Aaru/CRC64Context.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : CRC64Context.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Checksums.
//
// --[ Description ] ----------------------------------------------------------
//
//     Implements a CRC64 algorithm.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library is distributed in the hope that it will be useful, but
//     WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2021 Natalia Portillo
// ****************************************************************************/

using System.IO;
using System.Text;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;

namespace Aaru.Checksums
{
    /// <inheritdoc />
    /// <summary>Implements a CRC64 algorithm</summary>
    public sealed class Crc64Context : IChecksum
    {
        /// <summary>ECMA CRC64 polynomial</summary>
        public const ulong CRC64_ECMA_POLY = 0xC96C5795D7870F42;
        /// <summary>ECMA CRC64 seed</summary>
        public const ulong CRC64_ECMA_SEED = 0xFFFFFFFFFFFFFFFF;

        static readonly ulong[] _ecmaCrc64Table =
        {
            0x0000000000000000, 0xb32e4cbe03a75f6f, 0xf4843657a840a05b, 0x47aa7ae9abe7ff34, 0x7bd0c384ff8f5e33,
            0xc8fe8f3afc28015c, 0x8f54f5d357cffe68, 0x3c7ab96d5468a107, 0xf7a18709ff1ebc66, 0x448fcbb7fcb9e309,
            0x0325b15e575e1c3d, 0xb00bfde054f94352, 0x8c71448d0091e255, 0x3f5f08330336bd3a, 0x78f572daa8d1420e,
            0xcbdb3e64ab761d61, 0x7d9ba13851336649, 0xceb5ed8652943926, 0x891f976ff973c612, 0x3a31dbd1fad4997d,
            0x064b62bcaebc387a, 0xb5652e02ad1b6715, 0xf2cf54eb06fc9821, 0x41e11855055bc74e, 0x8a3a2631ae2dda2f,
            0x39146a8fad8a8540, 0x7ebe1066066d7a74, 0xcd905cd805ca251b, 0xf1eae5b551a2841c, 0x42c4a90b5205db73,
            0x056ed3e2f9e22447, 0xb6409f5cfa457b28, 0xfb374270a266cc92, 0x48190ecea1c193fd, 0x0fb374270a266cc9,
            0xbc9d3899098133a6, 0x80e781f45de992a1, 0x33c9cd4a5e4ecdce, 0x7463b7a3f5a932fa, 0xc74dfb1df60e6d95,
            0x0c96c5795d7870f4, 0xbfb889c75edf2f9b, 0xf812f32ef538d0af, 0x4b3cbf90f69f8fc0, 0x774606fda2f72ec7,
            0xc4684a43a15071a8, 0x83c230aa0ab78e9c, 0x30ec7c140910d1f3, 0x86ace348f355aadb, 0x3582aff6f0f2f5b4,
            0x7228d51f5b150a80, 0xc10699a158b255ef, 0xfd7c20cc0cdaf4e8, 0x4e526c720f7dab87, 0x09f8169ba49a54b3,
            0xbad65a25a73d0bdc, 0x710d64410c4b16bd, 0xc22328ff0fec49d2, 0x85895216a40bb6e6, 0x36a71ea8a7ace989,
            0x0adda7c5f3c4488e, 0xb9f3eb7bf06317e1, 0xfe5991925b84e8d5, 0x4d77dd2c5823b7ba, 0x64b62bcaebc387a1,
            0xd7986774e864d8ce, 0x90321d9d438327fa, 0x231c512340247895, 0x1f66e84e144cd992, 0xac48a4f017eb86fd,
            0xebe2de19bc0c79c9, 0x58cc92a7bfab26a6, 0x9317acc314dd3bc7, 0x2039e07d177a64a8, 0x67939a94bc9d9b9c,
            0xd4bdd62abf3ac4f3, 0xe8c76f47eb5265f4, 0x5be923f9e8f53a9b, 0x1c4359104312c5af, 0xaf6d15ae40b59ac0,
            0x192d8af2baf0e1e8, 0xaa03c64cb957be87, 0xeda9bca512b041b3, 0x5e87f01b11171edc, 0x62fd4976457fbfdb,
            0xd1d305c846d8e0b4, 0x96797f21ed3f1f80, 0x2557339fee9840ef, 0xee8c0dfb45ee5d8e, 0x5da24145464902e1,
            0x1a083bacedaefdd5, 0xa9267712ee09a2ba, 0x955cce7fba6103bd, 0x267282c1b9c65cd2, 0x61d8f8281221a3e6,
            0xd2f6b4961186fc89, 0x9f8169ba49a54b33, 0x2caf25044a02145c, 0x6b055fede1e5eb68, 0xd82b1353e242b407,
            0xe451aa3eb62a1500, 0x577fe680b58d4a6f, 0x10d59c691e6ab55b, 0xa3fbd0d71dcdea34, 0x6820eeb3b6bbf755,
