From 2b9f565b03549f3c09fa0819875d7ea96fd672aa Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Fri, 2 Mar 2018 00:39:17 +1100
Subject: [PATCH] Begin bulk conversion API

---
 .../Conversion/ColorSpaceConverter.CieLab.cs  | 277 +++++++++++++++++-
 src/ImageSharp/Common/Helpers/Guard.cs        |  22 ++
 2 files changed, 298 insertions(+), 1 deletion(-)

diff --git a/src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLab.cs b/src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLab.cs
index 2720b81fe1..17cdb2ef27 100644
--- a/src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLab.cs
+++ b/src/ImageSharp/ColorSpaces/Conversion/ColorSpaceConverter.CieLab.cs
@@ -1,6 +1,8 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
+using System.Runtime.CompilerServices;
 using SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation;
 
 namespace SixLabors.ImageSharp.ColorSpaces.Conversion
@@ -24,7 +26,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
         {
             Guard.NotNull(color, nameof(color));
 
-            // Conversion (perserving white point)
+            // Conversion (preserving white point)
             CieLab unadapted = CieLchToCieLabConverter.Convert(color);
 
             if (!this.IsChromaticAdaptationPerformed)
@@ -36,6 +38,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.Adapt(unadapted);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="CieLch"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<CieLch> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref CieLch sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref CieLch sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="CieLchuv"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -49,6 +72,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="CieLchuv"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<CieLchuv> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref CieLchuv sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref CieLchuv sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="CieLuv"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -62,6 +106,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="CieLuv"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<CieLuv> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref CieLuv sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref CieLuv sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="CieXyy"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -75,6 +140,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="CieXyy"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<CieXyy> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref CieXyy sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref CieXyy sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="CieXyz"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -94,6 +180,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return converter.Convert(adapted);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="CieXyz"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<CieXyz> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref CieXyz sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref CieXyz sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="Cmyk"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -107,6 +214,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="Cmyk"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<Cmyk> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref Cmyk sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref Cmyk sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="Hsl"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -120,6 +248,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="Hsl"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<Hsl> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref Hsl sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref Hsl sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="Hsv"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -133,6 +282,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="Hsv"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<Hsv> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref Hsv sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref Hsv sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="HunterLab"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -146,6 +316,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="HunterLab"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<HunterLab> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref HunterLab sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref HunterLab sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="Lms"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -159,6 +350,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="Lms"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<Lms> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref Lms sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref Lms sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="LinearRgb"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -172,6 +384,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="LinearRgb"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<LinearRgb> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref LinearRgb sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref LinearRgb sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="Rgb"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -185,6 +418,27 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             return this.ToCieLab(xyzColor);
         }
 
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="LinearRgb"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<Rgb> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref Rgb sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref Rgb sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
+
         /// <summary>
         /// Converts a <see cref="YCbCr"/> into a <see cref="CieLab"/>
         /// </summary>
@@ -197,5 +451,26 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion
             var xyzColor = this.ToCieXyz(color);
             return this.ToCieLab(xyzColor);
         }
+
+        /// <summary>
+        /// Performs the bulk conversion from <see cref="YCbCr"/> into <see cref="CieLab"/>
+        /// </summary>
+        /// <param name="source">The span to the source colors</param>
+        /// <param name="destination">The span to the destination colors</param>
+        /// <param name="count">The number of colors to convert.</param>
+        public void Convert(Span<YCbCr> source, Span<CieLab> destination, int count)
+        {
+            Guard.SpansMustBeSizedAtLeast(source, nameof(source), destination, nameof(destination), count);
+
+            ref YCbCr sourceRef = ref source.DangerousGetPinnableReference();
+            ref CieLab destRef = ref destination.DangerousGetPinnableReference();
+
+            for (int i = 0; i < count; i++)
+            {
+                ref Rgb sp = ref Unsafe.Add(ref sourceRef, i);
+                ref CieLab dp = ref Unsafe.Add(ref destRef, i);
+                dp = this.ToCieLab(sp);
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/src/ImageSharp/Common/Helpers/Guard.cs b/src/ImageSharp/Common/Helpers/Guard.cs
index b0546bf9a9..279c67b3e4 100644
--- a/src/ImageSharp/Common/Helpers/Guard.cs
+++ b/src/ImageSharp/Common/Helpers/Guard.cs
@@ -246,5 +246,27 @@ namespace SixLabors.ImageSharp
                 throw new ArgumentException($"Span-s must be at least of length {minLength}!", parameterName);
             }
         }
+
+        /// <summary>
+        /// Verifies that the given 'source' and 'dest' spans are at least of 'minLength' size.
+        /// Throwing an <see cref="ArgumentException"/> if the condition is not met.
+        /// </summary>
+        /// <typeparam name="TSource">The source element type</typeparam>
+        /// <typeparam name="TDest">The destination element type</typeparam>
+        /// <param name="source">The source span</param>
+        /// <param name="sourceParamName">The source parameter name</param>
+        /// <param name="dest">The destination span</param>
+        /// <param name="destParamName">The destination parameter name</param>
+        /// <param name="minLength">The minimum length</param>
+        public static void SpansMustBeSizedAtLeast<TSource, TDest>(
+            Span<TSource> source,
+            string sourceParamName,
+            Span<TDest> dest,
+            string destParamName,
+            int minLength)
+        {
+            MustBeSizedAtLeast(source, minLength, sourceParamName);
+            MustBeSizedAtLeast(dest, minLength, destParamName);
+        }
     }
 }