LHA (LHarc, LZH) is a file format used by a popular freeware eponymous archiver, created in 1988 by Haruyasu Yoshizaki. Over the years, many ports and implementations were developed, sporting many extensions to original 1988 LZH.
File format is pretty simple and essentially consists of a stream of records.
This page hosts a formal specification of .lzh file format of LHA (AKA LHarc) by Yoshizaki Haruyasu using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
# type: ignore
import kaitaistruct
from kaitaistruct import ReadWriteKaitaiStruct, KaitaiStream, BytesIO
import dos_datetime
if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 11):
raise Exception("Incompatible Kaitai Struct Python API: 0.11 or later is required, but you have %s" % (kaitaistruct.__version__))
class Lzh(ReadWriteKaitaiStruct):
"""LHA (LHarc, LZH) is a file format used by a popular freeware
eponymous archiver, created in 1988 by Haruyasu Yoshizaki. Over the
years, many ports and implementations were developed, sporting many
extensions to original 1988 LZH.
File format is pretty simple and essentially consists of a stream of
records.
"""
def __init__(self, _io=None, _parent=None, _root=None):
super(Lzh, self).__init__(_io)
self._parent = _parent
self._root = _root or self
def _read(self):
self.entries = []
i = 0
while not self._io.is_eof():
_t_entries = Lzh.Record(self._io, self, self._root)
try:
_t_entries._read()
finally:
self.entries.append(_t_entries)
i += 1
self._dirty = False
def _fetch_instances(self):
pass
for i in range(len(self.entries)):
pass
self.entries[i]._fetch_instances()
def _write__seq(self, io=None):
super(Lzh, self)._write__seq(io)
for i in range(len(self.entries)):
pass
if self._io.is_eof():
raise kaitaistruct.ConsistencyError(u"entries", 0, self._io.size() - self._io.pos())
self.entries[i]._write__seq(self._io)
if not self._io.is_eof():
raise kaitaistruct.ConsistencyError(u"entries", 0, self._io.size() - self._io.pos())
def _check(self):
for i in range(len(self.entries)):
pass
if self.entries[i]._root != self._root:
raise kaitaistruct.ConsistencyError(u"entries", self._root, self.entries[i]._root)
if self.entries[i]._parent != self:
raise kaitaistruct.ConsistencyError(u"entries", self, self.entries[i]._parent)
self._dirty = False
class FileRecord(ReadWriteKaitaiStruct):
def __init__(self, _io=None, _parent=None, _root=None):
super(Lzh.FileRecord, self).__init__(_io)
self._parent = _parent
self._root = _root
def _read(self):
self._raw_header = self._io.read_bytes(self._parent.header_len - 1)
_io__raw_header = KaitaiStream(BytesIO(self._raw_header))
self.header = Lzh.Header(_io__raw_header, self, self._root)
self.header._read()
if self.header.header1.lha_level == 0:
pass
self.file_uncompr_crc16 = self._io.read_u2le()
self.body = self._io.read_bytes(self.header.header1.file_size_compr)
self._dirty = False
def _fetch_instances(self):
pass
self.header._fetch_instances()
if self.header.header1.lha_level == 0:
pass
def _write__seq(self, io=None):
super(Lzh.FileRecord, self)._write__seq(io)
_io__raw_header = KaitaiStream(BytesIO(bytearray(self._parent.header_len - 1)))
self._io.add_child_stream(_io__raw_header)
_pos2 = self._io.pos()
self._io.seek(self._io.pos() + (self._parent.header_len - 1))
def handler(parent, _io__raw_header=_io__raw_header):
self._raw_header = _io__raw_header.to_byte_array()
if len(self._raw_header) != self._parent.header_len - 1:
raise kaitaistruct.ConsistencyError(u"raw(header)", self._parent.header_len - 1, len(self._raw_header))
parent.write_bytes(self._raw_header)
_io__raw_header.write_back_handler = KaitaiStream.WriteBackHandler(_pos2, handler)
self.header._write__seq(_io__raw_header)
if self.header.header1.lha_level == 0:
pass
self._io.write_u2le(self.file_uncompr_crc16)
self._io.write_bytes(self.body)
def _check(self):
if self.header._root != self._root:
raise kaitaistruct.ConsistencyError(u"header", self._root, self.header._root)
if self.header._parent != self:
raise kaitaistruct.ConsistencyError(u"header", self, self.header._parent)
if self.header.header1.lha_level == 0:
pass
if len(self.body) != self.header.header1.file_size_compr:
raise kaitaistruct.ConsistencyError(u"body", self.header.header1.file_size_compr, len(self.body))
self._dirty = False
class Header(ReadWriteKaitaiStruct):
def __init__(self, _io=None, _parent=None, _root=None):
super(Lzh.Header, self).__init__(_io)
self._parent = _parent
self._root = _root
def _read(self):
self.header1 = Lzh.Header1(self._io, self, self._root)
self.header1._read()
if self.header1.lha_level == 0:
pass
self.filename_len = self._io.read_u1()
