pass

Author: molpopgen

src/sys/mod.rs

@@ -141,19 +141,35 @@ unsafe fn tsk_column_access<
     tsk_column_access_detail(row, column, column_length).map(|v| v.into())
 }
 
+/// # SAFETY
+///
+/// The safety requirements here are a bit fiddly.
+///
+/// The hard case is when the columns contain data:
+///
+/// * column and offset must both not be NULL
+/// * column_length and offset_length must both be
+///   the correct lengths for the input pointers
+/// * we return None if row < 0 or row > array length.
+/// * Thus, the requirement is that the two _lengths
+///   == 0 or (pointer both not NULL and the lengths are correct)
+///
+/// When the lengths of each column are 0, we
+/// don't worry about anything else
 fn tsk_ragged_column_access_detail<'a, T>(
     row: usize,
     column: &'a [T],
     raw_offset: &'a [bindings::tsk_size_t],
 ) -> Option<&'a [T]> {
-    if row >= column.len() || raw_offset.is_empty() {
+    //if row < 0 || row as bindings::tsk_size_t > column_length || raw_offset.is_empty(){
+    if row >= raw_offset.len() || raw_offset.is_empty() {
         None
     } else {
         let start = usize::try_from(raw_offset[row]).ok()?;
-        let stop = if row < column.len() {
+        let stop = if row < raw_offset.len() - 1 {
             usize::try_from(raw_offset[row + 1]).ok()?
         } else {
-            raw_offset.len()
+            column.len()
         };
         if start == stop {
             None
@@ -163,6 +179,9 @@ fn tsk_ragged_column_access_detail<'a, T>(
     }
 }
 
+// SAFETY: see tsk_ragged_column_access_detail
+// We further erquire that a pointer to a T can
+// be safely cast to a pointer to an O.
 fn tsk_ragged_column_access<'a, O, R: Into<bindings::tsk_id_t>>(
     row: R,
     column: &'a [O],
@@ -171,6 +190,12 @@ fn tsk_ragged_column_access<'a, O, R: Into<bindings::tsk_id_t>>(
     let row = row.into();
     let row = usize::try_from(row).ok()?;
     tsk_ragged_column_access_detail(row, column, raw_offset)
+    //unsafe {
+    //    tsk_ragged_column_access_detail(row, column, column_length, offset, offset_length)
+    //        // If the safety requirements of tsk_ragged_column_access_detail are upheld,
+    //        // then we have received a valid pointer + length from which to make a slice
+    //        .map(|(p, n)| std::slice::from_raw_parts(p.cast::<O>(), n))
+    //}
 }
 
 /// # SAFETY