tsai
/
ImageSharp
mirror of https://github.com/SixLabors/ImageSharp
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

Reduce additions and use Unsafe.As

pull/525/head
James Jackson-South 8 years ago
parent
819c8ac58a
commit
df8000dbb6
2 changed files with 87 additions and 43 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 102
      src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsIDCT.cs
  2. 28
      tests/ImageSharp.Benchmarks/General/StructCasting.cs

102
src/ImageSharp/Formats/Jpeg/PdfJsPort/Components/PdfJsIDCT.cs
View File

@ -43,15 +43,23 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
// inverse DCT on rows
for (int row = 0; row < 64; row += 8)
{
int r1 = row + 1;
int r2 = row + 2;
int r3 = row + 3;
int r4 = row + 4;
int r5 = row + 5;
int r6 = row + 6;
int r7 = row + 7;
// gather block data
p0 = Unsafe.Add(ref blockDataRef, row);
p1 = Unsafe.Add(ref blockDataRef, row + 1);
p2 = Unsafe.Add(ref blockDataRef, row + 2);
p3 = Unsafe.Add(ref blockDataRef, row + 3);
p4 = Unsafe.Add(ref blockDataRef, row + 4);
p5 = Unsafe.Add(ref blockDataRef, row + 5);
p6 = Unsafe.Add(ref blockDataRef, row + 6);
p7 = Unsafe.Add(ref blockDataRef, row + 7);
p1 = Unsafe.Add(ref blockDataRef, r1);
p2 = Unsafe.Add(ref blockDataRef, r2);
p3 = Unsafe.Add(ref blockDataRef, r3);
p4 = Unsafe.Add(ref blockDataRef, r4);
p5 = Unsafe.Add(ref blockDataRef, r5);
p6 = Unsafe.Add(ref blockDataRef, r6);
p7 = Unsafe.Add(ref blockDataRef, r7);
// dequant p0
p0 *= Unsafe.Add(ref quantizationTableRef, row);
@ -62,24 +70,24 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
t = ((DctSqrt2 * p0) + 512) >> 10;
short st = (short)t;
Unsafe.Add(ref computationBufferRef, row) = st;
Unsafe.Add(ref computationBufferRef, row + 1) = st;
Unsafe.Add(ref computationBufferRef, row + 2) = st;
Unsafe.Add(ref computationBufferRef, row + 3) = st;
Unsafe.Add(ref computationBufferRef, row + 4) = st;
Unsafe.Add(ref computationBufferRef, row + 5) = st;
Unsafe.Add(ref computationBufferRef, row + 6) = st;
Unsafe.Add(ref computationBufferRef, row + 7) = st;
Unsafe.Add(ref computationBufferRef, r1) = st;
Unsafe.Add(ref computationBufferRef, r2) = st;
Unsafe.Add(ref computationBufferRef, r3) = st;
Unsafe.Add(ref computationBufferRef, r4) = st;
Unsafe.Add(ref computationBufferRef, r5) = st;
Unsafe.Add(ref computationBufferRef, r6) = st;
Unsafe.Add(ref computationBufferRef, r7) = st;
continue;
}
// dequant p1 ... p7
p1 *= Unsafe.Add(ref quantizationTableRef, row + 1);
p2 *= Unsafe.Add(ref quantizationTableRef, row + 2);
p3 *= Unsafe.Add(ref quantizationTableRef, row + 3);
p4 *= Unsafe.Add(ref quantizationTableRef, row + 4);
p5 *= Unsafe.Add(ref quantizationTableRef, row + 5);
p6 *= Unsafe.Add(ref quantizationTableRef, row + 6);
p7 *= Unsafe.Add(ref quantizationTableRef, row + 7);
p1 *= Unsafe.Add(ref quantizationTableRef, r1);
p2 *= Unsafe.Add(ref quantizationTableRef, r2);
p3 *= Unsafe.Add(ref quantizationTableRef, r3);
p4 *= Unsafe.Add(ref quantizationTableRef, r4);
p5 *= Unsafe.Add(ref quantizationTableRef, r5);
p6 *= Unsafe.Add(ref quantizationTableRef, r6);
p7 *= Unsafe.Add(ref quantizationTableRef, r7);
// stage 4
v0 = ((DctSqrt2 * p0) + CenterJSample) >> 8;
@ -128,14 +136,22 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
// inverse DCT on columns
for (int col = 0; col < 8; ++col)
{
int c8 = col + 8;
int c16 = col + 16;
int c24 = col + 24;
int c32 = col + 32;
int c40 = col + 40;
