37 lines
938 B
C#
37 lines
938 B
C#
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using System;
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using System.Text;
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public static class Crc16IbmSdlc
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{
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private const ushort PolyReversed = 0x8408; // Reflected 0x1021
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private const ushort Init = 0xFFFF;
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private const ushort XorOut = 0xFFFF;
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private static readonly ushort[] Table = new ushort[256];
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static Crc16IbmSdlc()
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{
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for (ushort i = 0; i < 256; i++)
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{
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ushort value = i;
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for (byte j = 0; j < 8; j++)
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{
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if ((value & 1) != 0)
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value = (ushort)((value >> 1) ^ PolyReversed);
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else
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value >>= 1;
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}
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Table[i] = value;
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}
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}
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public static ushort ComputeChecksum(ReadOnlySpan<byte> data)
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{
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ushort crc = Init;
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foreach (byte b in data)
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{
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crc = (ushort)((crc >> 8) ^ Table[(crc ^ b) & 0xFF]);
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}
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return (ushort)(crc ^ XorOut);
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}
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}
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