Updated a lot of packed structs to extern struct

Specified int types for remaining packed structs
Instead of manually decoding File & ExtFile structs, decode an extern struct first
Fixed some zstd issues
Some more File stuff

src/file.zig

@@ -3,6 +3,8 @@
 const std = @import("std");
 const Io = std.Io;
 
+const Archive = @import("archive.zig");
+const DirEntry = @import("directory.zig");
 const ExtractionOptions = @import("options.zig");
 const Inode = @import("inode.zig");
 
@@ -10,17 +12,21 @@ const File = @This();
 
 alloc: std.mem.Allocator,
 
+archive: Archive,
+
 inode: Inode,
 name: []const u8,
 
 /// Creates a new File from an inode. Takes ownership of the Inode and creates a copy of the given name.
 /// Requires the given allocator was used to create the Inode.
-pub fn init(alloc: std.mem.Allocator, in: Inode, name: []const u8) !File {
+pub fn init(alloc: std.mem.Allocator, archive: Archive, in: Inode, name: []const u8) !File {
     const new_name = try alloc.alloc(u8, name.len);
     @memcpy(new_name, name);
     return .{
         .alloc = alloc,
 
+        .archive = archive,
+
         .inode = in,
         .name = new_name,
     };
@@ -31,10 +37,10 @@ pub fn deinit(self: File) void {
 }
 
 pub fn open(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !File {
-    _ = self;
-    _ = alloc;
-    _ = io;
-    _ = filepath;
+    switch (self.inode.hdr.inode_type) {
+        .dir, .ext_dir => {},
+        else => return Error.NotDirectory,
+    }
     return error.TODO;
 }
 
@@ -46,3 +52,12 @@ pub fn extract(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u
     _ = options;
     return error.TODO;
 }
+
+// Types
+
+pub const Error = error{
+    NotDirectory,
+    NotRegularFile,
+    NotSymlink,
+    NotDevice,
+};