Example Zobrist Hashing 64-Bit<\/p>\n\n\n\n
using System;\nusing System.Runtime.InteropServices;\nusing System.Security.Cryptography;\n\/\/\/ <summary>\n\/\/\/ \n\/\/\/ https:\/\/en.wikipedia.org\/wiki\/Zobrist_hashing\n\/\/\/ \n\/\/\/ <\/summary>\npublic class ZOB64 : HashAlgorithm\n{\n private readonly ulong starthash = 0x391615744853B307;\n private ulong[] _table;\n private ulong hash;\n private uint hash32;\n private ZOB32State zhs;\n public ZOB64()\n {\n hash = starthash;\n BuildTable(0x7965CBDDD4A9E7AF);\n }\n public override int HashSize => 64;\n public override void Initialize()\n {\n hash = starthash;\n }\n protected override void HashCore(byte[] bytes, int ibStart, int cbSize)\n {\n Hash64(bytes, ibStart, cbSize);\n }\n private static ulong RotateLeft(ulong value, int count)\n {\n return(value << count) | (value >> (64 - count % 64));\n }\n private unsafe void Hash64(byte[] bytes, int ibStart, int cbSize)\n {\n if(bytes == null)\n return;\n if(ibStart >= bytes.Length || cbSize > bytes.Length)\n return;\n var i = 1;\n fixed(byte* pb = bytes)\n {\n var nb = pb + ibStart;\n while(cbSize >= 1)\n {\n hash ^= RotateLeft(_table[*nb], i++);\n nb += 1;\n cbSize -= 1;\n }\n }\n }\n protected override byte[] HashFinal()\n {\n zhs.hash64 = hash;\n hash32 = zhs.hi ^ zhs.lo;\n return hash.GetBytes();\n }\n public void BuildTable(ulong seed)\n {\n var s1 = (int) seed;\n var s2 = (int) (seed >> 32);\n var rnd = new Random(s1);\n var rnd1 = new Random(s2);\n var tt = new DynHashSet32<ulong>();\n _table = new ulong[256];\n var u = new ZOB32State();\n for(var i = 0; i < 256; i++)\n {\n ulong v;\n do\n {\n u.hi = (uint) rnd.Next();\n u.lo = (uint) rnd1.Next();\n v = u.hash64;\n } while(tt.Contains(v));\n tt.Add(v);\n _table[i] = v;\n }\n }\n [StructLayout(LayoutKind.Explicit)]\n public struct ZOB32State\n {\n [FieldOffset(0)] public ulong hash64;\n [FieldOffset(0)] public uint lo;\n [FieldOffset(4)] public uint hi;\n }\n}<\/pre>\n","protected":false},"excerpt":{"rendered":"Example Zobrist Hashing 64-Bit<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[2],"tags":[36,76,75],"_links":{"self":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts\/162"}],"collection":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/comments?post=162"}],"version-history":[{"count":1,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts\/162\/revisions"}],"predecessor-version":[{"id":163,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/posts\/162\/revisions\/163"}],"wp:attachment":[{"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/media?parent=162"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/categories?post=162"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/michaeljohnsteiner.com\/index.php\/wp-json\/wp\/v2\/tags?post=162"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}