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 @_consume_leading_whitespace
 140 def _binary_parser(s):
 141     match = _BINARY_MATCHER.match(s)
 142
 143     if match:
 144         return _shared.ParseResult(
 145             success = True,
 146             value = binascii.unhexlify(match.group(1)),
 147             remaining = s[match.end():],
 148         )
 149
 150     return _shared._FAILED_PARSE_RESULT
 151
 152 def _make_utf_parser(encoding):
 153     matcher = re.compile(r'"(.*?)"' + encoding)
 154
 155     @_consume_leading_whitespace
 156     def utf_parser(s):
 157         match = matcher.match(s)
 158
 159         if match:
 160             return _shared.ParseResult(
 161                 success = True,
 162                 value = match.group(1),
 163                 remaining = s[match.end():],
 164             )
 165
 166         return _shared._FAILED_PARSE_RESULT
 167
 168     return utf_parser
 169
 170 def _make_consume_constant_parser(constant):
 171     def consume_character_parser(s):
 172         if s.startswith(constant):
 173             return _shared.ParseResult(
 174                 success = True,
 175                 value = None,
 176                 remaining = s[len(constant):],
 177             )
 178         return _shared._FAILED_PARSE_RESULT
 179
 180     return consume_character_parser
 181
 182 _consume_comma_parser = _make_consume_constant_parser(',')
 183
 184 def _prefix_with_comma(parser):
 185     def wrapped(s):
 186         result = _consume_comma_parser(s)
 187         if result.success:
 188             s = result.remaining
 189         else:
 190             return _shared._FAILED_PARSE_RESULT
 191
 192         result = parser(s)
 193         if not result.success:
 194             raise Exception('Trailing comma before "{}"'.format(s))
 195
 196         return result
 197
 198     return wrapped
 199
 200 def _comma_separate_and_wrap(wrapped_parser, start_wrap, end_wrap, typecaster):
 201     parser_prefixed_with_comma = _prefix_with_comma(wrapped_parser)
 202     start_wrap_parser = _make_consume_constant_parser(start_wrap)
 203     end_wrap_parser = _make_consume_constant_parser(end_wrap)
 204
 205     def parser(s):
 206         result = start_wrap_parser(s)
 207         if result.success:
 208             s = result.remaining
 209         else:
 210             return _shared._FAILED_PARSE_RESULT
 211
 212         value = []
 213         first = True
 214
 215         parse_result = wrapped_parser(s)
 216
 217         while parse_result.success:
 218             value.append(parse_result.value)
 219             s = parse_result.remaining
 220             parse_result = parser_prefixed_with_comma(s)
 221
 222         result = end_wrap_parser(s)
 223         if result.success:
 224             s = result.remaining
 225         else:
 226             return _shared._FAILED_PARSE_RESULT
 227
 228         return _shared.ParseResult(
 229             success = True,
 230             value = typecaster(value),
 231             remaining = s,
 232         )
 233
 234     return parser
 235
 236 # This uses _PARSERS which has not been defined yet, but is defined here so it can be used in
 237 # the definition of _list_parser
 238 def _object_parser(source):
 239     for parser in _PARSERS:
 240         result = parser(source)
 241
 242         if result.success:
 243             return result
 244
 245     return _shared._FAILED_PARSE_RESULT
 246
 247 _list_parser = _comma_separate_and_wrap(_object_parser, '[', ']', list)
 248
 249 _consume_colon_parser = _make_consume_constant_parser(':')
 250
 251 def _kvp_parser(s):
 252     key_parse_result = _object_parser(s)
 253     if key_parse_result.success:
 254         s = key_parse_result.remaining
 255     else:
 256         return _shared._FAILED_PARSE_RESULT
 257
 258     result = _consume_colon_parser(s)
 259     if result.success:
 260         s = result.remaining
 261     else:
 262         return _shared._FAILED_PARSE_RESULT
 263
 264     value_parse_result = _object_parser(s)
 265     if value_parse_result.success:
 266         s = value_parse_result.remaining
 267     else:
 268         return _shared._FAILED_PARSE_RESULT
 269
 270     return _shared.ParseResult(
 271         success = True,
 272         value = (key_parse_result.value, value_parse_result.value),
 273         remaining = s,
 274     )
 275
 276 _dictionary_parser = _comma_separate_and_wrap(_kvp_parser, '{', '}', collections.OrderedDict)
 277
 278
 279 _PARSERS = [
 280     _make_constant_parser('null', None),
 281     _make_constant_parser('true', True),
 282     _make_constant_parser('false', False),
 283     _make_integer_parser(8),
 284     _make_integer_parser(16),
 285     _make_integer_parser(32),
 286     _make_integer_parser(64),
 287     _binary32_parser,
 288     _binary64_parser,
 289     _binary_parser,
 290     _make_utf_parser('utf8'),
 291     _make_utf_parser('utf16'),
 292     _make_utf_parser('utf32'),
 293     _list_parser,
 294     _dictionary_parser,
 295 ]
 296
 297 def _parse(parser, source):
 298     result = parser(source)
 299
 300     if result.success:
 301         if result.remaining.strip() == '':
 302             return result.value
 303
 304         raise Exception('Unparsed trailing characters: "{}"'.format(result.remaining))
 305
 306     raise Exception('Unable to parse: "{}"'.format(source))
 307
 308 def deserialize(s):
 309     return _parse(_object_parser, s)