| | | 1 | | using System; |
| | | 2 | | using System.Runtime.CompilerServices; |
| | | 3 | | |
| | | 4 | | namespace Chronicler; |
| | | 5 | | |
| | | 6 | | /// <summary> |
| | | 7 | | /// Writes deterministic primitive payloads into a fixed-width record hash. |
| | | 8 | | /// </summary> |
| | | 9 | | /// <remarks> |
| | | 10 | | /// This is a non-cryptographic conformance/replay hash writer. It is intended for deterministic |
| | | 11 | | /// state comparison, not for security or tamper resistance. |
| | | 12 | | /// </remarks> |
| | | 13 | | public struct ChronicleHashWriter |
| | | 14 | | { |
| | | 15 | | private const ulong FnvPrime = 1099511628211UL; |
| | | 16 | | private const ulong LowOffset = 14695981039346656037UL; |
| | | 17 | | private const ulong HighOffset = 7809847782465536322UL; |
| | | 18 | | |
| | | 19 | | private ulong _low; |
| | | 20 | | private ulong _high; |
| | | 21 | | private bool _initialized; |
| | | 22 | | |
| | | 23 | | /// <summary> |
| | | 24 | | /// Creates a writer seeded for an empty deterministic hash stream. |
| | | 25 | | /// </summary> |
| | | 26 | | public ChronicleHashWriter() |
| | | 27 | | { |
| | 110664 | 28 | | _low = LowOffset; |
| | 110664 | 29 | | _high = HighOffset; |
| | 110664 | 30 | | _initialized = true; |
| | 110664 | 31 | | } |
| | | 32 | | |
| | | 33 | | /// <summary> |
| | | 34 | | /// Writes a stable ASCII section tag and schema version. |
| | | 35 | | /// </summary> |
| | | 36 | | public void WriteSection(string tag, int version) |
| | | 37 | | { |
| | 479450 | 38 | | if (tag == null) |
| | 1 | 39 | | throw new ArgumentNullException(nameof(tag)); |
| | 479449 | 40 | | if (tag.Length == 0) |
| | 1 | 41 | | throw new ArgumentException("Record hash section tags must not be empty.", nameof(tag)); |
| | | 42 | | |
| | 17850114 | 43 | | for (int i = 0; i < tag.Length; i++) |
| | | 44 | | { |
| | 8445610 | 45 | | if (tag[i] > 0x7f) |
| | 1 | 46 | | throw new ArgumentException("Record hash section tags must be stable ASCII.", nameof(tag)); |
| | | 47 | | } |
| | | 48 | | |
| | 479447 | 49 | | WriteInt32(tag.Length); |
| | 17850108 | 50 | | for (int i = 0; i < tag.Length; i++) |
| | | 51 | | { |
| | 8445607 | 52 | | WriteByte((byte)tag[i]); |
| | | 53 | | } |
| | | 54 | | |
| | 479447 | 55 | | WriteInt32(version); |
| | 479447 | 56 | | } |
| | | 57 | | |
| | | 58 | | /// <summary> |
| | | 59 | | /// Writes a Boolean value as one canonical byte. |
| | | 60 | | /// </summary> |
| | | 61 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 62 | | public void WriteBool(bool value) |
| | | 63 | | { |
| | 1623472 | 64 | | WriteByte(value ? (byte)1 : (byte)0); |
| | 1623472 | 65 | | } |
| | | 66 | | |
| | | 67 | | /// <summary> |
| | | 68 | | /// Writes an unsigned 8-bit value. |
| | | 69 | | /// </summary> |
| | | 70 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 71 | | public void WriteByte(byte value) |
| | | 72 | | { |
| | 68465456 | 73 | | EnsureInitialized(); |
| | | 74 | | |
| | | 75 | | unchecked |
| | | 76 | | { |
| | 68465456 | 77 | | _low ^= value; |
| | 68465456 | 78 | | _low *= FnvPrime; |
| | | 79 | | |
