58 lines
1.7 KiB
C#
58 lines
1.7 KiB
C#
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namespace Uwaa.PNG;
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/// <summary>
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/// The header for a data chunk in a PNG file.
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/// </summary>
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public readonly struct ChunkHeader
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{
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/// <summary>
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/// The position/start of the chunk header within the stream.
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/// </summary>
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public long Position { get; }
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/// <summary>
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/// The length of the chunk in bytes.
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/// </summary>
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public int Length { get; }
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/// <summary>
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/// The name of the chunk, uppercase first letter means the chunk is critical (vs. ancillary).
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/// </summary>
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public string Name { get; }
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/// <summary>
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/// Whether the chunk is critical (must be read by all readers) or ancillary (may be ignored).
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/// </summary>
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public bool IsCritical => char.IsUpper(Name[0]);
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/// <summary>
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/// A public chunk is one that is defined in the International Standard or is registered in the list of public chunk types maintained by the Registration Authority.
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/// Applications can also define private (unregistered) chunk types for their own purposes.
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/// </summary>
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public bool IsPublic => char.IsUpper(Name[1]);
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/// <summary>
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/// Whether the (if unrecognized) chunk is safe to copy.
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/// </summary>
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public bool IsSafeToCopy => char.IsUpper(Name[3]);
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/// <summary>
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/// Create a new <see cref="ChunkHeader"/>.
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/// </summary>
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public ChunkHeader(long position, int length, string name)
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{
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if (length < 0)
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{
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throw new ArgumentException($"Length less than zero ({length}) encountered when reading chunk at position {position}.");
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}
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Position = position;
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Length = length;
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Name = name;
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}
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public override string ToString()
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{
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return $"{Name} at {Position} (length: {Length}).";
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}
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}
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