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Fix warnings
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@mbalous
mbalous committed Aug 7, 2023
1 parent 95695de commit 6ae7193
Showing 1 changed file with 154 additions and 124 deletions.
278 changes: 154 additions & 124 deletions GZipTool.Core/CustomGZipFooter.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,128 +9,158 @@ namespace GzipTool.Core;

public sealed class CustomGZipFooter
{
[DebuggerDisplay("{" + nameof(GetDebuggerDisplay) + "(),nq}")]
public sealed record CompressedChunkInfo
{
public long OriginalStart { get; set; }
public long CompressedStart { get; set; }

public long OriginalLength { get; set; }
public long CompressedLength { get; set; }

internal static readonly long ChunkInfoSize = sizeof(long) * 4; // number of fields

private string GetDebuggerDisplay()
{
return
$"{nameof(OriginalStart)}= {OriginalStart}; " +
$"{nameof(CompressedStart)}= {CompressedStart}; " +
$"{nameof(OriginalLength)}= {OriginalLength}; " +
$"{nameof(CompressedLength)}= {CompressedLength};";
}
}

public long OriginalFileSize { get; private set; } = 0;

public IReadOnlyList<CompressedChunkInfo> Chunks => _chunks;
private readonly List<CompressedChunkInfo> _chunks = new List<CompressedChunkInfo>();

private static readonly Encoding FooterEncoding = Encoding.ASCII;

public CustomGZipFooter()
{
}

public long GetFooterSize()
{
return _chunks.Count * CompressedChunkInfo.ChunkInfoSize +
sizeof(long) + // original size
sizeof(long); // footer size
}

public void AddChunkInfo(long originalStart, long compressedStart, long originalLength, long compressedLength)
{
// TODO: checks args

_chunks.Add(new CompressedChunkInfo()
{
OriginalStart = originalStart,
CompressedStart = compressedStart,
OriginalLength = originalLength,
CompressedLength = compressedLength
});

OriginalFileSize += originalLength;
}

public void WriteToStream(Stream stream)
{
using (BinaryWriter bw = new BinaryWriter(stream, FooterEncoding, true))
{
// chunks are ordered in footer the way they're ordered in the compressed file
foreach (var blockInfo in Chunks.OrderBy(x => x.CompressedStart))
{
bw.Write(blockInfo.OriginalStart);
bw.Write(blockInfo.CompressedStart);
bw.Write(blockInfo.OriginalLength);
bw.Write(blockInfo.CompressedLength);
}

bw.Write(OriginalFileSize);
bw.Write(GetFooterSize());
}
}

public static CustomGZipFooter FromStream(Stream stream)
{
if (!stream.CanSeek)
throw new ArgumentException("Given stream must allow seeking.", nameof(stream));

CustomGZipFooter footer = new CustomGZipFooter();

// seek to read the footer size
stream.Seek(-sizeof(ulong), SeekOrigin.End);

using (BinaryReader br = new BinaryReader(stream, FooterEncoding, true))
{
var footerSize = br.ReadInt64();

br.BaseStream.Seek(-footerSize, SeekOrigin.End);

var chunkInfosCount = GetNumberOfChunksFromByteSize(footerSize);

for (int i = 0; i < chunkInfosCount; i++)
{
long originalStart = br.ReadInt64();
long compressedStart = br.ReadInt64();
long originalLength = br.ReadInt64();
long compressedLength = br.ReadInt64();

footer.AddChunkInfo(originalStart, compressedStart, originalLength, compressedLength);
}

long originalSize = br.ReadInt64();
footer.OriginalFileSize = originalSize;
}

return footer;
}

private static long GetNumberOfChunksFromByteSize(long size)
{
return (size - sizeof(long)) / (CompressedChunkInfo.ChunkInfoSize);
}

public override bool Equals(object obj)
{
if (obj is CustomGZipFooter otherFooter)
{

