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introduce bespoke Heap type for in-heap partial strings

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This commit is contained in:
Mark Thom
2024-05-13 18:00:56 -06:00
committed by Mark Thom
parent f7bbdfe73a
commit c0f72704ec
54 changed files with 7836 additions and 7167 deletions
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51
src/machine/cycle_detection.rs
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@@ -1,4 +1,5 @@
use crate::atom_table::*;
use crate::machine::heap::*;
use crate::types::*;
/* Use the pointer reversal technique of the Deutsch-Schorr-Waite
@@ -11,7 +12,7 @@ use crate::types::*;
* - Cells are only marked during the backward phase
* - Visiting subterms of a visited compound does not immediately shift to the backward phase
* - The heads of LIS structures are both marked and forwarded rather
* than just forwarded to distinguish them from tails;
* than just forwarded to distinguish them from tails
* continue_forwarding() checks for this before entering the forward
* phase
*
@@ -22,7 +23,7 @@ use crate::types::*;
#[derive(Debug)]
pub(crate) struct CycleDetectingIter<'a, const STOP_AT_CYCLES: bool> {
pub(crate) heap: &'a mut [HeapCellValue],
pub(crate) heap: &'a mut Heap,
start: usize,
current: usize,
next: u64,
@@ -31,7 +32,7 @@ pub(crate) struct CycleDetectingIter<'a, const STOP_AT_CYCLES: bool> {
}
impl<'a, const STOP_AT_CYCLES: bool> CycleDetectingIter<'a, STOP_AT_CYCLES> {
pub(crate) fn new(heap: &'a mut [HeapCellValue], start: usize) -> Self {
pub(crate) fn new(heap: &'a mut Heap, start: usize) -> Self {
heap[start].set_forwarding_bit(true);
let next = heap[start].get_value();
@@ -127,7 +128,7 @@ impl<'a, const STOP_AT_CYCLES: bool> CycleDetectingIter<'a, STOP_AT_CYCLES> {
self.current = next;
self.next = temp;
if self.next < self.heap.len() as u64 {
if self.next < self.heap.cell_len() as u64 {
return Some(HeapCellValue::build_with(tag, next as u64));
}
}
@@ -205,8 +206,7 @@ impl<'a, const STOP_AT_CYCLES: bool> CycleDetectingIter<'a, STOP_AT_CYCLES> {
}
HeapCellValueTag::PStrLoc => {
let h = self.next as usize;
let cell = self.heap[h];
let last_cell_loc = h + 1;
let (_, last_cell_loc) = self.heap.scan_slice_to_str(h);
if self.heap[last_cell_loc].get_forwarding_bit() {
if self.cycle_detection_active() {
@@ -225,39 +225,7 @@ impl<'a, const STOP_AT_CYCLES: bool> CycleDetectingIter<'a, STOP_AT_CYCLES> {
self.heap[last_cell_loc].set_value(self.current as u64);
self.current = last_cell_loc;
return Some(cell);
}
HeapCellValueTag::PStrOffset => {
let h = self.next as usize;
let cell = self.heap[h];
let last_cell_loc = h + 1;
if self.heap[h].get_tag() == HeapCellValueTag::PStr {
if self.heap[last_cell_loc].get_forwarding_bit() {
if self.cycle_detection_active() {
self.cycle_found = true;
return None;
} else if self.backward() {
return None;
}
continue;
}
self.heap[last_cell_loc].set_forwarding_bit(true);
self.next = self.heap[last_cell_loc].get_value();
self.heap[last_cell_loc].set_value(self.current as u64);
self.current = last_cell_loc;
} else {
debug_assert!(self.heap[h].get_tag() == HeapCellValueTag::CStr);
self.next = self.heap[h].get_value();
self.heap[h].set_value(self.current as u64);
self.current = h;
}
return Some(cell);
return Some(pstr_loc_as_cell!(h));
}
tag @ HeapCellValueTag::Atom => {
let cell = HeapCellValue::build_with(tag, self.next);
@@ -269,11 +237,6 @@ impl<'a, const STOP_AT_CYCLES: bool> CycleDetectingIter<'a, STOP_AT_CYCLES> {
return None;
}
}
HeapCellValueTag::PStr => {
if self.backward() {
return None;
}
}
_ => {
return Some(self.backward_and_return());
}