            0xdb0ea20db51ca83a, 0x9ca4d8e41efb570e, 0x2f8a945a1d5c0861, 0x13f02d374934a966, 0xa0de61894a93f609,
            0xe7741b60e174093d, 0x545a57dee2d35652, 0xe21ac88218962d7a, 0x5134843c1b317215, 0x169efed5b0d68d21,
            0xa5b0b26bb371d24e, 0x99ca0b06e7197349, 0x2ae447b8e4be2c26, 0x6d4e3d514f59d312, 0xde6071ef4cfe8c7d,
            0x15bb4f8be788911c, 0xa6950335e42fce73, 0xe13f79dc4fc83147, 0x521135624c6f6e28, 0x6e6b8c0f1807cf2f,
            0xdd45c0b11ba09040, 0x9aefba58b0476f74, 0x29c1f6e6b3e0301b, 0xc96c5795d7870f42, 0x7a421b2bd420502d,
            0x3de861c27fc7af19, 0x8ec62d7c7c60f076, 0xb2bc941128085171, 0x0192d8af2baf0e1e, 0x4638a2468048f12a,
            0xf516eef883efae45, 0x3ecdd09c2899b324, 0x8de39c222b3eec4b, 0xca49e6cb80d9137f, 0x7967aa75837e4c10,
            0x451d1318d716ed17, 0xf6335fa6d4b1b278, 0xb199254f7f564d4c, 0x02b769f17cf11223, 0xb4f7f6ad86b4690b,
            0x07d9ba1385133664, 0x4073c0fa2ef4c950, 0xf35d8c442d53963f, 0xcf273529793b3738, 0x7c0979977a9c6857,
            0x3ba3037ed17b9763, 0x888d4fc0d2dcc80c, 0x435671a479aad56d, 0xf0783d1a7a0d8a02, 0xb7d247f3d1ea7536,
            0x04fc0b4dd24d2a59, 0x3886b22086258b5e, 0x8ba8fe9e8582d431, 0xcc0284772e652b05, 0x7f2cc8c92dc2746a,
            0x325b15e575e1c3d0, 0x8175595b76469cbf, 0xc6df23b2dda1638b, 0x75f16f0cde063ce4, 0x498bd6618a6e9de3,
            0xfaa59adf89c9c28c, 0xbd0fe036222e3db8, 0x0e21ac88218962d7, 0xc5fa92ec8aff7fb6, 0x76d4de52895820d9,
            0x317ea4bb22bfdfed, 0x8250e80521188082, 0xbe2a516875702185, 0x0d041dd676d77eea, 0x4aae673fdd3081de,
            0xf9802b81de97deb1, 0x4fc0b4dd24d2a599, 0xfceef8632775faf6, 0xbb44828a8c9205c2, 0x086ace348f355aad,
            0x34107759db5dfbaa, 0x873e3be7d8faa4c5, 0xc094410e731d5bf1, 0x73ba0db070ba049e, 0xb86133d4dbcc19ff,
            0x0b4f7f6ad86b4690, 0x4ce50583738cb9a4, 0xffcb493d702be6cb, 0xc3b1f050244347cc, 0x709fbcee27e418a3,
            0x3735c6078c03e797, 0x841b8ab98fa4b8f8, 0xadda7c5f3c4488e3, 0x1ef430e13fe3d78c, 0x595e4a08940428b8,
            0xea7006b697a377d7, 0xd60abfdbc3cbd6d0, 0x6524f365c06c89bf, 0x228e898c6b8b768b, 0x91a0c532682c29e4,
            0x5a7bfb56c35a3485, 0xe955b7e8c0fd6bea, 0xaeffcd016b1a94de, 0x1dd181bf68bdcbb1, 0x21ab38d23cd56ab6,
            0x9285746c3f7235d9, 0xd52f0e859495caed, 0x6601423b97329582, 0xd041dd676d77eeaa, 0x636f91d96ed0b1c5,
            0x24c5eb30c5374ef1, 0x97eba78ec690119e, 0xab911ee392f8b099, 0x18bf525d915feff6, 0x5f1528b43ab810c2,
            0xec3b640a391f4fad, 0x27e05a6e926952cc, 0x94ce16d091ce0da3, 0xd3646c393a29f297, 0x604a2087398eadf8,
            0x5c3099ea6de60cff, 0xef1ed5546e415390, 0xa8b4afbdc5a6aca4, 0x1b9ae303c601f3cb, 0x56ed3e2f9e224471,
            0xe5c372919d851b1e, 0xa26908783662e42a, 0x114744c635c5bb45, 0x2d3dfdab61ad1a42, 0x9e13b115620a452d,
            0xd9b9cbfcc9edba19, 0x6a978742ca4ae576, 0xa14cb926613cf817, 0x1262f598629ba778, 0x55c88f71c97c584c,
            0xe6e6c3cfcadb0723, 0xda9c7aa29eb3a624, 0x69b2361c9d14f94b, 0x2e184cf536f3067f, 0x9d36004b35545910,
            0x2b769f17cf112238, 0x9858d3a9ccb67d57, 0xdff2a94067518263, 0x6cdce5fe64f6dd0c, 0x50a65c93309e7c0b,
            0xe388102d33392364, 0xa4226ac498dedc50, 0x170c267a9b79833f, 0xdcd7181e300f9e5e, 0x6ff954a033a8c131,
            0x28532e49984f3e05, 0x9b7d62f79be8616a, 0xa707db9acf80c06d, 0x14299724cc279f02, 0x5383edcd67c06036,
            0xe0ada17364673f59
        };

