def get_header_zip(self, header):
if 'zip' in header:
z = header['zip']
if self._algorithms and z not in self._algorithms:
raise UnsupportedCompressionAlgorithmError()
if z not in self.ZIP_REGISTRY:
raise UnsupportedCompressionAlgorithmError()
return self.ZIP_REGISTRY[z]
def _pre_validate_header(self, header):
if 'alg' not in header:
raise MissingAlgorithmError()
alg = header['alg']
if alg not in self._alg_algorithms:
raise UnsupportedAlgorithmError()
if 'enc' not in header:
raise MissingEncryptionAlgorithmError()
enc = header['enc']
if enc not in self._enc_algorithms:
raise UnsupportedEncryptionAlgorithmError()
zip = header.get('zip')
if zip and zip not in self._zip_algorithms:
raise UnsupportedCompressionAlgorithmError()