// TODO: the collections are considered to be equal even when not in the same order
return OriginalFileSize == otherFooter.OriginalFileSize &&
Enumerable.SequenceEqual(Chunks, otherFooter.Chunks);
}

return false;
}
[DebuggerDisplay("{" + nameof(GetDebuggerDisplay) + "(),nq}")]
public sealed record CompressedChunkInfo
{
public long OriginalStart { get; }
public long CompressedStart { get; }

public long OriginalLength { get; }
public long CompressedLength { get; }

internal static readonly long ChunkInfoSize = sizeof(long) * 4; // number of fields

public CompressedChunkInfo(long originalStart, long compressedStart, long originalLength, long compressedLength)
{
OriginalStart = originalStart;
CompressedStart = compressedStart;
OriginalLength = originalLength;
CompressedLength = compressedLength;
}

private string GetDebuggerDisplay()
{
return
$"{nameof(OriginalStart)}= {OriginalStart}; " +
$"{nameof(CompressedStart)}= {CompressedStart}; " +
$"{nameof(OriginalLength)}= {OriginalLength}; " +
$"{nameof(CompressedLength)}= {CompressedLength};";
}

#region Equality members

public bool Equals(CompressedChunkInfo? other)
{
if (ReferenceEquals(null, other))
return false;
if (ReferenceEquals(this, other))
return true;
return OriginalStart == other.OriginalStart &&
CompressedStart == other.CompressedStart &&
OriginalLength == other.OriginalLength &&
CompressedLength == other.CompressedLength;
}

public override int GetHashCode()
{
return HashCode.Combine(OriginalStart, CompressedStart, OriginalLength, CompressedLength);
}

#endregion
}

public long OriginalFileSize { get; private set; } = 0;

public IReadOnlyList<CompressedChunkInfo> Chunks => _chunks;
private readonly List<CompressedChunkInfo> _chunks = new List<CompressedChunkInfo>();

private static readonly Encoding FooterEncoding = Encoding.ASCII;

public CustomGZipFooter()
{
}

public long GetFooterSize()
{
return _chunks.Count * CompressedChunkInfo.ChunkInfoSize +
sizeof(long) + // original size
sizeof(long); // footer size
}

public void AddChunkInfo(long originalStart, long compressedStart, long originalLength, long compressedLength)
{
// TODO: checks args
_chunks.Add(new CompressedChunkInfo(originalStart, compressedStart, originalLength, compressedLength));
OriginalFileSize += originalLength;
}

public void WriteToStream(Stream stream)
{
using (BinaryWriter bw = new BinaryWriter(stream, FooterEncoding, true))
{
// chunks are ordered in footer the way they're ordered in the compressed file
foreach (var blockInfo in Chunks.OrderBy(x => x.CompressedStart))
{
bw.Write(blockInfo.OriginalStart);
bw.Write(blockInfo.CompressedStart);
bw.Write(blockInfo.OriginalLength);
bw.Write(blockInfo.CompressedLength);
}

bw.Write(OriginalFileSize);
bw.Write(GetFooterSize());
}
}

public static CustomGZipFooter FromStream(Stream stream)
{
if (!stream.CanSeek)
throw new ArgumentException("Given stream must allow seeking.", nameof(stream));

CustomGZipFooter footer = new CustomGZipFooter();

// seek to read the footer size
stream.Seek(-sizeof(ulong), SeekOrigin.End);

using (BinaryReader br = new BinaryReader(stream, FooterEncoding, true))
{
var footerSize = br.ReadInt64();

br.BaseStream.Seek(-footerSize, SeekOrigin.End);

var chunkInfosCount = GetNumberOfChunksFromByteSize(footerSize);

for (int i = 0; i < chunkInfosCount; i++)
{
long originalStart = br.ReadInt64();
long compressedStart = br.ReadInt64();
long originalLength = br.ReadInt64();
long compressedLength = br.ReadInt64();

footer.AddChunkInfo(originalStart, compressedStart, originalLength, compressedLength);
}

long originalSize = br.ReadInt64();
footer.OriginalFileSize = originalSize;
}

return footer;
}

private static long GetNumberOfChunksFromByteSize(long size)
{
return (size - sizeof(long)) / (CompressedChunkInfo.ChunkInfoSize);
}

#region Equality members

public override bool Equals(object? obj)
{
return ReferenceEquals(this, obj) || obj is CustomGZipFooter other && Equals(other);
}

private bool Equals(CustomGZipFooter other)
{
return OriginalFileSize == other.OriginalFileSize && _chunks.SequenceEqual(other._chunks);
}

public override int GetHashCode()
{
unchecked
{
return (_chunks.GetHashCode() * 397);
}
}

#endregion
}

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