using System.Buffers.Binary; using System.Runtime.CompilerServices; namespace System.IO.Hashing { public sealed class Crc64 : NonCryptographicHashAlgorithm { private const ulong InitialState = 0; private const int Size = 8; private ulong _crc; private static ReadOnlySpan<ulong> CrcLookup { get { object obj = global::<PrivateImplementationDetails>.9510833BE85D6E7BDB0A990BB21B3E1C205A015F87BC5382489CDAF427C2AA8B_A15; if (obj == null) { obj = new ulong[256] { 0, 4823603603198064275, 9647207206396128550, 14344283933443513269, 5274672035359026399, 847670339082705484, 14759040976900489721, 10241823793177474922, 10549344070718052798, 15030250704074698541, 1695340678165410968, 6158653484774949387, 15804726273676621153, 11071337880091427826, 6824194888265062471, 2036903512645398228, 7367177604490692079, 2651944067726553980, 16419204125234161865, 11613757334439845466, 3390681356330821936, 7926053118503640995, 12317306969549898774, 16726154088988619397, 17607865585094646865, 13162708473643690690, 8194994013375312247, 3695931686473304036, 13648389776530124942, 18417527692557321757, 4073807025290796456, 8825348881154370363, 14734355208981384158, 10271039580541631821, 5303888135453107960, 822984195088142443, 9604374506261047041, 14391664176758772114, 47380625301539367, 4780770595170139316, 6781362712661643872, 2084283301222999283, 15852106237007281990, 11028505464239851989, 1670654249350217407, 6187869865390245932, 10578560694269006745, 15005564104267687178, 12269926345859042865, 16768987096479742114, 3433514057002836759, 7878672873577829764, 16389988026750624494, 11638443477897467005, 7391863372946608072, 2622728278751721819, 4044590402276644751, 8850035479350698268, 13673076206955870889, 18388311311405091898, 8147614050581592912, 3738764100714335683, 17650697762308740726, 13115328684529279205, 15709965168302367023, 11021966344253216700, 6909860770376862729, 2095335087373712026, 10607776270906215920, 15115916238825782115, 1645968390176284886, 6063892853452478021, 5216239979862816913, 762004938812542466, 14808413130408695223, 10336584279807992612, 94761250603078734, 4872975272980325085, 9561541190340278632, 14285852213486374907, 13562725425323287744, 18359094313119879763, 4168566602445998566, 8874722219015798645, 17657238303940757535, 13257468400305012364, 8136561383943382329, 3610266854770152362, 3341308498700434814, 7831293060043656173, 12375739730780491864, 16811819059476047563, 7452841817450123681, 2710377314828461874, 16324444680414493831, 11564384134825822740, 1621282580641819377, 6093108618008534114, 10636992411005044695, 15091230119249932612, 6867028114005673518, 2142715359940571325, 15757345747155659528, 10979133309658045851, 9518708972583580495, 14333231979791697372, 142141253402664553, 4830142882085382394, 14783726745893216144, 10365800689136969987, 5245456557503443638, 737318311902463013, 8089180804553289502, 3653099890976004493, 17700070958701396536, 13210088128275084459, 4139350461810230209, 8899408340202190162, 13587411233247080167, 18329878549100632180, 16295228101163185824, 11589070762272702515, 7477528201428671366, 2681160907110034709, 12328359726370364031, 16854651450907929836, 3384140715920324441, 7783913295349006794, 17796789492404876493, 12973186262895182430, 8294265019745835499, 3597188614796881784, 13819721540753725458, 18246723593521770113, 4190670174747424052, 8707887697765516199, 7249714899603402099, 2768808468102880224, 16248400991498780757, 11785088403942012614, 3291936780352569772, 8025325358597240639, 12127785706904956042, 16915077318774037017, 10432479959725633826, 15147713122803500977, 1524009877625084932, 6329456346323069591, 15705454305770282493, 11170082187107838830, 6635271944638132443, 2226424485906433608, 189522501206157468, 4634679410803088911, 9745950545960650170, 14245012653811987241, 5445476407655580739, 676338306971005648, 14876502445374089573, 10124960353263198198, 4215391513593610003, 8678706776937023872, 13790540925671641653, 18271444552530207910, 8337133204891997132, 3549843186494580063, 17749444438031597290, 13016054137459951737, 12170653315997410989, 16867732534171963454, 3244592164593781643, 