Aaru/Aaru.Images/CopyTape/Identify.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : Identify.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Disk image plugins.
//
// --[ Description ] ----------------------------------------------------------
//
//     Identifies CopyTape images.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library 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
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2025 Natalia Portillo
// ****************************************************************************/

using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using Aaru.CommonTypes.Interfaces;
using Aaru.Helpers;

namespace Aaru.Images;

public sealed partial class CopyTape
{
#region IWritableTapeImage Members

    /// <inheritdoc />
    public bool Identify(IFilter imageFilter)
    {
        if(imageFilter.DataForkLength <= 16) return false;

        var header = new byte[16];

        Stream strm = imageFilter.GetDataForkStream();
        strm.Position = 0;
        strm.EnsureRead(header, 0, 16);

        string mark = Encoding.ASCII.GetString(header);

        var   blockRx = new Regex(BLOCK_REGEX);
        Match blockMt = blockRx.Match(mark);

        if(!blockMt.Success) return false;

        string blkSize = blockMt.Groups["blockSize"].Value;

        if(string.IsNullOrWhiteSpace(blkSize)) return false;

        if(!uint.TryParse(blkSize, out uint blockSize)) return false;

        if(blockSize == 0 || blockSize + 17 >= imageFilter.DataForkLength) return false;

        strm.Position += blockSize;

        int newLine = strm.ReadByte();

        return newLine == 0x0A;
    }

#endregion
}