        readonly ulong   _finalSeed;
        readonly ulong[] _table;
        ulong            _hashInt;

        /// <summary>Initializes the CRC64 table and seed as CRC64-ECMA</summary>
        public Crc64Context()
        {
            _hashInt   = CRC64_ECMA_SEED;
            _table     = _ecmaCrc64Table;
            _finalSeed = CRC64_ECMA_SEED;
        }

        /// <summary>Initializes the CRC16 table with a custom polynomial and seed</summary>
        public Crc64Context(ulong polynomial, ulong seed)
        {
            _hashInt = seed;

            _table = new ulong[256];

            for(int i = 0; i < 256; i++)
            {
                ulong entry = (ulong)i;

                for(int j = 0; j < 8; j++)
                    if((entry & 1) == 1)
                        entry = (entry >> 1) ^ polynomial;
                    else
                        entry >>= 1;

                _table[i] = entry;
            }

            _finalSeed = seed;
        }

        /// <inheritdoc />
        /// <summary>Updates the hash with data.</summary>
        /// <param name="data">Data buffer.</param>
        /// <param name="len">Length of buffer to hash.</param>
        public void Update(byte[] data, uint len)
        {
            for(int i = 0; i < len; i++)
                _hashInt = (_hashInt >> 8) ^ _table[data[i] ^ (_hashInt & 0xff)];
        }

        /// <inheritdoc />
        /// <summary>Updates the hash with data.</summary>
        /// <param name="data">Data buffer.</param>
        public void Update(byte[] data) => Update(data, (uint)data.Length);

        /// <inheritdoc />
        /// <summary>Returns a byte array of the hash value.</summary>
        public byte[] Final() => BigEndianBitConverter.GetBytes(_hashInt ^= _finalSeed);

