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# Copyright 2014 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import collections
import struct
from . import packer
from .compat import import_numpy, NumpyRequiredForThisFeature
np = import_numpy()
# For reference, see:
# https://docs.python.org/2/library/ctypes.html#ctypes-fundamental-data-types-2
# These classes could be collections.namedtuple instances, but those are new
# in 2.6 and we want to work towards 2.5 compatability.
class BoolFlags(object):
bytewidth = 1
min_val = False
max_val = True
py_type = bool
name = "bool"
packer_type = packer.boolean
class Uint8Flags(object):
bytewidth = 1
min_val = 0
max_val = (2**8) - 1
py_type = int
name = "uint8"
packer_type = packer.uint8
class Uint16Flags(object):
bytewidth = 2
min_val = 0
max_val = (2**16) - 1
py_type = int
name = "uint16"
packer_type = packer.uint16
class Uint32Flags(object):
bytewidth = 4
min_val = 0
max_val = (2**32) - 1
py_type = int
name = "uint32"
packer_type = packer.uint32
class Uint64Flags(object):
bytewidth = 8
min_val = 0
max_val = (2**64) - 1
py_type = int
name = "uint64"
packer_type = packer.uint64
class Int8Flags(object):
bytewidth = 1
min_val = -(2**7)
max_val = (2**7) - 1
py_type = int
name = "int8"
packer_type = packer.int8
class Int16Flags(object):
bytewidth = 2
min_val = -(2**15)
max_val = (2**15) - 1
py_type = int
name = "int16"
packer_type = packer.int16
class Int32Flags(object):
bytewidth = 4
min_val = -(2**31)
max_val = (2**31) - 1
py_type = int
name = "int32"
packer_type = packer.int32
class Int64Flags(object):
bytewidth = 8
min_val = -(2**63)
max_val = (2**63) - 1
py_type = int
name = "int64"
packer_type = packer.int64
class Float32Flags(object):
bytewidth = 4
min_val = None
max_val = None
py_type = float
name = "float32"
packer_type = packer.float32
class Float64Flags(object):
bytewidth = 8
min_val = None
max_val = None
py_type = float
name = "float64"
packer_type = packer.float64
class SOffsetTFlags(Int32Flags):
pass
class UOffsetTFlags(Uint32Flags):
pass
class VOffsetTFlags(Uint16Flags):
pass
def valid_number(n, flags):
if flags.min_val is None and flags.max_val is None:
return True
return flags.min_val <= n <= flags.max_val
def enforce_number(n, flags):
if flags.min_val is None and flags.max_val is None:
return
if not flags.min_val <= n <= flags.max_val:
raise TypeError("bad number %s for type %s" % (str(n), flags.name))
def float32_to_uint32(n):
packed = struct.pack("<1f", n)
(converted,) = struct.unpack("<1L", packed)
return converted
def uint32_to_float32(n):
packed = struct.pack("<1L", n)
(unpacked,) = struct.unpack("<1f", packed)
return unpacked
def float64_to_uint64(n):
packed = struct.pack("<1d", n)
(converted,) = struct.unpack("<1Q", packed)
return converted
def uint64_to_float64(n):
packed = struct.pack("<1Q", n)
(unpacked,) = struct.unpack("<1d", packed)
return unpacked
def to_numpy_type(number_type):
if np is not None:
return np.dtype(number_type.name).newbyteorder('<')
else:
raise NumpyRequiredForThisFeature('Numpy was not found.')
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