zstandard: vendor python-zstandard 0.9.0
This was just released. It features a number of goodies. More info at
https://gregoryszorc.com/blog/2018/04/09/release-of-python-zstandard-0.9/.
The clang-format ignore list was updated to reflect the new source
of files.
The project contains a vendored copy of zstandard 1.3.4. The old
version was 1.1.3. One of the changes between those versions is that
zstandard is now dual licensed BSD + GPLv2 and the patent rights grant
has been removed. Good riddance.
The API should be backwards compatible. So no changes in core
should be needed. However, there were a number of changes in the
library that we'll want to adapt to. Those will be addressed in
subsequent commits.
Differential Revision: https://phab.mercurial-scm.org/D3198
# Copyright (c) 2016-present, Gregory Szorc
# All rights reserved.
#
# This software may be modified and distributed under the terms
# of the BSD license. See the LICENSE file for details.
"""Python interface to the Zstandard (zstd) compression library."""
from __future__ import absolute_import, unicode_literals
# This should match what the C extension exports.
__all__ = [
#'BufferSegment',
#'BufferSegments',
#'BufferWithSegments',
#'BufferWithSegmentsCollection',
'CompressionParameters',
'ZstdCompressionDict',
'ZstdCompressionParameters',
'ZstdCompressor',
'ZstdError',
'ZstdDecompressor',
'FrameParameters',
'estimate_decompression_context_size',
'frame_content_size',
'frame_header_size',
'get_frame_parameters',
'train_dictionary',
# Constants.
'COMPRESSOBJ_FLUSH_FINISH',
'COMPRESSOBJ_FLUSH_BLOCK',
'ZSTD_VERSION',
'FRAME_HEADER',
'CONTENTSIZE_UNKNOWN',
'CONTENTSIZE_ERROR',
'MAX_COMPRESSION_LEVEL',
'COMPRESSION_RECOMMENDED_INPUT_SIZE',
'COMPRESSION_RECOMMENDED_OUTPUT_SIZE',
'DECOMPRESSION_RECOMMENDED_INPUT_SIZE',
'DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE',
'MAGIC_NUMBER',
'WINDOWLOG_MIN',
'WINDOWLOG_MAX',
'CHAINLOG_MIN',
'CHAINLOG_MAX',
'HASHLOG_MIN',
'HASHLOG_MAX',
'HASHLOG3_MAX',
'SEARCHLOG_MIN',
'SEARCHLOG_MAX',
'SEARCHLENGTH_MIN',
'SEARCHLENGTH_MAX',
'TARGETLENGTH_MIN',
'LDM_MINMATCH_MIN',
'LDM_MINMATCH_MAX',
'LDM_BUCKETSIZELOG_MAX',
'STRATEGY_FAST',
'STRATEGY_DFAST',
'STRATEGY_GREEDY',
'STRATEGY_LAZY',
'STRATEGY_LAZY2',
'STRATEGY_BTLAZY2',
'STRATEGY_BTOPT',
'STRATEGY_BTULTRA',
'DICT_TYPE_AUTO',
'DICT_TYPE_RAWCONTENT',
'DICT_TYPE_FULLDICT',
'FORMAT_ZSTD1',
'FORMAT_ZSTD1_MAGICLESS',
]
import io
import os
import sys
from _zstd_cffi import (
ffi,
lib,
)
if sys.version_info[0] == 2:
bytes_type = str
int_type = long
else:
bytes_type = bytes
int_type = int
COMPRESSION_RECOMMENDED_INPUT_SIZE = lib.ZSTD_CStreamInSize()
COMPRESSION_RECOMMENDED_OUTPUT_SIZE = lib.ZSTD_CStreamOutSize()
DECOMPRESSION_RECOMMENDED_INPUT_SIZE = lib.ZSTD_DStreamInSize()
DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE = lib.ZSTD_DStreamOutSize()
new_nonzero = ffi.new_allocator(should_clear_after_alloc=False)
MAX_COMPRESSION_LEVEL = lib.ZSTD_maxCLevel()
MAGIC_NUMBER = lib.ZSTD_MAGICNUMBER
FRAME_HEADER = b'\x28\xb5\x2f\xfd'
CONTENTSIZE_UNKNOWN = lib.ZSTD_CONTENTSIZE_UNKNOWN
CONTENTSIZE_ERROR = lib.ZSTD_CONTENTSIZE_ERROR
ZSTD_VERSION = (lib.ZSTD_VERSION_MAJOR, lib.ZSTD_VERSION_MINOR, lib.ZSTD_VERSION_RELEASE)
WINDOWLOG_MIN = lib.ZSTD_WINDOWLOG_MIN
WINDOWLOG_MAX = lib.ZSTD_WINDOWLOG_MAX
CHAINLOG_MIN = lib.ZSTD_CHAINLOG_MIN
CHAINLOG_MAX = lib.ZSTD_CHAINLOG_MAX
HASHLOG_MIN = lib.ZSTD_HASHLOG_MIN
HASHLOG_MAX = lib.ZSTD_HASHLOG_MAX
HASHLOG3_MAX = lib.ZSTD_HASHLOG3_MAX
SEARCHLOG_MIN = lib.ZSTD_SEARCHLOG_MIN
SEARCHLOG_MAX = lib.ZSTD_SEARCHLOG_MAX
SEARCHLENGTH_MIN = lib.ZSTD_SEARCHLENGTH_MIN
SEARCHLENGTH_MAX = lib.ZSTD_SEARCHLENGTH_MAX
TARGETLENGTH_MIN = lib.ZSTD_TARGETLENGTH_MIN
LDM_MINMATCH_MIN = lib.ZSTD_LDM_MINMATCH_MIN
LDM_MINMATCH_MAX = lib.ZSTD_LDM_MINMATCH_MAX
LDM_BUCKETSIZELOG_MAX = lib.ZSTD_LDM_BUCKETSIZELOG_MAX
STRATEGY_FAST = lib.ZSTD_fast
STRATEGY_DFAST = lib.ZSTD_dfast
STRATEGY_GREEDY = lib.ZSTD_greedy
STRATEGY_LAZY = lib.ZSTD_lazy
STRATEGY_LAZY2 = lib.ZSTD_lazy2
STRATEGY_BTLAZY2 = lib.ZSTD_btlazy2
STRATEGY_BTOPT = lib.ZSTD_btopt
STRATEGY_BTULTRA = lib.ZSTD_btultra
DICT_TYPE_AUTO = lib.ZSTD_dct_auto
DICT_TYPE_RAWCONTENT = lib.ZSTD_dct_rawContent
DICT_TYPE_FULLDICT = lib.ZSTD_dct_fullDict
FORMAT_ZSTD1 = lib.ZSTD_f_zstd1
FORMAT_ZSTD1_MAGICLESS = lib.ZSTD_f_zstd1_magicless
COMPRESSOBJ_FLUSH_FINISH = 0
COMPRESSOBJ_FLUSH_BLOCK = 1
def _cpu_count():
