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correctly increment s_offset for partial strings (#2897)

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This commit is contained in:
Mark Thom
2025-04-20 16:53:36 -07:00
committed by Mark Thom
parent e1e52338d6
commit 6bcbb91e08
2 changed files with 13 additions and 63 deletions
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10
src/machine/machine_state_impl.rs
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@@ -342,16 +342,16 @@ impl MachineState {
}
// return the read value and the succeeding HeapPtr
pub(crate) fn read_s(&mut self) -> HeapCellValue {
pub(crate) fn read_s(&mut self) -> (HeapCellValue, usize) {
match self.s {
HeapPtr::HeapCell(h) => self.deref(self.heap[h + self.s_offset]),
HeapPtr::HeapCell(h) => (self.deref(self.heap[h + self.s_offset]), 1),
HeapPtr::PStr(byte_index) => {
let mut char_iter = self.heap.char_iter(byte_index);
if self.s_offset == 0 {
// read the car of the list
let c = char_iter.next().unwrap();
char_as_cell!(c)
(char_as_cell!(c), c.len_utf8())
} else {
// read the (self.s_offset)^{th} cdr of the list
// self.s_offset is the number of bytes offset into the PStr
@@ -361,11 +361,11 @@ impl MachineState {
if self.heap.char_iter(new_h).next().is_some() {
self.s = HeapPtr::PStr(new_h);
pstr_loc_as_cell!(new_h)
(pstr_loc_as_cell!(new_h), 0)
} else {
let h = Heap::pstr_tail_idx(new_h);
self.s = HeapPtr::HeapCell(h);
self.deref(heap_loc_as_cell!(h))
(self.deref(heap_loc_as_cell!(h)), 0)
}
}
}