File size: 2,318 Bytes
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# The Python Imaging Library.
# $Id$
#
# DCX file handling
#
# DCX is a container file format defined by Intel, commonly used
# for fax applications. Each DCX file consists of a directory
# (a list of file offsets) followed by a set of (usually 1-bit)
# PCX files.
#
# History:
# 1995-09-09 fl Created
# 1996-03-20 fl Properly derived from PcxImageFile.
# 1998-07-15 fl Renamed offset attribute to avoid name clash
# 2002-07-30 fl Fixed file handling
#
# Copyright (c) 1997-98 by Secret Labs AB.
# Copyright (c) 1995-96 by Fredrik Lundh.
#
# See the README file for information on usage and redistribution.
#
from __future__ import annotations
__lazy_modules__ = {"PIL._binary", "PIL._util"}
from . import Image
from ._binary import i32le as i32
from ._util import DeferredError
from .PcxImagePlugin import PcxImageFile
MAGIC = 0x3ADE68B1 # QUIZ: what's this value, then?
def _accept(prefix: bytes) -> bool:
return len(prefix) >= 4 and i32(prefix) == MAGIC
##
# Image plugin for the Intel DCX format.
class DcxImageFile(PcxImageFile):
format = "DCX"
format_description = "Intel DCX"
_close_exclusive_fp_after_loading = False
def _open(self) -> None:
# Header
assert self.fp is not None
s = self.fp.read(4)
if not _accept(s):
msg = "not a DCX file"
raise SyntaxError(msg)
# Component directory
self._offset = []
for i in range(1024):
offset = i32(self.fp.read(4))
if not offset:
break
self._offset.append(offset)
self._fp = self.fp
self.frame = -1
self.n_frames = len(self._offset)
self.is_animated = self.n_frames > 1
self.seek(0)
def seek(self, frame: int) -> None:
if not self._seek_check(frame):
return
if isinstance(self._fp, DeferredError):
raise self._fp.ex
self.frame = frame
self.fp = self._fp
self.fp.seek(self._offset[frame])
PcxImageFile._open(self)
Image._decompression_bomb_check(self.size)
Image.Image.seek(self, frame)
def tell(self) -> int:
return self.frame
Image.register_open(DcxImageFile.format, DcxImageFile, _accept)
Image.register_extension(DcxImageFile.format, ".dcx")
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