SickGear/lib/hachoir/parser/archive/bzip2_parser.py

250 lines
9.3 KiB
Python

"""
BZIP2 archive file
Author: Victor Stinner, Robert Xiao
"""
from hachoir.parser import Parser
from hachoir.core.tools import paddingSize
from hachoir.field import (Field, FieldSet, GenericVector,
ParserError, String,
PaddingBits, Bit, Bits, Character,
UInt32, Enum, CompressedField)
from hachoir.core.endian import BIG_ENDIAN
from hachoir.core.text_handler import textHandler, hexadecimal
from hachoir.parser.archive.zlib import build_tree, HuffmanCode
try:
from bz2 import BZ2Decompressor
class Bunzip2:
def __init__(self, stream):
self.bzip2 = BZ2Decompressor()
def __call__(self, size, data=''):
try:
return self.bzip2.decompress(data)
except EOFError:
return ''
has_deflate = True
except ImportError:
has_deflate = False
class ZeroTerminatedNumber(Field):
"""Zero (bit) terminated number: e.g. 11110 is 4."""
def __init__(self, parent, name, description=None):
Field.__init__(self, parent, name, 0, description)
endian = self.parent.endian
stream = self.parent.stream
addr = self.absolute_address
value = 0
while True:
bit = stream.readBits(addr, 1, endian)
addr += 1
self._size += 1
if not bit:
break
value += 1
self._value = value
def createValue(self):
return self._value
def move_to_front(seq, index):
seq[:] = seq[index:index + 1] + seq[0:index] + seq[index + 1:]
class Bzip2Bitmap(FieldSet):
def __init__(self, parent, name, nb_items, start_index, *args, **kwargs):
FieldSet.__init__(self, parent, name, *args, **kwargs)
self.nb_items = nb_items
self.start_index = start_index
def createFields(self):
for i in range(self.start_index, self.start_index + self.nb_items):
yield Bit(self, "symbol_used[%i]" % i, "Is the symbol %i (%r) used?" % (i, chr(i)))
class Bzip2Lengths(FieldSet):
def __init__(self, parent, name, symbols, *args, **kwargs):
FieldSet.__init__(self, parent, name, *args, **kwargs)
self.symbols = symbols
def createFields(self):
yield Bits(self, "start_length", 5)
length = self["start_length"].value
lengths = []
for i in range(self.symbols):
while True:
bit = Bit(
self, "change_length[%i][]" % i, "Should the length be changed for symbol %i?" % i)
yield bit
if not bit.value:
break
else:
bit = Enum(Bit(self, "length_decrement[%i][]" % i, "Decrement the value?"), {
True: "Decrement", False: "Increment"})
yield bit
if bit.value:
length -= 1
else:
length += 1
lengths.append(length)
self.final_length = length
self.tree = build_tree(lengths)
class Bzip2Selectors(FieldSet):
def __init__(self, parent, name, ngroups, *args, **kwargs):
FieldSet.__init__(self, parent, name, *args, **kwargs)
self.groups = list(range(ngroups))
def createFields(self):
for i in range(self["../selectors_used"].value):
field = ZeroTerminatedNumber(self, "selector_list[]")
move_to_front(self.groups, field.value)
field.realvalue = self.groups[0]
field._description = "MTF'ed selector index: raw value %i, real value %i" % (
field.value, field.realvalue)
yield field
class Bzip2Block(FieldSet):
def createFields(self):
yield textHandler(Bits(self, "blockheader", 48, "Block header"), hexadecimal)
if self["blockheader"].value != 0x314159265359: # pi
raise ParserError("Invalid block header!")
yield textHandler(UInt32(self, "crc32", "CRC32 for this block"), hexadecimal)
yield Bit(self, "randomized", "Is this block randomized?")
