mirror of
https://github.com/claunia/cuetools.net.git
synced 2025-12-16 18:14:25 +00:00
500 lines
13 KiB
C#
500 lines
13 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Text;
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using CUETools.Codecs;
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using CUETools.Parity;
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namespace CUETools.CDRepair
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{
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public class CDRepair : IAudioDest
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{
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protected int sampleCount;
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protected int finalSampleCount;
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protected Galois galois;
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protected RsDecode rs;
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protected Crc32 crc32;
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protected uint crc;
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protected int[] encodeGx;
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protected int stride;
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protected int laststride;
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protected int stridecount;
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protected int npar;
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public CDRepair(int finalSampleCount, int stride, int npar)
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{
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this.npar = npar;
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this.stride = stride;
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this.finalSampleCount = finalSampleCount;
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sampleCount = 0;
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galois = Galois16.instance;
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rs = new RsDecode16(npar, galois);
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crc32 = new Crc32();
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crc = 0xffffffff;
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encodeGx = galois.makeEncodeGxLog(npar);
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laststride = stride + (finalSampleCount * 2) % stride;
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stridecount = (finalSampleCount * 2) / stride - 2; // minus one for leadin and one for leadout
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if ((finalSampleCount * 2 + stride - 1) / stride + npar > galois.Max)
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throw new Exception("invalid stride");
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}
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public CDRepair(CDRepair src)
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: this(src.finalSampleCount, src.stride, src.npar)
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{
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}
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public unsafe void Write(AudioBuffer sampleBuffer)
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{
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throw new Exception("unsupported");
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}
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public unsafe void Close()
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{
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if (sampleCount != finalSampleCount)
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throw new Exception("sampleCount != finalSampleCount");
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}
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public void Delete()
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{
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throw new Exception("unsupported");
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}
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public int CompressionLevel
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{
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get { return 0; }
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set { }
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}
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public string Options
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{
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set
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{
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if (value == null || value == "") return;
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throw new Exception("Unsupported options " + value);
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}
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}
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public AudioPCMConfig PCM
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{
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get { return AudioPCMConfig.RedBook; }
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}
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public long FinalSampleCount
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{
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set
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{
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if (value < 0) // != _toc.Length?
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throw new Exception("invalid FinalSampleCount");
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finalSampleCount = (int)value;
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}
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}
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public long BlockSize
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{
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set { throw new Exception("unsupported"); }
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}
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public string Path
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{
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get { throw new Exception("unsupported"); }
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}
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public uint CRC
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{
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get
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{
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return crc ^ 0xffffffff;
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}
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}
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}
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public class CDRepairEncode : CDRepair
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{
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protected byte[] parity;
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protected ushort[,] syndrome;
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protected ushort[] leadin;
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protected ushort[] leadout;
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protected bool verify;
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protected bool hasErrors = false, canRecover = true;
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protected int actualOffset = 0;
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internal int[,] sigma;
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internal int[,] omega;
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internal int[,] errpos;
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internal int[,] erroff;
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internal int[] errors;
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public CDRepairEncode(int finalSampleCount, int stride, int npar, bool verify)
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: base (finalSampleCount, stride, npar)
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{
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this.verify = verify;
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parity = new byte[stride * npar * 2];
