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Add Hardware Accelerated Checksums #1201

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Merged
Parent: Added missing CancellationToken parameters to Image
merged 6 commits into from
May 18, 2020
Merged

Add Hardware Accelerated Checksums #1201

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6bbe57c
Add hardware accelerated checksums
JimBobSquarePants May 16, 2020
ad01391
Merge branch 'master' into js/fast-hash
JimBobSquarePants May 17, 2020
c910a81
Add default seed values
JimBobSquarePants May 17, 2020
f8809f5
Update Adler32.cs
JimBobSquarePants May 18, 2020
179dc94
Update Crc32 based on feedback
JimBobSquarePants May 18, 2020
f6f6b51
Better checksum tests
JimBobSquarePants May 18, 2020
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14 changes: 4 additions & 10 deletions src/ImageSharp/Formats/Png/PngDecoderCore.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,11 +30,6 @@ internal sealed class PngDecoderCore
/// </summary>
private readonly byte[] buffer = new byte[4];

/// <summary>
/// Reusable CRC for validating chunks.
/// </summary>
private readonly Crc32 crc = new Crc32();

/// <summary>
/// The global configuration.
/// </summary>
Expand Down Expand Up @@ -1159,18 +1154,17 @@ private bool TryReadChunk(out PngChunk chunk)
/// <param name="chunk">The <see cref="PngChunk"/>.</param>
private void ValidateChunk(in PngChunk chunk)
{
uint crc = this.ReadChunkCrc();
uint inputCrc = this.ReadChunkCrc();

if (chunk.IsCritical)
{
Span<byte> chunkType = stackalloc byte[4];
BinaryPrimitives.WriteUInt32BigEndian(chunkType, (uint)chunk.Type);

this.crc.Reset();
this.crc.Update(chunkType);
this.crc.Update(chunk.Data.GetSpan());
uint validCrc = Crc32.Calculate(chunkType);
validCrc = Crc32.Calculate(validCrc, chunk.Data.GetSpan());

if (this.crc.Value != crc)
if (validCrc != inputCrc)
{
string chunkTypeName = Encoding.ASCII.GetString(chunkType);
PngThrowHelper.ThrowInvalidChunkCrc(chunkTypeName);
Expand Down
13 changes: 3 additions & 10 deletions src/ImageSharp/Formats/Png/PngEncoderCore.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -47,11 +47,6 @@ internal sealed class PngEncoderCore : IDisposable
/// </summary>
private readonly byte[] chunkDataBuffer = new byte[16];

/// <summary>
/// Reusable CRC for validating chunks.
/// </summary>
private readonly Crc32 crc = new Crc32();

/// <summary>
/// The encoder options
/// </summary>
Expand Down Expand Up @@ -1120,18 +1115,16 @@ private void WriteChunk(Stream stream, PngChunkType type, byte[] data, int offse

stream.Write(this.buffer, 0, 8);

this.crc.Reset();

this.crc.Update(this.buffer.AsSpan(4, 4)); // Write the type buffer
uint crc = Crc32.Calculate(this.buffer.AsSpan(4, 4)); // Write the type buffer

if (data != null && length > 0)
{
stream.Write(data, offset, length);

this.crc.Update(data.AsSpan(offset, length));
crc = Crc32.Calculate(crc, data.AsSpan(offset, length));
}

BinaryPrimitives.WriteUInt32BigEndian(this.buffer, (uint)this.crc.Value);
BinaryPrimitives.WriteUInt32BigEndian(this.buffer, crc);

stream.Write(this.buffer, 0, 4); // write the crc
}
Expand Down
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