Add snappy decompression

dissect/util/compression/snappy.py

@@ -0,0 +1,86 @@
+# References:
+# - https://github.com/google/snappy/blob/main/format_description.txt
+from __future__ import annotations
+
+import io
+import struct
+from typing import BinaryIO
+
+_H = struct.Struct("<H")
+_I = struct.Struct("<I")
+
+
+def varint(src: BinaryIO) -> int:
+    result = 0
+    shift = 0
+
+    while byte := src.read(1):
+        value = byte[0]
+        if value < 0x80:
+            return result | (value << shift)
+        result |= (value & 0x7F) << shift
+        shift += 7
+
+    raise EOFError("Unexpected EOF while reading varint")
+
+
+def decompress(src: bytes | BinaryIO) -> bytes:
+    """Snappy decompress from a file-like object or bytes.
+
+    Decompresses until the stored uncompressed length in the preamble.
+
+    Args:
+        src: File-like object or bytes to decompress.
+
+    Returns:
+        The decompressed data.
+    """
+    if not hasattr(src, "read"):
+        src = io.BytesIO(src)
+
+    dst = io.BytesIO()
+
+    uncompressed_length = varint(src)
+
+    while dst.tell() < uncompressed_length:
+        tag_byte = src.read(1)[0]
+
+        if (tag := tag_byte & 0b11) == 0:
+            # Literal
+            length = tag_byte >> 2
+            if length < 60:
+                length += 1
+            elif length == 60:
+                length = src.read(1)[0] + 1
+            elif length == 61:
+                length = _H.unpack(src.read(2))[0] + 1
+            elif length == 62:
+                length = _I.unpack(src.read(3) + b"\x00")[0] + 1
+            elif length == 63:
+                length = _I.unpack(src.read(4))[0] + 1
+
+            if len(buf := src.read(length)) < length:
+                raise EOFError("Unexpected EOF while reading literal")
+
+            dst.write(buf)
+            continue
+
+        # Copy with 1, 2 or 4 byte offset
+        if tag == 1:
+            length = ((tag_byte >> 2) & 0b111) + 4
+            offset = ((tag_byte & 0b11100000) << 3) | src.read(1)[0]
+        elif tag == 2:
+            length = (tag_byte >> 2) + 1
+            offset = _H.unpack(src.read(2))[0]
+        else:
+            length = (tag_byte >> 2) + 1
+            offset = _I.unpack(src.read(4))[0]
+
+        dst_offset = dst.tell() - offset
+        buf = dst.getbuffer()[dst_offset : dst_offset + length].tobytes()
+        if offset - length <= 0:
+            buf = (buf * ((length // len(buf)) + 1))[:length]
+
+        dst.write(buf)
+
+    return dst.getvalue()

tests/compression/test_lz4.py

@@ -11,7 +11,7 @@
     from pytest_benchmark.fixture import BenchmarkFixture
 
 
-@pytest.mark.parametrize(
+PARAMS = (
     ("data", "digest"),
     [
         pytest.param(
@@ -41,37 +41,14 @@
         ),
     ],
 )
-def test_lz4_decompress(lz4: ModuleType, data: str, digest: str) -> None:
-    assert hashlib.sha256(lz4.decompress(bytes.fromhex(data))).hexdigest() == digest
 
 
-@pytest.mark.benchmark
-def test_benchmark_lz4_decompress(lz4: ModuleType, benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex("ff0c4c5a3420636f6d7072657373696f6e207465737420737472696e671b00db507472696e67")
-    assert benchmark(lz4.decompress, buf) == b"LZ4 compression test string" * 10
+@pytest.mark.parametrize(*PARAMS)
+def test_lz4_decompress(lz4: ModuleType, data: str, digest: str) -> None:
+    assert hashlib.sha256(lz4.decompress(bytes.fromhex(data))).hexdigest() == digest
 