# os.cpu_count() was introducd in Python 3.4.
try:
return os.cpu_count() or 0
except AttributeError:
pass
# Linux.
try:
if sys.version_info[0] == 2:
return os.sysconf(b'SC_NPROCESSORS_ONLN')
else:
return os.sysconf(u'SC_NPROCESSORS_ONLN')
except (AttributeError, ValueError):
pass
# TODO implement on other platforms.
return 0
class ZstdError(Exception):
pass
def _zstd_error(zresult):
# Resolves to bytes on Python 2 and 3. We use the string for formatting
# into error messages, which will be literal unicode. So convert it to
# unicode.
return ffi.string(lib.ZSTD_getErrorName(zresult)).decode('utf-8')
def _make_cctx_params(params):
res = lib.ZSTD_createCCtxParams()
if res == ffi.NULL:
raise MemoryError()
res = ffi.gc(res, lib.ZSTD_freeCCtxParams)
attrs = [
(lib.ZSTD_p_format, params.format),
(lib.ZSTD_p_compressionLevel, params.compression_level),
(lib.ZSTD_p_windowLog, params.window_log),
(lib.ZSTD_p_hashLog, params.hash_log),
(lib.ZSTD_p_chainLog, params.chain_log),
(lib.ZSTD_p_searchLog, params.search_log),
(lib.ZSTD_p_minMatch, params.min_match),
(lib.ZSTD_p_targetLength, params.target_length),
(lib.ZSTD_p_compressionStrategy, params.compression_strategy),
(lib.ZSTD_p_contentSizeFlag, params.write_content_size),
(lib.ZSTD_p_checksumFlag, params.write_checksum),
(lib.ZSTD_p_dictIDFlag, params.write_dict_id),
(lib.ZSTD_p_nbWorkers, params.threads),
(lib.ZSTD_p_jobSize, params.job_size),
(lib.ZSTD_p_overlapSizeLog, params.overlap_size_log),
(lib.ZSTD_p_compressLiterals, params.compress_literals),
(lib.ZSTD_p_forceMaxWindow, params.force_max_window),
(lib.ZSTD_p_enableLongDistanceMatching, params.enable_ldm),
(lib.ZSTD_p_ldmHashLog, params.ldm_hash_log),
(lib.ZSTD_p_ldmMinMatch, params.ldm_min_match),
(lib.ZSTD_p_ldmBucketSizeLog, params.ldm_bucket_size_log),
(lib.ZSTD_p_ldmHashEveryLog, params.ldm_hash_every_log),
]
for param, value in attrs:
_set_compression_parameter(res, param, value)
return res
class ZstdCompressionParameters(object):
@staticmethod
def from_level(level, source_size=0, dict_size=0, **kwargs):
params = lib.ZSTD_getCParams(level, source_size, dict_size)
args = {
'window_log': 'windowLog',
'chain_log': 'chainLog',
'hash_log': 'hashLog',
'search_log': 'searchLog',
'min_match': 'searchLength',
'target_length': 'targetLength',
'compression_strategy': 'strategy',
}
for arg, attr in args.items():
if arg not in kwargs:
kwargs[arg] = getattr(params, attr)
if 'compress_literals' not in kwargs:
kwargs['compress_literals'] = 1 if level >= 0 else 0
return ZstdCompressionParameters(**kwargs)
def __init__(self, format=0, compression_level=0, window_log=0, hash_log=0,
chain_log=0, search_log=0, min_match=0, target_length=0,
compression_strategy=0, write_content_size=1, write_checksum=0,
write_dict_id=0, job_size=0, overlap_size_log=0,
force_max_window=0, enable_ldm=0, ldm_hash_log=0,
ldm_min_match=0, ldm_bucket_size_log=0, ldm_hash_every_log=0,
threads=0, compress_literals=None):
if threads < 0:
threads = _cpu_count()
if compress_literals is None:
compress_literals = compression_level >= 0
self.format = format
self.compression_level = compression_level
self.window_log = window_log
self.hash_log = hash_log
self.chain_log = chain_log
self.search_log = search_log
self.min_match = min_match
self.target_length = target_length
self.compression_strategy = compression_strategy
self.write_content_size = write_content_size
self.write_checksum = write_checksum
self.write_dict_id = write_dict_id
self.job_size = job_size
self.overlap_size_log = overlap_size_log
self.compress_literals = compress_literals
self.force_max_window = force_max_window
self.enable_ldm = enable_ldm
self.ldm_hash_log = ldm_hash_log
self.ldm_min_match = ldm_min_match
self.ldm_bucket_size_log = ldm_bucket_size_log
self.ldm_hash_every_log = ldm_hash_every_log
self.threads = threads
self.params = _make_cctx_params(self)
def estimated_compression_context_size(self):
return lib.ZSTD_estimateCCtxSize_usingCCtxParams(self.params)
CompressionParameters = ZstdCompressionParameters
def estimate_decompression_context_size():
return lib.ZSTD_estimateDCtxSize()
def _set_compression_parameter(params, param, value):
zresult = lib.ZSTD_CCtxParam_setParameter(params, param,
ffi.cast('unsigned', value))
if lib.ZSTD_isError(zresult):
raise ZstdError('unable to set compression context parameter: %s' %
_zstd_error(zresult))
class ZstdCompressionWriter(object):
def __init__(self, compressor, writer, source_size, write_size):
self._compressor = compressor
self._writer = writer
self._source_size = source_size
self._write_size = write_size
self._entered = False
self._bytes_compressed = 0
def __enter__(self):
if self._entered:
raise ZstdError('cannot __enter__ multiple times')
zresult = lib.ZSTD_CCtx_setPledgedSrcSize(self._compressor._cctx,
self._source_size)
if lib.ZSTD_isError(zresult):
raise ZstdError('error setting source size: %s' %
_zstd_error(zresult))
self._entered = True
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self._entered = False
if not exc_type and not exc_value and not exc_tb:
dst_buffer = ffi.new('char[]', self._write_size)
out_buffer = ffi.new('ZSTD_outBuffer *')
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer.dst = dst_buffer
out_buffer.size = len(dst_buffer)
out_buffer.pos = 0
in_buffer.src = ffi.NULL
in_buffer.size = 0
in_buffer.pos = 0
while True:
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
out_buffer, in_buffer,
lib.ZSTD_e_end)
if lib.ZSTD_isError(zresult):
raise ZstdError('error ending compression stream: %s' %
_zstd_error(zresult))
if out_buffer.pos:
self._writer.write(ffi.buffer(out_buffer.dst, out_buffer.pos)[:])
out_buffer.pos = 0
if zresult == 0:
break
self._compressor = None
return False
def memory_size(self):
