Mercurial > hg
view contrib/python-zstandard/tests/test_compressor.py @ 30822:b54a2984cdd4
zstd: vendor python-zstandard 0.6.0
Commit 63c68d6f5fc8de4afd9bde81b13b537beb4e47e8 from
https://github.com/indygreg/python-zstandard is imported without
modifications (other than removing unwanted files).
This includes minor performance and feature improvements. It also
changes the vendored zstd library from 1.1.1 to 1.1.2.
# no-check-commit
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sat, 14 Jan 2017 19:41:43 -0800 |
parents | b86a448a2965 |
children | c32454d69b85 |
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import hashlib import io import struct import sys try: import unittest2 as unittest except ImportError: import unittest import zstd from .common import OpCountingBytesIO if sys.version_info[0] >= 3: next = lambda it: it.__next__() else: next = lambda it: it.next() class TestCompressor(unittest.TestCase): def test_level_bounds(self): with self.assertRaises(ValueError): zstd.ZstdCompressor(level=0) with self.assertRaises(ValueError): zstd.ZstdCompressor(level=23) class TestCompressor_compress(unittest.TestCase): def test_compress_empty(self): cctx = zstd.ZstdCompressor(level=1) cctx.compress(b'') cctx = zstd.ZstdCompressor(level=22) cctx.compress(b'') def test_compress_empty(self): cctx = zstd.ZstdCompressor(level=1) self.assertEqual(cctx.compress(b''), b'\x28\xb5\x2f\xfd\x00\x48\x01\x00\x00') # TODO should be temporary until https://github.com/facebook/zstd/issues/506 # is fixed. cctx = zstd.ZstdCompressor(write_content_size=True) with self.assertRaises(ValueError): cctx.compress(b'') cctx.compress(b'', allow_empty=True) def test_compress_large(self): chunks = [] for i in range(255): chunks.append(struct.Struct('>B').pack(i) * 16384) cctx = zstd.ZstdCompressor(level=3) result = cctx.compress(b''.join(chunks)) self.assertEqual(len(result), 999) self.assertEqual(result[0:4], b'\x28\xb5\x2f\xfd') def test_write_checksum(self): cctx = zstd.ZstdCompressor(level=1) no_checksum = cctx.compress(b'foobar') cctx = zstd.ZstdCompressor(level=1, write_checksum=True) with_checksum = cctx.compress(b'foobar') self.assertEqual(len(with_checksum), len(no_checksum) + 4) def test_write_content_size(self): cctx = zstd.ZstdCompressor(level=1) no_size = cctx.compress(b'foobar' * 256) cctx = zstd.ZstdCompressor(level=1, write_content_size=True) with_size = cctx.compress(b'foobar' * 256) self.assertEqual(len(with_size), len(no_size) + 1) def test_no_dict_id(self): samples = [] for i in range(128): samples.append(b'foo' * 64) samples.append(b'bar' * 64) samples.append(b'foobar' * 64) d = zstd.train_dictionary(1024, samples) cctx = zstd.ZstdCompressor(level=1, dict_data=d) with_dict_id = cctx.compress(b'foobarfoobar') cctx = zstd.ZstdCompressor(level=1, dict_data=d, write_dict_id=False) no_dict_id = cctx.compress(b'foobarfoobar') self.assertEqual(len(with_dict_id), len(no_dict_id) + 4) def test_compress_dict_multiple(self): samples = [] for i in range(128): samples.append(b'foo' * 64) samples.append(b'bar' * 64) samples.append(b'foobar' * 64) d = zstd.train_dictionary(8192, samples) cctx = zstd.ZstdCompressor(level=1, dict_data=d) for i in range(32): cctx.compress(b'foo bar foobar foo bar foobar') class TestCompressor_compressobj(unittest.TestCase): def test_compressobj_empty(self): cctx = zstd.ZstdCompressor(level=1) cobj = cctx.compressobj() self.assertEqual(cobj.compress(b''), b'') self.assertEqual(cobj.flush(), b'\x28\xb5\x2f\xfd\x00\x48\x01\x00\x00') def test_compressobj_large(self): chunks = [] for i in range(255): chunks.append(struct.Struct('>B').pack(i) * 16384) cctx = zstd.ZstdCompressor(level=3) cobj = cctx.compressobj() result = cobj.compress(b''.join(chunks)) + cobj.flush() self.assertEqual(len(result), 999) self.assertEqual(result[0:4], b'\x28\xb5\x2f\xfd') def