Merge pull request #1201 from SixLabors/js/fast-hash

Add Hardware Accelerated Checksums

Author: JimBobSquarePants

src/ImageSharp/Formats/Png/PngDecoderCore.cs

@@ -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>
@@ -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);

src/ImageSharp/Formats/Png/PngEncoderCore.cs

@@ -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>
@@ -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
         }