if not self._entered:
raise ZstdError('cannot determine size of an inactive compressor; '
'call when a context manager is active')
return lib.ZSTD_sizeof_CCtx(self._compressor._cctx)
def write(self, data):
if not self._entered:
raise ZstdError('write() must be called from an active context '
'manager')
total_write = 0
data_buffer = ffi.from_buffer(data)
in_buffer = ffi.new('ZSTD_inBuffer *')
in_buffer.src = data_buffer
in_buffer.size = len(data_buffer)
in_buffer.pos = 0
out_buffer = ffi.new('ZSTD_outBuffer *')
dst_buffer = ffi.new('char[]', self._write_size)
out_buffer.dst = dst_buffer
out_buffer.size = self._write_size
out_buffer.pos = 0
while in_buffer.pos < in_buffer.size:
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
out_buffer, in_buffer,
lib.ZSTD_e_continue)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd compress error: %s' %
_zstd_error(zresult))
if out_buffer.pos:
self._writer.write(ffi.buffer(out_buffer.dst, out_buffer.pos)[:])
total_write += out_buffer.pos
self._bytes_compressed += out_buffer.pos
out_buffer.pos = 0
return total_write
def flush(self):
if not self._entered:
raise ZstdError('flush must be called from an active context manager')
total_write = 0
out_buffer = ffi.new('ZSTD_outBuffer *')
dst_buffer = ffi.new('char[]', self._write_size)
out_buffer.dst = dst_buffer
out_buffer.size = self._write_size
out_buffer.pos = 0
in_buffer = ffi.new('ZSTD_inBuffer *')
in_buffer.src = ffi.NULL
in_buffer.size = 0
in_buffer.pos = 0
while True:
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
out_buffer, in_buffer,
lib.ZSTD_e_flush)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd compress error: %s' %
_zstd_error(zresult))
if not out_buffer.pos:
break
self._writer.write(ffi.buffer(out_buffer.dst, out_buffer.pos)[:])
total_write += out_buffer.pos
self._bytes_compressed += out_buffer.pos
out_buffer.pos = 0
return total_write
def tell(self):
return self._bytes_compressed
class ZstdCompressionObj(object):
def compress(self, data):
if self._finished:
raise ZstdError('cannot call compress() after compressor finished')
data_buffer = ffi.from_buffer(data)
source = ffi.new('ZSTD_inBuffer *')
source.src = data_buffer
source.size = len(data_buffer)
source.pos = 0
chunks = []
while source.pos < len(data):
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
self._out,
source,
lib.ZSTD_e_continue)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd compress error: %s' %
_zstd_error(zresult))
if self._out.pos:
chunks.append(ffi.buffer(self._out.dst, self._out.pos)[:])
self._out.pos = 0
return b''.join(chunks)
def flush(self, flush_mode=COMPRESSOBJ_FLUSH_FINISH):
if flush_mode not in (COMPRESSOBJ_FLUSH_FINISH, COMPRESSOBJ_FLUSH_BLOCK):
raise ValueError('flush mode not recognized')
if self._finished:
raise ZstdError('compressor object already finished')
assert self._out.pos == 0
in_buffer = ffi.new('ZSTD_inBuffer *')
in_buffer.src = ffi.NULL
in_buffer.size = 0
in_buffer.pos = 0
if flush_mode == COMPRESSOBJ_FLUSH_BLOCK:
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
self._out,
in_buffer,
lib.ZSTD_e_flush)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd compress error: %s' %
_zstd_error(zresult))
# Output buffer is guaranteed to hold full block.
assert zresult == 0
if self._out.pos:
result = ffi.buffer(self._out.dst, self._out.pos)[:]
self._out.pos = 0
return result
else:
return b''
assert flush_mode == COMPRESSOBJ_FLUSH_FINISH
self._finished = True
chunks = []
while True:
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
self._out,
in_buffer,
lib.ZSTD_e_end)
if lib.ZSTD_isError(zresult):
raise ZstdError('error ending compression stream: %s' %
_zstd_error(zresult))
if self._out.pos:
chunks.append(ffi.buffer(self._out.dst, self._out.pos)[:])
self._out.pos = 0
if not zresult:
break
return b''.join(chunks)
class CompressionReader(object):
def __init__(self, compressor, source, size, read_size):
self._compressor = compressor
self._source = source
self._source_size = size
self._read_size = read_size
self._entered = False
self._closed = False
self._bytes_compressed = 0
self._finished_input = False
self._finished_output = False
self._in_buffer = ffi.new('ZSTD_inBuffer *')
# Holds a ref so backing bytes in self._in_buffer stay alive.
self._source_buffer = None
def __enter__(self):
if self._entered:
raise ValueError('cannot __enter__ multiple times')
zresult = lib.ZSTD_CCtx_setPledgedSrcSize(self._compressor._cctx,
self._source_size)
if lib.ZSTD_isError(zresult):
raise ZstdError('error setting source size: %s' %
_zstd_error(zresult))
self._entered = True
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self._entered = False
self._closed = True
self._source = None
self._compressor = None
return False
def readable(self):
return True
def writable(self):
return False
def seekable(self):
return False
def readline(self):
raise io.UnsupportedOperation()
def readlines(self):
raise io.UnsupportedOperation()
def write(self, data):
raise OSError('stream is not writable')
def writelines(self, ignored):
raise OSError('stream is not writable')
def isatty(self):
return False
def flush(self):
return None
def close(self):
self._closed = True
return None
def closed(self):
return self._closed
def tell(self):
return self._bytes_compressed
def readall(self):
raise NotImplementedError()
def __iter__(self):
raise io.UnsupportedOperation()
def __next__(self):
raise io.UnsupportedOperation()
next = __next__
def read(self, size=-1):
if not self._entered:
raise ZstdError('read() must be called from an active context manager')
if self._closed:
raise ValueError('stream is closed')
if self._finished_output:
return b''
if size < 1:
raise ValueError('cannot read negative or size 0 amounts')
