def __init__(self,
p,
metadata={},
codec_name="none",
magic=MAGIC,
bad_header_checksum=False,
header_extra=""):
self.f = open(p, "w+b")
self.hasher = hashlib.sha256()
assert len(magic) == len(MAGIC)
self._magic = magic
self._bad_header_checksum = bad_header_checksum
self.f.write(INCOMPLETE_MAGIC)
self._header = {
"root_index_offset": 2**63 - 1,
"root_index_length": 0,
"total_file_length": 0,
"sha256": b"\x00" * 32,
"codec": codec_name,
"metadata": metadata,
}
self._header_extra = header_extra
encoded_header = _encode_header(self._header) + self._header_extra
self._header_length = len(encoded_header)
self.f.write(
struct.pack(header_data_length_format, len(encoded_header)))
self._header_offset = self.f.tell()
self.f.write(encoded_header)
self.f.write(encoded_crc64xz(encoded_header))
self._have_root = False
def __init__(self, p, metadata={}, codec_name="none", magic=MAGIC,
bad_header_checksum=False, header_extra=""):
self.f = open(p, "w+b")
self.hasher = hashlib.sha256()
assert len(magic) == len(MAGIC)
self._magic = magic
self._bad_header_checksum = bad_header_checksum
self.f.write(INCOMPLETE_MAGIC)
self._header = {
"root_index_offset": 2 ** 63 - 1,
"root_index_length": 0,
"total_file_length": 0,
"sha256": b"\x00" * 32,
"codec": codec_name,
"metadata": metadata,
}
self._header_extra = header_extra
encoded_header = _encode_header(self._header) + self._header_extra
self._header_length = len(encoded_header)
self.f.write(struct.pack(header_data_length_format,
len(encoded_header)))
self._header_offset = self.f.tell()
self.f.write(encoded_header)
self.f.write(encoded_crc64xz(encoded_header))
self._have_root = False
def close(self, header_overrides={}):
assert self._have_root
self.f.seek(0, 2)
self._header["total_file_length"] = self.f.tell()
self._header["sha256"] = self.hasher.digest()
self._header.update(header_overrides)
encoded_header = _encode_header(self._header) + self._header_extra
assert len(encoded_header) == self._header_length
self.f.seek(self._header_offset)
self.f.write(encoded_header)
checksum = encoded_crc64xz(encoded_header)
if self._bad_header_checksum:
checksum = b"\x00" * len(checksum)
self.f.write(checksum)
self.f.seek(0)
self.f.write(self._magic)
self.f.flush()
self.f.close()
def close(self, header_overrides={}):
assert self._have_root
self.f.seek(0, 2)
self._header["total_file_length"] = self.f.tell()
self._header["sha256"] = self.hasher.digest()
self._header.update(header_overrides)
encoded_header = _encode_header(self._header) + self._header_extra
assert len(encoded_header) == self._header_length
self.f.seek(self._header_offset)
self.f.write(encoded_header)
checksum = encoded_crc64xz(encoded_header)
if self._bad_header_checksum:
checksum = b"\x00" * len(checksum)
self.f.write(checksum)
self.f.seek(0)
self.f.write(self._magic)
self.f.flush()
self.f.close()