test_write_checksum(self): cctx = zstd.ZstdCompressor(level=1) cobj = cctx.compressobj() no_checksum = cobj.compress(b'foobar') + cobj.flush() cctx = zstd.ZstdCompressor(level=1, write_checksum=True) cobj = cctx.compressobj() with_checksum = cobj.compress(b'foobar') + cobj.flush() self.assertEqual(len(with_checksum), len(no_checksum) + 4) def test_write_content_size(self): cctx = zstd.ZstdCompressor(level=1) cobj = cctx.compressobj(size=len(b'foobar' * 256)) no_size = cobj.compress(b'foobar' * 256) + cobj.flush() cctx = zstd.ZstdCompressor(level=1, write_content_size=True) cobj = cctx.compressobj(size=len(b'foobar' * 256)) with_size = cobj.compress(b'foobar' * 256) + cobj.flush() self.assertEqual(len(with_size), len(no_size) + 1) def test_compress_after_finished(self): cctx = zstd.ZstdCompressor() cobj = cctx.compressobj() cobj.compress(b'foo') cobj.flush() with self.assertRaisesRegexp(zstd.ZstdError, 'cannot call compress\(\) after compressor'): cobj.compress(b'foo') with self.assertRaisesRegexp(zstd.ZstdError, 'compressor object already finished'): cobj.flush() def test_flush_block_repeated(self): cctx = zstd.ZstdCompressor(level=1) cobj = cctx.compressobj() self.assertEqual(cobj.compress(b'foo'), b'') self.assertEqual(cobj.flush(zstd.COMPRESSOBJ_FLUSH_BLOCK), b'\x28\xb5\x2f\xfd\x00\x48\x18\x00\x00foo') self.assertEqual(cobj.compress(b'bar'), b'') # 3 byte header plus content. self.assertEqual(cobj.flush(), b'\x19\x00\x00bar') def test_flush_empty_block(self): cctx = zstd.ZstdCompressor(write_checksum=True) cobj = cctx.compressobj() cobj.compress(b'foobar') cobj.flush(zstd.COMPRESSOBJ_FLUSH_BLOCK) # No-op if no block is active (this is internal to zstd). self.assertEqual(cobj.flush(zstd.COMPRESSOBJ_FLUSH_BLOCK), b'') trailing = cobj.flush() # 3 bytes block header + 4 bytes frame checksum self.assertEqual(len(trailing), 7) header = trailing[0:3] self.assertEqual(header, b'\x01\x00\x00') class TestCompressor_copy_stream(unittest.TestCase): def test_no_read(self): source = object() dest = io.BytesIO() cctx = zstd.ZstdCompressor() with self.assertRaises(ValueError): cctx.copy_stream(source, dest) def test_no_write(self): source = io.BytesIO() dest = object() cctx = zstd.ZstdCompressor() with self.assertRaises(ValueError): cctx.copy_stream(source, dest) def test_empty(self): source = io.BytesIO() dest = io.BytesIO() cctx = zstd.ZstdCompressor(level=1) r, w = cctx.copy_stream(source, dest) self.assertEqual(int(r), 0) self.assertEqual(w, 9) self.assertEqual(dest.getvalue(), b'\x28\xb5\x2f\xfd\x00\x48\x01\x00\x00') def test_large_data(self): source = io.BytesIO() for i in range(255): source.write(struct.Struct('>B').pack(i) * 16384) source.seek(0) dest = io.BytesIO() cctx = zstd.ZstdCompressor() r, w = cctx.copy_stream(source, dest) self.assertEqual(r, 255 * 16384) self.assertEqual(w, 999) def test_write_checksum(self): source = io.BytesIO(b'foobar') no_checksum = io.BytesIO() cctx = zstd.ZstdCompressor(level=1) cctx.copy_stream(source, no_checksum) source.seek(0) with_checksum = io.BytesIO() cctx = zstd.ZstdCompressor(level=1, write_checksum=True) cctx.copy_stream(source, with_checksum) self.assertEqual(len(with_checksum.getvalue()), len(no_checksum.getvalue()) + 4) def test_write_content_size(self): source = io.BytesIO(b'foobar' * 256) no_size = io.BytesIO() cctx = zstd.ZstdCompressor(level=1) cctx.copy_stream(source, no_size) source.seek(0) with_size = io.BytesIO() cctx = zstd.ZstdCompressor(level=1, write_content_size=True) cctx.copy_stream(source, with_size) # Source content size is unknown, so no content size written. self.assertEqual(len(with_size.getvalue()), len(no_size.getvalue())) source.seek(0) with_size = io.BytesIO() cctx.copy_stream(source, with_size, size=len(source.getvalue())) # We specified source size, so