| # 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. |
| |
| from . import number_types as N |
| from . import packer |
| from .compat import memoryview_type |
| from .compat import import_numpy, NumpyRequiredForThisFeature |
| |
| np = import_numpy() |
| |
| FILE_IDENTIFIER_LENGTH=4 |
| |
| def Get(packer_type, buf, head): |
| """ Get decodes a value at buf[head] using `packer_type`. """ |
| return packer_type.unpack_from(memoryview_type(buf), head)[0] |
| |
| |
| def GetVectorAsNumpy(numpy_type, buf, count, offset): |
| """ GetVecAsNumpy decodes values starting at buf[head] as |
| `numpy_type`, where `numpy_type` is a numpy dtype. """ |
| if np is not None: |
| # TODO: could set .flags.writeable = False to make users jump through |
| # hoops before modifying... |
| return np.frombuffer(buf, dtype=numpy_type, count=count, offset=offset) |
| else: |
| raise NumpyRequiredForThisFeature('Numpy was not found.') |
| |
| |
| def Write(packer_type, buf, head, n): |
| """ Write encodes `n` at buf[head] using `packer_type`. """ |
| packer_type.pack_into(buf, head, n) |