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if (verify)
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{
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syndrome = new ushort[stride, npar];
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leadin = new ushort[stride * 2];
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leadout = new ushort[stride + laststride];
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} else
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syndrome = new ushort[1, npar];
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}
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new public unsafe void Write(AudioBuffer sampleBuffer)
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{
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sampleBuffer.Prepare(this);
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if ((sampleBuffer.ByteLength & 1) != 0)
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throw new Exception("never happens");
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int firstPos = Math.Max(0, stride - sampleCount * 2);
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int lastPos = Math.Min(sampleBuffer.ByteLength >> 1, (finalSampleCount - sampleCount) * 2 - laststride);
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fixed (byte* bytes = sampleBuffer.Bytes, par = parity)
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fixed (int* gx = encodeGx)
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fixed (uint* t = crc32.table)
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fixed (ushort* exp = galois.ExpTbl, log = galois.LogTbl, synptr = syndrome)
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{
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ushort* data = (ushort*)bytes;
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if (verify)
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for (int pos = 0; pos < (sampleBuffer.ByteLength >> 1); pos++)
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{
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ushort dd = data[pos];
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if (sampleCount * 2 + pos < 2 * stride)
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leadin[sampleCount * 2 + pos] = dd;
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int remaining = (finalSampleCount - sampleCount) * 2 - pos - 1;
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if (remaining < stride + laststride)
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leadout[remaining] = dd;
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}
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if (npar == 8)
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{
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for (int pos = firstPos; pos < lastPos; pos++)
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{
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int part = (sampleCount * 2 + pos) % stride;
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ushort* wr = ((ushort*)par) + part * 8;
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ushort dd = data[pos];
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crc = (crc >> 8) ^ t[(byte)(crc ^ dd)];
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crc = (crc >> 8) ^ t[(byte)(crc ^ (dd >> 8))];
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int ib = wr[0] ^ dd;
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if (ib != 0)
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{
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ushort* myexp = exp + log[ib];
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wr[0] = (ushort)(wr[1] ^ myexp[19483]);
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wr[1] = (ushort)(wr[2] ^ myexp[41576]);
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wr[2] = (ushort)(wr[3] ^ myexp[9460]);
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wr[3] = (ushort)(wr[4] ^ myexp[52075]);
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wr[4] = (ushort)(wr[5] ^ myexp[9467]);
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wr[5] = (ushort)(wr[6] ^ myexp[41590]);
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wr[6] = (ushort)(wr[7] ^ myexp[19504]);
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wr[7] = myexp[28];
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}
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else
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{
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wr[0] = wr[1];
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wr[1] = wr[2];
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wr[2] = wr[3];
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wr[3] = wr[4];
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wr[4] = wr[5];
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wr[5] = wr[6];
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wr[6] = wr[7];
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wr[7] = 0;
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}
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// syn[i] += data[pos] * α^(pos*i)
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if (verify && dd != 0)
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{
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ushort* syn = synptr + part * 8;
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ushort* myexp = exp + log[dd];
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int offs = stridecount - (sampleCount * 2 + pos) / stride;
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syn[0] ^= dd;
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syn[1] ^= myexp[offs];
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syn[2] ^= myexp[(offs * 2) % 65535];
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syn[3] ^= myexp[(offs * 3) % 65535];
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syn[4] ^= myexp[(offs * 4) % 65535];
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syn[5] ^= myexp[(offs * 5) % 65535];
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syn[6] ^= myexp[(offs * 6) % 65535];
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syn[7] ^= myexp[(offs * 7) % 65535];
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//ushort logdd = log[dd];
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//syn[1] ^= exp[(logdd + offs) % 65535];
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//syn[2] ^= exp[(logdd + offs * 2) % 65535];
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//syn[3] ^= exp[(logdd + offs * 3) % 65535];
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//syn[4] ^= exp[(logdd + offs * 4) % 65535];
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//syn[5] ^= exp[(logdd + offs * 5) % 65535];
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//syn[6] ^= exp[(logdd + offs * 6) % 65535];
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//syn[7] ^= exp[(logdd + offs * 7) % 65535];
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}
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}
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}
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else
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{
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for (int pos = firstPos; pos < lastPos; pos++)
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{
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int part = (sampleCount * 2 + pos) % stride;
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ushort* wr = ((ushort*)par) + part * npar;
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ushort dd = data[pos];
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crc = (crc >> 8) ^ t[(byte)(crc ^ dd)];
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crc = (crc >> 8) ^ t[(byte)(crc ^ (dd >> 8))];
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if (verify)
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{
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ushort* syn = synptr + part * npar;
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syn[0] ^= dd; // wk += data
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for (int i = 1; i < npar; i++)
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syn[i] = (ushort)(dd ^ galois.mulExp(syn[i], i)); // wk = data + wk * α^i
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}