int c48 = col + 48;
int c56 = col + 56;
p0 = Unsafe.Add(ref computationBufferRef, col);
p1 = Unsafe.Add(ref computationBufferRef, col + 8);
p2 = Unsafe.Add(ref computationBufferRef, col + 16);
p3 = Unsafe.Add(ref computationBufferRef, col + 24);
p4 = Unsafe.Add(ref computationBufferRef, col + 32);
p5 = Unsafe.Add(ref computationBufferRef, col + 40);
p6 = Unsafe.Add(ref computationBufferRef, col + 48);
p7 = Unsafe.Add(ref computationBufferRef, col + 56);
p1 = Unsafe.Add(ref computationBufferRef, c8);
p2 = Unsafe.Add(ref computationBufferRef, c16);
p3 = Unsafe.Add(ref computationBufferRef, c24);
p4 = Unsafe.Add(ref computationBufferRef, c32);
p5 = Unsafe.Add(ref computationBufferRef, c40);
p6 = Unsafe.Add(ref computationBufferRef, c48);
p7 = Unsafe.Add(ref computationBufferRef, c56);
// check for all-zero AC coefficients
if ((p1 | p2 | p3 | p4 | p5 | p6 | p7) == 0)
@ -147,13 +163,13 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
short st = (short)t;
Unsafe.Add(ref blockDataRef, col) = st;
Unsafe.Add(ref blockDataRef, col + 8) = st;
Unsafe.Add(ref blockDataRef, col + 16) = st;
Unsafe.Add(ref blockDataRef, col + 24) = st;
Unsafe.Add(ref blockDataRef, col + 32) = st;
Unsafe.Add(ref blockDataRef, col + 40) = st;
Unsafe.Add(ref blockDataRef, col + 48) = st;
Unsafe.Add(ref blockDataRef, col + 56) = st;
Unsafe.Add(ref blockDataRef, c8) = st;
Unsafe.Add(ref blockDataRef, c16) = st;
Unsafe.Add(ref blockDataRef, c24) = st;
Unsafe.Add(ref blockDataRef, c32) = st;
Unsafe.Add(ref blockDataRef, c40) = st;
Unsafe.Add(ref blockDataRef, c48) = st;
Unsafe.Add(ref blockDataRef, c56) = st;
continue;
}
@ -213,14 +229,14 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort.Components
p7 = (p7 < 16) ? 0 : (p7 >= 4080) ? MaxJSample : p7 >> 4;
// store block data
Unsafe.Add(ref blockDataRef, col) = (short)p0;
Unsafe.Add(ref blockDataRef, col + 8) = (short)p1;
Unsafe.Add(ref blockDataRef, col + 16) = (short)p2;
Unsafe.Add(ref blockDataRef, col + 24) = (short)p3;
Unsafe.Add(ref blockDataRef, col + 32) = (short)p4;
Unsafe.Add(ref blockDataRef, col + 40) = (short)p5;
Unsafe.Add(ref blockDataRef, col + 48) = (short)p6;
Unsafe.Add(ref blockDataRef, col + 56) = (short)p7;
Unsafe.Add(ref blockDataRef, col) = Unsafe.As<int, short>(ref Unsafe.AsRef(p0));
Unsafe.Add(ref blockDataRef, c8) = Unsafe.As<int, short>(ref Unsafe.AsRef(p1));
Unsafe.Add(ref blockDataRef, c16) = Unsafe.As<int, short>(ref Unsafe.AsRef(p2));
Unsafe.Add(ref blockDataRef, c24) = Unsafe.As<int, short>(ref Unsafe.AsRef(p3));
Unsafe.Add(ref blockDataRef, c32) = Unsafe.As<int, short>(ref Unsafe.AsRef(p4));
Unsafe.Add(ref blockDataRef, c40) = Unsafe.As<int, short>(ref Unsafe.AsRef(p5));
Unsafe.Add(ref blockDataRef, c48) = Unsafe.As<int, short>(ref Unsafe.AsRef(p6));
Unsafe.Add(ref blockDataRef, c56) = Unsafe.As<int, short>(ref Unsafe.AsRef(p7));
}
}
}

28
tests/ImageSharp.Benchmarks/General/StructCasting.cs
View File

@ -0,0 +1,28 @@
using System.Runtime.CompilerServices;
using BenchmarkDotNet.Attributes;
namespace SixLabors.ImageSharp.Benchmarks.General
{
public class StructCasting
{
[Benchmark(Baseline = true)]
public short ExplicitCast()
{
int x = 5 * 2;
return (short)x;
}
[Benchmark]
public short UnsafeCast()
{
int x = 5 * 2;
return Unsafe.As<int, short>(ref x);
}
[Benchmark]
public short UnsafeCastRef()
{
return Unsafe.As<int, short>(ref Unsafe.AsRef(5 * 2));
}
}
}
Write Preview
Loading…
Cancel
Save