198             value.append(parse_result.value)
 199             s = parse_result.remaining
 200             parse_result = parser_prefixed_with_comma(s)
 201
 202         if s.startswith(end_wrap):
 203             s = s[1:]
 204         else:
 205             return _shared._FAILED_PARSE_RESULT
 206
 207         return _shared.ParseResult(
 208             success = True,
 209             value = typecaster(value),
 210             remaining = s,
 211         )
 212
 213     return parser
 214
 215 # This uses _PARSERS which has not been defined yet, but is defined here so it can be used in
 216 # the definition of _list_parser
 217 def _object_parser(source):
 218     for parser in _PARSERS:
 219         result = parser(source)
 220
 221         if result.success:
 222             return result
 223
 224     return _shared._FAILED_PARSE_RESULT
 225
 226 _list_parser = _comma_separate_and_wrap(_object_parser, '[', ']', list)
 227
 228 def _kvp_parser(s):
 229     key_parse_result = _object_parser(s)
 230     if key_parse_result.success:
 231         s = key_parse_result.remaining
 232     else:
 233         return _shared._FAILED_PARSE_RESULT
 234
 235     if s.startswith(':'):
 236         s = s[1:]
 237     else:
 238         return _shared._FAILED_PARSE_RESULT
 239
 240     value_parse_result = _object_parser(s)
 241     if value_parse_result.success:
 242         s = value_parse_result.remaining
 243     else:
 244         return _shared._FAILED_PARSE_RESULT
 245
 246     return _shared.ParseResult(
 247         success = True,
 248         value = (key_parse_result.value, value_parse_result.value),
 249         remaining = s,
 250     )
 251
 252 _dictionary_parser = _comma_separate_and_wrap(_kvp_parser, '{', '}', collections.OrderedDict)
 253
 254
 255 _PARSERS = [
 256     _make_constant_parser('null', None),
 257     _make_constant_parser('true', True),
 258     _make_constant_parser('false', False),
 259     _make_integer_parser(8),
 260     _make_integer_parser(16),
 261     _make_integer_parser(32),
 262     _make_integer_parser(64),
 263     _binary32_parser,
 264     _binary64_parser,
 265     _binary_parser,
 266     _make_utf_parser('utf8'),
 267     _make_utf_parser('utf16'),
 268     _make_utf_parser('utf32'),
 269     _list_parser,
 270     _dictionary_parser,
 271 ]
 272
 273 def _parse(parser, source):
 274     result = parser(source)
 275
 276     if result.success:
 277         if result.remaining.strip() == '':
 278             return result.value
 279
 280         raise Exception('Unparsed trailing characters: "{}"'.format(result.remaining))
 281
 282     raise Exception('Unable to parse: "{}"'.format(source))
 283
 284 def deserialize(s):
 285     return _parse(_object_parser, s)