def get_coldata(coldata):
""" return values and rowmask """
dtype = np.dtype(coldata[DTYPE])
values = np.frombuffer(decompress(coldata[DATA]), dtype=dtype)
rowmask = np.unpackbits(
np.frombuffer(decompress(coldata[ROWMASK]), dtype='uint8'))
return list(values), list(rowmask)
def _read_bucket(self, doc, column_set, column_dtypes, include_symbol,
include_images, columns):
rtn = {}
if doc[VERSION] != 3:
raise ArcticException("Unhandled document version: %s" %
doc[VERSION])
# np.cumsum copies the read-only array created with frombuffer
rtn[INDEX] = np.cumsum(
np.frombuffer(decompress(doc[INDEX]), dtype='uint64'))
doc_length = len(rtn[INDEX])
column_set.update(doc[COLUMNS].keys())
# get the mask for the columns we're about to load
union_mask = np.zeros((doc_length + 7) // 8, dtype='uint8')
for c in column_set:
try:
coldata = doc[COLUMNS][c]
# the or below will make a copy of this read-only array
mask = np.frombuffer(decompress(coldata[ROWMASK]),
dtype='uint8')
union_mask = union_mask | mask
except KeyError:
rtn[c] = None
union_mask = np.unpackbits(union_mask)[:doc_length].astype('bool')
rtn_length = np.sum(union_mask)
rtn[INDEX] = rtn[INDEX][union_mask]
if include_symbol:
rtn['SYMBOL'] = [
doc[SYMBOL],
] * rtn_length
# Unpack each requested column in turn
for c in column_set:
try:
coldata = doc[COLUMNS][c]
dtype = np.dtype(coldata[DTYPE])
# values ends up being copied by pandas before being returned to the user. However, we
# copy it into a bytearray here for safety.
values = np.frombuffer(bytearray(decompress(coldata[DATA])),
dtype=dtype)
self._set_or_promote_dtype(column_dtypes, c, dtype)
rtn[c] = self._empty(rtn_length, dtype=column_dtypes[c])
# unpackbits will make a copy of the read-only array created by frombuffer
rowmask = np.unpackbits(
np.frombuffer(decompress(coldata[ROWMASK]),
dtype='uint8'))[:doc_length].astype('bool')
rowmask = rowmask[union_mask]
rtn[c][rowmask] = values
except KeyError:
rtn[c] = None
if include_images and doc.get(IMAGE_DOC, {}).get(IMAGE, {}):
rtn = self._prepend_image(rtn, doc[IMAGE_DOC], rtn_length,
column_dtypes, column_set, columns)
return rtn
def test_exceptions():
data = c.compress(b'1010101010100000000000000000000000000000000000000000000000000000000011111111111111111111111111111')
data = data[0:16]
with pytest.raises(Exception) as e:
c.decompress(data)
assert("decompressor wrote" in str(e.value).lower() or "corrupt input at" in str(e.value).lower() or "decompression failed: corrupt input" in str(e.value).lower())
data = c.compress(b'1010101010100000000000000000000000000000000000000000000000000000000011111111111111111111111111111')
data = [data[0:16] for x in (1, 2, 3)]
with pytest.raises(Exception) as e:
c.decompress_array(data)
assert ("decompressor wrote" in str(e.value).lower() or "corrupt input at" in str(e.value).lower() or "decompression failed: corrupt input" in str(e.value).lower())
def test_exceptions():
data = c.compress(b'1010101010100000000000000000000000000000000000000000000000000000000011111111111111111111111111111')
data = data[0:16]
with pytest.raises(Exception) as e:
c.decompress(data)
assert("decompressor wrote" in str(e).lower() or "corrupt input at" in str(e).lower() or "decompression failed: corrupt input" in str(e).lower())
data = c.compress(b'1010101010100000000000000000000000000000000000000000000000000000000011111111111111111111111111111')
data = [data[0:16] for x in (1, 2, 3)]
with pytest.raises(Exception) as e:
