Replace VsPointer with cached decoding

valuescript_vm/src/bytecode.rs

@@ -0,0 +1,44 @@
+use std::{cell::RefCell, collections::HashMap, fmt, ops::Index, rc::Rc, slice::SliceIndex};
+
+use crate::{bytecode_decoder::BytecodeDecoder, vs_value::Val};
+
+pub struct Bytecode {
+  pub code: Vec<u8>,
+  pub cache: RefCell<HashMap<usize, Val>>,
+}
+
+impl<I: SliceIndex<[u8]>> Index<I> for Bytecode {
+  type Output = I::Output;
+
+  fn index(&self, index: I) -> &Self::Output {
+    &self.code[index]
+  }
+}
+
+impl fmt::Debug for Bytecode {
+  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+    write!(f, "Bytecode {{ code: {:?} }}", self.code)
+  }
+}
+
+impl Bytecode {
+  pub fn new(code: Vec<u8>) -> Bytecode {
+    Bytecode {
+      code,
+      cache: RefCell::new(HashMap::new()),
+    }
+  }
+}
+
+pub trait DecoderMaker {
+  fn decoder(&self, pos: usize) -> BytecodeDecoder;
+}
+
+impl DecoderMaker for Rc<Bytecode> {
+  fn decoder(&self, pos: usize) -> BytecodeDecoder {
+    BytecodeDecoder {
+      bytecode: self.clone(),
+      pos,
+    }
+  }
+}