feat(common/base)!: Implement parser for numeric ranges (#83)

cryptoparser/common/base.py

@@ -1044,3 +1044,52 @@ def compose(self):
     @classmethod
     def get_encoding(cls):
         return 'utf-8'
+
+
+@attr.s
+class NumericRangeParsableBase(ParsableBase, Serializable):
+    value = attr.ib(validator=attr.validators.instance_of(six.integer_types))
+
+    @value.validator
+    def _validator_variant(self, _, value):
+        if value < self._get_value_min():
+            raise InvalidValue(value, type(self))
+
+        if value > self._get_value_max():
+            raise InvalidValue(value, type(self))
+
+    @classmethod
+    @abc.abstractmethod
+    def _get_value_min(cls):
+        raise NotImplementedError()
+
+    @classmethod
+    @abc.abstractmethod
+    def _get_value_max(cls):
+        raise NotImplementedError()
+
+    @classmethod
+    @abc.abstractmethod
+    def _get_value_length(cls):
+        raise NotImplementedError()
+
+    @classmethod
+    def _parse(cls, parsable):
+        parser = ParserBinary(parsable)
+
+        parser.parse_numeric('value', cls._get_value_length())
+
+        return cls(**parser), parser.parsed_length
+
+    def compose(self):
+        composer = ComposerBinary()
+
+        composer.compose_numeric(self.value, self._get_value_length())
+
+        return composer.composed
+
+    def __str__(self):
+        return str(self.value)
+
+    def _as_markdown(self, level):
+        return self._markdown_result(str(self), level)

test/common/classes.py

@@ -31,6 +31,7 @@
     FourByteEnumParsable,
     ListParamParsable,
     ListParsable,
+    NumericRangeParsableBase,
     OneByteEnumComposer,
     OneByteEnumParsable,
     OpaqueEnumComposer,
@@ -789,3 +790,17 @@ def _get_pem_str(self, public_key_file_name):
 
     def _get_public_key_x509(self, public_key_file_name):
         return PublicKeyX509.from_pem(self._get_pem_str(public_key_file_name))
+
+
+class NumericRangeParsableTest(NumericRangeParsableBase):
+    @classmethod
+    def _get_value_min(cls):
+        return 0x01
+
+    @classmethod
+    def _get_value_max(cls):
+        return 0xfe
+
+    @classmethod
+    def _get_value_length(cls):
+        return 1

test/common/test_base.py

@@ -35,6 +35,7 @@
     FourByteEnumParsableTest,
     ListParsableTest,
     NByteEnumTest,
+    NumericRangeParsableTest,
     OneByteEnumComposerTest,
     OneByteEnumParsableTest,
     OneByteOddParsable,
@@ -868,3 +869,24 @@ def test_parse(self):
         parsable = bytearray(b'aaa')
         self.assertEqual(VariantParsableExactTest.parse_mutable(parsable), StringEnumAAA.AAA)
         self.assertEqual(parsable, b'')
+
+
+class TestNumericRangeParsable(unittest.TestCase):
+    def test_error(self):
+        with self.assertRaises(InvalidValue) as context_manager:
+            NumericRangeParsableTest.parse_exact_size(b'\x00')
+        self.assertEqual(context_manager.exception.value, 0x00)
+
+        with self.assertRaises(InvalidValue) as context_manager:
+            NumericRangeParsableTest.parse_exact_size(b'\xff')
+        self.assertEqual(context_manager.exception.value, 0xff)
+
+    def test_parse(self):
+        self.assertEqual(NumericRangeParsableTest.parse_exact_size(b'\x01'), NumericRangeParsableTest(1))
+        self.assertEqual(NumericRangeParsableTest(1).compose(), b'\x01')
+
+    def test_str(self):
+        self.assertEqual(str(NumericRangeParsableTest(1)), '1')
+
+    def test_as_markdown(self):
+        self.assertEqual(NumericRangeParsableTest(1).as_markdown(), '1')