Aaru/Aaru.Core/Devices/Dumping/CompactDisc/Offset.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : CompactDisc.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Core algorithms.
//
// --[ Description ] ----------------------------------------------------------
//
//     Dumps CDs and DDCDs.
//
// --[ License ] --------------------------------------------------------------
//
//     This program is free software: you can redistribute it and/or modify
//     it under the terms of the GNU General Public License as
//     published by the Free Software Foundation, either version 3 of the
//     License, or (at your option) any later version.
//
//     This program is distributed in the hope that it will be useful,
//     but WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//     GNU General Public License for more details.
//
//     You should have received a copy of the GNU General Public License
//     along with this program.  If not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2020 Natalia Portillo
// ****************************************************************************/

using System;
using Aaru.Devices;

// ReSharper disable JoinDeclarationAndInitializer
// ReSharper disable InlineOutVariableDeclaration
// ReSharper disable TooWideLocalVariableScope

namespace Aaru.Core.Devices.Dumping
{
    partial class Dump
    {
        static void FixOffsetData(int offsetBytes, uint sectorSize, int sectorsForOffset,
                                  MmcSubchannel supportedSubchannel, ref uint blocksToRead, uint subSize,
                                  ref byte[] cmdBuf, uint blockSize, bool failedCrossingLeadOut)
        {
            if(cmdBuf.Length == 0)
                return;

            int offsetFix = offsetBytes < 0 ? (int)((sectorSize * sectorsForOffset) + offsetBytes) : offsetBytes;

            byte[] tmpBuf;

            if(supportedSubchannel != MmcSubchannel.None)
            {
                // De-interleave subchannel
                byte[] data = new byte[sectorSize * blocksToRead];
                byte[] sub  = new byte[subSize    * blocksToRead];

                for(int b = 0; b < blocksToRead; b++)
                {
                    Array.Copy(cmdBuf, (int)(0          + (b * blockSize)), data, sectorSize * b, sectorSize);
                    Array.Copy(cmdBuf, (int)(sectorSize + (b * blockSize)), sub, subSize     * b, subSize);
                }

                if(failedCrossingLeadOut)
                {
                    blocksToRead += (uint)sectorsForOffset;

                    tmpBuf = new byte[sectorSize * blocksToRead];
                    Array.Copy(data, 0, tmpBuf, 0, data.Length);
                    data   = tmpBuf;
                    tmpBuf = new byte[subSize * blocksToRead];
                    Array.Copy(sub, 0, tmpBuf, 0, sub.Length);
                    sub = tmpBuf;
                }

                tmpBuf = new byte[sectorSize * (blocksToRead - sectorsForOffset)];
                Array.Copy(data, offsetFix, tmpBuf, 0, tmpBuf.Length);
                data = tmpBuf;

                blocksToRead -= (uint)sectorsForOffset;

                // Re-interleave subchannel
                cmdBuf = new byte[blockSize * blocksToRead];

                for(int b = 0; b < blocksToRead; b++)
                {
                    Array.Copy(data, sectorSize * b, cmdBuf, (int)(0          + (b * blockSize)), sectorSize);
                    Array.Copy(sub, subSize     * b, cmdBuf, (int)(sectorSize + (b * blockSize)), subSize);
                }
            }
            else
            {
                if(failedCrossingLeadOut)
                {
                    blocksToRead += (uint)sectorsForOffset;

                    tmpBuf = new byte[blockSize * blocksToRead];
                    Array.Copy(cmdBuf, 0, tmpBuf, 0, cmdBuf.Length);
                    cmdBuf = tmpBuf;
                }

                tmpBuf = new byte[blockSize * (blocksToRead - sectorsForOffset)];
                Array.Copy(cmdBuf, offsetFix, tmpBuf, 0, tmpBuf.Length);
                cmdBuf       =  tmpBuf;
                blocksToRead -= (uint)sectorsForOffset;
            }
        }
    }
}