86 lines
2.8 KiB
Python
86 lines
2.8 KiB
Python
"""
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BZIP2 archive file
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Author: Victor Stinner
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"""
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from lib.hachoir_parser import Parser
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from lib.hachoir_core.field import (ParserError, String,
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Bytes, Character, UInt8, UInt32, CompressedField)
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from lib.hachoir_core.endian import LITTLE_ENDIAN
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from lib.hachoir_core.text_handler import textHandler, hexadecimal
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try:
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from bz2 import BZ2Decompressor
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class Bunzip2:
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def __init__(self, stream):
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self.bzip2 = BZ2Decompressor()
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def __call__(self, size, data=''):
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try:
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return self.bzip2.decompress(data)
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except EOFError:
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return ''
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has_deflate = True
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except ImportError:
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has_deflate = False
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class Bzip2Parser(Parser):
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PARSER_TAGS = {
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"id": "bzip2",
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"category": "archive",
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"file_ext": ("bz2",),
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"mime": (u"application/x-bzip2",),
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"min_size": 10*8,
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"magic": (('BZh', 0),),
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"description": "bzip2 archive"
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}
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endian = LITTLE_ENDIAN
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def validate(self):
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if self.stream.readBytes(0, 3) != 'BZh':
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return "Wrong file signature"
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if not("1" <= self["blocksize"].value <= "9"):
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return "Wrong blocksize"
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return True
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def createFields(self):
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yield String(self, "id", 3, "Identifier (BZh)", charset="ASCII")
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yield Character(self, "blocksize", "Block size (KB of memory needed to uncompress)")
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yield UInt8(self, "blockheader", "Block header")
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if self["blockheader"].value == 0x17:
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yield String(self, "id2", 4, "Identifier2 (re8P)", charset="ASCII")
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yield UInt8(self, "id3", "Identifier3 (0x90)")
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elif self["blockheader"].value == 0x31:
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yield String(self, "id2", 5, "Identifier 2 (AY&SY)", charset="ASCII")
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if self["id2"].value != "AY&SY":
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raise ParserError("Invalid identifier 2 (AY&SY)!")
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else:
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raise ParserError("Invalid block header!")
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yield textHandler(UInt32(self, "crc32", "CRC32"), hexadecimal)
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if self._size is None: # TODO: is it possible to handle piped input?
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raise NotImplementedError
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size = (self._size - self.current_size)/8
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if size:
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for tag, filename in self.stream.tags:
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if tag == "filename" and filename.endswith(".bz2"):
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filename = filename[:-4]
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break
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else:
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filename = None
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data = Bytes(self, "file", size)
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if has_deflate:
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CompressedField(self, Bunzip2)
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def createInputStream(**args):
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if filename:
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args.setdefault("tags",[]).append(("filename", filename))
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return self._createInputStream(**args)
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data._createInputStream = createInputStream
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yield data
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