content size header is present. self.assertEqual(len(with_size.getvalue()), len(no_size.getvalue()) + 1) def test_read_write_size(self): source = OpCountingBytesIO(b'foobarfoobar') dest = OpCountingBytesIO() cctx = zstd.ZstdCompressor() r, w = cctx.copy_stream(source, dest, read_size=1, write_size=1) self.assertEqual(r, len(source.getvalue())) self.assertEqual(w, 21) self.assertEqual(source._read_count, len(source.getvalue()) + 1) self.assertEqual(dest._write_count, len(dest.getvalue())) def compress(data, level): buffer = io.BytesIO() cctx = zstd.ZstdCompressor(level=level) with cctx.write_to(buffer) as compressor: compressor.write(data) return buffer.getvalue() class TestCompressor_write_to(unittest.TestCase): def test_empty(self): self.assertEqual(compress(b'', 1), b'\x28\xb5\x2f\xfd\x00\x48\x01\x00\x00') def test_multiple_compress(self): buffer = io.BytesIO() cctx = zstd.ZstdCompressor(level=5) with cctx.write_to(buffer) as compressor: compressor.write(b'foo') compressor.write(b'bar') compressor.write(b'x' * 8192) result = buffer.getvalue() self.assertEqual(result, b'\x28\xb5\x2f\xfd\x00\x50\x75\x00\x00\x38\x66\x6f' b'\x6f\x62\x61\x72\x78\x01\x00\xfc\xdf\x03\x23') def test_dictionary(self): samples = [] for i in range(128): samples.append(b'foo' * 64) samples.append(b'bar' * 64) samples.append(b'foobar' * 64) d = zstd.train_dictionary(8192, samples) buffer = io.BytesIO() cctx = zstd.ZstdCompressor(level=9, dict_data=d) with cctx.write_to(buffer) as compressor: compressor.write(b'foo') compressor.write(b'bar') compressor.write(b'foo' * 16384) compressed = buffer.getvalue() h = hashlib.sha1(compressed).hexdigest() self.assertEqual(h, '1c5bcd25181bcd8c1a73ea8773323e0056129f92') def test_compression_params(self): params = zstd.CompressionParameters(20, 6, 12, 5, 4, 10, zstd.STRATEGY_FAST) buffer = io.BytesIO() cctx = zstd.ZstdCompressor(compression_params=params) with cctx.write_to(buffer) as compressor: compressor.write(b'foo') compressor.write(b'bar') compressor.write(b'foobar' * 16384) compressed = buffer.getvalue() h = hashlib.sha1(compressed).hexdigest() self.assertEqual(h, '1ae31f270ed7de14235221a604b31ecd517ebd99') def test_write_checksum(self): no_checksum = io.BytesIO() cctx = zstd.ZstdCompressor(level=1) with cctx.write_to(no_checksum) as compressor: compressor.write(b'foobar') with_checksum = io.BytesIO() cctx = zstd.ZstdCompressor(level=1, write_checksum=True) with cctx.write_to(with_checksum) as compressor: compressor.write(b'foobar') self.assertEqual(len(with_checksum.getvalue()), len(no_checksum.getvalue()) + 4) def test_write_content_size(self): no_size = io.BytesIO() cctx = zstd.ZstdCompressor(level=1) with cctx.write_to(no_size) as compressor: compressor.write(b'foobar' * 256) with_size = io.BytesIO() cctx = zstd.ZstdCompressor(level=1, write_content_size=True) with cctx.write_to(with_size) as compressor: compressor.write(b'foobar' * 256) # Source size is not known in streaming mode, so header not # written. self.assertEqual(len(with_size.getvalue()), len(no_size.getvalue())) # Declaring size will write the header. with_size = io.BytesIO() with cctx.write_to(with_size, size=len(b'foobar' * 256)) as compressor: compressor.write(b'foobar' * 256) self.assertEqual(len(with_size.getvalue()), len(no_size.getvalue()) + 1) def test_no_dict_id(self): samples = [] for i in range(128): samples.append(b'foo' * 64) samples.append(b'bar' * 64) samples.append(b'foobar' * 64) d = zstd.train_dictionary(1024, samples) with_dict_id = io.BytesIO() cctx = zstd.ZstdCompressor(level=1, dict_data=d) with cctx.write_to(with_dict_id) as compressor: compressor.write(b'foobarfoobar') cctx = zstd.ZstdCompressor(level=1, dict_data=d, write_dict_id=False) no_dict_id = io.BytesIO() with cctx.write_to(no_dict_id) as compressor: