| ################################################################################ |
| # Licensed to the Apache Software Foundation (ASF) under one |
| # or more contributor license agreements. See the NOTICE file |
| # distributed with this work for additional information |
| # regarding copyright ownership. The ASF licenses this file |
| # to you 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 io |
| |
| |
| class ResettableIO(io.RawIOBase): |
| """ |
| Raw I/O implementation the input and output stream is resettable. |
| """ |
| |
| def set_input_bytes(self, b): |
| self._input_bytes = b |
| self._input_offset = 0 |
| self._size = len(b) |
| |
| def readinto(self, b): |
| """ |
| Read up to len(b) bytes into the writable buffer *b* and return |
| the number of bytes read. If no bytes are available, None is returned. |
| """ |
| output_buffer_len = len(b) |
| remaining = self._size - self._input_offset |
| |
| if remaining >= output_buffer_len: |
| b[:] = self._input_bytes[self._input_offset:self._input_offset + output_buffer_len] |
| self._input_offset += output_buffer_len |
| return output_buffer_len |
| elif remaining > 0: |
| b[:remaining] = self._input_bytes[self._input_offset:self._input_offset + remaining] |
| self._input_offset = self._size |
| return remaining |
| else: |
| return None |
| |
| def set_output_stream(self, output_stream): |
| self._output_stream = output_stream |
| |
| def write(self, b): |
| """ |
| Write the given bytes or pyarrow.Buffer object *b* to the underlying |
| output stream and return the number of bytes written. |
| """ |
| if isinstance(b, bytes): |
| self._output_stream.write(b) |
| else: |
| # pyarrow.Buffer |
| self._output_stream.write(b.to_pybytes()) |
| return len(b) |
| |
| def seekable(self): |
| return False |
| |
| def readable(self): |
| return self._size - self._input_offset |
| |
| def writable(self): |
| return True |
