Implement Attrib for ZipEntry

src/SharpCompress/Common/Zip/Headers/DirectoryEntryHeader.cs

@@ -123,8 +123,6 @@ internal override void Read(BinaryReader reader)
 
     public long RelativeOffsetOfEntryHeader { get; set; }
 
-    public uint ExternalFileAttributes { get; set; }
-
     public ushort InternalFileAttributes { get; set; }
 
     public ushort DiskNumberStart { get; set; }

src/SharpCompress/Common/Zip/Headers/ZipFileEntry.cs

@@ -121,5 +121,7 @@ protected void LoadExtra(byte[] extra)
 
     internal bool IsZip64 => CompressedSize >= uint.MaxValue;
 
+    internal uint ExternalFileAttributes { get; set; }
+
     internal string? Comment { get; set; }
 }

src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs

@@ -152,6 +152,7 @@ DirectoryEntryHeader directoryEntryHeader
 
         // populate fields only known from the DirectoryEntryHeader
         localEntryHeader.HasData = directoryEntryHeader.HasData;
+        localEntryHeader.ExternalFileAttributes = directoryEntryHeader.ExternalFileAttributes;
         localEntryHeader.Comment = directoryEntryHeader.Comment;
 
         if (FlagUtility.HasFlag(localEntryHeader.Flags, HeaderFlags.UsePostDataDescriptor))

src/SharpCompress/Common/Zip/ZipEntry.cs

@@ -84,5 +84,7 @@ internal ZipEntry(ZipFilePart? filePart)
 
     internal override IEnumerable<FilePart> Parts => _filePart.Empty();
 
+    public override int? Attrib => (int?)_filePart?.Header.ExternalFileAttributes;
+
     public string? Comment => _filePart?.Header.Comment;
 }

tests/SharpCompress.Test/Zip/ZipArchiveTests.cs

@@ -832,4 +832,15 @@ public void Zip_EntryCommentAfterEntryRead()
         using var _ = firstEntry.OpenEntryStream();
         Assert.Equal(29, firstEntry.Comment.Length);
     }
+
+    [Fact]
+    public void Zip_FilePermissions()
+    {
+        using var archive = ArchiveFactory.Open(Path.Combine(TEST_ARCHIVES_PATH, "Zip.644.zip"));
+
+        var firstEntry = archive.Entries.First();
+        const int S_IFREG = 0x8000;
+        const int expected = (S_IFREG | 0b110_100_100) << 16; // 0644 mode regular file
+        Assert.Equal(expected, firstEntry.Attrib);
+    }
 }