Aaru/SCSI/Modes/07.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : 07.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
//     Decodes SCSI MODE PAGE 07h: Verify error recovery page.
//
// --[ 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 © 2011-2022 Natalia Portillo
// ****************************************************************************/

namespace Aaru.Decoders.SCSI;

using System.Diagnostics.CodeAnalysis;
using System.Text;

[SuppressMessage("ReSharper", "InconsistentNaming"), SuppressMessage("ReSharper", "MemberCanBeInternal"),
 SuppressMessage("ReSharper", "MemberCanBePrivate.Global"), SuppressMessage("ReSharper", "NotAccessedField.Global")]
public static partial class Modes
{
    #region Mode Page 0x07: Verify error recovery page
    /// <summary>Disconnect-reconnect page Page code 0x07 12 bytes in SCSI-2, SBC-1, SBC-2</summary>
    public struct ModePage_07
    {
        /// <summary>Parameters can be saved</summary>
        public bool PS;
        /// <summary>Enable early recovery</summary>
        public bool EER;
        /// <summary>Post error reporting</summary>
        public bool PER;
        /// <summary>Disable transfer on error</summary>
        public bool DTE;
        /// <summary>Disable correction</summary>
        public bool DCR;
        /// <summary>How many times to retry a verify operation</summary>
        public byte VerifyRetryCount;
        /// <summary>How many bits of largest data burst error is maximum to apply error correction on it</summary>
        public byte CorrectionSpan;
        /// <summary>Maximum time in ms to use in data error recovery procedures</summary>
        public ushort RecoveryTimeLimit;
    }

    public static ModePage_07? DecodeModePage_07(byte[] pageResponse)
    {
        if((pageResponse?[0] & 0x40) == 0x40)
            return null;

        if((pageResponse?[0] & 0x3F) != 0x07)
            return null;

        if(pageResponse[1] + 2 != pageResponse.Length)
            return null;

        if(pageResponse.Length < 12)
            return null;

        var decoded = new ModePage_07();

        decoded.PS  |= (pageResponse[0] & 0x80) == 0x80;
        decoded.EER |= (pageResponse[2] & 0x08) == 0x08;
        decoded.PER |= (pageResponse[2] & 0x04) == 0x04;
        decoded.DTE |= (pageResponse[2] & 0x02) == 0x02;
        decoded.DCR |= (pageResponse[2] & 0x01) == 0x01;

        decoded.VerifyRetryCount  = pageResponse[3];
        decoded.CorrectionSpan    = pageResponse[4];
        decoded.RecoveryTimeLimit = (ushort)((pageResponse[10] << 8) + pageResponse[11]);

        return decoded;
    }

    public static string PrettifyModePage_07(byte[] pageResponse) =>
        PrettifyModePage_07(DecodeModePage_07(pageResponse));

    public static string PrettifyModePage_07(ModePage_07? modePage)
    {
        if(!modePage.HasValue)
            return null;

        ModePage_07 page = modePage.Value;
        var         sb   = new StringBuilder();

        sb.AppendLine("SCSI Verify error recovery page:");

        if(page.PS)
            sb.AppendLine("\tParameters can be saved");

        if(page.EER)
            sb.AppendLine("\tDrive will use the most expedient form of error recovery first");

        if(page.PER)
            sb.AppendLine("\tDrive shall report recovered errors");

        if(page.DTE)
            sb.AppendLine("\tTransfer will be terminated upon error detection");

        if(page.DCR)
            sb.AppendLine("\tError correction is disabled");

        if(page.VerifyRetryCount > 0)
            sb.AppendFormat("\tDrive will repeat verify operations {0} times", page.VerifyRetryCount).AppendLine();

        if(page.RecoveryTimeLimit > 0)
            sb.AppendFormat("\tDrive will employ a maximum of {0} ms to recover data", page.RecoveryTimeLimit).
               AppendLine();

        return sb.ToString();
    }
    #endregion Mode Page 0x07: Verify error recovery page
}