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import unittest
import zstandard as zstd
class TestCompressionParameters(unittest.TestCase):
def test_bounds(self):
zstd.ZstdCompressionParameters(
window_log=zstd.WINDOWLOG_MIN,
chain_log=zstd.CHAINLOG_MIN,
hash_log=zstd.HASHLOG_MIN,
search_log=zstd.SEARCHLOG_MIN,
min_match=zstd.MINMATCH_MIN + 1,
target_length=zstd.TARGETLENGTH_MIN,
strategy=zstd.STRATEGY_FAST,
)
zstd.ZstdCompressionParameters(
window_log=zstd.WINDOWLOG_MAX,
chain_log=zstd.CHAINLOG_MAX,
hash_log=zstd.HASHLOG_MAX,
search_log=zstd.SEARCHLOG_MAX,
min_match=zstd.MINMATCH_MAX - 1,
target_length=zstd.TARGETLENGTH_MAX,
strategy=zstd.STRATEGY_BTULTRA2,
)
def test_from_level(self):
p = zstd.ZstdCompressionParameters.from_level(1)
self.assertIsInstance(p, zstd.ZstdCompressionParameters)
self.assertEqual(p.window_log, 19)
p = zstd.ZstdCompressionParameters.from_level(-4)
self.assertEqual(p.window_log, 19)
def test_members(self):
p = zstd.ZstdCompressionParameters(
window_log=10,
chain_log=6,
hash_log=7,
search_log=4,
min_match=5,
target_length=8,
strategy=1,
)
self.assertEqual(p.window_log, 10)
self.assertEqual(p.chain_log, 6)
self.assertEqual(p.hash_log, 7)
self.assertEqual(p.search_log, 4)
self.assertEqual(p.min_match, 5)
self.assertEqual(p.target_length, 8)
self.assertEqual(p.strategy, 1)
p = zstd.ZstdCompressionParameters(compression_level=2)
self.assertEqual(p.compression_level, 2)
p = zstd.ZstdCompressionParameters(threads=4)
self.assertEqual(p.threads, 4)
p = zstd.ZstdCompressionParameters(
threads=2, job_size=1048576, overlap_log=6
)
self.assertEqual(p.threads, 2)
self.assertEqual(p.job_size, 1048576)
self.assertEqual(p.overlap_log, 6)
p = zstd.ZstdCompressionParameters(compression_level=-1)
self.assertEqual(p.compression_level, -1)
p = zstd.ZstdCompressionParameters(compression_level=-2)
self.assertEqual(p.compression_level, -2)
p = zstd.ZstdCompressionParameters(force_max_window=True)
self.assertEqual(p.force_max_window, 1)
p = zstd.ZstdCompressionParameters(enable_ldm=True)
self.assertEqual(p.enable_ldm, 1)
p = zstd.ZstdCompressionParameters(ldm_hash_log=7)
self.assertEqual(p.ldm_hash_log, 7)
p = zstd.ZstdCompressionParameters(ldm_min_match=6)
self.assertEqual(p.ldm_min_match, 6)
p = zstd.ZstdCompressionParameters(ldm_bucket_size_log=7)
self.assertEqual(p.ldm_bucket_size_log, 7)
p = zstd.ZstdCompressionParameters(ldm_hash_rate_log=8)
self.assertEqual(p.ldm_hash_rate_log, 8)
def test_estimated_compression_context_size(self):
p = zstd.ZstdCompressionParameters(
window_log=20,
chain_log=16,
hash_log=17,
search_log=1,
min_match=5,
target_length=16,
strategy=zstd.STRATEGY_DFAST,
)
# 32-bit has slightly different values from 64-bit.
self.assertAlmostEqual(
p.estimated_compression_context_size(), 1303304, delta=4000
)
def test_strategy(self):
p = zstd.ZstdCompressionParameters(strategy=2)
self.assertEqual(p.strategy, 2)
p = zstd.ZstdCompressionParameters(strategy=3)
self.assertEqual(p.strategy, 3)
def test_ldm_hash_rate_log(self):
p = zstd.ZstdCompressionParameters(ldm_hash_rate_log=8)
self.assertEqual(p.ldm_hash_rate_log, 8)
def test_overlap_log(self):
p = zstd.ZstdCompressionParameters(overlap_log=2)
self.assertEqual(p.overlap_log, 2)
class TestFrameParameters(unittest.TestCase):
def test_invalid_type(self):
with self.assertRaises(TypeError):
zstd.get_frame_parameters(None)
with self.assertRaises(TypeError):
zstd.get_frame_parameters("foobarbaz")
def test_invalid_input_sizes(self):
with self.assertRaisesRegex(
zstd.ZstdError, "not enough data for frame"
):
zstd.get_frame_parameters(b"")
with self.assertRaisesRegex(
zstd.ZstdError, "not enough data for frame"
):
zstd.get_frame_parameters(zstd.FRAME_HEADER)
def test_invalid_frame(self):
with self.assertRaisesRegex(zstd.ZstdError, "Unknown frame descriptor"):
zstd.get_frame_parameters(b"foobarbaz")
def test_attributes(self):
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x00\x00")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)
# Lowest 2 bits indicate a dictionary and length. Here, the dict id is 1 byte.
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x01\x00\xff")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 255)
self.assertFalse(params.has_checksum)
# Lowest 3rd bit indicates if checksum is present.
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x04\x00")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertTrue(params.has_checksum)
# Upper 2 bits indicate content size.
params = zstd.get_frame_parameters(
zstd.FRAME_HEADER + b"\x40\x00\xff\x00"
)
self.assertEqual(params.content_size, 511)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)
# Window descriptor is 2nd byte after frame header.
params = zstd.get_frame_parameters(zstd.FRAME_HEADER + b"\x00\x40")
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 262144)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)
# Set multiple things.
params = zstd.get_frame_parameters(
zstd.FRAME_HEADER + b"\x45\x40\x0f\x10\x00"
)
self.assertEqual(params.content_size, 272)
self.assertEqual(params.window_size, 262144)
self.assertEqual(params.dict_id, 15)
self.assertTrue(params.has_checksum)
def test_input_types(self):
v = zstd.FRAME_HEADER + b"\x00\x00"
mutable_array = bytearray(len(v))
mutable_array[:] = v
sources = [
memoryview(v),
bytearray(v),
mutable_array,
]
for source in sources:
params = zstd.get_frame_parameters(source)
self.assertEqual(params.content_size, zstd.CONTENTSIZE_UNKNOWN)
self.assertEqual(params.window_size, 1024)
self.assertEqual(params.dict_id, 0)
self.assertFalse(params.has_checksum)
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