updates

Backend/venv/lib/python3.12/site-packages/PIL/MpegImagePlugin.py

@@ -12,46 +12,47 @@
 #
 # See the README file for information on usage and redistribution.
 #
-
+from __future__ import annotations
 
 from . import Image, ImageFile
 from ._binary import i8
+from ._typing import SupportsRead
 
 #
 # Bitstream parser
 
 
 class BitStream:
-    def __init__(self, fp):
+    def __init__(self, fp: SupportsRead[bytes]) -> None:
         self.fp = fp
         self.bits = 0
         self.bitbuffer = 0
 
-    def next(self):
+    def next(self) -> int:
         return i8(self.fp.read(1))
 
-    def peek(self, bits):
+    def peek(self, bits: int) -> int:
         while self.bits < bits:
-            c = self.next()
-            if c < 0:
-                self.bits = 0
-                continue
-            self.bitbuffer = (self.bitbuffer << 8) + c
+            self.bitbuffer = (self.bitbuffer << 8) + self.next()
             self.bits += 8
         return self.bitbuffer >> (self.bits - bits) & (1 << bits) - 1
 
-    def skip(self, bits):
+    def skip(self, bits: int) -> None:
         while self.bits < bits:
             self.bitbuffer = (self.bitbuffer << 8) + i8(self.fp.read(1))
             self.bits += 8
         self.bits = self.bits - bits
 
-    def read(self, bits):
+    def read(self, bits: int) -> int:
         v = self.peek(bits)
         self.bits = self.bits - bits
         return v
 
 
+def _accept(prefix: bytes) -> bool:
+    return prefix.startswith(b"\x00\x00\x01\xb3")
+
+
 ##
 # Image plugin for MPEG streams.  This plugin can identify a stream,
 # but it cannot read it.
@@ -61,9 +62,10 @@ class MpegImageFile(ImageFile.ImageFile):
     format = "MPEG"
     format_description = "MPEG"
 
-    def _open(self):
-        s = BitStream(self.fp)
+    def _open(self) -> None:
+        assert self.fp is not None
 
+        s = BitStream(self.fp)
         if s.read(32) != 0x1B3:
             msg = "not an MPEG file"
             raise SyntaxError(msg)
@@ -75,7 +77,7 @@ class MpegImageFile(ImageFile.ImageFile):
 # --------------------------------------------------------------------
 # Registry stuff
 
-Image.register_open(MpegImageFile.format, MpegImageFile)
+Image.register_open(MpegImageFile.format, MpegImageFile, _accept)
 
 Image.register_extensions(MpegImageFile.format, [".mpg", ".mpeg"])