Merge pull request #1054 from SixLabors/js/managed-zlib

Fix Png Encoder Compression

Author: JimBobSquarePants

src/ImageSharp/Formats/Png/PngEncoderCore.cs

@@ -699,7 +699,7 @@ private byte[] GetCompressedTextBytes(byte[] textBytes)
         {
             using (var memoryStream = new MemoryStream())
             {
-                using (var deflateStream = new ZlibDeflateStream(memoryStream, this.options.CompressionLevel))
+                using (var deflateStream = new ZlibDeflateStream(this.memoryAllocator, memoryStream, this.options.CompressionLevel))
                 {
                     deflateStream.Write(textBytes);
                 }
@@ -790,7 +790,7 @@ private void WriteDataChunks<TPixel>(ImageFrame<TPixel> pixels, IQuantizedFrame<
 
             using (var memoryStream = new MemoryStream())
             {
-                using (var deflateStream = new ZlibDeflateStream(memoryStream, this.options.CompressionLevel))
+                using (var deflateStream = new ZlibDeflateStream(this.memoryAllocator, memoryStream, this.options.CompressionLevel))
                 {
                     if (this.options.InterlaceMethod == PngInterlaceMode.Adam7)
                     {

src/ImageSharp/Formats/Png/Zlib/Adler32.cs

@@ -1,8 +1,9 @@
-// Copyright (c) Six Labors and contributors.
+// Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
 using System;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 namespace SixLabors.ImageSharp.Formats.Png.Zlib
 {
@@ -112,7 +113,7 @@ public void Update(int value)
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Update(ReadOnlySpan<byte> data)
         {
-            // (By Per Bothner)
+            ref byte dataRef = ref MemoryMarshal.GetReference(data);
             uint s1 = this.checksum & 0xFFFF;
             uint s2 = this.checksum >> 16;
 
@@ -133,8 +134,8 @@ public void Update(ReadOnlySpan<byte> data)
                 count -= n;
                 while (--n >= 0)
                 {
-                    s1 = s1 + (uint)(data[offset++] & 0xff);
-                    s2 = s2 + s1;
+                    s1 += Unsafe.Add(ref dataRef, offset++);
+                    s2 += s1;
                 }
 
                 s1 %= Base;
@@ -144,4 +145,4 @@ public void Update(ReadOnlySpan<byte> data)
             this.checksum = (s2 << 16) | s1;
         }
     }
-}
+}

src/ImageSharp/Formats/Png/Zlib/Crc32.cs

@@ -1,8 +1,9 @@
-// Copyright (c) Six Labors and contributors.
+// Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
 using System;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 namespace SixLabors.ImageSharp.Formats.Png.Zlib
 {
@@ -141,9 +142,10 @@ public void Update(ReadOnlySpan<byte> data)
         {
             this.crc ^= CrcSeed;
 
+            ref uint crcTableRef = ref MemoryMarshal.GetReference(CrcTable.AsSpan());
             for (int i = 0; i < data.Length; i++)
             {
-                this.crc = CrcTable[(this.crc ^ data[i]) & 0xFF] ^ (this.crc >> 8);
+                this.crc = Unsafe.Add(ref crcTableRef, (int)((this.crc ^ data[i]) & 0xFF)) ^ (this.crc >> 8);
             }
 
             this.crc ^= CrcSeed;

src/ImageSharp/Formats/Png/Zlib/DeflateThrowHelper.cs

@@ -0,0 +1,35 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Runtime.CompilerServices;
+
+namespace SixLabors.ImageSharp.Formats.Png.Zlib
+{
+    internal static class DeflateThrowHelper
+    {
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowAlreadyFinished() => throw new InvalidOperationException("Finish() already called.");
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowAlreadyClosed() => throw new InvalidOperationException("Deflator already closed.");
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowUnknownCompression() => throw new InvalidOperationException("Unknown compression function.");
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowNotProcessed() => throw new InvalidOperationException("Old input was not completely processed.");
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowNull(string name) => throw new ArgumentNullException(name);
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowOutOfRange(string name) => throw new ArgumentOutOfRangeException(name);
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowHeapViolated() => throw new InvalidOperationException("Huffman heap invariant violated.");
+
+        [MethodImpl(InliningOptions.ColdPath)]
+        public static void ThrowNoDeflate() => throw new ImageFormatException("Cannot deflate all input.");
+    }
+}