mirror of https://github.com/SixLabors/ImageSharp
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Former-commit-id: af0313bdaeecaa56e576f25a1fa688a333468759 Former-commit-id: 64319b3f8faaa68997ce43ffb284a1d5d4937a78 Former-commit-id: 971cc28d2e1a019c99800f231c3451c89d1bca49pull/1/head
James Jackson-South
10 years ago
5 changed files with 271 additions and 55 deletions
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namespace ImageProcessorCore.Formats |
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// <copyright file="Block.cs" company="James Jackson-South">
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// Copyright (c) James Jackson-South and contributors.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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namespace ImageProcessorCore.Formats |
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{ |
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/// <summary>
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/// Represents an 8x8 block of coefficients to transform and encode.
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/// </summary>
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internal class Block |
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{ |
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public const int blockSize = 64; |
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private int[] _data; |
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/// <summary>
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/// Gets the size of the block.
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/// </summary>
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public const int BlockSize = 64; |
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/// <summary>
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/// The array of block data.
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/// </summary>
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private readonly int[] data; |
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/// <summary>
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/// Initializes a new instance of the <see cref="Block"/> class.
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/// </summary>
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public Block() |
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{ |
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_data = new int[blockSize]; |
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this.data = new int[BlockSize]; |
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} |
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public int this[int idx] |
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/// <summary>
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/// Gets the pixel data at the given block index.
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/// </summary>
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/// <param name="index">The index of the data to return.</param>
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/// <returns>
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/// The <see cref="int"/>.
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/// </returns>
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public int this[int index] |
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{ |
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get { return _data[idx]; } |
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set { _data[idx] = value; } |
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get { return this.data[index]; } |
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set { this.data[index] = value; } |
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} |
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} |
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} |
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@ -0,0 +1,171 @@ |
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// <copyright file="JpegConstants.cs" company="James Jackson-South">
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// Copyright (c) James Jackson-South and contributors.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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namespace ImageProcessorCore.Formats |
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{ |
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/// <summary>
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/// Defines jpeg constants defined in the specification.
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/// </summary>
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internal static class JpegConstants |
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{ |
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/// <summary>
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/// The maximum allowable length in each dimension of a jpeg image.
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/// </summary>
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public const ushort MaxLength = 65535; |
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/// <summary>
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/// Represents high detail chroma horizontal subsampling.
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/// </summary>
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public static readonly byte[] ChromaFourFourFourHorizontal = { 1, 1, 1 }; |
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/// <summary>
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/// Represents high detail chroma vertical subsampling.
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/// </summary>
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public static readonly byte[] ChromaFourFourFourVertical = { 1, 1, 1 }; |
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/// <summary>
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/// Represents medium detail chroma horizontal subsampling.
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/// </summary>
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public static readonly byte[] ChromaFourTwoTwoHorizontal = { 2, 1, 1 }; |
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/// <summary>
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/// Represents medium detail chroma vertical subsampling.
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/// </summary>
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public static readonly byte[] ChromaFourTwoTwoVertical = { 1, 1, 1 }; |
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/// <summary>
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/// Represents low detail chroma horizontal subsampling.
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/// </summary>
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public static readonly byte[] ChromaFourTwoZeroHorizontal = { 2, 1, 1 }; |
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/// <summary>
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/// Represents low detail chroma vertical subsampling.
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/// </summary>
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public static readonly byte[] ChromaFourTwoZeroVertical = { 2, 1, 1 }; |
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/// <summary>
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/// Describes component ids for start of frame components.
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/// </summary>
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internal static class Components |
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{ |
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/// <summary>
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/// The YCbCr luminance component id.
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/// </summary>
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public const byte Y = 1; |
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/// <summary>
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/// The YCbCr chroma component id.
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/// </summary>
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public const byte Cb = 2; |
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/// <summary>
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/// The YCbCr chroma component id.
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/// </summary>
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public const byte Cr = 3; |
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/// <summary>
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/// The YIQ x coordinate component id.
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/// </summary>
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public const byte I = 4; |
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/// <summary>
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/// The YIQ y coordinate component id.
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/// </summary>
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public const byte Q = 5; |
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} |
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/// <summary>
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/// Describes common Jpeg markers
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/// </summary>
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internal static class Markers |
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{ |
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/// <summary>
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/// Marker prefix. Next byte is a marker.
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/// </summary>
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public const byte XFF = 0xff; |
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/// <summary>
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/// Start of Image
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/// </summary>
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public const byte SOI = 0xd8; |
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/// <summary>
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/// Start of Frame (baseline DCT)
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/// <remarks>
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/// Indicates that this is a baseline DCT-based JPEG, and specifies the width, height, number of components,
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/// and component subsampling (e.g., 4:2:0).
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/// </remarks>
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/// </summary>
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public const byte SOF0 = 0xc0; |
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/// <summary>
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/// Start Of Frame (progressive DCT)
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/// <remarks>
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/// Indicates that this is a progressive DCT-based JPEG, and specifies the width, height, number of components,
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/// and component subsampling (e.g., 4:2:0).
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/// </remarks>
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/// </summary>
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public const byte SOF2 = 0xc0; |
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/// <summary>
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/// Define Huffman Table(s)
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/// <remarks>
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/// Specifies one or more Huffman tables.
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/// </remarks>
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/// </summary>
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public const byte DHT = 0xc4; |
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/// <summary>
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/// Define Quantization Table(s)
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/// <remarks>
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/// Specifies one or more quantization tables.
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/// </remarks>
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/// </summary>
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public const byte DQT = 0xdb; |
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/// <summary>
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/// Define Restart Interval
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/// <remarks>
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/// Specifies the interval between RSTn markers, in macroblocks. This marker is followed by two bytes
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/// indicating the fixed size so it can be treated like any other variable size segment.
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/// </remarks>
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/// </summary>
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public const byte DRI = 0xdd; |
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/// <summary>
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/// Start of Scan
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/// <remarks>
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/// Begins a top-to-bottom scan of the image. In baseline DCT JPEG images, there is generally a single scan.
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/// Progressive DCT JPEG images usually contain multiple scans. This marker specifies which slice of data it
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/// will contain, and is immediately followed by entropy-coded data.
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/// </remarks>
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/// </summary>
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public const byte SOS = 0xda; |
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/// <summary>
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/// Comment
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/// <remarks>
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/// Contains a text comment.
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/// </remarks>
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/// </summary>
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public const byte COM = 0xfe; |
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/// <summary>
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/// End of Image
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/// </summary>
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public const byte EOI = 0xd9; |
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/// <summary>
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/// Application specific marker for marking the jpeg format.
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/// </summary>
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public const byte APP0 = 0xe0; |
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/// <summary>
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/// Application specific marker for marking where to store metadata.
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/// </summary>
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public const byte APP1 = 0xe1; |
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} |
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} |
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} |
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@ -1 +1 @@ |
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07d53b1f9ee1e867cfd8bb664c2cf3f31c0e8289 |
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af4a353d1d290be5dd231656bdb558fcdc143805 |
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