[STFS] Implement GetEntryNumber.

Aaru.Archives/Arc/Files.cs

@@ -86,7 +86,6 @@ public sealed partial class Arc
     /// <inheritdoc />
     public ErrorNumber GetAttributes(int entryNumber, out FileAttributes attributes)
     {
-        // DOS version of ZOO ignores the attributes, so we just say it's a file
         attributes = FileAttributes.None;
 
         if(!Opened) return ErrorNumber.NotOpened;

Aaru.Archives/Stfs/Files.cs

@@ -1,3 +1,4 @@
+using System;
 using Aaru.CommonTypes.Enums;
 
 namespace Aaru.Archives;
@@ -20,5 +21,30 @@ public sealed partial class Stfs
         return ErrorNumber.NoError;
     }
 
+    /// <inheritdoc />
+    public ErrorNumber GetEntryNumber(string fileName, bool caseInsensitiveMatch, out int entryNumber)
+    {
+        entryNumber = -1;
+
+        if(!Opened) return ErrorNumber.NotOpened;
+
+        if(entryNumber < 0 || entryNumber >= _entries.Length) return ErrorNumber.OutOfRange;
+
+        StringComparison comparison = caseInsensitiveMatch
+                                          ? StringComparison.CurrentCultureIgnoreCase
+                                          : StringComparison.CurrentCulture;
+
+        for(int i = 0, count = _entries.Length; i < count; i++)
+        {
+            if(!_entries[i].Filename.Equals(fileName, comparison)) continue;
+
+            entryNumber = i;
+
+            return ErrorNumber.NoError;
+        }
+
+        return ErrorNumber.NoSuchFile;
+    }
+
 #endregion
 }

Aaru.Archives/Stfs/Unimplemented.cs

@@ -11,10 +11,6 @@ public sealed partial class Stfs
 {
 #region IArchive Members
 
-    /// <inheritdoc />
-    public ErrorNumber GetEntryNumber(string fileName, bool caseInsensitiveMatch, out int entryNumber) =>
-        throw new NotImplementedException();
-
     /// <inheritdoc />
     public ErrorNumber GetCompressedSize(int entryNumber, out long length) => throw new NotImplementedException();