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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))
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