third_party/google/protobuf/internal/type_checkers.py - depot_tools - Git at Google

 # Protocol Buffers - Google's data interchange format
 # Copyright 2008 Google Inc.  All rights reserved.
 # http://code.google.com/p/protobuf/
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
 # in the documentation and/or other materials provided with the
 # distribution.
 #     * Neither the name of Google Inc. nor the names of its
 # contributors may be used to endorse or promote products derived from
 # this software without specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 #PY25 compatible for GAE.
 #
 # Copyright 2008 Google Inc. All Rights Reserved.

 """Provides type checking routines.

 This module defines type checking utilities in the forms of dictionaries:

 VALUE_CHECKERS: A dictionary of field types and a value validation object.
 TYPE_TO_BYTE_SIZE_FN: A dictionary with field types and a size computing
   function.
 TYPE_TO_SERIALIZE_METHOD: A dictionary with field types and serialization
   function.
 FIELD_TYPE_TO_WIRE_TYPE: A dictionary with field typed and their
   coresponding wire types.
 TYPE_TO_DESERIALIZE_METHOD: A dictionary with field types and deserialization
   function.
 """

 __author__ = 'robinson@google.com (Will Robinson)'

 import sys  ##PY25
 if sys.version < '2.6': bytes = str  ##PY25
 from google.protobuf.internal import api_implementation
 from google.protobuf.internal import decoder
 from google.protobuf.internal import encoder
 from google.protobuf.internal import wire_format
 from google.protobuf import descriptor

 _FieldDescriptor = descriptor.FieldDescriptor


 def GetTypeChecker(field):
   """Returns a type checker for a message field of the specified types.

   Args:
     field: FieldDescriptor object for this field.

   Returns:
     An instance of TypeChecker which can be used to verify the types
     of values assigned to a field of the specified type.
   """
   if (field.cpp_type == _FieldDescriptor.CPPTYPE_STRING and
       field.type == _FieldDescriptor.TYPE_STRING):
     return UnicodeValueChecker()
   if field.cpp_type == _FieldDescriptor.CPPTYPE_ENUM:
     return EnumValueChecker(field.enum_type)
   return _VALUE_CHECKERS[field.cpp_type]


 # None of the typecheckers below make any attempt to guard against people
 # subclassing builtin types and doing weird things.  We're not trying to
 # protect against malicious clients here, just people accidentally shooting
 # themselves in the foot in obvious ways.

 class TypeChecker(object):

   """Type checker used to catch type errors as early as possible
   when the client is setting scalar fields in protocol messages.
   """

   def __init__(self, *acceptable_types):
     self._acceptable_types = acceptable_types

   def CheckValue(self, proposed_value):
     """Type check the provided value and return it.

     The returned value might have been normalized to another type.
     """
     if not isinstance(proposed_value, self._acceptable_types):
       message = ('%.1024r has type %s, but expected one of: %s' %
                  (proposed_value, type(proposed_value), self._acceptable_types))
       raise TypeError(message)
     return proposed_value


 # IntValueChecker and its subclasses perform integer type-checks
 # and bounds-checks.
 class IntValueChecker(object):

   """Checker used for integer fields.  Performs type-check and range check."""

   def CheckValue(self, proposed_value):
     if not isinstance(proposed_value, (int, long)):
       message = ('%.1024r has type %s, but expected one of: %s' %
                  (proposed_value, type(proposed_value), (int, long)))
       raise TypeError(message)
     if not self._MIN <= proposed_value <= self._MAX:
       raise ValueError('Value out of range: %d' % proposed_value)
     # We force 32-bit values to int and 64-bit values to long to make
     # alternate implementations where the distinction is more significant
     # (e.g. the C++ implementation) simpler.
     proposed_value = self._TYPE(proposed_value)
     return proposed_value


 class EnumValueChecker(object):

   """Checker used for enum fields.  Performs type-check and range check."""

   def __init__(self, enum_type):
     self._enum_type = enum_type

   def CheckValue(self, proposed_value):
     if not isinstance(proposed_value, (int, long)):
       message = ('%.1024r has type %s, but expected one of: %s' %
                  (proposed_value, type(proposed_value), (int, long)))
       raise TypeError(message)
     if proposed_value not in self._enum_type.values_by_number:
       raise ValueError('Unknown enum value: %d' % proposed_value)
     return proposed_value


 class UnicodeValueChecker(object):

   """Checker used for string fields.

