1# Copyright 2018 Google LLC 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# https://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 15import warnings 16 17_SLOW_CRC32C_WARNING = ( 18 "As the c extension couldn't be imported, `google-crc32c` is using a " 19 "pure python implementation that is significantly slower. If possible, " 20 "please configure a c build environment and compile the extension" 21) 22 23# Default to C exstension Implementation, falling back to pure python. 24try: 25 from google_crc32c import cext as impl 26 implementation = "c" 27except ImportError as exc: 28 from google_crc32c import python as impl 29 warnings.warn(_SLOW_CRC32C_WARNING, RuntimeWarning) 30 implementation = "python" 31 32extend = impl.extend 33value = impl.value 34 35Checksum = impl.Checksum 36 37__all__ = ["extend", "value", "Checksum", "implementation"] 38