c.decompress_array(data)
assert ("decompressor wrote" in str(e).lower() or "corrupt input at" in str(e).lower() or "decompression failed: corrupt input" in str(e).lower())
def _read_bucket(self, doc, column_set, column_dtypes, include_symbol,
include_images, columns):
rtn = {}
if doc[VERSION] != 3:
raise ArcticException("Unhandled document version: %s" %
doc[VERSION])
rtn[INDEX] = np.cumsum(
np.frombuffer(decompress(doc[INDEX]), dtype='uint64'))
doc_length = len(rtn[INDEX])
column_set.update(doc[COLUMNS].keys())
# get the mask for the columns we're about to load
union_mask = np.zeros((doc_length + 7) // 8, dtype='uint8')
for c in column_set:
try:
coldata = doc[COLUMNS][c]
mask = np.frombuffer(decompress(coldata[ROWMASK]),
dtype='uint8')
union_mask = union_mask | mask
except KeyError:
rtn[c] = None
union_mask = np.unpackbits(union_mask)[:doc_length].astype('bool')
rtn_length = np.sum(union_mask)
rtn[INDEX] = rtn[INDEX][union_mask]
if include_symbol:
rtn['SYMBOL'] = [
doc[SYMBOL],
] * rtn_length
# Unpack each requested column in turn
for c in column_set:
try:
coldata = doc[COLUMNS][c]
dtype = np.dtype(coldata[DTYPE])
values = np.frombuffer(decompress(coldata[DATA]), dtype=dtype)
self._set_or_promote_dtype(column_dtypes, c, dtype)
rtn[c] = self._empty(rtn_length, dtype=column_dtypes[c])
rowmask = np.unpackbits(
np.frombuffer(decompress(coldata[ROWMASK]),
dtype='uint8'))[:doc_length].astype('bool')
rowmask = rowmask[union_mask]
rtn[c][rowmask] = values
except KeyError:
rtn[c] = None
if include_images and doc.get(IMAGE_DOC, {}).get(IMAGE, {}):
rtn = self._prepend_image(rtn, doc[IMAGE_DOC], rtn_length,
column_dtypes, column_set, columns)
return rtn
def test_tickstore_pandas_to_bucket_image():
symbol = 'SYM'
tz = 'UTC'
initial_image = {'index': dt(2014, 1, 1, 0, 0, tzinfo=mktz(tz)), 'A': 123, 'B': 54.4, 'C': 'DESC'}
data = [{'A': 120, 'D': 1}, {'A': 122, 'B': 2.0}, {'A': 3, 'B': 3.0, 'D': 1}]
tick_index = [dt(2014, 1, 2, 0, 0, tzinfo=mktz(tz)),
dt(2014, 1, 3, 0, 0, tzinfo=mktz(tz)),
dt(2014, 1, 4, 0, 0, tzinfo=mktz(tz))]
data = pd.DataFrame(data, index=tick_index)
bucket, final_image = TickStore._pandas_to_bucket(data, symbol, initial_image)
assert final_image == {'index': dt(2014, 1, 4, 0, 0, tzinfo=mktz(tz)), 'A': 3, 'B': 3.0, 'C': 'DESC', 'D': 1}
assert IMAGE_DOC in bucket
assert bucket[COUNT] == 3
assert bucket[START] == dt(2014, 1, 1, 0, 0, tzinfo=mktz(tz))
assert bucket[END] == dt(2014, 1, 4, 0, 0, tzinfo=mktz(tz))
assert set(bucket[COLUMNS]) == set(('A', 'B', 'D'))
assert set(bucket[COLUMNS]['A']) == set((ROWMASK, DTYPE, DATA))
assert get_coldata(bucket[COLUMNS]['A']) == ([120, 122, 3], [1, 1, 1, 0, 0, 0, 0, 0])
values, rowmask = get_coldata(bucket[COLUMNS]['B'])
assert np.isnan(values[0]) and values[1:] == [2.0, 3.0]
assert rowmask == [1, 1, 1, 0, 0, 0, 0, 0]
values, rowmask = get_coldata(bucket[COLUMNS]['D'])
assert np.isnan(values[1])
assert values[0] == 1 and values[2] == 1
assert rowmask == [1, 1, 1, 0, 0, 0, 0, 0]
index = [dt.fromtimestamp(int(i/1000)).replace(tzinfo=mktz(tz)) for i in
list(np.cumsum(np.frombuffer(decompress(bucket[INDEX]), dtype='uint64')))]
assert index == tick_index
assert bucket[COLUMNS]['A'][DTYPE] == 'int64'
assert bucket[COLUMNS]['B'][DTYPE] == 'float64'
assert bucket[SYMBOL] == symbol
assert bucket[IMAGE_DOC] == {IMAGE: initial_image,
IMAGE_TIME: initial_image['index']}
def test_tickstore_to_bucket_with_image():
symbol = 'SYM'
tz = 'UTC'
