Add benchmarks for Apple RLE decompression.

Aaru6.Compression/Aaru6.Compression.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

Aaru6.Compression/AppleRle.cs

@@ -0,0 +1,128 @@
+// /***************************************************************************
+// Aaru Data Preservation Suite
+// ----------------------------------------------------------------------------
+//
+// Filename       : AppleRle.cs
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : Compression algorithms.
+//
+// --[ Description ] ----------------------------------------------------------
+//
+//     Decompress Apple variant of RLE.
+//
+// --[ License ] --------------------------------------------------------------
+//
+//     This library is free software; you can redistribute it and/or modify
+//     it under the terms of the GNU Lesser General Public License as
+//     published by the Free Software Foundation; either version 2.1 of the
+//     License, or (at your option) any later version.
+//
+//     This library is distributed in the hope that it will be useful, but
+//     WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+//     Lesser General Public License for more details.
+//
+//     You should have received a copy of the GNU Lesser General Public
+//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
+//
+// ----------------------------------------------------------------------------
+// Copyright © 2011-2021 Natalia Portillo
+// Copyright © 2018-2019 David Ryskalczyk
+// ****************************************************************************/
+
+using System.IO;
+
+namespace Aaru6.Compression
+{
+    /// <summary>Implements the Apple version of RLE</summary>
+    public class AppleRle
+    {
+        const uint DART_CHUNK = 20960;
+
+        readonly Stream _inStream;
+        int             _count;
+        bool            _nextA; // true if A, false if B
+        byte            _repeatedByteA, _repeatedByteB;
+        bool            _repeatMode; // true if we're repeating, false if we're just copying
+
+        /// <summary>Initializes a decompressor for the specified stream</summary>
+        /// <param name="stream">Stream containing the compressed data</param>
+        public AppleRle(Stream stream)
+        {
+            _inStream = stream;
+            Reset();
+        }
+
+        void Reset()
+        {
+            _repeatedByteA = _repeatedByteB = 0;
+            _count         = 0;
+            _nextA         = true;
+            _repeatMode    = false;
+        }
+
+        /// <summary>Decompresses a byte</summary>
+        /// <returns>Decompressed byte</returns>
+        public int ProduceByte()
+        {
+            if(_repeatMode && _count > 0)
+            {
+                _count--;
+
+                if(_nextA)
+                {
+                    _nextA = false;
+
+                    return _repeatedByteA;
+                }
+
+                _nextA = true;
+
+                return _repeatedByteB;
+            }
+
+            if(!_repeatMode &&
+               _count > 0)
+            {
+                _count--;
+
+                return _inStream.ReadByte();
+            }
+
+            if(_inStream.Position == _inStream.Length)
+                return -1;
+
+            while(true)
+            {
+                byte  b1 = (byte)_inStream.ReadByte();
+                byte  b2 = (byte)_inStream.ReadByte();
+                short s  = (short)((b1 << 8) | b2);
+
+                if(s == 0          ||
+                   s >= DART_CHUNK ||
+                   s <= -DART_CHUNK)
+                    continue;
+
+                if(s < 0)
+                {
+                    _repeatMode    = true;
+                    _repeatedByteA = (byte)_inStream.ReadByte();
+                    _repeatedByteB = (byte)_inStream.ReadByte();
+                    _count         = (-s * 2) - 1;
+                    _nextA         = false;
+
+                    return _repeatedByteA;
+                }
+
+                if(s <= 0)
+                    continue;
+
+                _repeatMode = false;
+                _count      = (s * 2) - 1;
+
+                return _inStream.ReadByte();
+            }
+        }
+    }
+}

AaruBenchmark.sln

@@ -4,6 +4,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AaruBenchmark", "AaruBenchm
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Aaru6.Checksums", "Aaru6.Checksums\Aaru6.Checksums.csproj", "{CC48B324-A532-4A45-87A6-6F91F7141E8D}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Aaru6.Compression", "Aaru6.Compression\Aaru6.Compression.csproj", "{7B9BAFE0-E9D9-4EF4-B009-007F727DAB68}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -18,5 +20,9 @@ Global
 		{CC48B324-A532-4A45-87A6-6F91F7141E8D}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{CC48B324-A532-4A45-87A6-6F91F7141E8D}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{CC48B324-A532-4A45-87A6-6F91F7141E8D}.Release|Any CPU.Build.0 = Release|Any CPU
+		{7B9BAFE0-E9D9-4EF4-B009-007F727DAB68}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7B9BAFE0-E9D9-4EF4-B009-007F727DAB68}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7B9BAFE0-E9D9-4EF4-B009-007F727DAB68}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7B9BAFE0-E9D9-4EF4-B009-007F727DAB68}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