        /// <inheritdoc />
        /// <summary>Returns a hexadecimal representation of the hash value.</summary>
        public string End()
        {
            var crc64Output = new StringBuilder();

            for(int i = 0; i < BigEndianBitConverter.GetBytes(_hashInt ^= _finalSeed).Length; i++)
                crc64Output.Append(BigEndianBitConverter.GetBytes(_hashInt ^= _finalSeed)[i].ToString("x2"));

            return crc64Output.ToString();
        }

        /// <summary>Gets the hash of a file</summary>
        /// <param name="filename">File path.</param>
        public static byte[] File(string filename)
        {
            File(filename, out byte[] localHash);

            return localHash;
        }

        /// <summary>Gets the hash of a file in hexadecimal and as a byte array.</summary>
        /// <param name="filename">File path.</param>
        /// <param name="hash">Byte array of the hash value.</param>
        public static string File(string filename, out byte[] hash) =>
            File(filename, out hash, CRC64_ECMA_POLY, CRC64_ECMA_SEED);

        /// <summary>Gets the hash of a file in hexadecimal and as a byte array.</summary>
        /// <param name="filename">File path.</param>
        /// <param name="hash">Byte array of the hash value.</param>
        /// <param name="polynomial">CRC polynomial</param>
        /// <param name="seed">CRC seed</param>
        public static string File(string filename, out byte[] hash, ulong polynomial, ulong seed)
        {
            var fileStream = new FileStream(filename, FileMode.Open);

            ulong localHashInt = seed;

            ulong[] localTable = new ulong[256];

            for(int i = 0; i < 256; i++)
            {
                ulong entry = (ulong)i;

                for(int j = 0; j < 8; j++)
                    if((entry & 1) == 1)
                        entry = (entry >> 1) ^ polynomial;
                    else
                        entry >>= 1;

                localTable[i] = entry;
            }

            for(int i = 0; i < fileStream.Length; i++)
                localHashInt = (localHashInt >> 8) ^ localTable[(ulong)fileStream.ReadByte() ^ (localHashInt & 0xffL)];

            localHashInt ^= seed;
            hash         =  BigEndianBitConverter.GetBytes(localHashInt);

            var crc64Output = new StringBuilder();

            foreach(byte h in hash)
                crc64Output.Append(h.ToString("x2"));

            fileStream.Close();

            return crc64Output.ToString();
        }

        /// <summary>Gets the hash of the specified data buffer.</summary>
        /// <param name="data">Data buffer.</param>
        /// <param name="len">Length of the data buffer to hash.</param>
        /// <param name="hash">Byte array of the hash value.</param>
        public static string Data(byte[] data, uint len, out byte[] hash) =>
            Data(data, len, out hash, CRC64_ECMA_POLY, CRC64_ECMA_SEED);

        /// <summary>Gets the hash of the specified data buffer.</summary>
        /// <param name="data">Data buffer.</param>
        /// <param name="len">Length of the data buffer to hash.</param>
        /// <param name="hash">Byte array of the hash value.</param>
        /// <param name="polynomial">CRC polynomial</param>
        /// <param name="seed">CRC seed</param>
        public static string Data(byte[] data, uint len, out byte[] hash, ulong polynomial, ulong seed)
        {
            ulong localHashInt = seed;

            ulong[] localTable = new ulong[256];

            for(int i = 0; i < 256; i++)
            {
                ulong entry = (ulong)i;

                for(int j = 0; j < 8; j++)
                    if((entry & 1) == 1)
                        entry = (entry >> 1) ^ polynomial;
                    else
                        entry >>= 1;

                localTable[i] = entry;
            }

            for(int i = 0; i < len; i++)
                localHashInt = (localHashInt >> 8) ^ localTable[data[i] ^ (localHashInt & 0xff)];

            localHashInt ^= seed;
            hash         =  BigEndianBitConverter.GetBytes(localHashInt);

            var crc64Output = new StringBuilder();

            foreach(byte h in hash)
                crc64Output.Append(h.ToString("x2"));

            return crc64Output.ToString();
        }

        /// <summary>Gets the hash of the specified data buffer.</summary>
        /// <param name="data">Data buffer.</param>
        /// <param name="hash">Byte array of the hash value.</param>
        public static string Data(byte[] data, out byte[] hash) => Data(data, (uint)data.Length, out hash);
    }
}