Add support for Software computed CRC32

koculu · Oct 9, 2024 · 1eec365 · 1eec365
1 parent 6a2b178
commit 1eec365
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Showing 2 changed files with 126 additions and 1 deletion.
diff --git a/src/ZoneTree/WAL/Crc32Computer_Software.cs b/src/ZoneTree/WAL/Crc32Computer_Software.cs
@@ -0,0 +1,120 @@
+using System.Runtime.CompilerServices;
+
+namespace Tenray.ZoneTree.WAL;
+
+// See: https://github.com/dotnet/runtime/blob/main/src/libraries/System.IO.Hashing/src/System/IO/Hashing/Crc32.Table.cs
+public sealed class Crc32Computer_Software
+{
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Compute(uint crc, ulong data)
+    {
+        unsafe
+        {
+            return UpdateScalar(crc, new ReadOnlySpan<byte>(&data, sizeof(ulong)));
+        }
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Compute(uint crc, uint data)
+    {
+        unsafe
+        {
+            return UpdateScalar(crc, new ReadOnlySpan<byte>(&data, sizeof(uint)));
+        }
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Compute(uint crc, int data)
+    {
+        unsafe
+        {
+            return UpdateScalar(crc, new ReadOnlySpan<byte>(&data, sizeof(int)));
+        }
+    }
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public static uint Compute(uint crc, Span<byte> data)
+    {
+        return UpdateScalar(crc, data);
+    }
+
+    static uint UpdateScalar(uint crc, ReadOnlySpan<byte> source)
+    {
+        ReadOnlySpan<uint> crcLookup = CrcLookup;
+        for (int i = 0; i < source.Length; i++)
+        {
+            byte idx = (byte)crc;
+            idx ^= source[i];
+            crc = crcLookup[idx] ^ (crc >> 8);
+        }
+
+        return crc;
+    }
+
+    /// <summary>CRC-32 transition table</summary>
+    /// <remarks>
+    /// While this implementation is based on the standard CRC-32 polynomial,
+    /// x32 + x26 + x23 + x22 + x16 + x12 + x11 + x10 + x8 + x7 + x5 + x4 + x2 + x1 + x0,
+    /// this version uses reflected bit ordering, so 0x04C11DB7 becomes 0xEDB88320
+    /// </remarks>
+    static uint[] _crcLookupTable;
+    static ReadOnlySpan<uint> CrcLookup => _crcLookupTable ??= new uint[]
+    {
+        // Generated by GenerateTable(0xEDB88320u):
+        //
+        //     static uint[] GenerateTable(uint reflectedPolynomial)
+        //     {
+        //         uint[] table = new uint[256];
+        //         for (int i = 0; i < table.Length; i++)
+        //         {
+        //             uint val = (uint)i;
+        //             for (int j = 0; j < 8; j++)
+        //             {
+        //                 if ((val & 0b0000_0001) == 0)
+        //                 {
+        //                     val >>= 1;
+        //                 }
+        //                 else
+        //                 {
+        //                     val = (val >> 1) ^ reflectedPolynomial;
+        //                 }
+        //             }
+        //             table[i] = val;
+        //         }
+        //         return table;
+        //     }
+
+        0x0, 0x77073096, 0xEE0E612C, 0x990951BA, 0x76DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
+        0xEDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x9B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
+        0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
+        0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
+        0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
+        0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
+        0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
+        0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
+        0x76DC4190, 0x1DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x6B6B51F, 0x9FBFE4A5, 0xE8B8D433,
+        0x7807C9A2, 0xF00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x86D3D2D, 0x91646C97, 0xE6635C01,
+        0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
+        0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
+        0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
+        0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
+        0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
+        0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
+        0xEDB88320, 0x9ABFB3B6, 0x3B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x4DB2615, 0x73DC1683,
+        0xE3630B12, 0x94643B84, 0xD6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0xA00AE27, 0x7D079EB1,
+        0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
+        0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
+        0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
+        0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
+        0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
+        0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
+        0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x26D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x5005713,
+        0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0xCB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0xBDBDF21,
+        0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
+        0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
+        0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
+        0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
+        0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
+        0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
+    };
+}
diff --git a/src/ZoneTree/WAL/LogEntry.cs b/src/ZoneTree/WAL/LogEntry.cs
@@ -50,7 +50,12 @@ public uint CreateChecksum()
             return crc32;
         }
 
-        throw new PlatformNotSupportedException();
+        crc32 = Crc32Computer_Software.Compute(crc32, (ulong)OpIndex);
+        crc32 = Crc32Computer_Software.Compute(crc32, KeyLength);
+        crc32 = Crc32Computer_Software.Compute(crc32, ValueLength);
+        crc32 = Crc32Computer_Software.Compute(crc32, Key.Span);
+        crc32 = Crc32Computer_Software.Compute(crc32, Value.Span);
+        return crc32;
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]