Merge pull request #489 from vcsjones/hash-memory

Improve performance of hashing and reduce memory
Webreaper · Aug 24, 2023 · cdd2e12 · cdd2e12
2 parents 18e2180 + 564757f
commit cdd2e12
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Showing 2 changed files with 14 additions and 8 deletions.
diff --git a/Damselfly.Core.ImageProcessing/ImageSharpProcessor.cs b/Damselfly.Core.ImageProcessing/ImageSharpProcessor.cs
@@ -1,4 +1,4 @@
-using System.Runtime.InteropServices;
+using System.Runtime.InteropServices;
 using System.Security.Cryptography;
 using CoenM.ImageHash;
 using CoenM.ImageHash.HashAlgorithms;
@@ -238,20 +238,23 @@ public static string GetHash(Image<Rgba32> image)
         try
         {
             var hashWatch = new Stopwatch("CalcImageHash");
-            var hash = IncrementalHash.CreateHash(HashAlgorithmName.SHA1);
+            using var hash = IncrementalHash.CreateHash(HashAlgorithmName.SHA1);
 
             image.ProcessPixelRows(pixelAccessor =>
             {
                 for ( var y = 0; y < pixelAccessor.Height; y++ )
                 {
                     var pixelRowSpan = pixelAccessor.GetRowSpan(y);
 
-                    var rgbaBytes = MemoryMarshal.AsBytes(pixelRowSpan).ToArray();
+                    var rgbaBytes = MemoryMarshal.AsBytes(pixelRowSpan);
                     hash.AppendData(rgbaBytes);
                 }
             });
 
-            result = hash.GetHashAndReset().ToHex(true);
+            Span<byte> buffer = stackalloc byte[SHA1.HashSizeInBytes];
+            hash.GetHashAndReset(buffer);
+            result = Convert.ToHexString(buffer);
+
             hashWatch.Stop();
             Logging.LogVerbose($"Hashed image ({result}) in {hashWatch.HumanElapsedTime}");
         }

diff --git a/Damselfly.Core.ImageProcessing/SkiaSharpProcessor.cs b/Damselfly.Core.ImageProcessing/SkiaSharpProcessor.cs
@@ -1,4 +1,4 @@
-using System.Runtime.InteropServices;
+using System.Runtime.InteropServices;
 using System.Security.Cryptography;
 using Damselfly.Core.Constants;
 using Damselfly.Core.DbModels.Images;
@@ -187,17 +187,20 @@ public async Task TransformDownloadImage(string input, Stream output, IExportSet
 
             var pixels = sourceBitmap.GetPixelSpan();
 
-            var hash = IncrementalHash.CreateHash(HashAlgorithmName.SHA1);
+            using var hash = IncrementalHash.CreateHash(HashAlgorithmName.SHA1);
 
             for ( var row = 0; row < sourceBitmap.Height; row++ )
             {
                 var rowPixels = pixels.Slice(row * sourceBitmap.RowBytes, sourceBitmap.RowBytes);
 
-                var rgbaBytes = MemoryMarshal.AsBytes(rowPixels).ToArray();
+                var rgbaBytes = MemoryMarshal.AsBytes(rowPixels);
                 hash.AppendData(rgbaBytes);
             }
 
-            result = hash.GetHashAndReset().ToHex(true);
+            Span<byte> buffer = stackalloc byte[SHA1.HashSizeInBytes];
+            hash.GetHashAndReset(buffer);
+            result = Convert.ToHexString(buffer);
+
             hashWatch.Stop();
             Logging.LogVerbose($"Hashed image ({result}) in {hashWatch.HumanElapsedTime}");
         }