46 lines
1.5 KiB
Python
46 lines
1.5 KiB
Python
# Copyright 2014 Google Inc. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from . import number_types as N
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from . import packer
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from .compat import memoryview_type
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from .compat import NumpyRequiredForThisFeature, import_numpy
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np = import_numpy()
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FILE_IDENTIFIER_LENGTH = 4
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def Get(packer_type, buf, head):
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"""Get decodes a value at buf[head] using `packer_type`."""
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return packer_type.unpack_from(memoryview_type(buf), head)[0]
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def GetVectorAsNumpy(numpy_type, buf, count, offset):
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"""GetVecAsNumpy decodes values starting at buf[head] as
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`numpy_type`, where `numpy_type` is a numpy dtype.
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"""
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if np is not None:
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# TODO: could set .flags.writeable = False to make users jump through
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# hoops before modifying...
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return np.frombuffer(buf, dtype=numpy_type, count=count, offset=offset)
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else:
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raise NumpyRequiredForThisFeature('Numpy was not found.')
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def Write(packer_type, buf, head, n):
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"""Write encodes `n` at buf[head] using `packer_type`."""
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packer_type.pack_into(buf, head, n)
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