upgrade version check, feature for dropping checkpoints

src/bin/reencode.rs

@@ -14,6 +14,10 @@ fn main() {
     let mut rply = decode(&mut file).unwrap();
     let header = &rply.header;
     println!("{header:?}");
+    if header.version() == 0 {
+        println!("Can't upgrade v0 replays without a core");
+        std::process::exit(-1);
+    }
     let mut header_out = header.clone();
     header_out.upgrade();
     header_out.set_block_size(128);
@@ -34,9 +38,9 @@ fn main() {
             rply.frame_number,
             frame.inputs(),
         );
+        //frame.drop_checkpoint();
         out.write_frame(&frame).unwrap();
         if Some(rply.frame_number) == rply.header.frame_count() {
-            println!("Done!");
             break;
         }
     }

src/rply.rs

@@ -825,6 +825,11 @@ impl Frame {
         }
         output
     }
+    pub fn drop_checkpoint(&mut self) {
+        self.checkpoint_bytes.clear();
+        self.checkpoint_compression = Compression::None;
+        self.checkpoint_encoding = Encoding::Raw;
+    }
 }
 
 impl Default for Frame {