   Always returns a unicode value, even if the input is of type str.
   """

   def CheckValue(self, proposed_value):
     if not isinstance(proposed_value, (bytes, unicode)):
       message = ('%.1024r has type %s, but expected one of: %s' %
                  (proposed_value, type(proposed_value), (bytes, unicode)))
       raise TypeError(message)

     # If the value is of type 'bytes' make sure that it is in 7-bit ASCII
     # encoding.
     if isinstance(proposed_value, bytes):
       try:
         proposed_value = proposed_value.decode('ascii')
       except UnicodeDecodeError:
         raise ValueError('%.1024r has type bytes, but isn\'t in 7-bit ASCII '
                          'encoding. Non-ASCII strings must be converted to '
                          'unicode objects before being added.' %
                          (proposed_value))
     return proposed_value


 class Int32ValueChecker(IntValueChecker):
   # We're sure to use ints instead of longs here since comparison may be more
   # efficient.
   _MIN = -2147483648
   _MAX = 2147483647
   _TYPE = int


 class Uint32ValueChecker(IntValueChecker):
   _MIN = 0
   _MAX = (1 << 32) - 1
   _TYPE = int


 class Int64ValueChecker(IntValueChecker):
   _MIN = -(1 << 63)
   _MAX = (1 << 63) - 1
   _TYPE = long


 class Uint64ValueChecker(IntValueChecker):
   _MIN = 0
   _MAX = (1 << 64) - 1
   _TYPE = long


 # Type-checkers for all scalar CPPTYPEs.
 _VALUE_CHECKERS = {
     _FieldDescriptor.CPPTYPE_INT32: Int32ValueChecker(),
     _FieldDescriptor.CPPTYPE_INT64: Int64ValueChecker(),
     _FieldDescriptor.CPPTYPE_UINT32: Uint32ValueChecker(),
     _FieldDescriptor.CPPTYPE_UINT64: Uint64ValueChecker(),
     _FieldDescriptor.CPPTYPE_DOUBLE: TypeChecker(
         float, int, long),
     _FieldDescriptor.CPPTYPE_FLOAT: TypeChecker(
         float, int, long),
     _FieldDescriptor.CPPTYPE_BOOL: TypeChecker(bool, int),
     _FieldDescriptor.CPPTYPE_STRING: TypeChecker(bytes),
     }


 # Map from field type to a function F, such that F(field_num, value)
 # gives the total byte size for a value of the given type.  This
 # byte size includes tag information and any other additional space
 # associated with serializing "value".
 TYPE_TO_BYTE_SIZE_FN = {
     _FieldDescriptor.TYPE_DOUBLE: wire_format.DoubleByteSize,
     _FieldDescriptor.TYPE_FLOAT: wire_format.FloatByteSize,
     _FieldDescriptor.TYPE_INT64: wire_format.Int64ByteSize,
     _FieldDescriptor.TYPE_UINT64: wire_format.UInt64ByteSize,
     _FieldDescriptor.TYPE_INT32: wire_format.Int32ByteSize,
     _FieldDescriptor.TYPE_FIXED64: wire_format.Fixed64ByteSize,
     _FieldDescriptor.TYPE_FIXED32: wire_format.Fixed32ByteSize,
     _FieldDescriptor.TYPE_BOOL: wire_format.BoolByteSize,
     _FieldDescriptor.TYPE_STRING: wire_format.StringByteSize,
     _FieldDescriptor.TYPE_GROUP: wire_format.GroupByteSize,
     _FieldDescriptor.TYPE_MESSAGE: wire_format.MessageByteSize,
     _FieldDescriptor.TYPE_BYTES: wire_format.BytesByteSize,
     _FieldDescriptor.TYPE_UINT32: wire_format.UInt32ByteSize,
     _FieldDescriptor.TYPE_ENUM: wire_format.EnumByteSize,
     _FieldDescriptor.TYPE_SFIXED32: wire_format.SFixed32ByteSize,
     _FieldDescriptor.TYPE_SFIXED64: wire_format.SFixed64ByteSize,
     _FieldDescriptor.TYPE_SINT32: wire_format.SInt32ByteSize,
     _FieldDescriptor.TYPE_SINT64: wire_format.SInt64ByteSize
     }


