Add support for Microsoft SFX CAB detection (#56)

* Add support for Microsoft SFX CAB detection

* Address reviews

* Simplify GetVersion

* Fix GetVersion

BurnOutSharp/PackerType/MicrosoftCABSFX.cs

@@ -0,0 +1,55 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using BurnOutSharp.Matching;
+
+namespace BurnOutSharp.PackerType
+{
+    // TODO: Add extraction, which should be possible with LibMSPackN, but it refuses to extract due to SFX files lacking the typical CAB identifiers.
+    public class MicrosoftCABSFX : IContentCheck
+    {
+        /// <inheritdoc/>
+        public bool ShouldScan(byte[] magic) => true;
+
+        /// <inheritdoc/>
+        public string CheckContents(string file, byte[] fileContent, bool includePosition = false)
+        {
+            var fvinfo = Utilities.GetFileVersionInfo(file);
+
+            string name = fvinfo?.InternalName.Trim();
+            if (!string.IsNullOrWhiteSpace(name) && name.Equals("Wextract", StringComparison.OrdinalIgnoreCase))
+                return $"Microsoft CAB SFX v{Utilities.GetFileVersion(file)}";
+
+            name = fvinfo?.OriginalFilename.Trim();
+            if (!string.IsNullOrWhiteSpace(name) && name.Equals("WEXTRACT.EXE", StringComparison.OrdinalIgnoreCase))
+                return $"Microsoft CAB SFX v{Utilities.GetFileVersion(file)}";
+
+            var matchers = new List<ContentMatchSet>
+            {
+                // wextract_cleanup
+                new ContentMatchSet(new byte?[]
+                {
+                    0x77, 0x65, 0x78, 0x74, 0x72, 0x61, 0x63, 0x74, 
+                    0x5F, 0x63, 0x6C, 0x65, 0x61, 0x6E, 0x75, 0x70
+                }, GetVersion, "Microsoft CAB SFX"),
+
+                /* This detects a different but similar type of SFX that uses Microsoft CAB files.
+                   Further research is needed to see if it's just a different version or entirely separate. */
+                // MSCFu
+                new ContentMatchSet(new byte?[] { 0x4D, 0x53, 0x43, 0x46, 0x75 }, GetVersion, "Microsoft CAB SFX"),
+            };
+
+            return MatchUtil.GetFirstMatch(file, fileContent, matchers, includePosition);
+        }
+
+        // This method of version detection is suboptimal because the version is sometimes the version of the included software, not the SFX itself.
+        public static string GetVersion(string file, byte[] fileContent, List<int> positions)
+        {
+            string version = Utilities.GetFileVersion(file);
+            if (!string.IsNullOrWhiteSpace(version))
+                return $"v{version}";
+
+            return string.Empty;
+        }
+    }
+}

README.md

@@ -95,6 +95,7 @@ Below is a list of the executable packers that can be detected using this code:
 - EXE Stealth
 - Inno Setup
 - Installer VISE
+- Microsoft CAB SFX
 - NSIS
 - PECompact
 - Setup Factory