initial_image = {'index': dt(2014, 1, 1, 0, 0, tzinfo=mktz(tz)), 'A': 123, 'B': 54.4, 'C': 'DESC'}
data = [{'index': dt(2014, 1, 1, 0, 1, tzinfo=mktz(tz)), 'A': 124, 'D': 0},
{'index': dt(2014, 1, 1, 0, 2, tzinfo=mktz(tz)), 'A': 125, 'B': 27.2}]
bucket, final_image = TickStore._to_bucket(data, symbol, initial_image)
assert bucket[COUNT] == 2
assert bucket[END] == dt(2014, 1, 1, 0, 2, tzinfo=mktz(tz))
assert set(bucket[COLUMNS]) == set(('A', 'B', 'D'))
assert set(bucket[COLUMNS]['A']) == set((ROWMASK, DTYPE, DATA))
assert get_coldata(bucket[COLUMNS]['A']) == ([124, 125], [1, 1, 0, 0, 0, 0, 0, 0])
assert get_coldata(bucket[COLUMNS]['B']) == ([27.2], [0, 1, 0, 0, 0, 0, 0, 0])
assert get_coldata(bucket[COLUMNS]['D']) == ([0], [1, 0, 0, 0, 0, 0, 0, 0])
index = [dt.fromtimestamp(int(i/1000)).replace(tzinfo=mktz(tz)) for i in
list(np.cumsum(np.frombuffer(decompress(bucket[INDEX]), dtype='uint64')))]
assert index == [i['index'] for i in data]
assert bucket[COLUMNS]['A'][DTYPE] == 'int64'
assert bucket[COLUMNS]['B'][DTYPE] == 'float64'
assert bucket[SYMBOL] == symbol
assert bucket[START] == initial_image['index']
assert bucket[IMAGE_DOC][IMAGE] == initial_image
assert bucket[IMAGE_DOC] == {IMAGE: initial_image,
IMAGE_TIME: initial_image['index']}
assert final_image == {'index': data[-1]['index'], 'A': 125, 'B': 27.2, 'C': 'DESC', 'D': 0}
def _do_read(self,
backing_store,
library_name,
version,
symbol,
index_range=None):
'''
index_range is a 2-tuple of integers - a [from, to) range of segments to be read.
Either from or to can be None, indicating no bound.
'''
from_index = index_range[0] if index_range else None
to_index = version['up_to']
if index_range and index_range[1] and index_range[1] < version['up_to']:
to_index = index_range[1]
segment_keys = version['segment_keys']
filtered_segment_keys = []
for i, segment_index in enumerate(version['raw_segment_index']):
if (from_index is None or segment_index >= from_index) and \
(to_index is None or segment_index <= to_index):
filtered_segment_keys.append(segment_keys[i])
data = bytearray()
for segment in backing_store.read_segments(library_name,
filtered_segment_keys):
data.extend(decompress(segment))
dtype = self._dtype(version['dtype'],
version.get('dtype_metadata', {}))
rtn = np.frombuffer(data,
dtype=dtype).reshape(version.get('shape', (-1)))
return rtn
def test_exceptions():
data = c.compress(
b'1010101010100000000000000000000000000000000000000000000000000000000011111111111111111111111111111'
)
data = data[0:16]
with pytest.raises(Exception) as e:
c.decompress(data)
assert ("Decompressor wrote" in str(e) or "Corrupt input at" in str(e))
data = c.compress(
b'1010101010100000000000000000000000000000000000000000000000000000000011111111111111111111111111111'
)
data = [data[0:16] for x in (1, 2, 3)]
with pytest.raises(Exception) as e:
c.decompress_array(data)
assert ("Decompressor wrote" in str(e) or "Corrupt input at" in str(e))
def test_tickstore_to_bucket_with_image():
symbol = 'SYM'
tz = 'UTC'
initial_image = {'index': dt(2014, 1, 1, 0, 0, tzinfo=mktz(tz)), 'A': 123, 'B': 54.4, 'C': 'DESC'}
data = [{'index': dt(2014, 1, 1, 0, 1, tzinfo=mktz(tz)), 'A': 124, 'D': 0},
{'index': dt(2014, 1, 1, 0, 2, tzinfo=mktz(tz)), 'A': 125, 'B': 27.2}]
bucket, final_image = TickStore._to_bucket(data, symbol, initial_image)
assert bucket[COUNT] == 2
assert bucket[END] == dt(2014, 1, 1, 0, 2, tzinfo=mktz(tz))
assert set(bucket[COLUMNS]) == set(('A', 'B', 'D'))
