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# --------------------------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# Licensed under the MIT License. See License.txt in the project root for license information.
# --------------------------------------------------------------------------------------------
from typing import AsyncIterator
from io import BytesIO
from ._random_stream import get_random_bytes, _DEFAULT_LENGTH
class AsyncRandomStream(BytesIO):
def __init__(self, length, initial_buffer_length=_DEFAULT_LENGTH):
super().__init__()
self._base_data = get_random_bytes(initial_buffer_length)
self._data_length = length
self._base_buffer_length = initial_buffer_length
self._position = 0
self._remaining = length
self._closed = False
def __len__(self):
return self._remaining
def reset(self):
self._position = 0
self._remaining = self._data_length
self._closed = False
def read(self, size=None):
if self._remaining == 0:
return b""
if size is None:
e = self._base_buffer_length
else:
e = size
e = min(e, self._remaining)
if e > self._base_buffer_length:
self._base_data = get_random_bytes(e)
self._base_buffer_length = e
self._remaining = self._remaining - e
self._position += e
return self._base_data[:e]
def seek(self, index, whence=0):
if whence == 0:
self._position = index
elif whence == 1:
self._position = self._position + index
elif whence == 2:
self._position = self._data_length - 1 + index
def tell(self):
return self._position
def remaining(self):
return self._remaining
def close(self):
self._closed = True
class AsyncIteratorRandomStream(AsyncIterator[bytes]):
"""
Async random stream of bytes for methods that accept AsyncIterator as input.
"""
def __init__(self, length, initial_buffer_length=_DEFAULT_LENGTH):
self._base_data = get_random_bytes(initial_buffer_length)
self._data_length = length
self._base_buffer_length = initial_buffer_length
self._position = 0
self._remaining = length
def __len__(self):
return self._remaining
def __aiter__(self):
return self
async def __anext__(self):
if self._remaining == 0:
raise StopAsyncIteration
return self.read()
def reset(self):
self._position = 0
self._remaining = self._data_length
def read(self, size=None):
if self._remaining == 0:
return b""
if size is None:
e = self._base_buffer_length
else:
e = size
e = min(e, self._remaining)
if e > self._base_buffer_length:
self._base_data = get_random_bytes(e)
self._base_buffer_length = e
self._remaining = self._remaining - e
self._position += e
return self._base_data[:e]
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