From 49d41fff88c313e6b6ff5696592fc0efbfbd80ba Mon Sep 17 00:00:00 2001
From: Jason Nelson <jason@carbonmade.com>
Date: Wed, 18 Apr 2018 16:39:24 -0700
Subject: [PATCH] Add TryGetProperty to ImageMetadata and remove Linq call from
 GifEncoder

---
 src/ImageSharp/Formats/Gif/GifEncoderCore.cs  | 18 +++++++--------
 .../Formats/Gif/IGifEncoderOptions.cs         |  2 +-
 src/ImageSharp/MetaData/ImageMetaData.cs      | 23 +++++++++++++++++++
 3 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/src/ImageSharp/Formats/Gif/GifEncoderCore.cs b/src/ImageSharp/Formats/Gif/GifEncoderCore.cs
index 9c0ae9821..14bfa6fd0 100644
--- a/src/ImageSharp/Formats/Gif/GifEncoderCore.cs
+++ b/src/ImageSharp/Formats/Gif/GifEncoderCore.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Buffers.Binary;
 using System.IO;
-using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using System.Text;
@@ -23,7 +22,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
         private readonly MemoryManager memoryManager;
 
         /// <summary>
-        /// The temp buffer used to reduce allocations.
+        /// A reusable buffer used to reduce allocations.
         /// </summary>
         private readonly byte[] buffer = new byte[20];
 
@@ -129,7 +128,8 @@ namespace SixLabors.ImageSharp.Formats.Gif
         {
             // Transparent pixels are much more likely to be found at the end of a palette
             int index = -1;
-            var trans = default(Rgba32);
+            Rgba32 trans = default;
+
             ref TPixel paletteRef = ref MemoryMarshal.GetReference(quantized.Palette.AsSpan());
             for (int i = quantized.Palette.Length - 1; i >= 0; i--)
             {
@@ -221,8 +221,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                 return;
             }
 
-            ImageProperty property = metadata.Properties.FirstOrDefault(p => p.Name == GifConstants.Comments);
-            if (property == null || string.IsNullOrEmpty(property.Value))
+            if (!metadata.TryGetProperty(GifConstants.Comments, out ImageProperty property) || string.IsNullOrEmpty(property.Value))
             {
                 return;
             }
@@ -313,17 +312,15 @@ namespace SixLabors.ImageSharp.Formats.Gif
         private void WriteColorTable<TPixel>(QuantizedFrame<TPixel> image, Stream stream)
             where TPixel : struct, IPixel<TPixel>
         {
-            // Grab the palette and write it to the stream.
             int pixelCount = image.Palette.Length;
 
-            // Get max colors for bit depth.
-            int colorTableLength = (int)Math.Pow(2, this.bitDepth) * 3;
-            var rgb = default(Rgb24);
+            int colorTableLength = (int)Math.Pow(2, this.bitDepth) * 3; // The maximium number of colors for the bit depth
+            Rgb24 rgb = default;
+
             using (IManagedByteBuffer colorTable = this.memoryManager.AllocateManagedByteBuffer(colorTableLength))
             {
                 ref TPixel paletteRef = ref MemoryMarshal.GetReference(image.Palette.AsSpan());
                 ref Rgb24 rgb24Ref = ref Unsafe.As<byte, Rgb24>(ref MemoryMarshal.GetReference(colorTable.Span));
-
                 for (int i = 0; i < pixelCount; i++)
                 {
                     ref TPixel entry = ref Unsafe.Add(ref paletteRef, i);
@@ -331,6 +328,7 @@ namespace SixLabors.ImageSharp.Formats.Gif
                     Unsafe.Add(ref rgb24Ref, i) = rgb;
                 }
 
+                // Write the palette to the stream
                 stream.Write(colorTable.Array, 0, colorTableLength);
             }
         }
diff --git a/src/ImageSharp/Formats/Gif/IGifEncoderOptions.cs b/src/ImageSharp/Formats/Gif/IGifEncoderOptions.cs
index 1f1875789..f7bc5f4ed 100644
--- a/src/ImageSharp/Formats/Gif/IGifEncoderOptions.cs
+++ b/src/ImageSharp/Formats/Gif/IGifEncoderOptions.cs
@@ -7,7 +7,7 @@ using SixLabors.ImageSharp.Processing.Quantization;
 namespace SixLabors.ImageSharp.Formats.Gif
 {
     /// <summary>
-    /// The configuration options used for encoding gifs
+    /// The configuration options used for encoding gifs.
     /// </summary>
     internal interface IGifEncoderOptions
     {
diff --git a/src/ImageSharp/MetaData/ImageMetaData.cs b/src/ImageSharp/MetaData/ImageMetaData.cs
index 01b53a3fd..af3cc5f5f 100644
--- a/src/ImageSharp/MetaData/ImageMetaData.cs
+++ b/src/ImageSharp/MetaData/ImageMetaData.cs
@@ -120,6 +120,29 @@ namespace SixLabors.ImageSharp.MetaData
         /// </summary>
         public ushort RepeatCount { get; set; }
 
+        /// <summary>
+        /// Looks up a property with the provided name.
+        /// </summary>
+        /// <param name="name">The name of the property to lookup.</param>
+        /// <param name="result">The property, if found, with the provided name.</param>
+        /// <returns>Whether the property was found.</returns>
+        internal bool TryGetProperty(string name, out ImageProperty result)
+        {
+            foreach (ImageProperty property in this.Properties)
+            {
+                if (property.Name == name)
+                {
+                    result = property;
+
+                    return true;
+                }
+            }
+
+            result = default;
+
+            return false;
+        }
+
         /// <summary>
         /// Clones this into a new instance
         /// </summary>