yield Bits(self, "orig_bwt_pointer", 24, "Starting pointer into BWT after untransform")
yield GenericVector(self, "huffman_used_map", 16, Bit, 'block_used', "Bitmap showing which blocks (representing 16 literals each) are in use")
symbols_used = []
for index, block_used in enumerate(self["huffman_used_map"].array('block_used')):
if block_used.value:
start_index = index * 16
field = Bzip2Bitmap(self, "huffman_used_bitmap[%i]" % index, 16, start_index, "Bitmap for block %i (literals %i to %i) showing which symbols are in use" % (
index, start_index, start_index + 15))
yield field
for i, used in enumerate(field):
if used.value:
symbols_used.append(start_index + i)
yield Bits(self, "huffman_groups", 3, "Number of different Huffman tables in use")
yield Bits(self, "selectors_used", 15, "Number of times the Huffman tables are switched")
yield Bzip2Selectors(self, "selectors_list", self["huffman_groups"].value)
trees = []
for group in range(self["huffman_groups"].value):
field = Bzip2Lengths(self, "huffman_lengths[]",
len(symbols_used) + 2)
yield field
trees.append(field.tree)
counter = 0
rle_run = 0
selector_tree = None
while True:
if counter % 50 == 0:
select_id = self["selectors_list"].array(
"selector_list")[counter // 50].realvalue
selector_tree = trees[select_id]
field = HuffmanCode(self, "huffman_code[]", selector_tree)
if field.realvalue in [0, 1]:
# RLE codes
if rle_run == 0:
rle_power = 1
rle_run += (field.realvalue + 1) * rle_power
rle_power <<= 1
field._description = "RLE Run Code %i (for %r); Total accumulated run %i (Huffman Code %i)" % (
field.realvalue, chr(symbols_used[0]), rle_run, field.value)
elif field.realvalue == len(symbols_used) + 1:
field._description = "Block Terminator (%i) (Huffman Code %i)" % (
field.realvalue, field.value)
yield field
break
else:
rle_run = 0
move_to_front(symbols_used, field.realvalue - 1)
field._description = "Literal %r (value %i) (Huffman Code %i)" % (
chr(symbols_used[0]), field.realvalue, field.value)
yield field
if field.realvalue == len(symbols_used) + 1:
break
counter += 1
class Bzip2Stream(FieldSet):
START_BLOCK = 0x314159265359 # pi
END_STREAM = 0x177245385090 # sqrt(pi)
def createFields(self):
end = False
while not end:
marker = self.stream.readBits(
self.absolute_address + self.current_size, 48, self.endian)
if marker == self.START_BLOCK:
yield Bzip2Block(self, "block[]")
elif marker == self.END_STREAM:
yield textHandler(Bits(self, "stream_end", 48, "End-of-stream marker"), hexadecimal)
yield textHandler(UInt32(self, "crc32", "CRC32 for entire stream"), hexadecimal)
padding = paddingSize(self.current_size, 8)
if padding:
yield PaddingBits(self, "padding[]", padding)
end = True
else:
raise ParserError("Invalid marker 0x%02X!" % marker)
class Bzip2Parser(Parser):
PARSER_TAGS = {
"id": "bzip2",
"category": "archive",
"file_ext": ("bz2",),
"mime": ("application/x-bzip2",),
"min_size": 10 * 8,
"magic": ((b'BZh', 0),),
"description": "bzip2 archive"
}
endian = BIG_ENDIAN
def validate(self):
if self.stream.readBytes(0, 3) != b'BZh':
return "Wrong file signature"
if not ("1" <= self["blocksize"].value <= "9"):
return "Wrong blocksize"
return True
def createFields(self):
yield String(self, "id", 3, "Identifier (BZh)", charset="ASCII")
yield Character(self, "blocksize", "Block size (KB of memory needed to uncompress)")
if self._size is None: # TODO: is it possible to handle piped input?
raise NotImplementedError
size = (self._size - self.current_size) // 8
if size:
for tag, filename in self.stream.tags:
if tag == "filename" and filename.endswith(".bz2"):
filename = filename[:-4]
break
else:
filename = None
data = Bzip2Stream(self, "file", size=size * 8)
if has_deflate:
CompressedField(self, Bunzip2)
def createInputStream(**args):
if filename:
args.setdefault("tags", []).append(
("filename", filename))
return self._createInputStream(**args)
data._createInputStream = createInputStream
yield data