Finished(?) decompression stuff

src/decomp.zig

@@ -1,5 +1,7 @@
 const std = @import("std");
 
+pub const StatelessDecomp = *const fn (std.mem.Allocator, in: []u8, out: []u8) Error!usize;
+
 pub const Error = error{
     OutOfMemory,
     EndOfStream,
@@ -11,14 +13,17 @@ const Decompressor = @This();
 
 alloc: std.mem.Allocator = std.heap.page_allocator,
 vtable: *struct {
-    decompress: *const fn (*Decompressor, in: []u8, out: []u8) Error!usize = defaultDecompress,
-    stateless: *const fn (std.mem.Allocator, in: []u8, out: []u8) Error!usize,
+    decompress: *const fn (*const Decompressor, in: []u8, out: []u8) Error!usize = defaultDecompress,
+    stateless: StatelessDecomp,
 },
 
-pub fn decompress(self: *Decompressor, in: []u8, out: []u8) Error!usize {
+pub fn decompress(self: *const Decompressor, in: []u8, out: []u8) Error!usize {
     return self.vtable.decompress(self, in, out);
 }
+pub fn stateless(self: Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    return self.vtable.stateless(alloc, in, out);
+}
 
-fn defaultDecompress(self: *Decompressor, in: []u8, out: []u8) Error!usize {
+fn defaultDecompress(self: *const Decompressor, in: []u8, out: []u8) Error!usize {
     return self.vtable.stateless(self.alloc, in, out);
 }