 # Maps from field types to encoder constructors.
 TYPE_TO_ENCODER = {
     _FieldDescriptor.TYPE_DOUBLE: encoder.DoubleEncoder,
     _FieldDescriptor.TYPE_FLOAT: encoder.FloatEncoder,
     _FieldDescriptor.TYPE_INT64: encoder.Int64Encoder,
     _FieldDescriptor.TYPE_UINT64: encoder.UInt64Encoder,
     _FieldDescriptor.TYPE_INT32: encoder.Int32Encoder,
     _FieldDescriptor.TYPE_FIXED64: encoder.Fixed64Encoder,
     _FieldDescriptor.TYPE_FIXED32: encoder.Fixed32Encoder,
     _FieldDescriptor.TYPE_BOOL: encoder.BoolEncoder,
     _FieldDescriptor.TYPE_STRING: encoder.StringEncoder,
     _FieldDescriptor.TYPE_GROUP: encoder.GroupEncoder,
     _FieldDescriptor.TYPE_MESSAGE: encoder.MessageEncoder,
     _FieldDescriptor.TYPE_BYTES: encoder.BytesEncoder,
     _FieldDescriptor.TYPE_UINT32: encoder.UInt32Encoder,
     _FieldDescriptor.TYPE_ENUM: encoder.EnumEncoder,
     _FieldDescriptor.TYPE_SFIXED32: encoder.SFixed32Encoder,
     _FieldDescriptor.TYPE_SFIXED64: encoder.SFixed64Encoder,
     _FieldDescriptor.TYPE_SINT32: encoder.SInt32Encoder,
     _FieldDescriptor.TYPE_SINT64: encoder.SInt64Encoder,
     }


 # Maps from field types to sizer constructors.
 TYPE_TO_SIZER = {
     _FieldDescriptor.TYPE_DOUBLE: encoder.DoubleSizer,
     _FieldDescriptor.TYPE_FLOAT: encoder.FloatSizer,
     _FieldDescriptor.TYPE_INT64: encoder.Int64Sizer,
     _FieldDescriptor.TYPE_UINT64: encoder.UInt64Sizer,
     _FieldDescriptor.TYPE_INT32: encoder.Int32Sizer,
     _FieldDescriptor.TYPE_FIXED64: encoder.Fixed64Sizer,
     _FieldDescriptor.TYPE_FIXED32: encoder.Fixed32Sizer,
     _FieldDescriptor.TYPE_BOOL: encoder.BoolSizer,
     _FieldDescriptor.TYPE_STRING: encoder.StringSizer,
     _FieldDescriptor.TYPE_GROUP: encoder.GroupSizer,
     _FieldDescriptor.TYPE_MESSAGE: encoder.MessageSizer,
     _FieldDescriptor.TYPE_BYTES: encoder.BytesSizer,
     _FieldDescriptor.TYPE_UINT32: encoder.UInt32Sizer,
     _FieldDescriptor.TYPE_ENUM: encoder.EnumSizer,
     _FieldDescriptor.TYPE_SFIXED32: encoder.SFixed32Sizer,
     _FieldDescriptor.TYPE_SFIXED64: encoder.SFixed64Sizer,
     _FieldDescriptor.TYPE_SINT32: encoder.SInt32Sizer,
     _FieldDescriptor.TYPE_SINT64: encoder.SInt64Sizer,
     }


