rishi/scryer-prolog
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remove Addr::PStrTail (#276)

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This commit is contained in:
Mark Thom
2020-03-17 02:03:29 -06:00
parent f9c4a40d60
commit b1d8eff019
11 changed files with 181 additions and 431 deletions
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105
src/prolog/machine/copier.rs
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@@ -65,20 +65,6 @@ impl<T: CopierTarget> CopyTermState<T> {
false
}
fn copied_partial_string(&mut self, addr: usize) -> bool {
if let HeapCellValue::PartialString(ref pstr) = &self.target[addr] {
if let Addr::PStrLocation(h, n) = pstr.tail_addr() {
if *h >= self.old_h {
*self.value_at_scan() = HeapCellValue::Addr(Addr::PStrLocation(*h, *n));
self.scan += 1;
return true;
}
}
}
false
}
fn copy_list(&mut self, addr: usize) {
if self.copied_list(addr) {
return;
@@ -98,14 +84,13 @@ impl<T: CopierTarget> CopyTermState<T> {
self.target.push(hcv);
match rd.clone() {
Addr::AttrVar(h) | Addr::HeapCell(h) | Addr::PStrTail(h, _)
Addr::AttrVar(h) | Addr::HeapCell(h)
if h >= self.old_h => {
self.target[threshold] = HeapCellValue::Addr(rd)
}
var @ Addr::AttrVar(_)
| var @ Addr::HeapCell(..)
| var @ Addr::StackCell(..)
| var @ Addr::PStrTail(..) => {
| var @ Addr::StackCell(..) => {
if ra == rd {
self.reinstantiate_var(var, threshold);
@@ -130,57 +115,44 @@ impl<T: CopierTarget> CopyTermState<T> {
self.scan += 1;
}
fn copied_partial_string(&mut self, addr: usize) -> bool {
if let &HeapCellValue::Addr(Addr::PStrLocation(h, n)) = &self.target[addr + 1] {
if h >= self.old_h {
*self.value_at_scan() = HeapCellValue::Addr(Addr::PStrLocation(h, n));
self.scan += 1;
return true;
}
}
false
}
fn copy_partial_string(&mut self, addr: usize, n: usize) {
let threshold = self.target.threshold();
let tail_addr =
match &self.target[addr] {
HeapCellValue::PartialString(ref pstr) => {
self.trail.push((
Ref::PStrTail(addr, 0),
HeapCellValue::Addr(pstr.tail.clone()),
));
self.trail.push((
Ref::HeapCell(addr + 1),
self.target[addr + 1].clone(),
));
self.target.store(self.target.deref(pstr.tail.clone()))
}
_ => {
unreachable!()
}
};
let tail_addr = self.target[addr + 1].as_addr(addr + 1);
self.target[addr + 1] = HeapCellValue::Addr(
Addr::PStrLocation(threshold, 0)
);
let pstr =
match &mut self.target[addr] {
HeapCellValue::PartialString(ref mut pstr) => {
let mut new_pstr = pstr.clone_from_offset(n);
if let Addr::PStrTail(h, n) = &tail_addr {
new_pstr.tail = if *h == addr {
Addr::PStrTail(threshold, *n)
} else {
Addr::HeapCell(threshold + 1)
};
} else {
new_pstr.tail = Addr::HeapCell(threshold + 1);
}
pstr.tail = Addr::PStrLocation(threshold, 0);
new_pstr
match &self.target[addr] {
HeapCellValue::PartialString(ref pstr) => {
pstr.clone_from_offset(n)
}
_ => {
unreachable!()
}
};
match tail_addr {
Addr::PStrTail(h, _) if h == addr => {
self.target.push(HeapCellValue::PartialString(pstr));
}
addr => {
self.target.push(HeapCellValue::PartialString(pstr));
self.target.push(HeapCellValue::Addr(addr));
}
}
self.target.push(HeapCellValue::PartialString(pstr));
self.target.push(HeapCellValue::Addr(tail_addr));
}
fn copy_partial_string_from(&mut self, addr: usize, n: usize) {
@@ -216,22 +188,6 @@ impl<T: CopierTarget> CopyTermState<T> {
HeapCellValue::Addr(Addr::StackCell(fr, sc)),
));
}
Addr::PStrTail(h, n) => {
match &mut self.target[h] {
HeapCellValue::PartialString(ref mut pstr) => {
pstr.tail = Addr::PStrTail(frontier, n);
}
_ => {
unreachable!()
}
}
self.target[frontier] = HeapCellValue::Addr(Addr::PStrTail(frontier, n));
self.trail.push((
Ref::PStrTail(h, n),
HeapCellValue::Addr(Addr::PStrTail(h, n))
));
}
Addr::AttrVar(h) => {
let threshold = if let AttrVarPolicy::DeepCopy = self.attr_var_policy {
self.target.threshold()
@@ -320,8 +276,7 @@ impl<T: CopierTarget> CopyTermState<T> {
}
addr @ Addr::AttrVar(_)
| addr @ Addr::HeapCell(_)
| addr @ Addr::StackCell(..)
| addr @ Addr::PStrTail(..) => {
| addr @ Addr::StackCell(..) => {
self.copy_var(addr);
}
Addr::Str(addr) => {
@@ -349,10 +304,6 @@ impl<T: CopierTarget> CopyTermState<T> {
match r {
Ref::AttrVar(h) | Ref::HeapCell(h) =>
self.target[h] = value,
Ref::PStrTail(h, _) =>
if let HeapCellValue::PartialString(ref mut pstr) = &mut self.target[h] {
pstr.tail = value.as_addr(0);
},
Ref::StackCell(fr, sc) =>
self.target.stack().index_and_frame_mut(fr)[sc] = value.as_addr(0),
}