# Need a dedicated ref to dest buffer otherwise it gets collected.
dst_buffer = ffi.new('char[]', size)
out_buffer = ffi.new('ZSTD_outBuffer *')
out_buffer.dst = dst_buffer
out_buffer.size = size
out_buffer.pos = 0
def compress_input():
if self._in_buffer.pos >= self._in_buffer.size:
return
old_pos = out_buffer.pos
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
out_buffer, self._in_buffer,
lib.ZSTD_e_continue)
self._bytes_compressed += out_buffer.pos - old_pos
if self._in_buffer.pos == self._in_buffer.size:
self._in_buffer.src = ffi.NULL
self._in_buffer.pos = 0
self._in_buffer.size = 0
self._source_buffer = None
if not hasattr(self._source, 'read'):
self._finished_input = True
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd compress error: %s',
_zstd_error(zresult))
if out_buffer.pos and out_buffer.pos == out_buffer.size:
return ffi.buffer(out_buffer.dst, out_buffer.pos)[:]
def get_input():
if self._finished_input:
return
if hasattr(self._source, 'read'):
data = self._source.read(self._read_size)
if not data:
self._finished_input = True
return
self._source_buffer = ffi.from_buffer(data)
self._in_buffer.src = self._source_buffer
self._in_buffer.size = len(self._source_buffer)
self._in_buffer.pos = 0
else:
self._source_buffer = ffi.from_buffer(self._source)
self._in_buffer.src = self._source_buffer
self._in_buffer.size = len(self._source_buffer)
self._in_buffer.pos = 0
result = compress_input()
if result:
return result
while not self._finished_input:
get_input()
result = compress_input()
if result:
return result
# EOF
old_pos = out_buffer.pos
zresult = lib.ZSTD_compress_generic(self._compressor._cctx,
out_buffer, self._in_buffer,
lib.ZSTD_e_end)
self._bytes_compressed += out_buffer.pos - old_pos
if lib.ZSTD_isError(zresult):
raise ZstdError('error ending compression stream: %s',
_zstd_error(zresult))
if zresult == 0:
self._finished_output = True
return ffi.buffer(out_buffer.dst, out_buffer.pos)[:]
class ZstdCompressor(object):
def __init__(self, level=3, dict_data=None, compression_params=None,
write_checksum=None, write_content_size=None,
write_dict_id=None, threads=0):
if level > lib.ZSTD_maxCLevel():
raise ValueError('level must be less than %d' % lib.ZSTD_maxCLevel())
if threads < 0:
threads = _cpu_count()
if compression_params and write_checksum is not None:
raise ValueError('cannot define compression_params and '
'write_checksum')
if compression_params and write_content_size is not None:
raise ValueError('cannot define compression_params and '
'write_content_size')
if compression_params and write_dict_id is not None:
raise ValueError('cannot define compression_params and '
'write_dict_id')
if compression_params and threads:
raise ValueError('cannot define compression_params and threads')
if compression_params:
self._params = _make_cctx_params(compression_params)
else:
if write_dict_id is None:
write_dict_id = True
params = lib.ZSTD_createCCtxParams()
if params == ffi.NULL:
raise MemoryError()
self._params = ffi.gc(params, lib.ZSTD_freeCCtxParams)
_set_compression_parameter(self._params,
lib.ZSTD_p_compressionLevel,
level)
_set_compression_parameter(
self._params,
lib.ZSTD_p_contentSizeFlag,
write_content_size if write_content_size is not None else 1)
_set_compression_parameter(self._params,
lib.ZSTD_p_checksumFlag,
1 if write_checksum else 0)
_set_compression_parameter(self._params,
lib.ZSTD_p_dictIDFlag,
1 if write_dict_id else 0)
if threads:
_set_compression_parameter(self._params,
lib.ZSTD_p_nbWorkers,
threads)
cctx = lib.ZSTD_createCCtx()
if cctx == ffi.NULL:
raise MemoryError()
self._cctx = cctx
self._dict_data = dict_data
# We defer setting up garbage collection until after calling
# _ensure_cctx() to ensure the memory size estimate is more accurate.
try:
self._ensure_cctx()
finally:
self._cctx = ffi.gc(cctx, lib.ZSTD_freeCCtx,
size=lib.ZSTD_sizeof_CCtx(cctx))
def _ensure_cctx(self):
lib.ZSTD_CCtx_reset(self._cctx)
zresult = lib.ZSTD_CCtx_setParametersUsingCCtxParams(self._cctx,
self._params)
if lib.ZSTD_isError(zresult):
raise ZstdError('could not set compression parameters: %s' %
_zstd_error(zresult))
dict_data = self._dict_data
if dict_data:
if dict_data._cdict:
zresult = lib.ZSTD_CCtx_refCDict(self._cctx, dict_data._cdict)
else:
zresult = lib.ZSTD_CCtx_loadDictionary_advanced(
self._cctx, dict_data.as_bytes(), len(dict_data),
lib.ZSTD_dlm_byRef, dict_data._dict_type)
if lib.ZSTD_isError(zresult):
raise ZstdError('could not load compression dictionary: %s' %
_zstd_error(zresult))
def memory_size(self):
return lib.ZSTD_sizeof_CCtx(self._cctx)
def compress(self, data):
self._ensure_cctx()
data_buffer = ffi.from_buffer(data)
dest_size = lib.ZSTD_compressBound(len(data_buffer))
out = new_nonzero('char[]', dest_size)
zresult = lib.ZSTD_CCtx_setPledgedSrcSize(self._cctx, len(data_buffer))
if lib.ZSTD_isError(zresult):
raise ZstdError('error setting source size: %s' %
_zstd_error(zresult))
out_buffer = ffi.new('ZSTD_outBuffer *')
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer.dst = out
out_buffer.size = dest_size
out_buffer.pos = 0
in_buffer.src = data_buffer
in_buffer.size = len(data_buffer)
in_buffer.pos = 0
zresult = lib.ZSTD_compress_generic(self._cctx,
out_buffer,
in_buffer,
lib.ZSTD_e_end)
if lib.ZSTD_isError(zresult):
raise ZstdError('cannot compress: %s' %
_zstd_error(zresult))
elif zresult:
raise ZstdError('unexpected partial frame flush')
return ffi.buffer(out, out_buffer.pos)[:]
def compressobj(self, size=-1):
self._ensure_cctx()
if size < 0:
size = lib.ZSTD_CONTENTSIZE_UNKNOWN
zresult = lib.ZSTD_CCtx_setPledgedSrcSize(self._cctx, size)
if lib.ZSTD_isError(zresult):
raise ZstdError('error setting source size: %s' %
_zstd_error(zresult))
cobj = ZstdCompressionObj()
cobj._out = ffi.new('ZSTD_outBuffer *')
cobj._dst_buffer = ffi.new('char[]', COMPRESSION_RECOMMENDED_OUTPUT_SIZE)
cobj._out.dst = cobj._dst_buffer
cobj._out.size = COMPRESSION_RECOMMENDED_OUTPUT_SIZE
cobj._out.pos = 0
cobj._compressor = self
cobj._finished = False
return cobj
def copy_stream(self, ifh, ofh, size=-1,
read_size=COMPRESSION_RECOMMENDED_INPUT_SIZE,
write_size=COMPRESSION_RECOMMENDED_OUTPUT_SIZE):
if not hasattr(ifh, 'read'):
raise ValueError('first argument must have a read() method')
if not hasattr(ofh, 'write'):
raise ValueError('second argument must have a write() method')
self._ensure_cctx()
if size < 0:
size = lib.ZSTD_CONTENTSIZE_UNKNOWN
zresult = lib.ZSTD_CCtx_setPledgedSrcSize(self._cctx, size)
if lib.ZSTD_isError(zresult):
raise ZstdError('error setting source size: %s' %
_zstd_error(zresult))
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer = ffi.new('ZSTD_outBuffer *')
dst_buffer = ffi.new('char[]', write_size)
out_buffer.dst = dst_buffer
out_buffer.size = write_size
out_buffer.pos = 0
total_read, total_write = 0, 0
while True:
data = ifh.read(read_size)
if not data:
break
data_buffer = ffi.from_buffer(data)
total_read += len(data_buffer)
in_buffer.src = data_buffer
in_buffer.size = len(data_buffer)
in_buffer.pos = 0
while in_buffer.pos < in_buffer.size:
zresult = lib.ZSTD_compress_generic(self._cctx,
out_buffer,
in_buffer,
lib.ZSTD_e_continue)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd compress error: %s' %
_zstd_error(zresult))
if out_buffer.pos:
ofh.write(ffi.buffer(out_buffer.dst, out_buffer.pos))