 
 @pytest.mark.benchmark
-def test_benchmark_large_lz4_decompress(lz4: ModuleType, benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex(
-        "ffffa94c6f72656d20697073756d20646f6c6f722073697420616d657420636f"
-        "6e73656374657475722061646970697363696e6720656c69742e205175697371"
-        "75652066617563696275732065782073617069656e2076697461652070656c6c"
-        "656e7465737175652073656d20706c6163657261742e20496e20696420637572"
-        "737573206d69207072657469756d2074656c6c7573206475697320636f6e7661"
-        "6c6c69732e2054656d707573206c656f2065752061656e65616e207365642064"
-        "69616d2075726e612074656d706f722e2050756c76696e617220766976616d75"
-        "73206672696e67696c6c61206c61637573206e6563206d657475732062696265"
-        "6e64756d20656765737461732e20496163756c6973206d61737361206e69736c"
-        "206d616c657375616461206c6163696e696120696e7465676572206e756e6320"
-        "706f73756572652e2055742068656e6472657269742073656d7065722076656c"
-        "20636c61737320617074656e742074616369746920736f63696f7371752e2041"
-        "64206c69746f726120746f727175656e742070657220636f6e75626961206e6f"
-        "7374726120696e636570746f732068696d656e61656f732e0a0ab701ffffffff"
-        "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
-        "ffffffffffffffffffffffffffffffffff4550656f732e0a"
-    )
-    assert (
-        hashlib.sha256(benchmark(lz4.decompress, buf)).hexdigest()
-        == "73d3dd96ca2e2f0144a117019256d770ee7c6febeaee09b24956c723ae22b529"
-    )
+@pytest.mark.parametrize(*PARAMS)
+def test_benchmark_lz4_decompress(lz4: ModuleType, data: str, digest: str, benchmark: BenchmarkFixture) -> None:
+    assert hashlib.sha256(benchmark(lz4.decompress, bytes.fromhex(data))).hexdigest() == digest

tests/compression/test_lzbitmap.py

@@ -11,7 +11,7 @@
     from pytest_benchmark.fixture import BenchmarkFixture
 
 
-@pytest.mark.parametrize(
+PARAMS = (
     ("data", "digest"),
     [
         pytest.param(
@@ -49,41 +49,14 @@
         ),
     ],
 )
-def test_lzbitmap_decompress(data: str, digest: str) -> None:
-    assert hashlib.sha256(lzbitmap.decompress(bytes.fromhex(data))).hexdigest() == digest
 
 
-@pytest.mark.benchmark
-def test_benchmark_lzbitmap_decompress(benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex(
-        "5a424d092d0000a0000018000018000018000061616161616161617835ef"
-        "340f0000f10f00000000000000000000000000060000000000",
-    )
-    assert benchmark(lzbitmap.decompress, buf) == b"a" * 158 + b"xa"
+@pytest.mark.parametrize(*PARAMS)
+def test_lzbitmap_decompress(data: str, digest: str) -> None:
+    assert hashlib.sha256(lzbitmap.decompress(bytes.fromhex(data))).hexdigest() == digest
 
 
 @pytest.mark.benchmark
-def test_benchmark_large_lzbitmap_decompress(benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex(
-        "5a424d09d80100df36002301005001007601004c6f72656d20697073756d"
-        "20646f6c6f722073742061657420636e7365636574757220616469706973"
-        "696e67656c69742e517573716566617563627520657820736170656e7661"
-        "6570656c6c6e6573656d6c61637261496e20696475727573206d69707269"
-        "74656c757364206f76616c7354656d7075206c656f7561656e6561646469"
-        "6d206e2074656d706f72506c6e7276697675736672696c61206c636e636d"
-        "657473626962656e64756d67657461732e496c696d6173206e6c6d616c75"
-        "64616c696e616e746567726e6e63707365722e5574206864726572697473"
-        "6d7072766c637373207074656e74747469736f6f73712e41646c696f7261"
-        "6f7175657465727562696f74726370746f686d6f732e0a0a4c0d2c341b41"
-        "3e26113c5f6e805b6b7c65529d967ec4b310edb922ca7b1deca5faf4434a"
-        "fbfa52fb8272b2ffb7016f7fcbc1b9f1373af99e3eb4e94fa9b3bafe39d3"
-        "6959add6f36b55eecdb59d2ec3d1d029fc0055a9cbed016111718114103f"
-        "480147110116011040f125f3ffffffffffffffffffffffffffffffffffff"
-        "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
-        "ffffffffffffffff1f002cf68f57d9c576d73bfd7cd3d756000006000000"
-        "0000",
-    )
-    assert (
-        hashlib.sha256(benchmark(lzbitmap.decompress, buf)).hexdigest()
-        == "73d3dd96ca2e2f0144a117019256d770ee7c6febeaee09b24956c723ae22b529"
-    )
+@pytest.mark.parametrize(*PARAMS)
+def test_benchmark_lzbitmap_decompress(data: str, digest: str, benchmark: BenchmarkFixture) -> None:
+    assert hashlib.sha256(benchmark(lzbitmap.decompress, bytes.fromhex(data))).hexdigest() == digest