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int ib = wr[0] ^ dd;
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if (ib != 0)
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{
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ushort* myexp = exp + log[ib];
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for (int i = 0; i < npar - 1; i++)
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wr[i] = (ushort)(wr[i + 1] ^ myexp[gx[i]]);
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wr[npar - 1] = myexp[gx[npar - 1]];
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}
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else
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{
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for (int i = 0; i < npar - 1; i++)
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wr[i] = wr[i + 1];
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wr[npar - 1] = 0;
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}
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}
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}
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}
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sampleCount += sampleBuffer.Length;
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}
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public unsafe bool VerifyParity(byte[] parity2)
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{
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return VerifyParity(parity2, 0, parity2.Length);
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}
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public unsafe bool VerifyParity(byte[] parity2, int pos, int len)
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{
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if (!verify)
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throw new Exception("verify was not enabled");
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if (sampleCount != finalSampleCount)
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throw new Exception("sampleCount != finalSampleCount");
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if (len != stride * npar * 2)
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throw new Exception("wrong size");
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sigma = new int[stride, npar / 2 + 2];
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omega = new int[stride, npar / 2 + 1];
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errpos = new int[stride, npar / 2];
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erroff = new int[stride, npar / 2];
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errors = new int[stride];
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actualOffset = 0;
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// find offset
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fixed (byte* par2ptr = &parity2[pos])
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{
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ushort* par2 = (ushort*)par2ptr;
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int* syn = stackalloc int[npar];
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int* _sigma = stackalloc int[npar];
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int* _omega = stackalloc int[npar];
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int* _errpos = stackalloc int[npar];
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int bestErrors = npar;
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// We can only use offset if Abs(offset * 2) < stride,
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// else we might need to add/remove more than one sample
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// from syndrome calculations, and that would be too difficult
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// and will probably require longer leadin/leadout.
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for (int offset = 1 - stride / 2; offset < stride / 2; offset++)
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{
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int err = 0;
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for (int i = 0; i < npar; i++)
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{
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int part = (stride - 1) % stride;
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int part2 = (part + offset * 2 + stride) % stride;
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ushort* wr = par2 + part2 * npar;
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syn[i] = syndrome[part, i];
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// offset < 0
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if (part < -offset * 2)
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{
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syn[i] ^= galois.mulExp(leadin[stride + part], (i * (stridecount - 1)) % galois.Max);
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syn[i] = leadout[laststride - part - 1] ^ galois.mulExp(syn[i], i);
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}
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// offset > 0
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if (part >= stride - offset * 2)
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{
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syn[i] = galois.divExp(syn[i] ^ leadout[laststride + stride - part - 1], i);
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syn[i] ^= galois.mulExp(leadin[part], (i * (stridecount - 1)) % galois.Max);
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}
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for (int j = 0; j < npar; j++)
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syn[i] = wr[j] ^ galois.mulExp(syn[i], i);
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err |= syn[i];
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}
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if (err == 0)
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{
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actualOffset = offset;
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bestErrors = 0;
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break;
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}
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int err_count = rs.calcSigmaMBM(_sigma, _omega, syn);
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if (err_count > 0 && rs.chienSearch(_errpos, stridecount + npar, err_count, _sigma))
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{
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if (err_count < bestErrors)
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{
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actualOffset = offset;
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bestErrors = err_count;
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}
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}
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}
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}
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hasErrors = false;
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fixed (byte* par = &parity2[pos])
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fixed (ushort* exp = galois.ExpTbl, log = galois.LogTbl)
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{
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int* syn = stackalloc int[npar];
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int offset = actualOffset;
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for (int part = 0; part < stride; part++)
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{
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int part2 = (part + offset * 2 + stride) % stride;
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ushort* wr = (ushort*)par + part2 * npar;
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int err = 0;
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for (int i = 0; i < npar; i++)
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{
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syn[i] = syndrome[part, i];
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// offset < 0
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if (part < -offset * 2)
