Fixing hash code implementations.

Former-commit-id: f38a8859ae25e045a6778ff2393246ab0be95f9d
Former-commit-id: bc9b4d589a62248e50f2e8f77deb7edf0558e562

src/ImageProcessor/Imaging/CropLayer.cs

@@ -107,17 +107,22 @@ namespace ImageProcessor.Imaging
         }
 
         /// <summary>
-        /// Returns a hash code for this instance.
+        /// Serves as a hash function for a particular type. 
         /// </summary>
         /// <returns>
-        /// A hash code for this instance, suitable for use in hashing algorithms 
-        /// and data structures like a hash table. 
+        /// A hash code for the current <see cref="T:System.Object"/>.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.Top.GetHashCode() + this.Right.GetHashCode() +
-                   this.Bottom.GetHashCode() + this.Left.GetHashCode() +
-                   this.CropMode.GetHashCode();
+            unchecked
+            {
+                int hashCode = this.Left.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.Top.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.Right.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.Bottom.GetHashCode();
+                hashCode = (hashCode * 397) ^ (int)this.CropMode;
+                return hashCode;
+            }
         }
     }
 }

src/ImageProcessor/Imaging/FastBitmap.cs

@@ -213,6 +213,36 @@ namespace ImageProcessor.Imaging
             GC.SuppressFinalize(this);
         }
 
+        /// <summary>
+        /// Determines whether the specified <see cref="T:System.Object"/> is equal to the current <see cref="T:System.Object"/>.
+        /// </summary>
+        /// <returns>
+        /// true if the specified object  is equal to the current object; otherwise, false.
+        /// </returns>
+        /// <param name="obj">The object to compare with the current object. </param>
+        public override bool Equals(object obj)
+        {
+            FastBitmap fastBitmap = obj as FastBitmap;
+
+            if (fastBitmap == null)
+            {
+                return false;
+            }
+
+            return this.bitmap == fastBitmap.bitmap;
+        }
+
+        /// <summary>
+        /// Serves as a hash function for a particular type. 
+        /// </summary>
+        /// <returns>
+        /// A hash code for the current <see cref="T:System.Object"/>.
+        /// </returns>
+        public override int GetHashCode()
+        {
+            return this.bitmap.GetHashCode();
+        }
+
         /// <summary>
         /// Disposes the object and frees resources for the Garbage Collector.
         /// </summary>

src/ImageProcessor/Imaging/Filters/Photo/MatrixFilterBase.cs

@@ -54,14 +54,19 @@ namespace ImageProcessor.Imaging.Filters.Photo
         }
 
         /// <summary>
-        /// Returns a hash code for this instance.
+        /// Returns the hash code for this instance.
         /// </summary>
         /// <returns>
-        /// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table. 
+        /// A 32-bit signed integer that is the hash code for this instance.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.GetType().Name.GetHashCode() ^ this.Matrix.GetHashCode();
+            unchecked
+            {
+                int hashCode = GetType().Name.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.Matrix.GetHashCode();
+                return hashCode;
+            }
         }
     }
 }

src/ImageProcessor/Imaging/Formats/FormatBase.cs

@@ -147,14 +147,20 @@ namespace ImageProcessor.Imaging.Formats
         }
 
         /// <summary>
-        /// Returns a hash code for this instance.
+        /// Returns the hash code for this instance.
         /// </summary>
         /// <returns>
-        /// A hash code for this instance, suitable for use in hashing algorithms and data structures like a hash table. 
+        /// A 32-bit signed integer that is the hash code for this instance.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.MimeType.GetHashCode();
+            unchecked
+            {
+                int hashCode = this.MimeType.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.IsIndexed.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.Quality;
+                return hashCode;
+            }
         }
     }
 }