assert set(bucket[COLUMNS]['A']) == set((ROWMASK, DTYPE, DATA))
assert get_coldata(bucket[COLUMNS]['A']) == ([124, 125], [1, 1, 0, 0, 0, 0, 0, 0])
assert get_coldata(bucket[COLUMNS]['B']) == ([27.2], [0, 1, 0, 0, 0, 0, 0, 0])
assert get_coldata(bucket[COLUMNS]['D']) == ([0], [1, 0, 0, 0, 0, 0, 0, 0])
index = [dt.fromtimestamp(int(i/1000)).replace(tzinfo=mktz(tz)) for i in
list(np.cumsum(np.frombuffer(decompress(bucket[INDEX]), dtype='uint64')))]
assert index == [i['index'] for i in data]
assert bucket[COLUMNS]['A'][DTYPE] == 'int64'
assert bucket[COLUMNS]['B'][DTYPE] == 'float64'
assert bucket[SYMBOL] == symbol
assert bucket[START] == initial_image['index']
assert bucket[IMAGE_DOC][IMAGE] == initial_image
assert bucket[IMAGE_DOC] == {IMAGE: initial_image,
IMAGE_TIME: initial_image['index']}
assert final_image == {'index': data[-1]['index'], 'A': 125, 'B': 27.2, 'C': 'DESC', 'D': 0}
def test_tickstore_pandas_to_bucket_image():
symbol = 'SYM'
tz = 'UTC'
initial_image = {'index': dt(2014, 1, 1, 0, 0, tzinfo=mktz(tz)), 'A': 123, 'B': 54.4, 'C': 'DESC'}
data = [{'A': 120, 'D': 1}, {'A': 122, 'B': 2.0}, {'A': 3, 'B': 3.0, 'D': 1}]
tick_index = [dt(2014, 1, 2, 0, 0, tzinfo=mktz(tz)),
dt(2014, 1, 3, 0, 0, tzinfo=mktz(tz)),
dt(2014, 1, 4, 0, 0, tzinfo=mktz(tz))]
data = pd.DataFrame(data, index=tick_index)
bucket, final_image = TickStore._pandas_to_bucket(data, symbol, initial_image)
assert final_image == {'index': dt(2014, 1, 4, 0, 0, tzinfo=mktz(tz)), 'A': 3, 'B': 3.0, 'C': 'DESC', 'D': 1}
assert IMAGE_DOC in bucket
assert bucket[COUNT] == 3
assert bucket[START] == dt(2014, 1, 1, 0, 0, tzinfo=mktz(tz))
assert bucket[END] == dt(2014, 1, 4, 0, 0, tzinfo=mktz(tz))
assert set(bucket[COLUMNS]) == set(('A', 'B', 'D'))
assert set(bucket[COLUMNS]['A']) == set((ROWMASK, DTYPE, DATA))
assert get_coldata(bucket[COLUMNS]['A']) == ([120, 122, 3], [1, 1, 1, 0, 0, 0, 0, 0])
values, rowmask = get_coldata(bucket[COLUMNS]['B'])
assert np.isnan(values[0]) and values[1:] == [2.0, 3.0]
assert rowmask == [1, 1, 1, 0, 0, 0, 0, 0]
values, rowmask = get_coldata(bucket[COLUMNS]['D'])
assert np.isnan(values[1])
assert values[0] == 1 and values[2] == 1
assert rowmask == [1, 1, 1, 0, 0, 0, 0, 0]
index = [dt.fromtimestamp(int(i/1000)).replace(tzinfo=mktz(tz)) for i in
list(np.cumsum(np.frombuffer(decompress(bucket[INDEX]), dtype='uint64')))]
assert index == tick_index
assert bucket[COLUMNS]['A'][DTYPE] == 'int64'
assert bucket[COLUMNS]['B'][DTYPE] == 'float64'
assert bucket[SYMBOL] == symbol
assert bucket[IMAGE_DOC] == {IMAGE: initial_image,
IMAGE_TIME: initial_image['index']}
def test_compress_decompress_no_parallel():
with patch('arctic._compression.clz4', sentinel.clz4), \
patch('arctic._compression.ENABLE_PARALLEL', False), \
patch('arctic._compression.lz4', wraps=lz4) as patch_lz4:
# patching clz4 with sentinel will make accessing any clz4 function explode
assert decompress(compress(b'Foo')) == b'Foo'
assert patch_lz4.compress.call_args_list == [call(b'Foo')]
assert patch_lz4.decompress.call_args_list == [call(compress(b'Foo'))]
def test_compress_decompress_no_parallel():
with patch("arctic._compression.clz4", sentinel.clz4), patch("arctic._compression.ENABLE_PARALLEL", False), patch(
"arctic._compression.lz4", wraps=lz4
) as patch_lz4:
# patching clz4 with sentinel will make accessing any clz4 function explode
assert decompress(compress("Foo")) == "Foo"
