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374 lines (323 loc) · 13.4 KB
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from __future__ import annotations
from itertools import count
from typing import ClassVar, overload
from zlib import crc32
from refinery.lib.structures import MemoryFile, Struct, StructReader
from refinery.units import Unit
class State:
Count: ClassVar[int] = 12
__slots__ = '__value',
def __init__(self):
self.__value = 0
def set_char(self):
self.__value = (0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5)[self.__value]
def __index__(self):
return self.__value
@property
def is_char(self):
return self.__value < 7
def set_match(self):
self.__value = 7 if self.is_char else 10
def set_rep(self):
self.__value = 8 if self.is_char else 11
def set_short_rep(self):
self.__value = 9 if self.is_char else 11
_MIN_DICT_SIZE = 1 << 12 # noqa
_MAX_DICT_SIZE = 1 << 29 # noqa
_LITERAL_CONTEXT_BITS = 3 # noqa
_POS_STATE_BITS = 2 # noqa
_POS_STATES = 1 << _POS_STATE_BITS # noqa
_POS_STATE_MASK = _POS_STATES - 1 # noqa
_LEN_STATES = 4 # noqa
_DIS_SLOT_BITS = 6 # noqa
_START_DIS_MODEL = 4 # noqa
_END_DIS_MODEL = 14 # noqa
_MODELED_DISTANCES = 1 << (_END_DIS_MODEL // 2) # noqa
_DIS_ALIGN_BITS = 4 # noqa
_DIS_ALIGN_SIZE = 1 << _DIS_ALIGN_BITS # noqa
_LEN_L_BITS = 3 # noqa
_LEN_M_BITS = 3 # noqa
_LEN_H_BITS = 8 # noqa
_LEN_L_SYMB = 1 << _LEN_L_BITS # noqa
_LEN_M_SYMB = 1 << _LEN_M_BITS # noqa
_LEN_H_SYMB = 1 << _LEN_H_BITS # noqa
_MIN_MATCH_LEN = 2 # noqa
_BIT_MODEL_MOVE_BITS = 5 # noqa
_BIT_MODEL_TOTAL_BITS = 11 # noqa
_BIT_MODEL_TOTAL = 1 << _BIT_MODEL_TOTAL_BITS # noqa
class BitModel:
probability: int
__slots__ = 'probability',
def __init__(self):
self.probability = _BIT_MODEL_TOTAL // 2
@overload
@classmethod
def Array(cls, x: int) -> list[BitModel]:
...
@overload
@classmethod
def Array(cls, x: int, y: int) -> list[list[BitModel]]:
...
@classmethod
def Array(cls, x: int, y: int | None = None):
if y is None:
return [cls() for _ in range(x)]
return [cls.Array(y) for _ in range(x)]
class LenModel:
__slots__ = (
'choice1',
'choice2',
'bm_low',
'bm_mid',
'bm_high'
)
def __init__(self):
self.choice1 = BitModel()
self.choice2 = BitModel()
self.bm_low = BitModel.Array(_POS_STATES, _LEN_L_SYMB)
self.bm_mid = BitModel.Array(_POS_STATES, _LEN_M_SYMB)
self.bm_high = BitModel.Array(_LEN_H_SYMB)
class RangeDecoder(Struct):
member_pos: int
code: int
range: int
def __init__(self, reader: StructReader):
self.member_pos = 6
self.code = 0
self.range = 0xFFFFFFFF
self.reader = reader
for _ in range(5):
self.code = (self.code << 8) | self.get_byte()
def get_byte(self):
self.member_pos += 1
return self.reader.read_byte()
def decode(self, num_bits: int) -> int:
symbol = 0
for _ in range(num_bits):
self.range >>= 1
symbol <<= 1
if (self.code >= self.range):
self.code -= self.range
symbol |= 1
if (self.range <= 0x00FFFFFF):
self.range <<= 8
self.code = (self.code << 8) | self.get_byte()
return symbol
def decode_bit(self, bm: BitModel):
symbol = 0
bound = (self.range >> _BIT_MODEL_TOTAL_BITS) * bm.probability
if (self.code < bound):
self.range = bound
bm.probability += (_BIT_MODEL_TOTAL - bm.probability) >> _BIT_MODEL_MOVE_BITS
symbol = 0
else:
self.range -= bound
self.code -= bound
bm.probability -= bm.probability >> _BIT_MODEL_MOVE_BITS