total_write += out_buffer.pos
out_buffer.pos = 0
# We've finished reading. Flush the compressor.
while True:
zresult = lib.ZSTD_compress_generic(self._cctx,
out_buffer,
in_buffer,
lib.ZSTD_e_end)
if lib.ZSTD_isError(zresult):
raise ZstdError('error ending compression stream: %s' %
_zstd_error(zresult))
if out_buffer.pos:
ofh.write(ffi.buffer(out_buffer.dst, out_buffer.pos))
total_write += out_buffer.pos
out_buffer.pos = 0
if zresult == 0:
break
return total_read, total_write
def stream_reader(self, source, size=-1,
read_size=COMPRESSION_RECOMMENDED_INPUT_SIZE):
self._ensure_cctx()
try:
size = len(source)
except Exception:
pass
if size < 0:
size = lib.ZSTD_CONTENTSIZE_UNKNOWN
return CompressionReader(self, source, size, read_size)
def stream_writer(self, writer, size=-1,
write_size=COMPRESSION_RECOMMENDED_OUTPUT_SIZE):
if not hasattr(writer, 'write'):
raise ValueError('must pass an object with a write() method')
self._ensure_cctx()
if size < 0:
size = lib.ZSTD_CONTENTSIZE_UNKNOWN
return ZstdCompressionWriter(self, writer, size, write_size)
write_to = stream_writer
def read_to_iter(self, reader, size=-1,
read_size=COMPRESSION_RECOMMENDED_INPUT_SIZE,
write_size=COMPRESSION_RECOMMENDED_OUTPUT_SIZE):
if hasattr(reader, 'read'):
have_read = True
elif hasattr(reader, '__getitem__'):
have_read = False
buffer_offset = 0
size = len(reader)
else:
raise ValueError('must pass an object with a read() method or '
'conforms to buffer protocol')
self._ensure_cctx()
if size < 0:
size = lib.ZSTD_CONTENTSIZE_UNKNOWN
zresult = lib.ZSTD_CCtx_setPledgedSrcSize(self._cctx, size)
if lib.ZSTD_isError(zresult):
raise ZstdError('error setting source size: %s' %
_zstd_error(zresult))
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer = ffi.new('ZSTD_outBuffer *')
in_buffer.src = ffi.NULL
in_buffer.size = 0
in_buffer.pos = 0
dst_buffer = ffi.new('char[]', write_size)
out_buffer.dst = dst_buffer
out_buffer.size = write_size
out_buffer.pos = 0
while True:
# We should never have output data sitting around after a previous
# iteration.
assert out_buffer.pos == 0
# Collect input data.
if have_read:
read_result = reader.read(read_size)
else:
remaining = len(reader) - buffer_offset
slice_size = min(remaining, read_size)
read_result = reader[buffer_offset:buffer_offset + slice_size]
buffer_offset += slice_size
# No new input data. Break out of the read loop.
if not read_result:
break
# Feed all read data into the compressor and emit output until
# exhausted.
read_buffer = ffi.from_buffer(read_result)
in_buffer.src = read_buffer
in_buffer.size = len(read_buffer)
in_buffer.pos = 0
while in_buffer.pos < in_buffer.size:
zresult = lib.ZSTD_compress_generic(self._cctx, out_buffer, in_buffer,
lib.ZSTD_e_continue)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd compress error: %s' %
_zstd_error(zresult))
if out_buffer.pos:
data = ffi.buffer(out_buffer.dst, out_buffer.pos)[:]
out_buffer.pos = 0
yield data
assert out_buffer.pos == 0
# And repeat the loop to collect more data.
continue
# If we get here, input is exhausted. End the stream and emit what
# remains.
while True:
assert out_buffer.pos == 0
zresult = lib.ZSTD_compress_generic(self._cctx,
out_buffer,
in_buffer,
lib.ZSTD_e_end)
if lib.ZSTD_isError(zresult):
raise ZstdError('error ending compression stream: %s' %
_zstd_error(zresult))
if out_buffer.pos:
data = ffi.buffer(out_buffer.dst, out_buffer.pos)[:]
out_buffer.pos = 0
yield data
if zresult == 0:
break
read_from = read_to_iter
def frame_progression(self):
progression = lib.ZSTD_getFrameProgression(self._cctx)
return progression.ingested, progression.consumed, progression.produced
class FrameParameters(object):
def __init__(self, fparams):
self.content_size = fparams.frameContentSize
self.window_size = fparams.windowSize
self.dict_id = fparams.dictID
self.has_checksum = bool(fparams.checksumFlag)
def frame_content_size(data):
data_buffer = ffi.from_buffer(data)
size = lib.ZSTD_getFrameContentSize(data_buffer, len(data_buffer))
if size == lib.ZSTD_CONTENTSIZE_ERROR:
raise ZstdError('error when determining content size')
elif size == lib.ZSTD_CONTENTSIZE_UNKNOWN:
return -1
else:
return size
def frame_header_size(data):
data_buffer = ffi.from_buffer(data)
zresult = lib.ZSTD_frameHeaderSize(data_buffer, len(data_buffer))
if lib.ZSTD_isError(zresult):
raise ZstdError('could not determine frame header size: %s' %
_zstd_error(zresult))
return zresult
def get_frame_parameters(data):
params = ffi.new('ZSTD_frameHeader *')
data_buffer = ffi.from_buffer(data)
zresult = lib.ZSTD_getFrameHeader(params, data_buffer, len(data_buffer))
if lib.ZSTD_isError(zresult):
raise ZstdError('cannot get frame parameters: %s' %
_zstd_error(zresult))
if zresult:
raise ZstdError('not enough data for frame parameters; need %d bytes' %
zresult)
return FrameParameters(params[0])
class ZstdCompressionDict(object):
def __init__(self, data, dict_type=DICT_TYPE_AUTO, k=0, d=0):
assert isinstance(data, bytes_type)
self._data = data
self.k = k
self.d = d
if dict_type not in (DICT_TYPE_AUTO, DICT_TYPE_RAWCONTENT,
