Aaru/SCSI/SSC/BlockLimits.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : BlockLimits.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : Device structures decoders.
//
// --[ Description ] ----------------------------------------------------------
//
//     Decodes SCSI SSC block limits structures.
//
// --[ 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 © 2011-2023 Natalia Portillo
// ****************************************************************************/

using System;
using System.Diagnostics.CodeAnalysis;
using System.Text;
using Aaru.Localization;

namespace Aaru.Decoders.SCSI.SSC;

[SuppressMessage("ReSharper", "InconsistentNaming")]
[SuppressMessage("ReSharper", "MemberCanBeInternal")]
[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
public static class BlockLimits
{
    public static BlockLimitsData? Decode(byte[] response)
    {
        if(response?.Length != 6)
            return null;

        return new BlockLimitsData
        {
            granularity = (byte)(response[0] & 0x1F),
            maxBlockLen = (uint)((response[1]   << 16) + (response[2] << 8) + response[3]),
            minBlockLen = (ushort)((response[4] << 8)  + response[5])
        };
    }

    public static string Prettify(BlockLimitsData? decoded)
    {
        if(decoded == null)
            return null;

        var sb = new StringBuilder();

        if(decoded.Value.maxBlockLen == decoded.Value.minBlockLen)
            sb.AppendFormat(Core.Device_block_size_is_fixed_at_0_bytes, decoded.Value.minBlockLen).AppendLine();
        else
        {
            if(decoded.Value.maxBlockLen > 0)
                sb.AppendFormat(Core.Device_maximum_block_size_is_0_bytes, decoded.Value.maxBlockLen).AppendLine();
            else
                sb.AppendLine(Core.Device_does_not_specify_a_maximum_block_size);

            sb.AppendFormat(Core.Device_minimum_block_size_is_0_bytes, decoded.Value.minBlockLen).AppendLine();

            if(decoded.Value.granularity > 0)
            {
                sb.AppendFormat(Core.Device_needs_a_block_size_granularity_of_pow_0_1_bytes, decoded.Value.granularity,
                                Math.Pow(2, decoded.Value.granularity)).AppendLine();
            }
        }

        return sb.ToString();
    }

    public static string Prettify(byte[] response) => Prettify(Decode(response));

#region Nested type: BlockLimitsData

    public struct BlockLimitsData
    {
        /// <summary>All blocks size must be multiple of 2^<cref name="granularity" /></summary>
        public byte granularity;
        /// <summary>Maximum block length in bytes</summary>
        public uint maxBlockLen;
        /// <summary>Minimum block length in bytes</summary>
        public ushort minBlockLen;
    }

#endregion
}