if self.header1.lha_level == 0:
pass
self.filename = (self._io.read_bytes(self.filename_len)).decode(u"ASCII")
if self.header1.lha_level == 2:
pass
self.file_uncompr_crc16 = self._io.read_u2le()
if self.header1.lha_level == 2:
pass
self.os = self._io.read_u1()
if self.header1.lha_level == 2:
pass
self.ext_header_size = self._io.read_u2le()
self._dirty = False
def _fetch_instances(self):
pass
self.header1._fetch_instances()
if self.header1.lha_level == 0:
pass
if self.header1.lha_level == 0:
pass
if self.header1.lha_level == 2:
pass
if self.header1.lha_level == 2:
pass
if self.header1.lha_level == 2:
pass
def _write__seq(self, io=None):
super(Lzh.Header, self)._write__seq(io)
self.header1._write__seq(self._io)
if self.header1.lha_level == 0:
pass
self._io.write_u1(self.filename_len)
if self.header1.lha_level == 0:
pass
self._io.write_bytes((self.filename).encode(u"ASCII"))
if self.header1.lha_level == 2:
pass
self._io.write_u2le(self.file_uncompr_crc16)
if self.header1.lha_level == 2:
pass
self._io.write_u1(self.os)
if self.header1.lha_level == 2:
pass
self._io.write_u2le(self.ext_header_size)
def _check(self):
if self.header1._root != self._root:
raise kaitaistruct.ConsistencyError(u"header1", self._root, self.header1._root)
if self.header1._parent != self:
raise kaitaistruct.ConsistencyError(u"header1", self, self.header1._parent)
if self.header1.lha_level == 0:
pass
if self.header1.lha_level == 0:
pass
if len((self.filename).encode(u"ASCII")) != self.filename_len:
raise kaitaistruct.ConsistencyError(u"filename", self.filename_len, len((self.filename).encode(u"ASCII")))
if self.header1.lha_level == 2:
pass
if self.header1.lha_level == 2:
pass
if self.header1.lha_level == 2:
pass
self._dirty = False
class Header1(ReadWriteKaitaiStruct):
def __init__(self, _io=None, _parent=None, _root=None):
super(Lzh.Header1, self).__init__(_io)
self._parent = _parent
self._root = _root
def _read(self):
self.header_checksum = self._io.read_u1()
self.method_id = (self._io.read_bytes(5)).decode(u"ASCII")
self.file_size_compr = self._io.read_u4le()
self.file_size_uncompr = self._io.read_u4le()
self._raw_file_timestamp = self._io.read_bytes(4)
_io__raw_file_timestamp = KaitaiStream(BytesIO(self._raw_file_timestamp))
self.file_timestamp = dos_datetime.DosDatetime(_io__raw_file_timestamp)
self.file_timestamp._read()
self.attr = self._io.read_u1()
self.lha_level = self._io.read_u1()
self._dirty = False
def _fetch_instances(self):
pass
self.file_timestamp._fetch_instances()
def _write__seq(self, io=None):
super(Lzh.Header1, self)._write__seq(io)
self._io.write_u1(self.header_checksum)
self._io.write_bytes((self.method_id).encode(u"ASCII"))
self._io.write_u4le(self.file_size_compr)
self._io.write_u4le(self.file_size_uncompr)
_io__raw_file_timestamp = KaitaiStream(BytesIO(bytearray(4)))
self._io.add_child_stream(_io__raw_file_timestamp)
_pos2 = self._io.pos()
self._io.seek(self._io.pos() + (4))
def handler(parent, _io__raw_file_timestamp=_io__raw_file_timestamp):
self._raw_file_timestamp = _io__raw_file_timestamp.to_byte_array()
if len(self._raw_file_timestamp) != 4:
raise kaitaistruct.ConsistencyError(u"raw(file_timestamp)", 4, len(self._raw_file_timestamp))
parent.write_bytes(self._raw_file_timestamp)
_io__raw_file_timestamp.write_back_handler = KaitaiStream.WriteBackHandler(_pos2, handler)
self.file_timestamp._write__seq(_io__raw_file_timestamp)
self._io.write_u1(self.attr)
self._io.write_u1(self.lha_level)
def _check(self):
if len((self.method_id).encode(u"ASCII")) != 5:
raise kaitaistruct.ConsistencyError(u"method_id", 5, len((self.method_id).encode(u"ASCII")))
self._dirty = False
class Record(ReadWriteKaitaiStruct):
def __init__(self, _io=None, _parent=None, _root=None):
super(Lzh.Record, self).__init__(_io)
self._parent = _parent
self._root = _root
def _read(self):
self.header_len = self._io.read_u1()
if self.header_len > 0:
pass
self.file_record = Lzh.FileRecord(self._io, self, self._root)
self.file_record._read()
self._dirty = False
def _fetch_instances(self):
pass
if self.header_len > 0:
pass
self.file_record._fetch_instances()
def _write__seq(self, io=None):
super(Lzh.Record, self)._write__seq(io)
self._io.write_u1(self.header_len)
if self.header_len > 0:
pass
self.file_record._write__seq(self._io)
def _check(self):
if self.header_len > 0:
pass
if self.file_record._root != self._root:
raise kaitaistruct.ConsistencyError(u"file_record", self._root, self.file_record._root)
if self.file_record._parent != self:
raise kaitaistruct.ConsistencyError(u"file_record", self, self.file_record._parent)
self._dirty = False