symbol = 1
if (self.range <= 0x00FFFFFF):
self.range <<= 8
self.code = (self.code << 8) | self.get_byte()
return symbol
def decode_tree(self, bm: list[BitModel], num_bits: int, bmx: int = 0) -> int:
symbol = 1
for _ in range(num_bits):
symbol = (symbol << 1) | self.decode_bit(bm[bmx + symbol])
return symbol - (1 << num_bits)
def decode_tree_reversed(self, bm: list[BitModel], num_bits: int, bmx: int = 0) -> int:
symbol = self.decode_tree(bm, num_bits, bmx)
reversed_symbol = 0
for i in range(num_bits):
reversed_symbol = (reversed_symbol << 1) | (symbol & 1)
symbol >>= 1
return reversed_symbol
def decode_matched(self, bm: list[BitModel], match_byte: int) -> int:
symbol = 1
for i in range(7, -1, -1):
match_bit = (match_byte >> i) & 1
bit = self.decode_bit(bm[symbol + (match_bit << 8) + 0x100])
symbol = (symbol << 1) | bit
if match_bit != bit:
while symbol < 0x100:
symbol = (symbol << 1) | self.decode_bit(bm[symbol])
break
return symbol & 0xFF
def decode_len(self, lm: LenModel, pos_state: int):
if self.decode_bit(lm.choice1) == 0:
return self.decode_tree(lm.bm_low[pos_state], _LEN_L_BITS)
if self.decode_bit(lm.choice2) == 0:
return _LEN_L_SYMB + self.decode_tree(lm.bm_mid[pos_state], _LEN_M_BITS)
return _LEN_L_SYMB + _LEN_M_SYMB + self.decode_tree(lm.bm_high, _LEN_H_BITS)
class MemberDecoder:
partial_data_pos: int
rdec: RangeDecoder
dictionary_size: int
buffer: bytearray
pos: int
stream_pos: int
crc32: int
pos_wrapped: bool
reader: StructReader
output: MemoryFile
def flush_data(self):
if self.pos > self.stream_pos:
v = memoryview(self.buffer)
b = v[self.stream_pos:self.pos]
self.crc32 = crc32(b, self.crc32)
self.output.write(b)
if self.pos >= self.dictionary_size:
self.partial_data_pos += self.pos
self.pos = 0
self.pos_wrapped = True
self.stream_pos = self.pos
def peek(self, distance: int):
if self.pos > distance:
return self.buffer[self.pos - distance - 1]
if self.pos_wrapped:
return self.buffer[self.dictionary_size + self.pos - distance - 1]
return 0
def put_byte(self, b: int):
self.buffer[self.pos] = b
self.pos += 1
if self.pos >= self.dictionary_size:
self.flush_data()
def __init__(self, dict_size: int, reader: StructReader, output: MemoryFile):
self.reader = reader
self.output = output
self.rdec = RangeDecoder(reader)
self.partial_data_pos = 0
self.dictionary_size = dict_size
self.buffer = bytearray(dict_size)
self.pos = 0
self.stream_pos = 0
self.crc32 = 0
self.pos_wrapped = False
@property
def data_position(self):
return self.partial_data_pos + self.pos
@property
def member_position(self):
return self.rdec.member_pos
def __call__(self) -> bool:
bm_literal = BitModel.Array(1 << _LITERAL_CONTEXT_BITS, 0x300)
bm_match = BitModel.Array(State.Count, _POS_STATES)
bm_rep = BitModel.Array(State.Count)
bm_rep0 = BitModel.Array(State.Count)
bm_rep1 = BitModel.Array(State.Count)
bm_rep2 = BitModel.Array(State.Count)
bm_len = BitModel.Array(State.Count, _POS_STATES)
bm_dis_slot = BitModel.Array(_LEN_STATES, 1 << _DIS_SLOT_BITS)
bm_dis = BitModel.Array(_MODELED_DISTANCES - _END_DIS_MODEL + 1)
bm_align = BitModel.Array(_DIS_ALIGN_SIZE)
match_len_model = LenModel()
rep_len_model = LenModel()
rep0 = 0
rep1 = 0
rep2 = 0
rep3 = 0
state = State()
while not self.reader.eof:
pos_state = self.data_position & _POS_STATE_MASK