DICT_TYPE_FULLDICT):
raise ValueError('invalid dictionary load mode: %d; must use '
'DICT_TYPE_* constants')
self._dict_type = dict_type
self._cdict = None
def __len__(self):
return len(self._data)
def dict_id(self):
return int_type(lib.ZDICT_getDictID(self._data, len(self._data)))
def as_bytes(self):
return self._data
def precompute_compress(self, level=0, compression_params=None):
if level and compression_params:
raise ValueError('must only specify one of level or '
'compression_params')
if not level and not compression_params:
raise ValueError('must specify one of level or compression_params')
if level:
cparams = lib.ZSTD_getCParams(level, 0, len(self._data))
else:
cparams = ffi.new('ZSTD_compressionParameters')
cparams.chainLog = compression_params.chain_log
cparams.hashLog = compression_params.hash_log
cparams.searchLength = compression_params.min_match
cparams.searchLog = compression_params.search_log
cparams.strategy = compression_params.compression_strategy
cparams.targetLength = compression_params.target_length
cparams.windowLog = compression_params.window_log
cdict = lib.ZSTD_createCDict_advanced(self._data, len(self._data),
lib.ZSTD_dlm_byRef,
self._dict_type,
cparams,
lib.ZSTD_defaultCMem)
if cdict == ffi.NULL:
raise ZstdError('unable to precompute dictionary')
self._cdict = ffi.gc(cdict, lib.ZSTD_freeCDict,
size=lib.ZSTD_sizeof_CDict(cdict))
@property
def _ddict(self):
ddict = lib.ZSTD_createDDict_advanced(self._data, len(self._data),
lib.ZSTD_dlm_byRef,
self._dict_type,
lib.ZSTD_defaultCMem)
if ddict == ffi.NULL:
raise ZstdError('could not create decompression dict')
ddict = ffi.gc(ddict, lib.ZSTD_freeDDict,
size=lib.ZSTD_sizeof_DDict(ddict))
self.__dict__['_ddict'] = ddict
return ddict
def train_dictionary(dict_size, samples, k=0, d=0, notifications=0, dict_id=0,
level=0, steps=0, threads=0):
if not isinstance(samples, list):
raise TypeError('samples must be a list')
if threads < 0:
threads = _cpu_count()
total_size = sum(map(len, samples))
samples_buffer = new_nonzero('char[]', total_size)
sample_sizes = new_nonzero('size_t[]', len(samples))
offset = 0
for i, sample in enumerate(samples):
if not isinstance(sample, bytes_type):
raise ValueError('samples must be bytes')
l = len(sample)
ffi.memmove(samples_buffer + offset, sample, l)
offset += l
sample_sizes[i] = l
dict_data = new_nonzero('char[]', dict_size)
dparams = ffi.new('ZDICT_cover_params_t *')[0]
dparams.k = k
dparams.d = d
dparams.steps = steps
dparams.nbThreads = threads
dparams.zParams.notificationLevel = notifications
dparams.zParams.dictID = dict_id
dparams.zParams.compressionLevel = level
if (not dparams.k and not dparams.d and not dparams.steps
and not dparams.nbThreads and not dparams.zParams.notificationLevel
and not dparams.zParams.dictID
and not dparams.zParams.compressionLevel):
zresult = lib.ZDICT_trainFromBuffer(
ffi.addressof(dict_data), dict_size,
ffi.addressof(samples_buffer),
ffi.addressof(sample_sizes, 0), len(samples))
elif dparams.steps or dparams.nbThreads:
zresult = lib.ZDICT_optimizeTrainFromBuffer_cover(
ffi.addressof(dict_data), dict_size,
ffi.addressof(samples_buffer),
ffi.addressof(sample_sizes, 0), len(samples),
ffi.addressof(dparams))
else:
zresult = lib.ZDICT_trainFromBuffer_cover(
ffi.addressof(dict_data), dict_size,
ffi.addressof(samples_buffer),
ffi.addressof(sample_sizes, 0), len(samples),
dparams)
if lib.ZDICT_isError(zresult):
msg = ffi.string(lib.ZDICT_getErrorName(zresult)).decode('utf-8')
raise ZstdError('cannot train dict: %s' % msg)
return ZstdCompressionDict(ffi.buffer(dict_data, zresult)[:],
dict_type=DICT_TYPE_FULLDICT,
k=dparams.k, d=dparams.d)
class ZstdDecompressionObj(object):
def __init__(self, decompressor, write_size):
self._decompressor = decompressor
self._write_size = write_size
self._finished = False
def decompress(self, data):
if self._finished:
raise ZstdError('cannot use a decompressobj multiple times')
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer = ffi.new('ZSTD_outBuffer *')
data_buffer = ffi.from_buffer(data)
in_buffer.src = data_buffer
in_buffer.size = len(data_buffer)
in_buffer.pos = 0
dst_buffer = ffi.new('char[]', self._write_size)
out_buffer.dst = dst_buffer
out_buffer.size = len(dst_buffer)
out_buffer.pos = 0
chunks = []
while in_buffer.pos < in_buffer.size:
zresult = lib.ZSTD_decompress_generic(self._decompressor._dctx,
out_buffer, in_buffer)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd decompressor error: %s' %
_zstd_error(zresult))
if zresult == 0:
self._finished = True
self._decompressor = None
if out_buffer.pos:
chunks.append(ffi.buffer(out_buffer.dst, out_buffer.pos)[:])
out_buffer.pos = 0
return b''.join(chunks)
class DecompressionReader(object):
def __init__(self, decompressor, source, read_size):
self._decompressor = decompressor
self._source = source
self._read_size = read_size
self._entered = False
self._closed = False
self._bytes_decompressed = 0
self._finished_input = False
self._finished_output = False
self._in_buffer = ffi.new('ZSTD_inBuffer *')
