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import lz4.stream
import pytest
import sys
_1KB = 1024
_1MB = _1KB * 1024
_1GB = _1MB * 1024
def compress(x, c_kwargs):
c = []
with lz4.stream.LZ4StreamCompressor(**c_kwargs) as proc:
for start in range(0, len(x), c_kwargs['buffer_size']):
chunk = x[start:start + c_kwargs['buffer_size']]
block = proc.compress(chunk)
c.append(block)
if c_kwargs.get('return_bytearray', False):
return bytearray().join(c)
else:
return bytes().join(c)
def decompress(x, d_kwargs):
d = []
with lz4.stream.LZ4StreamDecompressor(**d_kwargs) as proc:
start = 0
while start < len(x):
block = proc.get_block(x[start:])
chunk = proc.decompress(block)
d.append(chunk)
start += d_kwargs['store_comp_size'] + len(block)
if d_kwargs.get('return_bytearray', False):
return bytearray().join(d)
else:
return bytes().join(d)
test_buffer_size = sorted(
[256,
1 * _1KB,
64 * _1KB,
1 * _1MB,
1 * _1GB,
lz4.stream.LZ4_MAX_INPUT_SIZE]
)
@pytest.fixture(
params=test_buffer_size,
ids=[
'buffer_size' + str(i) for i in range(len(test_buffer_size))
]
)
def buffer_size(request):
return request.param
test_data = [
(b'a' * _1MB),
]
@pytest.fixture(
params=test_data,
ids=[
'data' + str(i) for i in range(len(test_data))
]
)
def data(request):
return request.param
def test_block_decompress_mem_usage(data, buffer_size):
kwargs = {
'strategy': "double_buffer",
'buffer_size': buffer_size,
'store_comp_size': 4,
}
if sys.maxsize < 0xffffffff:
pytest.skip('Py_ssize_t too small for this test')
tracemalloc = pytest.importorskip('tracemalloc')
# Trace memory usage on compression
tracemalloc.start()
prev_snapshot = None
for i in range(1000):
compressed = compress(data, kwargs)
if i % 100 == 0:
snapshot = tracemalloc.take_snapshot()
if prev_snapshot:
# Filter on lz4.stream module'a allocations
stats = [x for x in snapshot.compare_to(prev_snapshot, 'lineno')
if lz4.stream.__file__ in x.traceback._frames[0][0]]
assert sum(map(lambda x: x.size_diff, stats)) < (1024 * 4)
prev_snapshot = snapshot
tracemalloc.stop()
tracemalloc.start()
prev_snapshot = None
for i in range(1000):
decompressed = decompress(compressed, kwargs) # noqa: F841
if i % 100 == 0:
snapshot = tracemalloc.take_snapshot()
if prev_snapshot:
# Filter on lz4.stream module'a allocations
stats = [x for x in snapshot.compare_to(prev_snapshot, 'lineno')
if lz4.stream.__file__ in x.traceback._frames[0][0]]
assert sum(map(lambda x: x.size_diff, stats)) < (1024 * 4)
prev_snapshot = snapshot
tracemalloc.stop()
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