if self.rdec.decode_bit(bm_match[state][pos_state]) == 0:
prev_byte = self.peek(0)
literal_state = prev_byte >> (8 - _LITERAL_CONTEXT_BITS)
bm = bm_literal[literal_state]
if state.is_char:
self.put_byte(self.rdec.decode_tree(bm, 8))
else:
self.put_byte(self.rdec.decode_matched(bm, self.peek(rep0)))
state.set_char()
continue
if self.rdec.decode_bit(bm_rep[state]) != 0:
if self.rdec.decode_bit(bm_rep0[state]) == 0:
if self.rdec.decode_bit(bm_len[state][pos_state]) == 0:
state.set_short_rep()
self.put_byte(self.peek(rep0))
continue
else:
if self.rdec.decode_bit(bm_rep1[state]) == 0:
distance = rep1
else:
if self.rdec.decode_bit(bm_rep2[state]) == 0:
distance = rep2
else:
distance = rep3
rep3 = rep2
rep2 = rep1
rep1 = rep0
rep0 = distance
state.set_rep()
lit_len = _MIN_MATCH_LEN + self.rdec.decode_len(rep_len_model, pos_state)
else:
rep3 = rep2
rep2 = rep1
rep1 = rep0
lit_len = _MIN_MATCH_LEN + self.rdec.decode_len(match_len_model, pos_state)
len_state = min(lit_len - _MIN_MATCH_LEN, _LEN_STATES - 1)
rep0 = self.rdec.decode_tree(bm_dis_slot[len_state], _DIS_SLOT_BITS)
if rep0 >= _START_DIS_MODEL:
dis_slot = rep0
direct_bits = (dis_slot >> 1) - 1
rep0 = (2 | (dis_slot & 1)) << direct_bits
if dis_slot < _END_DIS_MODEL:
rep0 += self.rdec.decode_tree_reversed(bm_dis, direct_bits, bmx=rep0 - dis_slot)
else:
rep0 += self.rdec.decode(direct_bits - _DIS_ALIGN_BITS) << _DIS_ALIGN_BITS
rep0 += self.rdec.decode_tree_reversed(bm_align, _DIS_ALIGN_BITS)
if rep0 == 0xFFFFFFFF:
self.flush_data()
return lit_len == _MIN_MATCH_LEN
state.set_match()
if rep0 >= self.dictionary_size or (rep0 >= self.pos and not self.pos_wrapped):
self.flush_data()
return False
for i in range(lit_len):
self.put_byte(self.peek(rep0))
self.flush_data()
return False
class lzip(Unit):
"""
LZIP decompression
"""
def process(self, data: bytearray):
view = memoryview(data)
with MemoryFile() as output, StructReader(view) as reader:
for k in count(1):
if reader.eof:
break
trailing_size = len(data) - reader.tell()
try:
ID, VN, DS = reader.read_struct('4sBB')
if ID != B'LZIP':
if k > 1:
raise EOFError
else:
self.log_warn(F'ignoring invalid LZIP signature: {ID.hex()}')
if VN != 1:
self.log_warn(F'ignoring invalid LZIP version: {VN}')
dict_size = 1 << (DS & 0x1F)
dict_size -= (dict_size // 16) * ((DS >> 5) & 7)
if dict_size not in range(_MIN_DICT_SIZE, _MAX_DICT_SIZE + 1):
raise ValueError(
F'The dictionary size {dict_size} is out of the valid range '
F'[{_MIN_DICT_SIZE}, {_MAX_DICT_SIZE}]; unable to proceed.'
)
decoder = MemberDecoder(dict_size, reader, output)
if not decoder():
raise ValueError(F'Data error in stream {k}.')
crc32, data_size, member_size = reader.read_struct('<LQQ')
if crc32 != decoder.crc32:
self.log_warn(F'checksum in stream {k} was {decoder.crc:08X}, should have been {crc32:08X}.')
if member_size - 20 != decoder.member_position:
self.log_warn(F'member size in stream {k} was {decoder.member_position}, should have been {member_size}.')
if data_size != decoder.data_position:
self.log_warn(F'data size in stream {k} was {decoder.data_position}, should have been {data_size}.')
except EOFError:
if k <= 1:
raise
self.log_info(F'silently ignoring {trailing_size} bytes of trailing data')
break
return output.getvalue()
@classmethod
def handles(cls, data):
return data[:4] == B'LZIP'