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https://github.com/aaru-dps/Aaru.git
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Natalia Portillo
828c1e3da0
Introduces constant fields for respective debug module names, replacing the hardcoded ones. This is done to standardize the naming convention, reduce redundancy and potentially avoid any typos or name mismatches across the project. This change makes the code more maintainable and easier to update in case module names need to be changed.
116 lines
4.9 KiB
C#
116 lines
4.9 KiB
C#
// /***************************************************************************
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// Aaru Data Preservation Suite
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// ----------------------------------------------------------------------------
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//
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// Filename : HDCopy.cs
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// Author(s) : Michael Drüing <michael@drueing.de>
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//
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// Component : Disk image plugins.
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//
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// --[ Description ] ----------------------------------------------------------
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//
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// Manages floppy disk images created with HD-Copy
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//
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// --[ License ] --------------------------------------------------------------
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//
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// This library is free software; you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; either version 2.1 of the
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// License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, see <http://www.gnu.org/licenses/>.
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//
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// ----------------------------------------------------------------------------
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// Copyright © 2017 Michael Drüing
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// Copyright © 2011-2023 Natalia Portillo
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// ****************************************************************************/
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/* Some information on the file format from Michal Necasek (www.os2museum.com):
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*
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* The HD-Copy diskette image format was used by the eponymous DOS utility,
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* written by Oliver Fromme around 1995. The HD-Copy format is relatively
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* straightforward, supporting images with 512-byte sector size and uniform
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* sectors per track count. A basic form of run-length compression is also
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* supported, and empty/unused tracks aren't stored in the image. Images
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* with up to 82 cylinders are supported.
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*
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* No provision appears to be made for single-sided images. The disk image
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* is stored as a sequence of compressed tracks (where a track refers to only
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* one side of the disk), and individual tracks may be left out.
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*
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* The HD-Copy RLE compression works as follows. The image is divided into a
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* number of independent blocks, one per track. Each compressed block starts
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* with a header which contains the size of compressed data (16-bit little
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* endian) and the escape byte. Whenever the escape byte is encountered in the
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* byte stream, it is followed by a data byte and a count byte.
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*
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* Note that HD-Copy uses RLE compression for sequences of as few as three
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* bytes, even though that provides no benefit.
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*
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* It would be tempting to perform in-place decompression to save memory.
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* Unfortunately the simplistic RLE algorithm means the encoded data may be
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* larger than the decoded version, with unknown worst case behavior. Hence
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* the compressed data for a sector may not fit into a buffer the size of the
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* uncompressed sector.
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*
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* There is no signature, hence heuristics must be used to identify a HD-Copy
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* diskette image. Fortunately, the HD-Copy header is highly recognizable.
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*/
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// ReSharper disable NotAccessedField.Local
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using System.Collections.Generic;
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using Aaru.CommonTypes.Enums;
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using Aaru.CommonTypes.Interfaces;
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using Aaru.CommonTypes.Structs;
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namespace Aaru.DiscImages;
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/// <inheritdoc />
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/// <summary>Implements reading HD-Copy disk images</summary>
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public sealed partial class HdCopy : IMediaImage
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{
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/// <summary>Every track that has been read is cached here</summary>
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readonly Dictionary<int, byte[]> _trackCache = new();
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/// <summary>The offset in the file where each track starts, or -1 if the track is not present</summary>
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readonly Dictionary<int, long> _trackOffset = new();
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/// <summary>The HDCP file header after the image has been opened</summary>
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FileHeader _fileHeader;
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/// <summary>The ImageFilter we're reading from, after the file has been opened</summary>
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IFilter _hdcpImageFilter;
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ImageInfo _imageInfo;
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public HdCopy() => _imageInfo = new ImageInfo
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{
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ReadableSectorTags = new List<SectorTagType>(),
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ReadableMediaTags = new List<MediaTagType>(),
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HasPartitions = false,
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HasSessions = false,
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Version = null,
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Application = null,
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ApplicationVersion = null,
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Creator = null,
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Comments = null,
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MediaManufacturer = null,
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MediaModel = null,
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MediaSerialNumber = null,
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MediaBarcode = null,
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MediaPartNumber = null,
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MediaSequence = 0,
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LastMediaSequence = 0,
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DriveManufacturer = null,
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DriveModel = null,
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DriveSerialNumber = null,
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DriveFirmwareRevision = null
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};
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const string MODULE_NAME = "HDCP plugin";
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} |