8068192726900473112, 16273122767886764658, 11755906975779290337, 7220533709540304724, 2793530071884239303, 6682616997400869628, 2183556611878603887, 15662586120087312346, 11217427617020813641, 1553190491096487459, 6304735387851432112, 10407758620342516485, 15176894045242543510, 14905683634900247362, 10100238751092381137, 5420754629656923748, 705519735670536439, 9793295161182637981, 14202145287119436046, 146654890503152315, 4682024195942093864, 3242565161283638754, 7930564333232481137, 12186217236017068228, 17000743249723264599, 7335380351123765565, 2827240748300537774, 16153640314560107547, 11735716164790313608, 13734056228011347036, 18188291445129067215, 4285430719881142650, 8757259798139230185, 17846161249714921603, 13067947420601767440, 8235833358291897765, 3511522545606540086, 5387043107155988493, 590673871457609374, 14925875833148783915, 10219719885873843128, 284282506805329106, 4684052045342640705, 9660285764170764788, 14186579979835500391, 15610694155489642931, 11120709418076880672, 6720936860919424149, 2284857304564388358, 10490913115006887276, 15233377424362361855, 1474636623804926026, 6234696958930763481, 16178361609106579004, 11706535215248140463, 7306199781952008986, 2851961734412043657, 12229085463316509411, 16953397843693241456, 3195220067441434565, 7973432182840617302, 8278700923620460418, 3464177731752866065, 17798816680404380324, 13110814815472245815, 4310152537884486493, 8728078392784608718, 13704874997943502459, 18213013024491712744, 9707630858549910483, 14143712128616820032, 241414281116563189, 4731397450835853414, 14955056402857342732, 10194998898151653791, 5362321814220069418, 619854820462849209, 1503817855483314797, 6209975379031176446, 10466191297540353867, 15262558828106308056, 6768281431840648882, 2241989909157107745, 15567826590698013588, 11168054230320002311 }; global::<PrivateImplementationDetails>.9510833BE85D6E7BDB0A990BB21B3E1C205A015F87BC5382489CDAF427C2AA8B_A15 = (ulong[])obj; } return new ReadOnlySpan<ulong>((ulong[])obj); } } public Crc64() : base(8) { } private Crc64(ulong crc) : base(8) { _crc = crc; } [System.Runtime.CompilerServices.NullableContext(1)] public Crc64 Clone() { return new Crc64(_crc); } public override void Append(ReadOnlySpan<byte> source) { _crc = Update(_crc, source); } public override void Reset() { _crc = 0; } protected override void GetCurrentHashCore(Span<byte> destination) { BinaryPrimitives.WriteUInt64BigEndian(destination, _crc); } protected override void GetHashAndResetCore(Span<byte> destination) { BinaryPrimitives.WriteUInt64BigEndian(destination, _crc); _crc = 0; } [CLSCompliant(false)] public ulong GetCurrentHashAsUInt64() { return _crc; } [System.Runtime.CompilerServices.NullableContext(1)] public static byte[] Hash(byte[] source) { ExceptionPolyfills.ThrowIfNull(source, "source"); return Hash(new ReadOnlySpan<byte>(source)); } [return: System.Runtime.CompilerServices.Nullable(1)] public static byte[] Hash(ReadOnlySpan<byte> source) { byte[] obj = new byte[8]; BinaryPrimitives.WriteUInt64BigEndian(value: HashToUInt64(source), destination: obj); return obj; } public static bool TryHash(ReadOnlySpan<byte> source, Span<byte> destination, out int bytesWritten) { if (destination.Length < 8) { bytesWritten = 0; return false; } ulong value = HashToUInt64(source); BinaryPrimitives.WriteUInt64BigEndian(destination, value); bytesWritten = 8; return true; } public static int Hash(ReadOnlySpan<byte> source, Span<byte> destination) { if (destination.Length < 8) NonCryptographicHashAlgorithm.ThrowDestinationTooShort(); ulong value = HashToUInt64(source); BinaryPrimitives.WriteUInt64BigEndian(destination, value); return 8; } [CLSCompliant(false)] public static ulong HashToUInt64(ReadOnlySpan<byte> source) { return Update(0, source); } private static ulong Update(ulong crc, ReadOnlySpan<byte> source) { return UpdateScalar(crc, source); } private static ulong UpdateScalar(ulong crc, ReadOnlySpan<byte> source) { ReadOnlySpan<ulong> crcLookup = CrcLookup; for (int i = 0; i < source.Length; i++) { ulong num = crc >> 56; num ^= source[i]; crc = (crcLookup[(int)num] ^ (crc << 8)); } return crc; } } }