src/ImageProcessor/Imaging/GaussianLayer.cs

@@ -166,14 +166,20 @@ namespace ImageProcessor.Imaging
         }
 
         /// <summary>
-        /// Returns a hash code value that represents this object.
+        /// Serves as a hash function for a particular type. 
         /// </summary>
         /// <returns>
-        /// A hash code that represents this object.
+        /// A hash code for the current <see cref="T:System.Object"/>.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.Size.GetHashCode() + this.Sigma.GetHashCode() + this.Threshold.GetHashCode();
+            unchecked
+            {
+                int hashCode = this.Size;
+                hashCode = (hashCode * 397) ^ this.Size.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.Threshold;
+                return hashCode;
+            }
         }
     }
 }

src/ImageProcessor/Imaging/PixelData.cs

@@ -10,6 +10,8 @@
 
 namespace ImageProcessor.Imaging
 {
+    using System.Collections.Generic;
+
     /// <summary>
     /// Contains the component parts that make up a single pixel.
     /// </summary>
@@ -34,5 +36,56 @@ namespace ImageProcessor.Imaging
         /// The alpha component.
         /// </summary>
         public byte A;
+
+        /// <summary>
+        /// Indicates whether this instance and a specified object are equal.
+        /// </summary>
+        /// <returns>
+        /// true if <paramref name="obj"/> and this instance are the same type and represent the same value; otherwise, false.
+        /// </returns>
+        /// <param name="obj">Another object to compare to. </param>
+        public override bool Equals(object obj)
+        {
+            if (obj is PixelData)
+            {
+                PixelData pixelData = (PixelData)obj;
+
+                return this.B == pixelData.B && this.G == pixelData.G & this.R == pixelData.R & this.A == pixelData.A;
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Returns the hash code for this instance.
+        /// </summary>
+        /// <returns>
+        /// A 32-bit signed integer that is the hash code for this instance.
+        /// </returns>
+        public override int GetHashCode()
+        {
+            return this.GetHashCode(this);
+        }
+
+        /// <summary>
+        /// Returns the hash code for the given instance.
+        /// </summary>
+        /// <param name="obj">
+        /// The instance of <see cref="PixelData"/> to return the hash code for.
+        /// </param>
+        /// <returns>
+        /// A 32-bit signed integer that is the hash code for this instance.
+        /// </returns>
+        private int GetHashCode(PixelData obj)
+        {
+            unchecked
+            {
+                int hashCode = obj.B.GetHashCode();
+                hashCode = (hashCode * 397) ^ obj.G.GetHashCode();
+                hashCode = (hashCode * 397) ^ obj.R.GetHashCode();
+                hashCode = (hashCode * 397) ^ obj.A.GetHashCode();
+                return hashCode;
+            }
+        }
     }
 }

src/ImageProcessor/Imaging/ResizeLayer.cs

@@ -100,21 +100,27 @@ namespace ImageProcessor.Imaging
             return this.Size == resizeLayer.Size
                 && this.ResizeMode == resizeLayer.ResizeMode
                 && this.AnchorPosition == resizeLayer.AnchorPosition
-                && this.Upscale == resizeLayer.Upscale;
+                && this.Upscale == resizeLayer.Upscale
+                && this.CenterCoordinates == resizeLayer.CenterCoordinates;
         }
 
         /// <summary>
-        /// Returns a hash code value that represents this object.
+        /// Returns the hash code for this instance.
         /// </summary>
         /// <returns>
-        /// A hash code that represents this object.
+        /// A 32-bit signed integer that is the hash code for this instance.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.Size.GetHashCode() +
-                this.ResizeMode.GetHashCode() +
-                this.AnchorPosition.GetHashCode() +
-                this.Upscale.GetHashCode();
+            unchecked
+            {
+                int hashCode = this.Size.GetHashCode();
+                hashCode = (hashCode * 397) ^ (int)this.ResizeMode;
+                hashCode = (hashCode * 397) ^ (int)this.AnchorPosition;
+                hashCode = (hashCode * 397) ^ this.Upscale.GetHashCode();
+                hashCode = (hashCode * 397) ^ (this.CenterCoordinates != null ? this.CenterCoordinates.GetHashCode() : 0);
+                return hashCode;
+            }
         }
     }
 }