# Holds a ref to self._in_buffer.src.
self._source_buffer = None
def __enter__(self):
if self._entered:
raise ValueError('cannot __enter__ multiple times')
self._decompressor._ensure_dctx()
self._entered = True
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self._entered = False
self._closed = True
self._source = None
self._decompressor = None
return False
def readable(self):
return True
def writable(self):
return False
def seekable(self):
return True
def readline(self):
raise NotImplementedError()
def readlines(self):
raise NotImplementedError()
def write(self, data):
raise io.UnsupportedOperation()
def writelines(self, lines):
raise io.UnsupportedOperation()
def isatty(self):
return False
def flush(self):
return None
def close(self):
self._closed = True
return None
def closed(self):
return self._closed
def tell(self):
return self._bytes_decompressed
def readall(self):
raise NotImplementedError()
def __iter__(self):
raise NotImplementedError()
def __next__(self):
raise NotImplementedError()
next = __next__
def read(self, size=-1):
if not self._entered:
raise ZstdError('read() must be called from an active context manager')
if self._closed:
raise ValueError('stream is closed')
if self._finished_output:
return b''
if size < 1:
raise ValueError('cannot read negative or size 0 amounts')
dst_buffer = ffi.new('char[]', size)
out_buffer = ffi.new('ZSTD_outBuffer *')
out_buffer.dst = dst_buffer
out_buffer.size = size
out_buffer.pos = 0
def decompress():
zresult = lib.ZSTD_decompress_generic(self._decompressor._dctx,
out_buffer, self._in_buffer)
if self._in_buffer.pos == self._in_buffer.size:
self._in_buffer.src = ffi.NULL
self._in_buffer.pos = 0
self._in_buffer.size = 0
self._source_buffer = None
if not hasattr(self._source, 'read'):
self._finished_input = True
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd decompress error: %s',
_zstd_error(zresult))
elif zresult == 0:
self._finished_output = True
if out_buffer.pos and out_buffer.pos == out_buffer.size:
self._bytes_decompressed += out_buffer.size
return ffi.buffer(out_buffer.dst, out_buffer.pos)[:]
def get_input():
if self._finished_input:
return
if hasattr(self._source, 'read'):
data = self._source.read(self._read_size)
if not data:
self._finished_input = True
return
self._source_buffer = ffi.from_buffer(data)
self._in_buffer.src = self._source_buffer
self._in_buffer.size = len(self._source_buffer)
self._in_buffer.pos = 0
else:
self._source_buffer = ffi.from_buffer(self._source)
self._in_buffer.src = self._source_buffer
self._in_buffer.size = len(self._source_buffer)
self._in_buffer.pos = 0
get_input()
result = decompress()
if result:
return result
while not self._finished_input:
get_input()
result = decompress()
if result:
return result
self._bytes_decompressed += out_buffer.pos
return ffi.buffer(out_buffer.dst, out_buffer.pos)[:]
def seek(self, pos, whence=os.SEEK_SET):
if not self._entered:
raise ZstdError('seek() must be called from an active context '
'manager')
if self._closed:
raise ValueError('stream is closed')
read_amount = 0
if whence == os.SEEK_SET:
if pos < 0:
raise ValueError('cannot seek to negative position with SEEK_SET')
if pos < self._bytes_decompressed:
raise ValueError('cannot seek zstd decompression stream '
'backwards')
read_amount = pos - self._bytes_decompressed
elif whence == os.SEEK_CUR:
if pos < 0:
raise ValueError('cannot seek zstd decompression stream '
'backwards')
read_amount = pos
elif whence == os.SEEK_END:
raise ValueError('zstd decompression streams cannot be seeked '
'with SEEK_END')
while read_amount:
result = self.read(min(read_amount,
DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE))
if not result:
break
read_amount -= len(result)
return self._bytes_decompressed
class ZstdDecompressionWriter(object):
def __init__(self, decompressor, writer, write_size):
self._decompressor = decompressor
self._writer = writer
self._write_size = write_size
self._entered = False
def __enter__(self):
if self._entered:
raise ZstdError('cannot __enter__ multiple times')
self._decompressor._ensure_dctx()
self._entered = True
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self._entered = False
def memory_size(self):
if not self._decompressor._dctx:
raise ZstdError('cannot determine size of inactive decompressor '
'call when context manager is active')
return lib.ZSTD_sizeof_DCtx(self._decompressor._dctx)
def write(self, data):
if not self._entered:
raise ZstdError('write must be called from an active context manager')
total_write = 0
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer = ffi.new('ZSTD_outBuffer *')
data_buffer = ffi.from_buffer(data)
in_buffer.src = data_buffer
in_buffer.size = len(data_buffer)
in_buffer.pos = 0
dst_buffer = ffi.new('char[]', self._write_size)
out_buffer.dst = dst_buffer
out_buffer.size = len(dst_buffer)
out_buffer.pos = 0
dctx = self._decompressor._dctx
while in_buffer.pos < in_buffer.size:
zresult = lib.ZSTD_decompress_generic(dctx, out_buffer, in_buffer)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd decompress error: %s' %
_zstd_error(zresult))
if out_buffer.pos:
self._writer.write(ffi.buffer(out_buffer.dst, out_buffer.pos)[:])
total_write += out_buffer.pos
out_buffer.pos = 0
return total_write
class ZstdDecompressor(object):
def __init__(self, dict_data=None, max_window_size=0, format=FORMAT_ZSTD1):
self._dict_data = dict_data
self._max_window_size = max_window_size
self._format = format
dctx = lib.ZSTD_createDCtx()
if dctx == ffi.NULL:
raise MemoryError()
self._dctx = dctx
# Defer setting up garbage collection until full state is loaded so
# the memory size is more accurate.
try:
self._ensure_dctx()
finally:
self._dctx = ffi.gc(dctx, lib.ZSTD_freeDCtx,
size=lib.ZSTD_sizeof_DCtx(dctx))
def memory_size(self):
return lib.ZSTD_sizeof_DCtx(self._dctx)
def decompress(self, data, max_output_size=0):
self._ensure_dctx()
data_buffer = ffi.from_buffer(data)
output_size = lib.ZSTD_getFrameContentSize(data_buffer, len(data_buffer))
if output_size == lib.ZSTD_CONTENTSIZE_ERROR:
raise ZstdError('error determining content size from frame header')
elif output_size == 0:
return b''
elif output_size == lib.ZSTD_CONTENTSIZE_UNKNOWN:
if not max_output_size:
raise ZstdError('could not determine content size in frame header')
result_buffer = ffi.new('char[]', max_output_size)
result_size = max_output_size
output_size = 0
else:
result_buffer = ffi.new('char[]', output_size)
result_size = output_size
out_buffer = ffi.new('ZSTD_outBuffer *')
out_buffer.dst = result_buffer
out_buffer.size = result_size
out_buffer.pos = 0
in_buffer = ffi.new('ZSTD_inBuffer *')
in_buffer.src = data_buffer
in_buffer.size = len(data_buffer)
in_buffer.pos = 0
zresult = lib.ZSTD_decompress_generic(self._dctx, out_buffer, in_buffer)
if lib.ZSTD_isError(zresult):
raise ZstdError('decompression error: %s' %
_zstd_error(zresult))
elif zresult:
raise ZstdError('decompression error: did not decompress full frame')
elif output_size and out_buffer.pos != output_size:
raise ZstdError('decompression error: decompressed %d bytes; expected %d' %
(zresult, output_size))
return ffi.buffer(result_buffer, out_buffer.pos)[:]
def stream_reader(self, source, read_size=DECOMPRESSION_RECOMMENDED_INPUT_SIZE):
self._ensure_dctx()
return DecompressionReader(self, source, read_size)
def decompressobj(self, write_size=DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE):
if write_size < 1:
raise ValueError('write_size must be positive')
self._ensure_dctx()
return ZstdDecompressionObj(self, write_size=write_size)
def read_to_iter(self, reader, read_size=DECOMPRESSION_RECOMMENDED_INPUT_SIZE,
write_size=DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE,
skip_bytes=0):
if skip_bytes >= read_size:
raise ValueError('skip_bytes must be smaller than read_size')
if hasattr(reader, 'read'):
have_read = True
elif hasattr(reader, '__getitem__'):
have_read = False
buffer_offset = 0
size = len(reader)
else:
raise ValueError('must pass an object with a read() method or '
'conforms to buffer protocol')
if skip_bytes:
if have_read:
reader.read(skip_bytes)
else:
if skip_bytes > size:
raise ValueError('skip_bytes larger than first input chunk')
buffer_offset = skip_bytes
self._ensure_dctx()
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer = ffi.new('ZSTD_outBuffer *')
dst_buffer = ffi.new('char[]', write_size)
out_buffer.dst = dst_buffer
out_buffer.size = len(dst_buffer)
out_buffer.pos = 0
while True:
assert out_buffer.pos == 0
if have_read:
read_result = reader.read(read_size)
else:
remaining = size - buffer_offset
slice_size = min(remaining, read_size)
read_result = reader[buffer_offset:buffer_offset + slice_size]
