Restart (once again)

src/util/metadata.zig

@@ -0,0 +1,34 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+const Writer = std.Io.Writer;
+const Limit = std.Io.Limit;
+const StreamError = std.Io.Reader.StreamError;
+
+const DecompMgr = @import("../decomp.zig");
+
+const This = @This();
+
+rdr: Reader,
+decomp: *DecompMgr,
+
+buf: [8192]u8 = undefined,
+
+interface: Reader,
+
+pub fn init(rdr: Reader, decomp: *DecompMgr) This {
+    return .{
+        .rdr = rdr,
+        .decomp = decomp,
+        .interface = .{
+            .buffer = &[0]u8{},
+            .end = 0,
+            .seek = 0,
+            .vtable = &{
+                .stream = stream,
+            },
+        },
+    };
+}
+
+fn stream(rdr: *Reader, wrt: *Writer, limit: Limit) StreamError!usize{
+}

src/util/offset_file.zig

@@ -0,0 +1,20 @@
+//! A File that's meant where it's meaningful content starts at a given offset.
+
+const std = @import("std");
+const File = std.fs.File;
+const Reader = std.fs.File.Reader;
+
+const OffsetFile = @This();
+
+fil: File,
+offset: u64,
+
+pub fn init(fil: File, init_offset: u64) OffsetFile {
+    return .{ .fil = fil, .offset = init_offset };
+}
+
+pub fn readerAt(self: OffsetFile, offset: u64, buffer: []u8) !Reader {
+    var rdr = self.fil.reader(buffer);
+    try rdr.seekTo(self.offset + offset);
+    return rdr;
+}