src/ImageProcessor/Imaging/RoundedCornerLayer.cs

@@ -96,16 +96,22 @@ namespace ImageProcessor.Imaging
         }
 
         /// <summary>
-        /// Returns a hash code value that represents this object.
+        /// Returns the hash code for this instance.
         /// </summary>
         /// <returns>
-        /// A hash code that represents this object.
+        /// A 32-bit signed integer that is the hash code for this instance.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.Radius.GetHashCode() +
-                   this.TopLeft.GetHashCode() + this.TopRight.GetHashCode() +
-                   this.BottomLeft.GetHashCode() + this.BottomRight.GetHashCode();
+            unchecked
+            {
+                int hashCode = this.Radius;
+                hashCode = (hashCode * 397) ^ this.TopLeft.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.TopRight.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.BottomLeft.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.BottomRight.GetHashCode();
+                return hashCode;
+            }
         }
     }
 }

src/ImageProcessor/Imaging/TextLayer.cs

@@ -160,21 +160,25 @@ namespace ImageProcessor.Imaging
         }
 
         /// <summary>
-        /// Returns a hash code value that represents this object.
+        /// Returns the hash code for this instance.
         /// </summary>
         /// <returns>
-        /// A hash code that represents this object.
+        /// A 32-bit signed integer that is the hash code for this instance.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.Text.GetHashCode() +
-                this.FontColor.GetHashCode() +
-                this.FontFamily.GetHashCode() +
-                this.FontSize.GetHashCode() +
-                this.Style.GetHashCode() +
-                this.DropShadow.GetHashCode() +
-                this.Opacity.GetHashCode() +
-                this.Position.GetHashCode();
+            unchecked
+            {
+                int hashCode = this.Text != null ? this.Text.GetHashCode() : 0;
+                hashCode = (hashCode * 397) ^ this.DropShadow.GetHashCode();
+                hashCode = (hashCode * 397) ^ (this.FontFamily != null ? this.FontFamily.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ (int)this.Style;
+                hashCode = (hashCode * 397) ^ this.FontColor.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.Opacity;
+                hashCode = (hashCode * 397) ^ this.FontSize;
+                hashCode = (hashCode * 397) ^ this.Position.GetHashCode();
+                return hashCode;
+            }
         }
     }
 }

src/Plugins/ImageProcessor/ImageProcessor.Plugins.Cair/Imaging/ContentAwareResizeLayer.cs

@@ -182,20 +182,24 @@ namespace ImageProcessor.Plugins.Cair.Imaging
         }
 
         /// <summary>
-        /// Returns a hash code value that represents this object.
+        /// Returns the hash code for this instance.
         /// </summary>
         /// <returns>
-        /// A hash code that represents this object.
+        /// A 32-bit signed integer that is the hash code for this instance.
         /// </returns>
         public override int GetHashCode()
         {
-            return this.Size.GetHashCode() +
-                   this.ConvolutionType.GetHashCode() +
-                   this.EnergyFunction.GetHashCode() +
-                   this.OutputType.GetHashCode() +
-                   this.Parallelize.GetHashCode() +
-                   this.Timeout.GetHashCode() +
-                   this.WeightPath.GetHashCode();
+            unchecked
+            {
+                int hashCode = (int)this.ConvolutionType;
+                hashCode = (hashCode * 397) ^ (int)this.EnergyFunction;
+                hashCode = (hashCode * 397) ^ this.Parallelize.GetHashCode();
+                hashCode = (hashCode * 397) ^ (int)this.OutputType;
+                hashCode = (hashCode * 397) ^ this.Timeout;
+                hashCode = (hashCode * 397) ^ this.Size.GetHashCode();
+                hashCode = (hashCode * 397) ^ (this.WeightPath != null ? this.WeightPath.GetHashCode() : 0);
+                return hashCode;
+            }
         }
     }
 }