| | 68465456 | 80 | | _high ^= (ulong)value + 0x9e3779b97f4a7c15UL + (_low << 6) + (_low >> 2); |
| | 68465456 | 81 | | _high *= FnvPrime; |
| | | 82 | | } |
| | 68465456 | 83 | | } |
| | | 84 | | |
| | | 85 | | /// <summary> |
| | | 86 | | /// Writes a signed 8-bit value by its two's-complement byte. |
| | | 87 | | /// </summary> |
| | | 88 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 89 | | public void WriteSByte(sbyte value) |
| | | 90 | | { |
| | 36894 | 91 | | WriteByte(unchecked((byte)value)); |
| | 36894 | 92 | | } |
| | | 93 | | |
| | | 94 | | /// <summary> |
| | | 95 | | /// Writes a signed 16-bit value in little-endian byte order. |
| | | 96 | | /// </summary> |
| | | 97 | | public void WriteInt16(short value) |
| | | 98 | | { |
| | 36895 | 99 | | WriteUInt16(unchecked((ushort)value)); |
| | 36895 | 100 | | } |
| | | 101 | | |
| | | 102 | | /// <summary> |
| | | 103 | | /// Writes an unsigned 16-bit value in little-endian byte order. |
| | | 104 | | /// </summary> |
| | | 105 | | public void WriteUInt16(ushort value) |
| | | 106 | | { |
| | 24088830 | 107 | | WriteByte((byte)value); |
| | 24088830 | 108 | | WriteByte((byte)(value >> 8)); |
| | 24088830 | 109 | | } |
| | | 110 | | |
| | | 111 | | /// <summary> |
| | | 112 | | /// Writes a signed 32-bit value in little-endian byte order. |
| | | 113 | | /// </summary> |
| | | 114 | | public void WriteInt32(int value) |
| | | 115 | | { |
| | 2102621 | 116 | | WriteUInt32(unchecked((uint)value)); |
| | 2102621 | 117 | | } |
| | | 118 | | |
| | | 119 | | /// <summary> |
| | | 120 | | /// Writes an unsigned 32-bit value in little-endian byte order. |
| | | 121 | | /// </summary> |
| | | 122 | | public void WriteUInt32(uint value) |
| | | 123 | | { |
| | 2250159 | 124 | | WriteByte((byte)value); |
| | 2250159 | 125 | | WriteByte((byte)(value >> 8)); |
| | 2250159 | 126 | | WriteByte((byte)(value >> 16)); |
| | 2250159 | 127 | | WriteByte((byte)(value >> 24)); |
| | 2250159 | 128 | | } |
| | | 129 | | |
| | | 130 | | /// <summary> |
| | | 131 | | /// Writes a signed 64-bit value in little-endian byte order. |
| | | 132 | | /// </summary> |
| | | 133 | | public void WriteInt64(long value) |
| | | 134 | | { |
| | 36895 | 135 | | WriteUInt64(unchecked((ulong)value)); |
| | 36895 | 136 | | } |
| | | 137 | | |
| | | 138 | | /// <summary> |
| | | 139 | | /// Writes an unsigned 64-bit value in little-endian byte order. |
| | | 140 | | /// </summary> |
| | | 141 | | public void WriteUInt64(ulong value) |
| | | 142 | | { |
| | 73832 | 143 | | WriteByte((byte)value); |
| | 73832 | 144 | | WriteByte((byte)(value >> 8)); |
| | 73832 | 145 | | WriteByte((byte)(value >> 16)); |
| | 73832 | 146 | | WriteByte((byte)(value >> 24)); |
| | 73832 | 147 | | WriteByte((byte)(value >> 32)); |
| | 73832 | 148 | | WriteByte((byte)(value >> 40)); |
| | 73832 | 149 | | WriteByte((byte)(value >> 48)); |
| | 73832 | 150 | | WriteByte((byte)(value >> 56)); |
| | 73832 | 151 | | } |
| | | 152 | | |
| | | 153 | | /// <summary> |
| | | 154 | | /// Writes a UTF-16 code unit in little-endian byte order. |
| | | 155 | | /// </summary> |
