Further work on getting everything working again

Mainly working on decompression interface

src/util/decompressor.zig

@@ -0,0 +1,19 @@
+//! A decompression interface
+
+const std = @import("std");
+
+const Decompressor = @This();
+
+pub const Error = std.Io.Reader.StreamError || std.mem.Allocator.Error;
+
+/// The actual decompression function.
+/// If the given decompressor is null, then the decompression should be done "stateless" without lasting allocations.
+decomp_fn: *fn (?*Decompressor, std.mem.Allocator, in: []u8, out: []u8) Error!usize,
+
+pub fn Decompress(self: *Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    return self.decomp_fn(self, alloc, in, out);
+}
+
+pub fn StatelessDecompression(self: Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    return self.decomp_fn(null, alloc, in, out);
+}