Files
scryer-prolog/src/prolog/machine/or_stack.rs

146 lines
2.7 KiB
Rust

use crate::prolog::machine::machine_indices::*;
use std::mem;
use std::ops::{Index, IndexMut};
use std::vec::Vec;
pub struct Frame {
pub global_index: usize,
pub e: usize,
pub cp: LocalCodePtr,
pub attr_var_init_b: usize,
pub b: usize,
pub bp: CodePtr,
pub tr: usize,
pub pstr_tr: usize,
pub h: usize,
pub b0: usize,
args: Vec<Addr>,
}
impl Frame {
fn new(
global_index: usize,
e: usize,
cp: LocalCodePtr,
attr_var_init_b: usize,
b: usize,
bp: CodePtr,
tr: usize,
pstr_tr: usize,
h: usize,
b0: usize,
n: usize,
) -> Self {
Frame {
global_index,
e,
cp,
attr_var_init_b,
b,
bp,
tr,
pstr_tr,
h,
b0,
args: vec![Addr::HeapCell(0); n],
}
}
pub fn num_args(&self) -> usize {
self.args.len()
}
}
pub struct OrStack(Vec<Frame>);
impl OrStack {
pub fn new() -> Self {
OrStack(Vec::new())
}
pub fn push(
&mut self,
global_index: usize,
e: usize,
cp: LocalCodePtr,
attr_var_init_b: usize,
b: usize,
bp: CodePtr,
tr: usize,
pstr_tr: usize,
h: usize,
b0: usize,
n: usize,
) {
self.0.push(Frame::new(
global_index,
e,
cp,
attr_var_init_b,
b,
bp,
tr,
pstr_tr,
h,
b0,
n,
));
}
#[inline]
pub(crate) fn take(&mut self) -> Self {
OrStack(mem::replace(&mut self.0, vec![]))
}
pub fn len(&self) -> usize {
self.0.len()
}
pub fn clear(&mut self) {
self.0.clear()
}
pub fn top(&self) -> Option<&Frame> {
self.0.last()
}
// truncate expects a 1-indexed new_b, ie.
// the value b of MachineState.
pub fn truncate(&mut self, new_b: usize) {
self.0.truncate(new_b);
}
pub fn is_empty(&self) -> bool {
self.0.is_empty()
}
}
impl Index<usize> for OrStack {
type Output = Frame;
fn index(&self, index: usize) -> &Self::Output {
self.0.index(index)
}
}
impl IndexMut<usize> for OrStack {
fn index_mut(&mut self, index: usize) -> &mut Self::Output {
self.0.index_mut(index)
}
}
impl Index<usize> for Frame {
type Output = Addr;
fn index(&self, index: usize) -> &Self::Output {
self.args.index(index - 1)
}
}
impl IndexMut<usize> for Frame {
fn index_mut(&mut self, index: usize) -> &mut Self::Output {
self.args.index_mut(index - 1)
}
}