| | | 156 | | public void WriteChar(char value) |
| | | 157 | | { |
| | 24014998 | 158 | | WriteUInt16(value); |
| | 24014998 | 159 | | } |
| | | 160 | | |
| | | 161 | | /// <summary> |
| | | 162 | | /// Writes a nullable string as a presence marker, length, and UTF-16 code units. |
| | | 163 | | /// </summary> |
| | | 164 | | public void WriteString(string? value) |
| | | 165 | | { |
| | 996186 | 166 | | if (value == null) |
| | | 167 | | { |
| | 36894 | 168 | | WriteBool(false); |
| | 36894 | 169 | | return; |
| | | 170 | | } |
| | | 171 | | |
| | 959292 | 172 | | WriteBool(true); |
| | 959292 | 173 | | WriteInt32(value.Length); |
| | 49874788 | 174 | | for (int i = 0; i < value.Length; i++) |
| | | 175 | | { |
| | 23978102 | 176 | | WriteChar(value[i]); |
| | | 177 | | } |
| | 959292 | 178 | | } |
| | | 179 | | |
| | | 180 | | /// <summary> |
| | | 181 | | /// Writes an enum value by its underlying integral bytes in little-endian byte order. |
| | | 182 | | /// </summary> |
| | | 183 | | public void WriteEnum<TEnum>(TEnum value) |
| | | 184 | | where TEnum : struct, Enum |
| | | 185 | | { |
| | 36881 | 186 | | if (Unsafe.SizeOf<TEnum>() == 1) |
| | | 187 | | { |
| | 2 | 188 | | WriteByte(Unsafe.As<TEnum, byte>(ref value)); |
| | 2 | 189 | | return; |
| | | 190 | | } |
| | | 191 | | |
| | 36879 | 192 | | if (Unsafe.SizeOf<TEnum>() == 2) |
| | | 193 | | { |
| | 2 | 194 | | WriteUInt16(Unsafe.As<TEnum, ushort>(ref value)); |
| | 2 | 195 | | return; |
| | | 196 | | } |
| | | 197 | | |
| | 36877 | 198 | | if (Unsafe.SizeOf<TEnum>() == 4) |
| | | 199 | | { |
| | 36875 | 200 | | WriteUInt32(Unsafe.As<TEnum, uint>(ref value)); |
| | 36875 | 201 | | return; |
| | | 202 | | } |
| | | 203 | | |
| | 2 | 204 | | WriteUInt64(Unsafe.As<TEnum, ulong>(ref value)); |
| | 2 | 205 | | } |
| | | 206 | | |
| | | 207 | | /// <summary> |
| | | 208 | | /// Finalizes and returns the current hash value. |
| | | 209 | | /// </summary> |
| | | 210 | | public ChronicleHash ToHash() |
| | | 211 | | { |
| | 110660 | 212 | | EnsureInitialized(); |
| | | 213 | | |
| | 110660 | 214 | | ulong low = FinalizeLane(_low); |
| | 110660 | 215 | | ulong high = FinalizeLane(_high ^ low); |
| | 110660 | 216 | | return new ChronicleHash(low, high); |
| | | 217 | | } |
| | | 218 | | |
| | | 219 | | [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| | | 220 | | private void EnsureInitialized() |
| | | 221 | | { |
| | 68576116 | 222 | | if (_initialized) |
| | 68576115 | 223 | | return; |
| | | 224 | | |
| | 1 | 225 | | _low = LowOffset; |
| | 1 | 226 | | _high = HighOffset; |
| | 1 | 227 | | _initialized = true; |
| | 1 | 228 | | } |
| | | 229 | | |
| | | 230 | | private static ulong FinalizeLane(ulong value) |
| | | 231 | | { |
| | | 232 | | unchecked |
| | | 233 | | { |
| | 221320 | 234 | | value ^= value >> 33; |
| | 221320 | 235 | | value *= 0xff51afd7ed558ccdUL; |
| | 221320 | 236 | | value ^= value >> 33; |
| | 221320 | 237 | | value *= 0xc4ceb9fe1a85ec53UL; |
| | 221320 | 238 | | value ^= value >> 33; |
| | 221320 | 239 | | return value; |
| | | 240 | | } |
| | | 241 | | } |
| | | 242 | | } |