 # Maps from field type to a decoder constructor.
 TYPE_TO_DECODER = {
     _FieldDescriptor.TYPE_DOUBLE: decoder.DoubleDecoder,
     _FieldDescriptor.TYPE_FLOAT: decoder.FloatDecoder,
     _FieldDescriptor.TYPE_INT64: decoder.Int64Decoder,
     _FieldDescriptor.TYPE_UINT64: decoder.UInt64Decoder,
     _FieldDescriptor.TYPE_INT32: decoder.Int32Decoder,
     _FieldDescriptor.TYPE_FIXED64: decoder.Fixed64Decoder,
     _FieldDescriptor.TYPE_FIXED32: decoder.Fixed32Decoder,
     _FieldDescriptor.TYPE_BOOL: decoder.BoolDecoder,
     _FieldDescriptor.TYPE_STRING: decoder.StringDecoder,
     _FieldDescriptor.TYPE_GROUP: decoder.GroupDecoder,
     _FieldDescriptor.TYPE_MESSAGE: decoder.MessageDecoder,
     _FieldDescriptor.TYPE_BYTES: decoder.BytesDecoder,
     _FieldDescriptor.TYPE_UINT32: decoder.UInt32Decoder,
     _FieldDescriptor.TYPE_ENUM: decoder.EnumDecoder,
     _FieldDescriptor.TYPE_SFIXED32: decoder.SFixed32Decoder,
     _FieldDescriptor.TYPE_SFIXED64: decoder.SFixed64Decoder,
     _FieldDescriptor.TYPE_SINT32: decoder.SInt32Decoder,
     _FieldDescriptor.TYPE_SINT64: decoder.SInt64Decoder,
     }

 # Maps from field type to expected wiretype.
 FIELD_TYPE_TO_WIRE_TYPE = {
     _FieldDescriptor.TYPE_DOUBLE: wire_format.WIRETYPE_FIXED64,
     _FieldDescriptor.TYPE_FLOAT: wire_format.WIRETYPE_FIXED32,
     _FieldDescriptor.TYPE_INT64: wire_format.WIRETYPE_VARINT,
     _FieldDescriptor.TYPE_UINT64: wire_format.WIRETYPE_VARINT,
     _FieldDescriptor.TYPE_INT32: wire_format.WIRETYPE_VARINT,
     _FieldDescriptor.TYPE_FIXED64: wire_format.WIRETYPE_FIXED64,
     _FieldDescriptor.TYPE_FIXED32: wire_format.WIRETYPE_FIXED32,
     _FieldDescriptor.TYPE_BOOL: wire_format.WIRETYPE_VARINT,
     _FieldDescriptor.TYPE_STRING:
       wire_format.WIRETYPE_LENGTH_DELIMITED,
     _FieldDescriptor.TYPE_GROUP: wire_format.WIRETYPE_START_GROUP,
     _FieldDescriptor.TYPE_MESSAGE:
       wire_format.WIRETYPE_LENGTH_DELIMITED,
     _FieldDescriptor.TYPE_BYTES:
       wire_format.WIRETYPE_LENGTH_DELIMITED,
     _FieldDescriptor.TYPE_UINT32: wire_format.WIRETYPE_VARINT,
     _FieldDescriptor.TYPE_ENUM: wire_format.WIRETYPE_VARINT,
     _FieldDescriptor.TYPE_SFIXED32: wire_format.WIRETYPE_FIXED32,
     _FieldDescriptor.TYPE_SFIXED64: wire_format.WIRETYPE_FIXED64,
     _FieldDescriptor.TYPE_SINT32: wire_format.WIRETYPE_VARINT,
     _FieldDescriptor.TYPE_SINT64: wire_format.WIRETYPE_VARINT,
     }
	# Protocol Buffers - Google's data interchange format
	# Copyright 2008 Google Inc. All rights reserved.
	# http://code.google.com/p/protobuf/
	#
	# Redistribution and use in source and binary forms, with or without
	# modification, are permitted provided that the following conditions are
	# met:
	#
	# * Redistributions of source code must retain the above copyright
	# notice, this list of conditions and the following disclaimer.
	# * Redistributions in binary form must reproduce the above
	# copyright notice, this list of conditions and the following disclaimer
	# in the documentation and/or other materials provided with the
	# distribution.
	# * Neither the name of Google Inc. nor the names of its
	# contributors may be used to endorse or promote products derived from
	# this software without specific prior written permission.
	#
	# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	#PY25 compatible for GAE.
	#
	# Copyright 2008 Google Inc. All Rights Reserved.