tests/compression/test_lzfse.py

@@ -11,7 +11,7 @@
     from pytest_benchmark.fixture import BenchmarkFixture
 
 
-@pytest.mark.parametrize(
+PARAMS = (
     ("data", "digest"),
     [
         pytest.param(
@@ -40,36 +40,14 @@
         ),
     ],
 )
-def test_lzfse_decompress(data: str, digest: str) -> None:
-    assert hashlib.sha256(lzfse.decompress(bytes.fromhex(data))).hexdigest() == digest
 
 
-@pytest.mark.benchmark
-def test_benchmark_lzfse_decompress(benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex("6276786e2c01000013000000c803616263f0fff005e163060000000000000062767824")
-    assert benchmark(lzfse.decompress, buf) == b"abc" * 100
+@pytest.mark.parametrize(*PARAMS)
+def test_lzfse_decompress(data: str, digest: str) -> None:
+    assert hashlib.sha256(lzfse.decompress(bytes.fromhex(data))).hexdigest() == digest
 
 
 @pytest.mark.benchmark
-def test_benchmark_large_lzfse_decompress(benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex(
-        "62767832df360000a401200e000d0030b92c8bef56220070a50000003984"
-        "70085f00b0000000383e59c0f1090000005fc027710c0000fc031c1f03c7"
-        "700cc70000000000000000006c00003600000000005f07000000e7000000"
-        "00100060418004120000e06338f9061e8067629dacdf013e836fe041f807"
-        "be80fd14fc0e3fc29f704700000000000000000000000000000000000000"
-        "000000000000000000000000000000000000101288d24318d9f446277ac6"
-        "885a4b5dea360854e4c4616262d667f9f1ff53187e598fe2f5ddf7b768f4"
-        "bcc1f6441b9e55e0d1be84b4b91544337f11c4d0d615068c79817f5d19f2"
-        "09c83975cf9669b7f3d1024d9cc795e8ac449090696a7660585fac1a891c"
-        "40557bb46c1b62a35ab2608d574e82ba9f3956d0f811370c78d69b24240f"
-        "fd80ec4eccb6dc1e7f1c6f2f276a71e9c73183844c3dce83088eeed6c77c"
-        "3e35316f414db430fcd2e22d0c07998d601addd5907f852df080386fe69e"
-        "b78675198704b4bf5361caaf482e9333c6de0d46fbf87b4387fc6ac57116"
-        "0300000000000000000066b7fffffff3fffa3ff7ff1fd2273e1f85c5f04f"
-        "0f4945ab8462767824"
-    )
-    assert (
-        hashlib.sha256(benchmark(lzfse.decompress, buf)).hexdigest()
-        == "73d3dd96ca2e2f0144a117019256d770ee7c6febeaee09b24956c723ae22b529"
-    )
+@pytest.mark.parametrize(*PARAMS)
+def test_benchmark_lzfse_decompress(data: str, digest: str, benchmark: BenchmarkFixture) -> None:
+    assert hashlib.sha256(benchmark(lzfse.decompress, bytes.fromhex(data))).hexdigest() == digest

tests/compression/test_lznt1.py

@@ -11,7 +11,7 @@
     from pytest_benchmark.fixture import BenchmarkFixture
 
 
-@pytest.mark.parametrize(
+PARAMS = (
     ("data", "digest"),
     [
         pytest.param(
@@ -130,131 +130,14 @@
         ),
     ],
 )
-def test_lznt1_decompress(data: str, digest: str) -> None:
-    assert hashlib.sha256(lznt1.decompress(bytes.fromhex(data)).rstrip(b"\x00")).hexdigest() == digest
 
