feat: add support for multiple hash algs

FindDuplicates/AlgListCommand.cs

@@ -0,0 +1,26 @@
+using System.ComponentModel;
+using Humanizer;
+using Spectre.Console;
+using Spectre.Console.Cli;
+
+namespace FindDuplicates;
+
+[Description("Display a list of usable hashing algorithms.")]
+internal sealed class AlgListCommand : Command
+{
+    public override int Execute(CommandContext context)
+    {
+        AnsiConsole.WriteLine("The default algorithm fdup uses is SHA512.");
+        AnsiConsole.MarkupLine("To specify a different one, use the [cyan]-a[/] or [cyan]--algorithm[/] flag, and pass one of the values below:");
+
+        var table = new Table();
+        table.AddColumn("Algorithm");
+        table.AddColumn("Value");
+
+        foreach (Algorithm algorithm in Enum.GetValues<Algorithm>())
+            table.AddRow($"{algorithm.Humanize()}", $"{algorithm.ToString().ToLower()}");
+
+        AnsiConsole.Write(table);
+        return 0;
+    }
+}

FindDuplicates/Algorithm.cs

@@ -0,0 +1,15 @@
+using System.ComponentModel;
+
+namespace FindDuplicates;
+
+internal enum Algorithm
+{
+    [Description("SHA512")] Sha512,
+    [Description("SHA384")] Sha384,
+    [Description("SHA256")] Sha256,
+    [Description("SHA3-512")] Sha3512,
+    [Description("SHA3-384")] Sha3384,
+    [Description("SHA3-256")] Sha3256,
+    [Description("SHA1")] Sha1,
+    [Description("MD5")] Md5
+}

FindDuplicates/AlgorithmExtensions.cs

@@ -0,0 +1,42 @@
+using System.Security.Cryptography;
+
+namespace FindDuplicates;
+
+internal static class AlgorithmExtensions
+{
+    public static int GetByteCount(this Algorithm algorithm)
+    {
+        return algorithm switch
+        {
+            Algorithm.Sha512 => SHA512.HashSizeInBytes,
+            Algorithm.Sha384 => SHA384.HashSizeInBytes,
+            Algorithm.Sha256 => SHA256.HashSizeInBytes,
+            Algorithm.Sha3512 => SHA3_512.HashSizeInBytes,
+            Algorithm.Sha3384 => SHA3_384.HashSizeInBytes,
+            Algorithm.Sha3256 => SHA3_256.HashSizeInBytes,
+            Algorithm.Sha1 => SHA1.HashSizeInBytes,
+            Algorithm.Md5 => MD5.HashSizeInBytes,
+            _ => 0
+        };
+    }
+
+    public static int HashData(this Algorithm algorithm, Stream source, Span<byte> destination)
+    {
+        // I'd love to use a dictionary to cache the function map, but you can't use Span<> as a type argument,
+        // probably due to the fact that a lambda heap allocs, and we can't have that for ref structs, oh no (!)
+        // so enjoy this absolutely cursed switch expression which checks each algorithm separately. I hate it too.
+
+        return algorithm switch
+        {
+            Algorithm.Sha512 => SHA512.HashData(source, destination),
+            Algorithm.Sha384 => SHA384.HashData(source, destination),
+            Algorithm.Sha256 => SHA256.HashData(source, destination),
+            Algorithm.Sha3512 => SHA3_512.HashData(source, destination),
+            Algorithm.Sha3384 => SHA3_384.HashData(source, destination),
+            Algorithm.Sha3256 => SHA3_256.HashData(source, destination),
+            Algorithm.Sha1 => SHA1.HashData(source, destination),
+            Algorithm.Md5 => MD5.HashData(source, destination),
+            _ => -1
+        };
+    }
+}

FindDuplicates/FindDuplicates.csproj

@@ -33,6 +33,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+        <PackageReference Include="Humanizer.Core" Version="2.14.1" />
         <PackageReference Include="Spectre.Console.Cli" Version="0.48.0"/>
     </ItemGroup>
 

FindDuplicates/ListCommand.cs

@@ -1,6 +1,6 @@
 using System.Collections.Concurrent;
-using System.Security.Cryptography;
 using System.Text;
+using Humanizer;
 using Spectre.Console;
 using Spectre.Console.Cli;
 
@@ -21,6 +21,7 @@ internal sealed class ListCommand : AsyncCommand<ListSettings>
 
         AnsiConsole.MarkupLineInterpolated($"Searching [cyan]{inputDirectory.FullName}[/]");
         AnsiConsole.MarkupLine($"Recursive mode is {(settings.Recursive ? "[green]ON" : "[red]OFF")}[/]");
+        AnsiConsole.MarkupLine($"Using hash algorithm [cyan]{settings.Algorithm.Humanize()}[/]");
 
         await AnsiConsole.Status()
             .StartAsync("Waiting to hash files...", DoHashWaitAsync)
@@ -109,12 +110,12 @@ internal sealed class ListCommand : AsyncCommand<ListSettings>
 
     private void ProcessFile(FileInfo file, ListSettings settings)
     {
-        Span<byte> buffer = stackalloc byte[64];
+        Span<byte> buffer = stackalloc byte[settings.Algorithm.GetByteCount()];
         try
         {
             using FileStream stream = file.OpenRead();
             using BufferedStream bufferedStream = new BufferedStream(stream, 1048576 /* 1MB */);
-            SHA512.HashData(bufferedStream, buffer);
+            settings.Algorithm.HashData(bufferedStream, buffer);
             string hash = ByteSpanToString(buffer);
             if (settings.Verbose)
                 AnsiConsole.WriteLine($"{file.FullName} ->\n    {hash}");
@@ -146,7 +147,7 @@ internal sealed class ListCommand : AsyncCommand<ListSettings>
 
     private static string ByteSpanToString(ReadOnlySpan<byte> buffer)
     {
-        var builder = new StringBuilder();
+        var builder = new StringBuilder(buffer.Length * 2);
 
         foreach (byte b in buffer)
             builder.Append($"{b:X2}");

FindDuplicates/ListSettings.cs

@@ -10,6 +10,11 @@ internal sealed class ListSettings : CommandSettings
     [DefaultValue(".")]
     public string InputPath { get; set; } = ".";
 
+    [CommandOption("-a|--algorithm <algorithm>")]
+    [Description("The hash algorithm used for comparison. Defaults to SHA512. For a list of all available algorithms, run fdup alglist")]
+    [DefaultValue(Algorithm.Sha512)]
+    public Algorithm Algorithm { get; set; } = Algorithm.Sha512;
+
     [CommandOption("-r|--recursive")]
     [Description("Scans the directory recursively. This may increase run time and is not advised to use when at high order directories such as C: or /")]
     [DefaultValue(false)]

FindDuplicates/Program.cs

@@ -2,4 +2,5 @@ using FindDuplicates;
 using Spectre.Console.Cli;
 
 var app = new CommandApp<ListCommand>();
+app.Configure(cfg => cfg.AddCommand<AlgListCommand>("alglist"));
 await app.RunAsync(args).ConfigureAwait(false);