	"""Provides type checking routines.

	This module defines type checking utilities in the forms of dictionaries:

	VALUE_CHECKERS: A dictionary of field types and a value validation object.
	TYPE_TO_BYTE_SIZE_FN: A dictionary with field types and a size computing
	function.
	TYPE_TO_SERIALIZE_METHOD: A dictionary with field types and serialization
	function.
	FIELD_TYPE_TO_WIRE_TYPE: A dictionary with field typed and their
	coresponding wire types.
	TYPE_TO_DESERIALIZE_METHOD: A dictionary with field types and deserialization
	function.
	"""

	__author__ = 'robinson@google.com (Will Robinson)'

	import sys ##PY25
	if sys.version < '2.6': bytes = str ##PY25
	from google.protobuf.internal import api_implementation
	from google.protobuf.internal import decoder
	from google.protobuf.internal import encoder
	from google.protobuf.internal import wire_format
	from google.protobuf import descriptor

	_FieldDescriptor = descriptor.FieldDescriptor


	def GetTypeChecker(field):
	"""Returns a type checker for a message field of the specified types.

	Args:
	field: FieldDescriptor object for this field.

	Returns:
	An instance of TypeChecker which can be used to verify the types
	of values assigned to a field of the specified type.
	"""
	if (field.cpp_type == _FieldDescriptor.CPPTYPE_STRING and
	field.type == _FieldDescriptor.TYPE_STRING):
	return UnicodeValueChecker()
	if field.cpp_type == _FieldDescriptor.CPPTYPE_ENUM:
	return EnumValueChecker(field.enum_type)
	return _VALUE_CHECKERS[field.cpp_type]


	# None of the typecheckers below make any attempt to guard against people
	# subclassing builtin types and doing weird things. We're not trying to
	# protect against malicious clients here, just people accidentally shooting
	# themselves in the foot in obvious ways.

	class TypeChecker(object):

	"""Type checker used to catch type errors as early as possible
	when the client is setting scalar fields in protocol messages.
	"""

	def __init__(self, *acceptable_types):
	self._acceptable_types = acceptable_types

	def CheckValue(self, proposed_value):
	"""Type check the provided value and return it.

	The returned value might have been normalized to another type.
	"""
	if not isinstance(proposed_value, self._acceptable_types):
	message = ('%.1024r has type %s, but expected one of: %s' %
	(proposed_value, type(proposed_value), self._acceptable_types))
	raise TypeError(message)
	return proposed_value


	# IntValueChecker and its subclasses perform integer type-checks
	# and bounds-checks.
	class IntValueChecker(object):

	"""Checker used for integer fields. Performs type-check and range check."""

	def CheckValue(self, proposed_value):
	if not isinstance(proposed_value, (int, long)):
	message = ('%.1024r has type %s, but expected one of: %s' %
	(proposed_value, type(proposed_value), (int, long)))
	raise TypeError(message)
	if not self._MIN <= proposed_value <= self._MAX:
	raise ValueError('Value out of range: %d' % proposed_value)
	# We force 32-bit values to int and 64-bit values to long to make
	# alternate implementations where the distinction is more significant
	# (e.g. the C++ implementation) simpler.
	proposed_value = self._TYPE(proposed_value)
	return proposed_value


	class EnumValueChecker(object):

