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Avoid using Dictionary's

pull/2134/head
Brian Popow 4 years ago
parent
98b96fe0a9
commit
d5a3de1184
3 changed files with 70 additions and 43 deletions
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  1. 12
      src/ImageSharp/Formats/Tiff/Compression/Decompressors/CcittTwoDimensionalCode.cs
  2. 98
      src/ImageSharp/Formats/Tiff/Compression/Decompressors/T6BitReader.cs
  3. 3
      src/ImageSharp/Formats/Tiff/Compression/Decompressors/T6TiffCompression.cs

12
src/ImageSharp/Formats/Tiff/Compression/Decompressors/CcittTwoDimensionalCode.cs
View File

@ -13,15 +13,21 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors
/// <summary>
/// Initializes a new instance of the <see cref="CcittTwoDimensionalCode"/> struct.
/// </summary>
/// <param name="type">The type.</param>
/// <param name="code">The code word.</param>
/// <param name="type">The type of the code.</param>
/// <param name="bitsRequired">The bits required.</param>
/// <param name="extensionBits">The extension bits.</param>
public CcittTwoDimensionalCode(CcittTwoDimensionalCodeType type, int bitsRequired, int extensionBits = 0)
=> this.value = (ushort)((byte)type | ((bitsRequired & 0b1111) << 8) | ((extensionBits & 0b111) << 11));
public CcittTwoDimensionalCode(int code, CcittTwoDimensionalCodeType type, int bitsRequired, int extensionBits = 0)
{
this.Code = code;
this.value = (ushort)((byte)type | ((bitsRequired & 0b1111) << 8) | ((extensionBits & 0b111) << 11));
}
/// <summary>
/// Gets the code type.
/// </summary>
public CcittTwoDimensionalCodeType Type => (CcittTwoDimensionalCodeType)(this.value & 0b11111111);
public int Code { get; }
}
}

98
src/ImageSharp/Formats/Tiff/Compression/Decompressors/T6BitReader.cs
View File

