@ -1,4 +1,4 @@
// Copyright (c) Six Labors.
// Copyright (c) Six Labors.
// Licensed under the Apache License, Version 2.0.
using System ;
@ -12,18 +12,19 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
/// Cache 8 pixel rows on the stack, which may originate from different buffers of a <see cref="MemoryGroup{T}"/>.
/// </summary>
[StructLayout(LayoutKind.Sequential)]
internal readonly re f struct RowOctet < T >
internal ref struct RowOctet < T >
where T : struct
{
private readonly Span < T > row0 ;
private readonly Span < T > row1 ;
private readonly Span < T > row2 ;
private readonly Span < T > row3 ;
private readonly Span < T > row4 ;
private readonly Span < T > row5 ;
private readonly Span < T > row6 ;
private readonly Span < T > row7 ;
private Span < T > row0 ;
private Span < T > row1 ;
private Span < T > row2 ;
private Span < T > row3 ;
private Span < T > row4 ;
private Span < T > row5 ;
private Span < T > row6 ;
private Span < T > row7 ;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public RowOctet ( Buffer2D < T > buffer , int startY )
{
int y = startY ;
@ -38,13 +39,12 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
this . row7 = y < height ? buffer . GetRowSpan ( y ) : default ;
}
// No unsafe tricks, since Span<T> can't be used as a generic argument
public Span < T > this [ int y ]
{
[MethodImpl(InliningOptions.ShortMethod)]
get
{
// No unsafe tricks, since Span<T> can't be used as a generic argument
return y switch
[MethodImpl(MethodImplOptions.AggressiveInlining)]
get = >
y switch
{
0 = > this . row0 ,
1 = > this . row1 ,
@ -56,13 +56,56 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components
7 = > this . row7 ,
_ = > ThrowIndexOutOfRangeException ( )
} ;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private set
{
switch ( y )
{
case 0 :
this . row0 = value ;
break ;
case 1 :
this . row1 = value ;
break ;
case 2 :
this . row2 = value ;
break ;
case 3 :
this . row3 = value ;
break ;
case 4 :
this . row4 = value ;
break ;
case 5 :
this . row5 = value ;
break ;
case 6 :
this . row6 = value ;
break ;
default :
this . row7 = value ;
break ;
}
}
}
[MethodImpl(InliningOptions.ColdPath)]
private static Span < T > ThrowIndexOutOfRangeException ( )
[MethodImpl(MethodImplOptions.AggressiveInlining )]
public void Update ( Buffer2D < T > buffer , int startY )
{
throw new IndexOutOfRangeException ( ) ;
int y = startY ;
int height = buffer . Height ;
// We don't actually have to assign values outside of the
// frame pixel buffer since they are never requested.
for ( int i = 0 ; i < 8 & & y < height ; i + + )
{
this [ i ] = buffer . GetRowSpan ( y + + ) ;
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
private static Span < T > ThrowIndexOutOfRangeException ( )
= > throw new IndexOutOfRangeException ( ) ;
}
}
James Jackson-South
5 years ago