	"""Checker used for enum fields. Performs type-check and range check."""

	def __init__(self, enum_type):
	self._enum_type = enum_type

	def CheckValue(self, proposed_value):
	if not isinstance(proposed_value, (int, long)):
	message = ('%.1024r has type %s, but expected one of: %s' %
	(proposed_value, type(proposed_value), (int, long)))
	raise TypeError(message)
	if proposed_value not in self._enum_type.values_by_number:
	raise ValueError('Unknown enum value: %d' % proposed_value)
	return proposed_value


	class UnicodeValueChecker(object):

	"""Checker used for string fields.

	Always returns a unicode value, even if the input is of type str.
	"""

	def CheckValue(self, proposed_value):
	if not isinstance(proposed_value, (bytes, unicode)):
	message = ('%.1024r has type %s, but expected one of: %s' %
	(proposed_value, type(proposed_value), (bytes, unicode)))
	raise TypeError(message)

	# If the value is of type 'bytes' make sure that it is in 7-bit ASCII
	# encoding.
	if isinstance(proposed_value, bytes):
	try:
	proposed_value = proposed_value.decode('ascii')
	except UnicodeDecodeError:
	raise ValueError('%.1024r has type bytes, but isn\'t in 7-bit ASCII '
	'encoding. Non-ASCII strings must be converted to '
	'unicode objects before being added.' %
	(proposed_value))
	return proposed_value


	class Int32ValueChecker(IntValueChecker):
	# We're sure to use ints instead of longs here since comparison may be more
	# efficient.
	_MIN = -2147483648
	_MAX = 2147483647
	_TYPE = int


	class Uint32ValueChecker(IntValueChecker):
	_MIN = 0
	_MAX = (1 << 32) - 1
	_TYPE = int


	class Int64ValueChecker(IntValueChecker):
	_MIN = -(1 << 63)
	_MAX = (1 << 63) - 1
	_TYPE = long


	class Uint64ValueChecker(IntValueChecker):
	_MIN = 0
	_MAX = (1 << 64) - 1
	_TYPE = long


	# Type-checkers for all scalar CPPTYPEs.
	_VALUE_CHECKERS = {
	_FieldDescriptor.CPPTYPE_INT32: Int32ValueChecker(),
	_FieldDescriptor.CPPTYPE_INT64: Int64ValueChecker(),
	_FieldDescriptor.CPPTYPE_UINT32: Uint32ValueChecker(),
	_FieldDescriptor.CPPTYPE_UINT64: Uint64ValueChecker(),
	_FieldDescriptor.CPPTYPE_DOUBLE: TypeChecker(
	float, int, long),
	_FieldDescriptor.CPPTYPE_FLOAT: TypeChecker(
	float, int, long),
	_FieldDescriptor.CPPTYPE_BOOL: TypeChecker(bool, int),
	_FieldDescriptor.CPPTYPE_STRING: TypeChecker(bytes),
	}


	# Map from field type to a function F, such that F(field_num, value)
	# gives the total byte size for a value of the given type. This
	# byte size includes tag information and any other additional space
	# associated with serializing "value".
	TYPE_TO_BYTE_SIZE_FN = {
	_FieldDescriptor.TYPE_DOUBLE: wire_format.DoubleByteSize,
	_FieldDescriptor.TYPE_FLOAT: wire_format.FloatByteSize,
	_FieldDescriptor.TYPE_INT64: wire_format.Int64ByteSize,
	_FieldDescriptor.TYPE_UINT64: wire_format.UInt64ByteSize,
	_FieldDescriptor.TYPE_INT32: wire_format.Int32ByteSize,
	_FieldDescriptor.TYPE_FIXED64: wire_format.Fixed64ByteSize,
	_FieldDescriptor.TYPE_FIXED32: wire_format.Fixed32ByteSize,
	_FieldDescriptor.TYPE_BOOL: wire_format.BoolByteSize,
	_FieldDescriptor.TYPE_STRING: wire_format.StringByteSize,
	_FieldDescriptor.TYPE_GROUP: wire_format.GroupByteSize,
	_FieldDescriptor.TYPE_MESSAGE: wire_format.MessageByteSize,
	_FieldDescriptor.TYPE_BYTES: wire_format.BytesByteSize,
	_FieldDescriptor.TYPE_UINT32: wire_format.UInt32ByteSize,
	_FieldDescriptor.TYPE_ENUM: wire_format.EnumByteSize,
	_FieldDescriptor.TYPE_SFIXED32: wire_format.SFixed32ByteSize,
	_FieldDescriptor.TYPE_SFIXED64: wire_format.SFixed64ByteSize,
	_FieldDescriptor.TYPE_SINT32: wire_format.SInt32ByteSize,
	_FieldDescriptor.TYPE_SINT64: wire_format.SInt64ByteSize
	}