AaruBenchmark/AaruBenchmark.csproj

@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="Aaru.Checksums" Version="5.3.0"/>
+    <PackageReference Include="Aaru.Compression" Version="5.3.0"/>
     <PackageReference Include="BenchmarkDotNet" Version="0.13.1"/>
     <PackageReference Include="DotNetZip" Version="1.15.0"/>
     <PackageReference Include="SharpCompress" Version="0.29.0"/>
@@ -25,10 +26,15 @@
     <Content Include="data\bzip2.bz2">
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
     </Content>
+    <None Remove="data\apple_rle.bin"/>
+    <Content Include="data\apple_rle.bin">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
   </ItemGroup>
 
   <ItemGroup>
     <ProjectReference Include="..\Aaru6.Checksums\Aaru6.Checksums.csproj"/>
+    <ProjectReference Include="..\Aaru6.Compression\Aaru6.Compression.csproj"/>
   </ItemGroup>
 
   <ItemGroup>

AaruBenchmark/Benchs.cs

@@ -5,6 +5,16 @@ using BenchmarkDotNet.Jobs;
 
 namespace AaruBenchmark
 {
+    [SimpleJob(RuntimeMoniker.Net60)]
+    public class AppleRleBenchs
+    {
+        [Benchmark(Baseline = true)]
+        public void Aaru() => Compression.Aaru.AppleRle();
+
+        [Benchmark]
+        public void Aaru6() => Compression.Aaru6.AppleRle();
+    }
+
     [SimpleJob(RuntimeMoniker.Net60)]
     public class GzipBenchs
     {

AaruBenchmark/Compression/Aaru.cs

@@ -0,0 +1,34 @@
+using System.IO;
+using Aaru.Compression;
+using Aaru6.Checksums;
+
+namespace AaruBenchmark.Compression
+{
+    public class Aaru
+    {
+        const int BUFFER_SIZE = 20960;
+
+        public static void AppleRle()
+        {
+            byte[] input = new byte[1102];
+
+            var fs = new FileStream(Path.Combine(Program.Folder, "apple_rle.bin"), FileMode.Open, FileAccess.Read);
+
+            fs.Read(input, 0, input.Length);
+            fs.Close();
+            fs.Dispose();
+
+            byte[] output = new byte[BUFFER_SIZE];
+
+            var rle = new AppleRle(new MemoryStream(input));
+
+            for(int i = 0; i < BUFFER_SIZE; i++)
+                output[i] = (byte)rle.ProduceByte();
+
+            string crc = Crc32Context.Data(output, out _);
+
+            if(crc != "3525ef06")
+                throw new InvalidDataException("Incorrect decompressed checksum");
+        }
+    }
+}

AaruBenchmark/Compression/Aaru6.cs

@@ -0,0 +1,34 @@
+using System.IO;
+using Aaru6.Checksums;
+using Aaru6.Compression;
+
+namespace AaruBenchmark.Compression
+{
+    public class Aaru6
+    {
+        const int BUFFER_SIZE = 20960;
+
+        public static void AppleRle()
+        {
+            byte[] input = new byte[1102];
+
+            var fs = new FileStream(Path.Combine(Program.Folder, "apple_rle.bin"), FileMode.Open, FileAccess.Read);
+
+            fs.Read(input, 0, input.Length);
+            fs.Close();
+            fs.Dispose();
+
+            byte[] output = new byte[BUFFER_SIZE];
+
+            var rle = new AppleRle(new MemoryStream(input));
+
+            for(int i = 0; i < BUFFER_SIZE; i++)
+                output[i] = (byte)rle.ProduceByte();
+
+            string crc = Crc32Context.Data(output, out _);
+
+            if(crc != "3525ef06")
+                throw new InvalidDataException("Incorrect decompressed checksum");
+        }
+    }
+}

AaruBenchmark/Program.cs

@@ -13,6 +13,7 @@ namespace AaruBenchmark
         {
             var config = ManualConfig.Create(DefaultConfig.Instance);
 
+            BenchmarkRunner.Run<AppleRleBenchs>(config);
             BenchmarkRunner.Run<GzipBenchs>(config);
             BenchmarkRunner.Run<Bzip2Benchs>(config);
             BenchmarkRunner.Run<Adler32Benchs>(config);