 
-@pytest.mark.benchmark
-def test_benchmark_lznt1_decompress(benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex(
-        "38b08846232000204720410010a24701a045204400084501507900c045200524"
-        "138805b4024a44ef0358028c091601484500be009e000401189000"
-    )
-    assert benchmark(lznt1.decompress, buf) == (
-        b"F# F# G A A G F# E D D E F# F# E E F# F# G A A "
-        b"G F# E D D E F# E D D E E F# D E F# G F# D E F# "
-        b"G F# E D E A F# F# G A A G F# E D D E F# E D D\x00"
-    )
+@pytest.mark.parametrize(*PARAMS)
+def test_lznt1_decompress(data: str, digest: str) -> None:
+    assert hashlib.sha256(lznt1.decompress(bytes.fromhex(data)).rstrip(b"\x00")).hexdigest() == digest
 
 
 @pytest.mark.benchmark
-def test_benchmark_large_lznt1_decompress(benchmark: BenchmarkFixture) -> None:
-    buf = bytes.fromhex(
-        "36b3004c6f72656d2069700073756d20646f6c6f00722073697420616d006574"
-        "20636f6e736500637465747572206100646970697363696e006720656c69742e"
-        "2000517569737175652000666175636962757300206578207361706900656e20"
-        "7669746165002070656c6c656e740a65024a7300c6706c616308657261007649"
-        "6e206940642063757273006e6d8069207072657469007f36740032001164005a"
-        "017c7661006c6c69732e205465046d7000166c656f206500752061656e65616e"
-        "002073656420646961006d2075726e6120740100226f722e2050756c2076696e"
-        "617200837661126d0034667200b2696c6c0c6120007d000f6e6563200300db00"
-        "09626962656e64810075656765737461803310496163750038206d6100737361"
-        "206e69736c8100056c6573756164021f40696e69612069006967006572206e75"
-        "6e632000706f73756572652e202055742068802672651672009e007670801076"
-        "656c0820636c802520617074018084207461636974694020736f63696f808a2e"
-        "902041642080a56f72805fa46f7200a66e74809a72017d84756200356e6f7374"
-        "800d00696e636570746f73002068696d656e6165e06f732e0a0a7fdbbf6dbf6d"
-        "fbbf6dbf6d758176c17b80cbbf6d7fdbb3c0e47fdb7320bf6dbf6d20bf6dce73"
-        "bf6dbf6dbf6d7175bf6dbf6def9fa49fa49fa49fa46cc0979fa49fa43c76699f"
-        "a49fa49fa49fa47373f99fa420749fa49fa47fdb7fdb7fdbff7fdb7fdb7fdb7f"
-        "db7fdb7fdbbf6de0757fbf6dbf6dbf6dbf6dbf6dbf6d2f8965fe742f896f1b2f"
-        "892f892f89b0352f89f7df362f892f89702f89d0052f892f89ff2f892f89118d"
-        "2f892f892f89df362f89ffdf362f89df369fa49fa49fa49fa49fa4ff9fa49fa4"
-        "2f899fa49fa49fa46f1b6f1bf9bf6d6d20df369fa49fa49fa49fa4fb9fa49fa4"
-        "69f0519fa42f899fa40fc03f0fc00fc0b0150fc00fc00fc02e207f0fc00fc0e0"
-        "940fc00fc00fc00fc067ff0fc0001d0fc00fc0bf6d0fc00fc0f097ff2f89c0bd"
-        "0fc00fc081039fa40fc00fc0ff7fdb4f524f524f524f524f52e0134f52df4f52"
-        "4f524f524f527fdb73df36df36cfb01a4f524f527fdb6e647fdb7fdbfb7fdb7f"
-        "db6edf36df36df36df36df363fdf369fa490c8df36df36eaf635b30073206475"
-        "69732063006f6e76616c6c6973002e2054656d70757300206c656f2065752000"
-        "61656e65616e2073006564206469616d204075726e61207400886f00722e2050"
-        "756c7669006e61722076697661026d00686672696e6769806c6c61206c616300"