buffer_offset += slice_size
# No new input. Break out of read loop.
if not read_result:
break
# Feed all read data into decompressor and emit output until
# exhausted.
read_buffer = ffi.from_buffer(read_result)
in_buffer.src = read_buffer
in_buffer.size = len(read_buffer)
in_buffer.pos = 0
while in_buffer.pos < in_buffer.size:
assert out_buffer.pos == 0
zresult = lib.ZSTD_decompress_generic(self._dctx, out_buffer, in_buffer)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd decompress error: %s' %
_zstd_error(zresult))
if out_buffer.pos:
data = ffi.buffer(out_buffer.dst, out_buffer.pos)[:]
out_buffer.pos = 0
yield data
if zresult == 0:
return
# Repeat loop to collect more input data.
continue
# If we get here, input is exhausted.
read_from = read_to_iter
def stream_writer(self, writer, write_size=DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE):
if not hasattr(writer, 'write'):
raise ValueError('must pass an object with a write() method')
return ZstdDecompressionWriter(self, writer, write_size)
write_to = stream_writer
def copy_stream(self, ifh, ofh,
read_size=DECOMPRESSION_RECOMMENDED_INPUT_SIZE,
write_size=DECOMPRESSION_RECOMMENDED_OUTPUT_SIZE):
if not hasattr(ifh, 'read'):
raise ValueError('first argument must have a read() method')
if not hasattr(ofh, 'write'):
raise ValueError('second argument must have a write() method')
self._ensure_dctx()
in_buffer = ffi.new('ZSTD_inBuffer *')
out_buffer = ffi.new('ZSTD_outBuffer *')
dst_buffer = ffi.new('char[]', write_size)
out_buffer.dst = dst_buffer
out_buffer.size = write_size
out_buffer.pos = 0
total_read, total_write = 0, 0
# Read all available input.
while True:
data = ifh.read(read_size)
if not data:
break
data_buffer = ffi.from_buffer(data)
total_read += len(data_buffer)
in_buffer.src = data_buffer
in_buffer.size = len(data_buffer)
in_buffer.pos = 0
# Flush all read data to output.
while in_buffer.pos < in_buffer.size:
zresult = lib.ZSTD_decompress_generic(self._dctx, out_buffer, in_buffer)
if lib.ZSTD_isError(zresult):
raise ZstdError('zstd decompressor error: %s' %
_zstd_error(zresult))
if out_buffer.pos:
ofh.write(ffi.buffer(out_buffer.dst, out_buffer.pos))
total_write += out_buffer.pos
out_buffer.pos = 0
# Continue loop to keep reading.
return total_read, total_write
def decompress_content_dict_chain(self, frames):
if not isinstance(frames, list):
raise TypeError('argument must be a list')
if not frames:
raise ValueError('empty input chain')
# First chunk should not be using a dictionary. We handle it specially.
chunk = frames[0]
if not isinstance(chunk, bytes_type):
raise ValueError('chunk 0 must be bytes')
# All chunks should be zstd frames and should have content size set.
chunk_buffer = ffi.from_buffer(chunk)
params = ffi.new('ZSTD_frameHeader *')
zresult = lib.ZSTD_getFrameHeader(params, chunk_buffer, len(chunk_buffer))
if lib.ZSTD_isError(zresult):
raise ValueError('chunk 0 is not a valid zstd frame')
elif zresult:
raise ValueError('chunk 0 is too small to contain a zstd frame')
if params.frameContentSize == lib.ZSTD_CONTENTSIZE_UNKNOWN:
raise ValueError('chunk 0 missing content size in frame')
self._ensure_dctx(load_dict=False)
last_buffer = ffi.new('char[]', params.frameContentSize)
out_buffer = ffi.new('ZSTD_outBuffer *')
out_buffer.dst = last_buffer
out_buffer.size = len(last_buffer)
out_buffer.pos = 0
in_buffer = ffi.new('ZSTD_inBuffer *')
in_buffer.src = chunk_buffer
in_buffer.size = len(chunk_buffer)
in_buffer.pos = 0
zresult = lib.ZSTD_decompress_generic(self._dctx, out_buffer, in_buffer)
if lib.ZSTD_isError(zresult):
raise ZstdError('could not decompress chunk 0: %s' %
_zstd_error(zresult))
elif zresult:
raise ZstdError('chunk 0 did not decompress full frame')
# Special case of chain length of 1
if len(frames) == 1:
return ffi.buffer(last_buffer, len(last_buffer))[:]
i = 1
while i < len(frames):
chunk = frames[i]
if not isinstance(chunk, bytes_type):
raise ValueError('chunk %d must be bytes' % i)
chunk_buffer = ffi.from_buffer(chunk)
zresult = lib.ZSTD_getFrameHeader(params, chunk_buffer, len(chunk_buffer))
if lib.ZSTD_isError(zresult):
raise ValueError('chunk %d is not a valid zstd frame' % i)
elif zresult:
raise ValueError('chunk %d is too small to contain a zstd frame' % i)
if params.frameContentSize == lib.ZSTD_CONTENTSIZE_UNKNOWN:
raise ValueError('chunk %d missing content size in frame' % i)
dest_buffer = ffi.new('char[]', params.frameContentSize)
out_buffer.dst = dest_buffer
out_buffer.size = len(dest_buffer)
out_buffer.pos = 0
in_buffer.src = chunk_buffer
in_buffer.size = len(chunk_buffer)
in_buffer.pos = 0
zresult = lib.ZSTD_decompress_generic(self._dctx, out_buffer, in_buffer)
if lib.ZSTD_isError(zresult):
raise ZstdError('could not decompress chunk %d: %s' %
_zstd_error(zresult))
elif zresult:
raise ZstdError('chunk %d did not decompress full frame' % i)
last_buffer = dest_buffer
i += 1
return ffi.buffer(last_buffer, len(last_buffer))[:]
def _ensure_dctx(self, load_dict=True):
lib.ZSTD_DCtx_reset(self._dctx)
if self._max_window_size:
zresult = lib.ZSTD_DCtx_setMaxWindowSize(self._dctx,
self._max_window_size)
if lib.ZSTD_isError(zresult):
raise ZstdError('unable to set max window size: %s' %
_zstd_error(zresult))
zresult = lib.ZSTD_DCtx_setFormat(self._dctx, self._format)
if lib.ZSTD_isError(zresult):
raise ZstdError('unable to set decoding format: %s' %
_zstd_error(zresult))
if self._dict_data and load_dict:
zresult = lib.ZSTD_DCtx_refDDict(self._dctx, self._dict_data._ddict)
if lib.ZSTD_isError(zresult):
raise ZstdError('unable to reference prepared dictionary: %s' %
_zstd_error(zresult))