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{
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syn[i] ^= galois.mulExp(leadin[stride + part], (i * (stridecount - 1)) % galois.Max);
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syn[i] = leadout[laststride - part - 1] ^ galois.mulExp(syn[i], i);
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}
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// offset > 0
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if (part >= stride - offset * 2)
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{
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syn[i] = galois.divExp(syn[i] ^ leadout[laststride + stride - part - 1], i);
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syn[i] ^= galois.mulExp(leadin[part], (i * (stridecount - 1)) % galois.Max);
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}
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//syn[i] = galois.mulExp(syn[i], i * npar);
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for (int j = 0; j < npar; j++)
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syn[i] = wr[j] ^ galois.mulExp(syn[i], i); // wk = data + wk * α^i
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err |= syn[i];
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}
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//for (int j = 0; j < npar; j++)
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// if (wr[j] != 0)
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// {
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// ushort* myexp = exp + log[wr[j]];
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// syn[0] ^= wr[j];
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// for (int i = 1; i < npar; i++)
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// syn[i] ^= myexp[(npar - j - 1) * i];
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// }
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//for (int i = 0; i < npar; i++)
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// err |= syn[i];
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if (err != 0)
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{
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hasErrors = true;
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fixed (int* s = &sigma[part, 0], o = &omega[part, 0], e = &errpos[part, 0], f = &erroff[part, 0])
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{
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errors[part] = rs.calcSigmaMBM(s, o, syn);
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if (errors[part] <= 0 || !rs.chienSearch(e, stridecount + npar, errors[part], s))
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canRecover = false;
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else
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{
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for (int i = 0; i < errors[part]; i++)
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f[i] = galois.toPos(stridecount + npar, e[i]);
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}
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}
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}
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else
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errors[part] = 0;
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}
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}
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return !hasErrors;
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}
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public byte[] Parity
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{
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get
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{
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return parity;
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}
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}
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public bool HasErrors
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{
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get
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{
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return hasErrors;
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}
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}
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public bool CanRecover
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{
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get
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{
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return canRecover;
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}
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}
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public int ActualOffset
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{
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get
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{
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return actualOffset;
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}
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}
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}
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public class CDRepairFix : CDRepair
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{
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CDRepairEncode decode;
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public CDRepairFix(CDRepairEncode decode)
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: base(decode)
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{
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this.decode = decode;
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}
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new public unsafe void Write(AudioBuffer sampleBuffer)
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{
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sampleBuffer.Prepare(this);
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if ((sampleBuffer.ByteLength & 1) != 0)
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throw new Exception("never happens");
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int firstPos = Math.Max(0, stride - sampleCount * 2 - decode.ActualOffset * 2);
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int lastPos = Math.Min(sampleBuffer.ByteLength >> 1, (finalSampleCount - sampleCount) * 2 - laststride - decode.ActualOffset * 2);
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fixed (byte* bytes = sampleBuffer.Bytes)
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fixed (uint* t = crc32.table)
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{
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ushort* data = (ushort*)bytes;
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for (int pos = firstPos; pos < lastPos; pos++)
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{
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int part = (sampleCount * 2 + pos) % stride;
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int errors = decode.errors[part];
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fixed (int* s = &decode.sigma[part, 0], o = &decode.omega[part, 0], f = &decode.erroff[part, 0])
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for (int i = 0; i < errors; i++)
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if (f[i] == (sampleCount * 2 + decode.ActualOffset * 2 + pos) / stride - 1)
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data[pos] ^= (ushort)rs.doForney(errors, decode.errpos[part, i], s, o);
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ushort dd = data[pos];
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crc = (crc >> 8) ^ t[(byte)(crc ^ dd)];
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crc = (crc >> 8) ^ t[(byte)(crc ^ (dd >> 8))];
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}
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}
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sampleCount += sampleBuffer.Length;
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}
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}
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}
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