-        "1e806e6563206d6574001200626962656e64756d802065676573746100ce0649"
-        "004200e0206d6173734061206e69736c000a6c206573756164023e696e406961"
-        "20696e7400307200206e756e6320706f0073756572652e205508742068004d72"
-        "6572692274009a6d70650082656c0820636c004b2061707400656e7420746163"
-        "6900746920736f63696f007371752e20416420206c69746f7200bf6f729c7175"
-        "01230138007d75620035106e6f7374800d696e63006570746f73206869006d65"
-        "6e61656f732e000a0a4c6f72656d20086970730060646f6c6f68722073803c61"
-        "006d819c7308656374007272206164206970697363808120653100352e205180"
-        "ad8034206620617563696200836578802073617069656e009900746165207065"
-        "6c6c9500446500506581642070009c00657261742e20496e0020696420637572"
-        "7301801b6d692070726574fa69803f74001980087fdbbf6dbf6d9f008ebf6dbf"
-        "6dbf6d7fdb73207fdbfdbf6d73407fdf36bf6dbf6dbf6dbf6df9bf6d6163bf6d"
-        "bf6d9fa49fa4a00c7f9fa49fa49fa49fa49fa49fa49fa467799fa476699fa49f"
-        "a47fdb7fdb737e207fdb7fdb7fdb7fdbe1d67fdb74fd40cb7281d37fdbbf6dbf"
-        "6dbf6dbf6de7bf6dbf6ddf367320bf6dbf6d2f89ffd0722f892f896f1b2f892f"
-        "892f892f89ff2f892f892f892f892f896f1b2f892f89f92f8974756f1b6f1b6f"
-        "1b6f1b6f1bff6f1b9fa49fa49fa49fa49fa49fa49fa4ff9fa49fa49fa4df36bf"
-        "6d9fa49fa4df36ff9fa49fa49fa49fa44f529fa44f52507aff2f899fa49fa40f"
-        "c00fc00fc00fc0e232ff106d2f894f520fc00fc00fc00fc00fc0bf0fc00fc04f"
-        "52bf6d0fc00fc065df36ff40bc0fc02f890fc02f894f527fdba034ff10177fdb"
-        "7fdb7fdb7fdb7fdb7fdb7fdbcfd0cb7fdb2f897fdb73737fdb7fdbcf7fdb0fc0"
-        "7fdb9fa465743156df365fdf36df36df36df367fdb6d40f36cde6cf019bf6dbf"
-        "6dbf6d70eff6b0040f2f89eff6eff67adb1fb3007375616461206c610063696e"
-        "696120696e007465676572206e75006e6320706f7375650072652e2055742068"
-        "00656e647265726974202073656d7000847665006c20636c6173732000617074"
-        "656e742074010084746920736f6369006f7371752e20416400206c69746f7261"
-        "20190008717501460170636f6e84756200d46e6f7374003600696e636570746f"
-        "73002068696d656e6165006f732e0a0a4c6f7200656d20697073756d0020646f"
-        "6c6f722073410079616d657420003e7300656374657475722040616469706973"
-        "00b967042065006a2e2051756901007a65206661756369006275732065782073"
-        "00617069656e207669007461652070656c6c4d008865022500c9207000f96500"
-        "7261742e20496e208069642063757273801b006d692070726574696d803f7400"
-        "19800864002d013e7600616c6c69732e2054030083000b6c656f206575802061"
-        "656e65616e808d0064206469616d20750c726e007b00116f722e200050756c76"
-        "696e617211804176616d001a667269606e67696c6c82bb80076e18656320806d"
-        "80046269624700b4803a80c2737461803349486163750038206d00b56120206e"
-        "69736c00056c65fb7fdbbf6d6ebf6dbf6dbf6dbf6d7fdbff7fdbbf6dbf6dbf6d"
-        "bf6dbf6dbf6dbf6df9bf6d7373bf6d9fa49fa49fa49fa46f9fa49fa49fa49fa4"
-        "209fa49fa476fe699fa49fa49fa47fdb7fdb40337fdb3f7fdb7fdbe0d37fdb40"
-        "677fdb7320df7fdbbf6d6f1bbf6d6f1b63a051bf6d7e20bf6dbf6d2f894f522f"
