piecrust: serializing free limit and gas hint w/o rkyv

piecrust/src/imports.rs

@@ -24,6 +24,8 @@ use crate::Error;
 
 pub const GAS_PASS_PCT: u64 = 93;
 
+const LEN_U64: usize = core::mem::size_of::<u64>();
+
 pub(crate) struct Imports;
 
 impl Imports {
@@ -490,14 +492,19 @@ fn free_limit(mut fenv: Caller<Env>, mod_id_ofs: usize) -> WasmtimeResult<i32> {
  match get_metadata(env, mod_id_ofs) {
  None => Ok(0),
  Some(metadata) => {
- let free_limit = metadata.free_limit;
-
  let len = instance.with_arg_buf_mut(|arg| {
- let vec = rkyv::to_bytes::<_, 8>(&free_limit)
- .expect("Serialization should succeed");
- let slice = vec.as_slice();
- arg[..slice.len()].copy_from_slice(slice);
- slice.len()
+ match metadata.free_limit {
+ Some(free_limit) => {
+ arg[0] = 1;
+ arg[1..LEN_U64 + 1]
+ .copy_from_slice(&free_limit.to_le_bytes()[..]);
+ }
+ _ => {
+ arg[0] = 0;
+ arg[1..LEN_U64 + 1].fill(0);
+ }
+ }
+ LEN_U64 + 1
  });
 
  Ok(len as i32)
@@ -515,14 +522,21 @@ fn free_price_hint(
  match get_metadata(env, mod_id_ofs) {
  None => Ok(0),
  Some(metadata) => {
- let free_price_hint = metadata.free_price_hint;
-
  let len = instance.with_arg_buf_mut(|arg| {
- let vec = rkyv::to_bytes::<_, 16>(&free_price_hint)
- .expect("Serialization should succeed");
- let slice = vec.as_slice();
- arg[..slice.len()].copy_from_slice(slice);
- slice.len()
+ match metadata.free_price_hint {
+ Some((num, denom)) => {
+ arg[0] = 1;
+ arg[1..LEN_U64 + 1]
+ .copy_from_slice(&num.to_le_bytes()[..]);
+ arg[LEN_U64 + 1..LEN_U64 * 2 + 1]
+ .copy_from_slice(&denom.to_le_bytes()[..]);
+ }
+ _ => {
+ arg[0] = 0;
+ arg[1..LEN_U64 * 2 + 1].fill(0);
+ }
+ }
+ LEN_U64 * 2 + 1
  });
 
  Ok(len as i32)