Current File : //opt/alt/python38/lib64/python3.8/site-packages/pyzstd/c/c_pyzstd.py
from collections import namedtuple
from enum import IntEnum
from ._zstd import *
from . import _zstd
__all__ = (# From this file
'compressionLevel_values', 'get_frame_info',
'CParameter', 'DParameter', 'Strategy',
# From _zstd
'ZstdCompressor', 'RichMemZstdCompressor',
'ZstdDecompressor', 'EndlessZstdDecompressor',
'ZstdDict', 'ZstdError', 'decompress', 'get_frame_size',
'compress_stream', 'decompress_stream',
'zstd_version', 'zstd_version_info', 'zstd_support_multithread')
# Used in __init__.py
_ZSTD_DStreamInSize = _zstd._ZSTD_DStreamInSize
_train_dict = _zstd._train_dict
_finalize_dict = _zstd._finalize_dict
# compressionLevel_values
_nt_values = namedtuple('values', ['default', 'min', 'max'])
compressionLevel_values = _nt_values(_zstd._ZSTD_defaultCLevel,
_zstd._ZSTD_minCLevel,
_zstd._ZSTD_maxCLevel)
_nt_frame_info = namedtuple('frame_info',
['decompressed_size', 'dictionary_id'])
def get_frame_info(frame_buffer):
"""Get zstd frame infomation from a frame header.
Parameter
frame_buffer: A bytes-like object. It should starts from the beginning of
a frame, and needs to include at least the frame header (6 to
18 bytes).
Return a two-items namedtuple: (decompressed_size, dictionary_id)
If decompressed_size is None, decompressed size is unknown.
dictionary_id is a 32-bit unsigned integer value. 0 means dictionary ID was
not recorded in the frame header, the frame may or may not need a dictionary
to be decoded, and the ID of such a dictionary is not specified.
It's possible to append more items to the namedtuple in the future."""
ret_tuple = _zstd._get_frame_info(frame_buffer)
return _nt_frame_info(*ret_tuple)
class CParameter(IntEnum):
"""Compression parameters"""
compressionLevel = _zstd._ZSTD_c_compressionLevel
windowLog = _zstd._ZSTD_c_windowLog
hashLog = _zstd._ZSTD_c_hashLog
chainLog = _zstd._ZSTD_c_chainLog
searchLog = _zstd._ZSTD_c_searchLog
minMatch = _zstd._ZSTD_c_minMatch
targetLength = _zstd._ZSTD_c_targetLength
strategy = _zstd._ZSTD_c_strategy
enableLongDistanceMatching = _zstd._ZSTD_c_enableLongDistanceMatching
ldmHashLog = _zstd._ZSTD_c_ldmHashLog
ldmMinMatch = _zstd._ZSTD_c_ldmMinMatch
ldmBucketSizeLog = _zstd._ZSTD_c_ldmBucketSizeLog
ldmHashRateLog = _zstd._ZSTD_c_ldmHashRateLog
contentSizeFlag = _zstd._ZSTD_c_contentSizeFlag
checksumFlag = _zstd._ZSTD_c_checksumFlag
dictIDFlag = _zstd._ZSTD_c_dictIDFlag
nbWorkers = _zstd._ZSTD_c_nbWorkers
jobSize = _zstd._ZSTD_c_jobSize
overlapLog = _zstd._ZSTD_c_overlapLog
def bounds(self):
"""Return lower and upper bounds of a compression parameter, both inclusive."""
# 1 means compression parameter
return _zstd._get_param_bounds(1, self.value)
class DParameter(IntEnum):
"""Decompression parameters"""
windowLogMax = _zstd._ZSTD_d_windowLogMax
def bounds(self):
"""Return lower and upper bounds of a decompression parameter, both inclusive."""
# 0 means decompression parameter
return _zstd._get_param_bounds(0, self.value)
class Strategy(IntEnum):
"""Compression strategies, listed from fastest to strongest.
Note : new strategies _might_ be added in the future, only the order
(from fast to strong) is guaranteed.
"""
fast = _zstd._ZSTD_fast
dfast = _zstd._ZSTD_dfast
greedy = _zstd._ZSTD_greedy
lazy = _zstd._ZSTD_lazy
lazy2 = _zstd._ZSTD_lazy2
btlazy2 = _zstd._ZSTD_btlazy2
btopt = _zstd._ZSTD_btopt
btultra = _zstd._ZSTD_btultra
btultra2 = _zstd._ZSTD_btultra2
# Set CParameter/DParameter types for validity check
_zstd._set_parameter_types(CParameter, DParameter)
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