from __future__ import absolute_import from ._snappy_cffi import ffi, lib try: unicode # Python 2 except NameError: unicode = str # Python 3 class UncompressError(Exception): pass class SnappyBufferSmallError(Exception): pass def prepare(data): _out_data = None _out_size = None _out_data = ffi.new('char[]', data) _out_size = ffi.cast('size_t', len(data)) return (_out_data, _out_size) def compress(data): if isinstance(data, unicode): data = data.encode('utf-8') _input_data, _input_size = prepare(data) max_compressed = lib.snappy_max_compressed_length(_input_size) _out_data = ffi.new('char[]', max_compressed) _out_size = ffi.new('size_t*', max_compressed) rc = lib.snappy_compress(_input_data, _input_size, _out_data, _out_size) if rc != lib.SNAPPY_OK: raise SnappyBufferSmallError() value = ffi.buffer(ffi.cast('char*', _out_data), _out_size[0]) return value[:] def uncompress(data): _out_data, _out_size = prepare(data) result = ffi.new('size_t*', 0) rc = lib.snappy_validate_compressed_buffer(_out_data, _out_size) if not rc == lib.SNAPPY_OK: raise UncompressError() rc = lib.snappy_uncompressed_length(_out_data, _out_size, result) if not rc == lib.SNAPPY_OK: raise UncompressError() _uncompressed_data = ffi.new('char[]', result[0]) rc = lib.snappy_uncompress(_out_data, _out_size, _uncompressed_data, result) if rc != lib.SNAPPY_OK: raise UncompressError() buf = ffi.buffer(ffi.cast('char*', _uncompressed_data), result[0]) return buf[:] def isValidCompressed(data): if isinstance(data, unicode): data = data.encode('utf-8') _out_data, _out_size= prepare(data) rc = lib.snappy_validate_compressed_buffer(_out_data, _out_size) return rc == lib.SNAPPY_OK decompress = uncompress def _crc32c(data): c_data = ffi.new('char[]', data) size = ffi.cast('int', len(data)) return int(lib._crc32c(c_data, size))