	# Maps from field types to encoder constructors.
	TYPE_TO_ENCODER = {
	_FieldDescriptor.TYPE_DOUBLE: encoder.DoubleEncoder,
	_FieldDescriptor.TYPE_FLOAT: encoder.FloatEncoder,
	_FieldDescriptor.TYPE_INT64: encoder.Int64Encoder,
	_FieldDescriptor.TYPE_UINT64: encoder.UInt64Encoder,
	_FieldDescriptor.TYPE_INT32: encoder.Int32Encoder,
	_FieldDescriptor.TYPE_FIXED64: encoder.Fixed64Encoder,
	_FieldDescriptor.TYPE_FIXED32: encoder.Fixed32Encoder,
	_FieldDescriptor.TYPE_BOOL: encoder.BoolEncoder,
	_FieldDescriptor.TYPE_STRING: encoder.StringEncoder,
	_FieldDescriptor.TYPE_GROUP: encoder.GroupEncoder,
	_FieldDescriptor.TYPE_MESSAGE: encoder.MessageEncoder,
	_FieldDescriptor.TYPE_BYTES: encoder.BytesEncoder,
	_FieldDescriptor.TYPE_UINT32: encoder.UInt32Encoder,
	_FieldDescriptor.TYPE_ENUM: encoder.EnumEncoder,
	_FieldDescriptor.TYPE_SFIXED32: encoder.SFixed32Encoder,
	_FieldDescriptor.TYPE_SFIXED64: encoder.SFixed64Encoder,
	_FieldDescriptor.TYPE_SINT32: encoder.SInt32Encoder,
	_FieldDescriptor.TYPE_SINT64: encoder.SInt64Encoder,
	}


	# Maps from field types to sizer constructors.
	TYPE_TO_SIZER = {
	_FieldDescriptor.TYPE_DOUBLE: encoder.DoubleSizer,
	_FieldDescriptor.TYPE_FLOAT: encoder.FloatSizer,
	_FieldDescriptor.TYPE_INT64: encoder.Int64Sizer,
	_FieldDescriptor.TYPE_UINT64: encoder.UInt64Sizer,
	_FieldDescriptor.TYPE_INT32: encoder.Int32Sizer,
	_FieldDescriptor.TYPE_FIXED64: encoder.Fixed64Sizer,
	_FieldDescriptor.TYPE_FIXED32: encoder.Fixed32Sizer,
	_FieldDescriptor.TYPE_BOOL: encoder.BoolSizer,
	_FieldDescriptor.TYPE_STRING: encoder.StringSizer,
	_FieldDescriptor.TYPE_GROUP: encoder.GroupSizer,
	_FieldDescriptor.TYPE_MESSAGE: encoder.MessageSizer,
	_FieldDescriptor.TYPE_BYTES: encoder.BytesSizer,
	_FieldDescriptor.TYPE_UINT32: encoder.UInt32Sizer,
	_FieldDescriptor.TYPE_ENUM: encoder.EnumSizer,
	_FieldDescriptor.TYPE_SFIXED32: encoder.SFixed32Sizer,
	_FieldDescriptor.TYPE_SFIXED64: encoder.SFixed64Sizer,
	_FieldDescriptor.TYPE_SINT32: encoder.SInt32Sizer,
	_FieldDescriptor.TYPE_SINT64: encoder.SInt64Sizer,
	}