-        "892f8969bf2f89101b2f892f896f1b2f89202f89ff2f892f892f8960972f892f"
-        "892f892f89be202f892f892f892f892f89652f89ff4f529fa49fa49fa49fa49f"
-        "a4df369fa4fb9fa49fa4746f1bbf6d9fa49fa4df36e79fa4df364f526d708032"
-        "6f1b6f1bff6f1b6f1b6f1b6f1bbf6d80790fc00fc0ff0fc04f520fc00fc00fc0"
-        "0fc00fc0df36ffdf36df36df36df36bf6d0fc00fc06f1b6c73650fc00fc0200f"
-        "c00fc067f76f1b6f1b6f1b6edf36df36df36df36ffdf36df36df36df36df367f"
-        "dbbf6d7fdbff7fdb7fdbbf6d2f89806bdf366f1b7fdbfe736f1b7fdbbf6dbf6d"
-        "bf6dbf6dbf6d3fbf6dbf6deff6f161bf6db86d0bb300732e0a0a4c6f7265006d"
-        "20697073756d2000646f6c6f72207369007420616d65742063006f6e73656374"
-        "6574007572206164697069007363696e6720656c0069742e2051756973007175"
-        "6520666175630069627573206578200073617069656e20760069746165207065"
-        "6ca06c656e7465024a7300c680706c6163657261007600496e20696420637504"
-        "727300376d6920707268657469007f74003200116403005a017c76616c6c6973"
-        "402e2054656d7000166c00656f206575206165006e65616e2073656400206469"
-        "616d207572106e61207400226f722e002050756c76696e612272008376616d00"
-        "346672c100b2696c6c6120007d000f306e65632000db000962691062656e6480"
-        "3a65676508737461803349616375010038206d6173736120106e69736c00056c"
-        "657308756164021f696e69610420690069676572206e00756e6320706f737500"
-        "6572652e2055742062688026726572009e00767081801076656c20636c802510"
-        "206170748084207461006369746920736f6304696f808a2e204164204980a56f"
-        "72805f6f7200a66e4a74809a72017d756200356e086f7374800d696e63650070"
-        "746f732068696de0656e61656f7fdb804fbf6dffbf6dbf6dbf6dbf6d7fdb7fdb"
-        "407dbf6dfbbf6dbf6d20bf6dbf6dbf6d2069bf6d7fbf6dbf6d81759fa49fa4c0"
-        "48409a6dfe209fa49fa49fa49fa49fa49fa49fa4efe0b49fa49fa494a4001f00"
-        "3f043f04ff3f043f043f043f043f043f041f021f01ff1f011f011f011f011f01"
-        "1f011f011f01ff1f011f011f011f011f011f011f011f01ff1f011f011f011f01"
-        "1f011f011f011f01ff1f011f011f011f011f011f011f011f01ff1f011f011f01"
-        "1f011f011f011f011f01ff1f011f011f011f011f011f011f011f01ff1f011f01"
-        "1f011f011f011f011f011f01ff1f011f011f011f011f011f011f011f01ff1f01"
-        "1f011f011f011f011f011f011f01ff1f011f011f011f011f011f011f011f01ff"
-        "1f011f011f011f011f011f011f011f01ff1f011f011f011f011f011f011f011f"
-        "01ff1f011f011f011f011f011f011f011f017f1f011f011f011f011f011f011b"
-        "0103b00200fc0f03b00200fc0f03b00200fc0f03b00200fc0f03b00200fc0f03"
-        "b00200fc0f03b00200fc0f03b00200fc0f03b00200fc0f03b00200fc0f03b002"
-        "00fc0f03b00200fc0f0000000000000000000000000000000000000000000000"
-    )
-    assert hashlib.sha256(benchmark(lznt1.decompress, buf).rstrip(b"\x00")).hexdigest() == (
-        "73d3dd96ca2e2f0144a117019256d770ee7c6febeaee09b24956c723ae22b529"
-    )
+@pytest.mark.parametrize(*PARAMS)
+def test_benchmark_lznt1_decompress(data: str, digest: str, benchmark: BenchmarkFixture) -> None:
+    assert hashlib.sha256(benchmark(lznt1.decompress, bytes.fromhex(data)).rstrip(b"\x00")).hexdigest() == digest