Slightly simplify BinaryReader

There was no need for the BufferedReader, since everything
is already in memory. Further, the stream parameter was never
used, so it was also unnecessary. The check for None when
reading length was also unnecessary, since we could just pass
-1 to begin with.

telethon/extensions/binaryreader.py

@@ -2,10 +2,10 @@
 This module contains the BinaryReader utility class.
 """
 import os
-from datetime import datetime, timezone, timedelta
-from io import BufferedReader, BytesIO
-from struct import unpack
 import time
+from datetime import datetime, timezone, timedelta
+from io import BytesIO
+from struct import unpack
 
 from ..errors import TypeNotFoundError
 from ..tl.alltlobjects import tlobjects
@@ -18,18 +18,10 @@ _EPOCH = _EPOCH_NAIVE.replace(tzinfo=timezone.utc)
 class BinaryReader:
     """
     Small utility class to read binary data.
-    Also creates a "Memory Stream" if necessary
     """
 
-    def __init__(self, data=None, stream=None):
-        if data:
+    def __init__(self, data):
         self.stream = BytesIO(data)
-        elif stream:
-            self.stream = stream
-        else:
-            raise ValueError('Either bytes or a stream must be provided')
-
-        self.reader = BufferedReader(self.stream)
         self._last = None  # Should come in handy to spot -404 errors
 
     # region Reading
@@ -61,13 +53,10 @@ class BinaryReader:
         return int.from_bytes(
             self.read(bits // 8), byteorder='little', signed=signed)
 
-    def read(self, length=None):
-        """Read the given amount of bytes."""
-        if length is None:
-            return self.reader.read()
-
-        result = self.reader.read(length)
-        if len(result) != length:
+    def read(self, length=-1):
+        """Read the given amount of bytes, or -1 to read all remaining."""
+        result = self.stream.read(length)
+        if (length >= 0) and (len(result) != length):
             raise BufferError(
                 'No more data left to read (need {}, got {}: {}); last read {}'
                 .format(length, len(result), repr(result), repr(self._last))
@@ -164,24 +153,24 @@ class BinaryReader:
 
     def close(self):
         """Closes the reader, freeing the BytesIO stream."""
-        self.reader.close()
+        self.stream.close()
 
     # region Position related
 
     def tell_position(self):
         """Tells the current position on the stream."""
-        return self.reader.tell()
+        return self.stream.tell()
 
     def set_position(self, position):
         """Sets the current position on the stream."""
-        self.reader.seek(position)
+        self.stream.seek(position)
 
     def seek(self, offset):
         """
         Seeks the stream position given an offset from the current position.
         The offset may be negative.
         """
-        self.reader.seek(offset, os.SEEK_CUR)
+        self.stream.seek(offset, os.SEEK_CUR)
 
     # endregion