@ -1,7 +1,6 @@
// Copyright (c) Six Labors.
// Licensed under the Apache License, Version 2.0.
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using SixLabors.ImageSharp.Formats.Tiff.Constants;
using SixLabors.ImageSharp.IO;
@ -16,38 +15,23 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors
{
private readonly int maxCodeLength = 12;
private static readonly CcittTwoDimensionalCode None = new(CcittTwoDimensionalCodeType.None, 0);
private static readonly CcittTwoDimensionalCode None = new(0, CcittTwoDimensionalCodeType.None, 0);
private static readonly Dictionary<uint, CcittTwoDimensionalCode> Len1Codes = new()
{
{ 0b1, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.Vertical0, 1) }
};
private static readonly CcittTwoDimensionalCode Len1Code1 = new(0b1, CcittTwoDimensionalCodeType.Vertical0, 1);
private static readonly Dictionary<uint, CcittTwoDimensionalCode> Len3Codes = new()
{
{ 0b001, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.Horizontal, 3) },
{ 0b010, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.VerticalL1, 3) },
{ 0b011, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.VerticalR1, 3) }
};
private static readonly CcittTwoDimensionalCode Len3Code001 = new(0b001, CcittTwoDimensionalCodeType.Horizontal, 3);
private static readonly CcittTwoDimensionalCode Len3Code010 = new(0b010, CcittTwoDimensionalCodeType.VerticalL1, 3);
private static readonly CcittTwoDimensionalCode Len3Code011 = new(0b011, CcittTwoDimensionalCodeType.VerticalR1, 3);
private static readonly Dictionary<uint, CcittTwoDimensionalCode> Len4Codes = new()
{
{ 0b0001, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.Pass, 4) }
};
private static readonly CcittTwoDimensionalCode Len4Code0001 = new(0b0001, CcittTwoDimensionalCodeType.Pass, 4);
private static readonly Dictionary<uint, CcittTwoDimensionalCode> Len6Codes = new()
{
{ 0b000011, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.VerticalR2, 6) },
{ 0b000010, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.VerticalL2, 6) }
};
private static readonly CcittTwoDimensionalCode Len6Code000011 = new(0b000011, CcittTwoDimensionalCodeType.VerticalR2, 6);
private static readonly CcittTwoDimensionalCode Len6Code000010 = new(0b000010, CcittTwoDimensionalCodeType.VerticalL2, 6);
private static readonly Dictionary<uint, CcittTwoDimensionalCode> Len7Codes = new()
{
{ 0b0000011, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.VerticalR3, 7) },
{ 0b0000010, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.VerticalL3, 7) },
{ 0b0000001, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.Extensions2D, 7) },
{ 0b0000000, new CcittTwoDimensionalCode(CcittTwoDimensionalCodeType.Extensions1D, 7) }
};
private static readonly CcittTwoDimensionalCode Len7Code0000011 = new(0b0000011, CcittTwoDimensionalCodeType.VerticalR3, 7);
private static readonly CcittTwoDimensionalCode Len7Code0000010 = new(0b0000010, CcittTwoDimensionalCodeType.VerticalL3, 7);
private static readonly CcittTwoDimensionalCode Len7Code0000001 = new(0b0000001, CcittTwoDimensionalCodeType.Extensions2D, 7);
private static readonly CcittTwoDimensionalCode Len7Code0000000 = new(0b0000000, CcittTwoDimensionalCodeType.Extensions1D, 7);
/// <summary>
/// Initializes a new instance of the <see cref="T6BitReader"/> class.
@ -61,7 +45,7 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors
}
/// <inheritdoc/>
public override bool HasMoreData => this.Position < (ulong)this.DataLength - 1 || ((uint)(this.BitsRead - 1) < (7 - 1));
public override bool HasMoreData => this.Position < (ulong)this.DataLength - 1 || (uint)(this.BitsRead - 1) < (7 - 1);
/// <summary>
/// Gets or sets the two dimensional code.
@ -84,45 +68,81 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors
switch (this.CurValueBitsRead)
{
case 1:
if (Len1Codes.ContainsKey(value))
if (value == Len1Code1.Code)
{
this.Code = Len1Codes[value];
this.Code = Len1Code1;
return false;
}
break;
case 3:
if (Len3Codes.ContainsKey(value))
if (value == Len3Code001.Code)
{
this.Code = Len3Codes[value];
this.Code = Len3Code001;
return false;
}
if (value == Len3Code010.Code)
{
this.Code = Len3Code010;
return false;
}
if (value == Len3Code011.Code)
{
this.Code = Len3Code011;
return false;
}
break;
case 4:
if (Len4Codes.ContainsKey(value))
if (value == Len4Code0001.Code)
{
this.Code = Len4Codes[value];
this.Code = Len4Code0001;
return false;
}
break;
case 6:
if (Len6Codes.ContainsKey(value))
if (value == Len6Code000010.Code)
{
this.Code = Len6Codes[value];
this.Code = Len6Code000010;
return false;
}
if (value == Len6Code000011.Code)
{
this.Code = Len6Code000011;
return false;
}
break;
case 7:
if (Len7Codes.ContainsKey(value))
if (value == Len7Code0000000.Code)
{
this.Code = Len7Code0000000;
return false;
}
if (value == Len7Code0000001.Code)
{
this.Code = Len7Code0000001;
return false;
}
if (value == Len7Code0000011.Code)
{
this.Code = Len7Code0000011;
return false;
}
if (value == Len7Code0000010.Code)
{
this.Code = Len7Codes[value];
this.Code = Len7Code0000010;
return false;
}

3
src/ImageSharp/Formats/Tiff/Compression/Decompressors/T6TiffCompression.cs
View File

@ -77,9 +77,10 @@ namespace SixLabors.ImageSharp.Formats.Tiff.Compression.Decompressors
{
nint bitPos = Numerics.Modulo8(bitsWritten);
nint bufferPos = bitsWritten / 8;
ref byte scanLineRef = ref MemoryMarshal.GetReference(scanLine);
for (nint i = 0; i < scanLine.Length; i++)
{
if (Unsafe.Add(ref MemoryMarshal.GetReference(scanLine), i) != this.white)
if (Unsafe.Add(ref scanLineRef, i) != this.white)
{
BitWriterUtils.WriteBit(buffer, bufferPos, bitPos);
}

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