assert patch_lz4.compress.call_args_list == [call("Foo")]
assert patch_lz4.decompress.call_args_list == [call(compress("Foo"))]
def test_compress_decompress_no_parallel():
with patch('arctic._compression.clz4', sentinel.clz4), \
patch('arctic._compression.ENABLE_PARALLEL', False), \
patch('arctic._compression.lz4', wraps=lz4) as patch_lz4:
# patching clz4 with sentinel will make accessing any clz4 function explode
assert decompress(compress(b'Foo')) == b'Foo'
assert patch_lz4.compress.call_args_list == [call(b'Foo')]
assert patch_lz4.decompress.call_args_list == [call(compress(b'Foo'))]
def _read_bucket(self, doc, column_set, column_dtypes, include_symbol, include_images, columns):
rtn = {}
if doc[VERSION] != 3:
raise ArcticException("Unhandled document version: %s" % doc[VERSION])
rtn[INDEX] = np.cumsum(np.fromstring(decompress(doc[INDEX]), dtype='uint64'))
doc_length = len(rtn[INDEX])
column_set.update(doc[COLUMNS].keys())
# get the mask for the columns we're about to load
union_mask = np.zeros((doc_length + 7) // 8, dtype='uint8')
for c in column_set:
try:
coldata = doc[COLUMNS][c]
mask = np.fromstring(decompress(coldata[ROWMASK]), dtype='uint8')
union_mask = union_mask | mask
except KeyError:
rtn[c] = None
union_mask = np.unpackbits(union_mask)[:doc_length].astype('bool')
rtn_length = np.sum(union_mask)
rtn[INDEX] = rtn[INDEX][union_mask]
if include_symbol:
rtn['SYMBOL'] = [doc[SYMBOL], ] * rtn_length
# Unpack each requested column in turn
for c in column_set:
try:
coldata = doc[COLUMNS][c]
dtype = np.dtype(coldata[DTYPE])
values = np.fromstring(decompress(coldata[DATA]), dtype=dtype)
self._set_or_promote_dtype(column_dtypes, c, dtype)
rtn[c] = self._empty(rtn_length, dtype=column_dtypes[c])
rowmask = np.unpackbits(np.fromstring(decompress(coldata[ROWMASK]),
dtype='uint8'))[:doc_length].astype('bool')
rowmask = rowmask[union_mask]
rtn[c][rowmask] = values
except KeyError:
rtn[c] = None
if include_images and doc.get(IMAGE_DOC, {}).get(IMAGE, {}):
rtn = self._prepend_image(rtn, doc[IMAGE_DOC], rtn_length, column_dtypes, column_set, columns)
return rtn
def test_performance_sequential(n, length):
_str = random_string(length)
_strarr = [_str for _ in range(n)]
now = dt.now()
[c.decompress(y) for y in [c.compressHC(x) for x in _strarr]]
clz4_time = (dt.now() - now).total_seconds()
now = dt.now()
c.decompress_array(c.compressHC_array(_strarr))
clz4_time_p = (dt.now() - now).total_seconds()
now = dt.now()
[lz4_decompress(y) for y in [lz4_compress(x) for x in _strarr]]
lz4_time = (dt.now() - now).total_seconds()
print()
print("LZ4 Test %sx len:%s" % (n, length))
print(" LZ4 HC %s s" % clz4_time)
print(" LZ4 HC Parallel %s s" % clz4_time_p)
print(" LZ4 %s s" % lz4_time)
def test_performance_sequential(n, length):
_str = random_string(length)
_strarr = [_str for _ in range(n)]
now = dt.now()
[c.decompress(y) for y in [c.compressHC(x) for x in _strarr]]
clz4_time = (dt.now() - now).total_seconds()
now = dt.now()
c.decompress_array(c.compressHC_array(_strarr))
clz4_time_p = (dt.now() - now).total_seconds()
now = dt.now()
[lz4_decompress(y) for y in [lz4_compress(x) for x in _strarr]]
lz4_time = (dt.now() - now).total_seconds()
print()
print("LZ4 Test %sx len:%s" % (n, length))
print(" LZ4 HC %s s" % clz4_time)
print(" LZ4 HC Parallel %s s" % clz4_time_p)
print(" LZ4 %s s" % lz4_time)
def _segment_index(self, recarr, existing_index, start, new_segments):
"""
Generate index of datetime64 -> item offset.
