| Austin Schuh | e89fa2d | 2019-08-14 20:24:23 -0700 | [diff] [blame^] | 1 | # Copyright 2014 Google Inc. All rights reserved. |
| 2 | # |
| 3 | # Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | # you may not use this file except in compliance with the License. |
| 5 | # You may obtain a copy of the License at |
| 6 | # |
| 7 | # http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | # |
| 9 | # Unless required by applicable law or agreed to in writing, software |
| 10 | # distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | # See the License for the specific language governing permissions and |
| 13 | # limitations under the License. |
| 14 | |
| 15 | from . import number_types as N |
| 16 | from . import packer |
| 17 | from .compat import memoryview_type |
| 18 | from .compat import import_numpy, NumpyRequiredForThisFeature |
| 19 | |
| 20 | np = import_numpy() |
| 21 | |
| 22 | FILE_IDENTIFIER_LENGTH=4 |
| 23 | |
| 24 | def Get(packer_type, buf, head): |
| 25 | """ Get decodes a value at buf[head] using `packer_type`. """ |
| 26 | return packer_type.unpack_from(memoryview_type(buf), head)[0] |
| 27 | |
| 28 | |
| 29 | def GetVectorAsNumpy(numpy_type, buf, count, offset): |
| 30 | """ GetVecAsNumpy decodes values starting at buf[head] as |
| 31 | `numpy_type`, where `numpy_type` is a numpy dtype. """ |
| 32 | if np is not None: |
| 33 | # TODO: could set .flags.writeable = False to make users jump through |
| 34 | # hoops before modifying... |
| 35 | return np.frombuffer(buf, dtype=numpy_type, count=count, offset=offset) |
| 36 | else: |
| 37 | raise NumpyRequiredForThisFeature('Numpy was not found.') |
| 38 | |
| 39 | |
| 40 | def Write(packer_type, buf, head, n): |
| 41 | """ Write encodes `n` at buf[head] using `packer_type`. """ |
| 42 | packer_type.pack_into(buf, head, n) |