compressor.write(b'foobarfoobar') self.assertEqual(len(with_dict_id.getvalue()), len(no_dict_id.getvalue()) + 4) def test_memory_size(self): cctx = zstd.ZstdCompressor(level=3) buffer = io.BytesIO() with cctx.write_to(buffer) as compressor: size = compressor.memory_size() self.assertGreater(size, 100000) def test_write_size(self): cctx = zstd.ZstdCompressor(level=3) dest = OpCountingBytesIO() with cctx.write_to(dest, write_size=1) as compressor: compressor.write(b'foo') compressor.write(b'bar') compressor.write(b'foobar') self.assertEqual(len(dest.getvalue()), dest._write_count) def test_flush_repeated(self): cctx = zstd.ZstdCompressor(level=3) dest = OpCountingBytesIO() with cctx.write_to(dest) as compressor: compressor.write(b'foo') self.assertEqual(dest._write_count, 0) compressor.flush() self.assertEqual(dest._write_count, 1) compressor.write(b'bar') self.assertEqual(dest._write_count, 1) compressor.flush() self.assertEqual(dest._write_count, 2) compressor.write(b'baz') self.assertEqual(dest._write_count, 3) def test_flush_empty_block(self): cctx = zstd.ZstdCompressor(level=3, write_checksum=True) dest = OpCountingBytesIO() with cctx.write_to(dest) as compressor: compressor.write(b'foobar' * 8192) count = dest._write_count offset = dest.tell() compressor.flush() self.assertGreater(dest._write_count, count) self.assertGreater(dest.tell(), offset) offset = dest.tell() # Ending the write here should cause an empty block to be written # to denote end of frame. trailing = dest.getvalue()[offset:] # 3 bytes block header + 4 bytes frame checksum self.assertEqual(len(trailing), 7) header = trailing[0:3] self.assertEqual(header, b'\x01\x00\x00') class TestCompressor_read_from(unittest.TestCase): def test_type_validation(self): cctx = zstd.ZstdCompressor() # Object with read() works. cctx.read_from(io.BytesIO()) # Buffer protocol works. cctx.read_from(b'foobar') with self.assertRaisesRegexp(ValueError, 'must pass an object with a read'): cctx.read_from(True) def test_read_empty(self): cctx = zstd.ZstdCompressor(level=1) source = io.BytesIO() it = cctx.read_from(source) chunks = list(it) self.assertEqual(len(chunks), 1) compressed = b''.join(chunks) self.assertEqual(compressed, b'\x28\xb5\x2f\xfd\x00\x48\x01\x00\x00') # And again with the buffer protocol. it = cctx.read_from(b'') chunks = list(it) self.assertEqual(len(chunks), 1) compressed2 = b''.join(chunks) self.assertEqual(compressed2, compressed) def test_read_large(self): cctx = zstd.ZstdCompressor(level=1) source = io.BytesIO() source.write(b'f' * zstd.COMPRESSION_RECOMMENDED_INPUT_SIZE) source.write(b'o') source.seek(0) # Creating an iterator should not perform any compression until # first read. it = cctx.read_from(source, size=len(source.getvalue())) self.assertEqual(source.tell(), 0) # We should have exactly 2 output chunks. chunks = [] chunk = next(it) self.assertIsNotNone(chunk) self.assertEqual(source.tell(), zstd.COMPRESSION_RECOMMENDED_INPUT_SIZE) chunks.append(chunk) chunk = next(it) self.assertIsNotNone(chunk) chunks.append(chunk) self.assertEqual(source.tell(), len(source.getvalue())) with self.assertRaises(StopIteration): next(it) # And again for good measure. with self.assertRaises(StopIteration): next(it) # We should get the same output as the one-shot compression mechanism. self.assertEqual(b''.join(chunks), cctx.compress(source.getvalue())) # Now check the buffer protocol. it = cctx.read_from(source.getvalue()) chunks = list(it) self.assertEqual(len(chunks), 2) self.assertEqual(b''.join(chunks), cctx.compress(source.getvalue())) def test_read_write_size(self): source = OpCountingBytesIO(b'foobarfoobar') cctx = zstd.ZstdCompressor(level=3) for chunk in cctx.read_from(source, read_size=1, write_size=1): self.assertEqual(len(chunk), 1) self.assertEqual(source._read_count, len(source.getvalue()) + 1)