42 lines
1.3 KiB
Python
42 lines
1.3 KiB
Python
import io
|
|
import os
|
|
|
|
class CappedBufferedReader(io.BufferedReader):
|
|
def __init__(self, raw, buffer_size=io.DEFAULT_BUFFER_SIZE, capped_size=None):
|
|
super().__init__(raw, buffer_size)
|
|
self.capped_size = capped_size
|
|
|
|
def read(self, size=None):
|
|
if self.capped_size is not None:
|
|
if size is None or size < 0 or size > self.capped_size:
|
|
size = self.capped_size
|
|
self.capped_size -= size
|
|
return super().read(size)
|
|
|
|
def seek(self, offset, whence=os.SEEK_SET):
|
|
if offset == 0 and whence == os.SEEK_END and self.capped_size is not None:
|
|
if self.capped_size < 0:
|
|
offset = 0
|
|
else:
|
|
real_end = super().seek(0, os.SEEK_END)
|
|
if self.capped_size > real_end:
|
|
offset = real_end
|
|
else:
|
|
offset = self.capped_size
|
|
whence = os.SEEK_SET
|
|
return super().seek(offset, whence)
|
|
|
|
@property
|
|
def name(self):
|
|
try:
|
|
return self._name
|
|
except AttributeError:
|
|
return super().name
|
|
|
|
@name.setter
|
|
def name(self, new_name):
|
|
self._name = new_name
|
|
|
|
def bopen(file, capped_size):
|
|
return CappedBufferedReader(open(file, 'rb', buffering=0), capped_size=capped_size)
|