A bit more work on metadata reader

metadata_reader.zig

@@ -1,11 +1,45 @@
 const std = @import("std");
+const io = std.io;
 
 const MetadataHeader = packed struct {
-    compressed: bool,
+    not_compressed: bool,
     size: u15,
 };
 
 const MetadataReader = struct {
     rdr: std.io.AnyReader,
+    alloc: std.heap.Allocator,
     curBlock: []const u8,
+    curOffset: u16,
+
+    pub fn init(rdr: io.AnyReader, alloc: std.heap.Allocator) !MetadataReader {
+        const out = .{
+            .rdr = rdr,
+            .alloc = alloc,
+            .curBlock = undefined,
+            .curOffset = 0,
+        };
+        try out.readNextBlock();
+        return out;
+    }
+    pub fn any(self: MetadataReader) !io.AnyReader {
+        return .{
+            .context = @ptrCast(&self),
+            .readFn = typeErasedReadFn,
+        };
+    }
+
+    fn readNextBlock(self: MetadataReader) !void {
+        if (self.curBlock != undefined) {
+            self.alloc.free(self.curBlock);
+        }
+        self.curOffset = 0;
+        const hdr = try self.rdr.readStruct(MetadataHeader);
+        const buf = try self.alloc.alloc(u8, hdr.size);
+        if (hdr.not_compressed) {
+            self.curBlock = buf;
+        } else {
+            //TODO: decompress
+        }
+    }
 };

squashfs.zig

@@ -23,7 +23,6 @@ pub fn newReader(filename: []const u8) !Reader {
     errdefer alloc.deinit();
     const super = try file.reader().readStruct(Superblock);
     try super.valid();
-
     return Reader{
         .super = super,
         .rdr = file,