	# Maps from field type to a decoder constructor.
	TYPE_TO_DECODER = {
	_FieldDescriptor.TYPE_DOUBLE: decoder.DoubleDecoder,
	_FieldDescriptor.TYPE_FLOAT: decoder.FloatDecoder,
	_FieldDescriptor.TYPE_INT64: decoder.Int64Decoder,
	_FieldDescriptor.TYPE_UINT64: decoder.UInt64Decoder,
	_FieldDescriptor.TYPE_INT32: decoder.Int32Decoder,
	_FieldDescriptor.TYPE_FIXED64: decoder.Fixed64Decoder,
	_FieldDescriptor.TYPE_FIXED32: decoder.Fixed32Decoder,
	_FieldDescriptor.TYPE_BOOL: decoder.BoolDecoder,
	_FieldDescriptor.TYPE_STRING: decoder.StringDecoder,
	_FieldDescriptor.TYPE_GROUP: decoder.GroupDecoder,
	_FieldDescriptor.TYPE_MESSAGE: decoder.MessageDecoder,
	_FieldDescriptor.TYPE_BYTES: decoder.BytesDecoder,
	_FieldDescriptor.TYPE_UINT32: decoder.UInt32Decoder,
	_FieldDescriptor.TYPE_ENUM: decoder.EnumDecoder,
	_FieldDescriptor.TYPE_SFIXED32: decoder.SFixed32Decoder,
	_FieldDescriptor.TYPE_SFIXED64: decoder.SFixed64Decoder,
	_FieldDescriptor.TYPE_SINT32: decoder.SInt32Decoder,
	_FieldDescriptor.TYPE_SINT64: decoder.SInt64Decoder,
	}

	# Maps from field type to expected wiretype.
	FIELD_TYPE_TO_WIRE_TYPE = {
	_FieldDescriptor.TYPE_DOUBLE: wire_format.WIRETYPE_FIXED64,
	_FieldDescriptor.TYPE_FLOAT: wire_format.WIRETYPE_FIXED32,
	_FieldDescriptor.TYPE_INT64: wire_format.WIRETYPE_VARINT,
	_FieldDescriptor.TYPE_UINT64: wire_format.WIRETYPE_VARINT,
	_FieldDescriptor.TYPE_INT32: wire_format.WIRETYPE_VARINT,
	_FieldDescriptor.TYPE_FIXED64: wire_format.WIRETYPE_FIXED64,
	_FieldDescriptor.TYPE_FIXED32: wire_format.WIRETYPE_FIXED32,
	_FieldDescriptor.TYPE_BOOL: wire_format.WIRETYPE_VARINT,
	_FieldDescriptor.TYPE_STRING:
	wire_format.WIRETYPE_LENGTH_DELIMITED,
	_FieldDescriptor.TYPE_GROUP: wire_format.WIRETYPE_START_GROUP,
	_FieldDescriptor.TYPE_MESSAGE:
	wire_format.WIRETYPE_LENGTH_DELIMITED,
	_FieldDescriptor.TYPE_BYTES:
	wire_format.WIRETYPE_LENGTH_DELIMITED,
	_FieldDescriptor.TYPE_UINT32: wire_format.WIRETYPE_VARINT,
	_FieldDescriptor.TYPE_ENUM: wire_format.WIRETYPE_VARINT,
	_FieldDescriptor.TYPE_SFIXED32: wire_format.WIRETYPE_FIXED32,
	_FieldDescriptor.TYPE_SFIXED64: wire_format.WIRETYPE_FIXED64,
	_FieldDescriptor.TYPE_SINT32: wire_format.WIRETYPE_VARINT,
	_FieldDescriptor.TYPE_SINT64: wire_format.WIRETYPE_VARINT,
	}