Parameters:
-----------
new_data: new data being written (or appended)
existing_index: index field from the versions document of the previous version
start: first (0-based) offset of the new data
segments: list of offsets. Each offset is the row index of the
the last row of a particular chunk relative to the start of the _original_ item.
array(new_data) - segments = array(offsets in item)
Returns:
--------
Binary(compress(array([(index, datetime)]))
Where index is the 0-based index of the datetime in the DataFrame
"""
# find the index of the first datetime64 column
idx_col = self._datetime64_index(recarr)
# if one exists let's create the index on it
if idx_col is not None:
new_segments = np.array(new_segments, dtype='i8')
last_rows = recarr[new_segments - start]
# create numpy index
index = np.core.records.fromarrays([last_rows[idx_col]] + [
new_segments,
],
dtype=INDEX_DTYPE)
# append to existing index if exists
if existing_index:
# existing_index_arr is read-only but it's never written to
existing_index_arr = np.frombuffer(decompress(existing_index),
dtype=INDEX_DTYPE)
if start > 0:
existing_index_arr = existing_index_arr[
existing_index_arr['index'] < start]
index = np.concatenate((existing_index_arr, index))
return Binary(compress(index.tostring()))
elif existing_index:
raise ArcticException(
"Could not find datetime64 index in item but existing data contains one"
)
return None
def _index_range(self, version, symbol, date_range=None, **kwargs):
""" Given a version, read the segment_index and return the chunks associated
with the date_range. As the segment index is (id -> last datetime)
we need to take care in choosing the correct chunks. """
if date_range and 'segment_index' in version:
# index is read-only but it's never written to
index = np.frombuffer(decompress(version['segment_index']),
dtype=INDEX_DTYPE)
dtcol = self._datetime64_index(index)
if dtcol and len(index):
dts = index[dtcol]
start, end = _start_end(date_range, dts)
if start > dts[-1]:
return -1, -1
idxstart = min(np.searchsorted(dts, start), len(dts) - 1)
idxend = min(np.searchsorted(dts, end, side='right'),
len(dts) - 1)
return int(
index['index'][idxstart]), int(index['index'][idxend] + 1)
return super(PandasStore, self)._index_range(version, symbol, **kwargs)
def test_roundtrip_multi(n):
_str = random_string(n)
cstr = c.compress(_str)
assert _str == c.decompress(cstr)
def test_decompress():
assert decompress(compress(b"foo")) == b"foo"
def test_decompress():
assert decompress(compress("foo")) == "foo"
def test_roundtrip_multi(n):
_str = random_string(n)
cstr = c.compress(_str)
assert _str == c.decompress(cstr)
def test_roundtrip(compress):
_str = b"hello world"
cstr = compress(_str)
assert _str == c.decompress(cstr)
def test_compress_empty_string():
assert(decompress(compress(b'')) == b'')
def get_coldata(coldata):
""" return values and rowmask """
dtype = np.dtype(coldata[DTYPE])
values = np.frombuffer(decompress(coldata[DATA]), dtype=dtype)
rowmask = np.unpackbits(np.frombuffer(decompress(coldata[ROWMASK]), dtype='uint8'))
return list(values), list(rowmask)
def test_compress_empty_string():
assert (decompress(compress(b'')) == b'')
def test_roundtrip(compress):
_str = b"hello world"
cstr = compress(_str)
assert _str == c.decompress(cstr)
