fixes and viz

Author: molpopgen

src/sys.rs

@@ -31,7 +31,7 @@ pub fn tsk_column_access<
     tsk_column_access_detail(row, column, column_length).map(|v| v.into())
 }
 
-pub fn tsk_ragged_column_access_detail<
+fn tsk_ragged_column_access_detail<
     R: Into<bindings::tsk_id_t>,
     L: Into<bindings::tsk_size_t>,
     T: Copy,
@@ -48,7 +48,9 @@ pub fn tsk_ragged_column_access_detail<
         None
     } else {
         assert!(!column.is_null());
-        assert!(!column.is_null());
+        assert!(!offset.is_null());
+        // SAFETY: pointers are not null
+        // and *_length are given by tskit-c
         let index = row as isize;
         let start = unsafe { *offset.offset(index) };
         let stop = if (row as bindings::tsk_size_t) < column_length {
@@ -80,8 +82,7 @@ pub fn tsk_ragged_column_access<
     offset: *const bindings::tsk_size_t,
     offset_length: bindings::tsk_size_t,
 ) -> Option<&'a [O]> {
-    match tsk_ragged_column_access_detail(row, column, column_length, offset, offset_length) {
-        Some((p, n)) => Some(unsafe { std::slice::from_raw_parts(p.cast::<O>(), n) }),
-        None => None,
-    }
+    // SAFETY: see tsk_ragged_column_access_detail
+    tsk_ragged_column_access_detail(row, column, column_length, offset, offset_length)
+        .map(|(p, n)| unsafe { std::slice::from_raw_parts(p.cast::<O>(), n) })
 }