70 lines
1.6 KiB
Rust
70 lines
1.6 KiB
Rust
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use crate::object::*;
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use crate::vm::error::*;
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use std::cell::RefCell;
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use std::rc::Rc;
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#[derive(Default)]
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pub struct MachineBuilder {
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max_stack_size: Option<usize>,
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max_arena_objects: Option<usize>,
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}
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impl MachineBuilder {
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pub fn max_stack_size(mut self, max_stack_size: Option<usize>) -> Self {
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self.max_stack_size = max_stack_size;
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self
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}
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pub fn max_arena_objects(mut self, max_arena_objects: Option<usize>) -> Self {
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self.max_arena_objects = max_arena_objects;
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self
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}
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pub fn finish(self) -> Machine {
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Machine::new(self.max_stack_size, Arena::new(self.max_arena_objects))
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}
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}
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/// The current state of a VM.
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#[derive(Debug)]
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pub struct Machine {
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stack: Vec<Value>,
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max_stack_size: Option<usize>,
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arena: Rc<RefCell<Arena>>,
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}
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impl Machine {
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pub fn new(max_stack_size: Option<usize>, arena: Arena) -> Self {
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Machine {
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stack: Default::default(),
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max_stack_size,
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arena: Rc::new(RefCell::new(arena)),
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}
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}
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pub fn max_stack_size(&self) -> Option<usize> {
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self.max_stack_size
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}
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pub fn stack(&self) -> &Vec<Value> {
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&self.stack
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}
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pub fn stack_mut(&mut self) -> &mut Vec<Value> {
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&mut self.stack
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}
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pub fn stack_push(&mut self, value: Value) -> Result<()> {
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if let Some(max) = self.max_stack_size() {
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if self.stack.len() >= max {
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return Err(RuntimeError::StackOverflow);
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}
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}
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self.stack_mut().push(value);
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Ok(())
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}
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pub fn stack_pop(&mut self) -> Option<Value> {
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self.stack_mut().pop()
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}
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}
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