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https://github.com/iKarith/cppo-ng.git
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6bb27a028f
I may not have done this 100% "properly"--this is really the first full application thingy I've ever tried to write in Python. I learned circular imports are possible and the error messages are not obvious when you do that. I've also learned that importing a package doesn't necessarily import the modules within that package--if you want that, the package needs to import its submodules into itself. That was not obvious either. It does explain why sometimes you must import subpackages directly and other times importing the package is all you need. This is probably obvious to Python developers who actually work on big projects, but ... I've only ever done single-file scripts before now so it wasn't obvious to me. For now, blocksfree is importing legacy. We don't have enough outside of legacy yet to make the alternative even remotely useful at this time. Eventually though the goal is to stop doing that.
98 lines
3.0 KiB
Python
98 lines
3.0 KiB
Python
import os
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import struct
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from collections import namedtuple
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# FIXME Move to_sys_name
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from . import legacy
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### NEW DISK CLASSES
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TWOIMG_V1_UNPACK = (
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'<' # use little-endian numbers
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'4s' # magic string '2IMG'
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'4s' # creator string
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'H' # header length
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'H' # 2mg version
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'L' # image format
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'L' # flags (we unpack it into "vol")
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'L' # number of 512 blocks
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'L' # image data offset
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'L' # image data length
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'L' # comment offset
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'L' # comment length
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'L' # creator private use offset
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'L' # creator private use length
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'16x' # reserved for future use
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)
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TWOIMG_V1_ATTRS = (
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'magic', 'creator', 'hdr_len', 'version',
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'img_fmt', 'flags', 'num_blocks',
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'data_offset', 'data_len',
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'comment_offset', 'comment_len',
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'creator_offset', 'creator_len'
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)
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TwoImgV1 = namedtuple('TwoImgV1', TWOIMG_V1_ATTRS)
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class Disk:
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def __init__(self, name=None):
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if name is not None:
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self.pathname = name
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self.path, self.filename = os.path.split(name)
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self.diskname, self.ext = os.path.splitext(self.filename)
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self.ext = os.path.splitext(name)[1].lower()
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# FIXME: Handle compressed images?
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with open(legacy.to_sys_name(name), "rb") as f:
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self.image = f.read()
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if self.ext in ('.2mg', '.2img'):
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self._parse_2mg()
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def _parse_2mg(self):
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self.twoimg = None
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self.twoimg_comment = None
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self.twoimg_creator = None
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self.twoimg_locked = None
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hdr = TwoImgV1(*struct.unpack_from(TWOIMG_V1_UNPACK, self.image))
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if hdr.magic == b'2IMG':
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self._raw_twoimg = self.image[:hdr.hdr_len]
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if hdr.version == 1:
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if hdr.hdr_len == 64:
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# Extract comment (if it exists and is valid)
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if hdr.comment_offset and hdr.comment_len:
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self.twoimg_comment = self.image[
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hdr.comment_offset
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: hdr.comment_offset + hdr.comment_len]
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if len(self.twoimg_comment) != hdr.comment_len:
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log.warn('invalid 2mg comment: {} bytes '
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'(expected {} bytes)'.format(
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len(self.twoimg_comment),
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hdr.comment_len))
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self.twoimg_comment = None
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# Extract creator area (if it exists and is valid)
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if hdr.creator_offset and hdr.creator_len:
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self.twoimg_creator = self.image[
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hdr.creator_offset
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: hdr.creator_offset + hdr.creator_len]
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if len(self.twoimg_creator) != hdr.creator_len:
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log.warn('invalid 2mg creator: {} bytes '
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'(expected {} bytes)'.format(
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len(self.twoimg_creator),
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hdr.creator_len))
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self.twoimg_creator = None
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self.twoimg_locked = bool(hdr.flags & 0x80000000)
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self.twoimg = hdr
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else:
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log.warn('2mg header length: {} (expected 64 '
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'for version 1)'.format(hdr.hdr_len))
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else:
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log.warn('2mg version unsupported: {} (only support '
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'version 1)'.format(hdr.version))
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else:
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log.warn('2mg header not found: magic is {}'.format(hdr.magic))
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self._raw_twoimg = None
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