convenience fns

Author: molpopgen

src/lib.rs

@@ -263,6 +263,27 @@ impl_size_type_comparisons_for_row_ids!(MigrationId);
 #[derive(Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, std::hash::Hash)]
 pub struct SizeType(tsk_size_t);
 
+impl SizeType {
+    /// Convenience function to convert to usize.
+    ///
+    /// Works via [`TryFrom`].
+    ///
+    /// # Returns
+    ///
+    /// * `None` if the underlying value is negative.
+    /// * `Some(usize)` otherwise.
+    pub fn to_usize(&self) -> Option<usize> {
+        (*self).try_into().ok()
+    }
+
+    /// Convenience function to convert to usize.
+    /// Implemented via `as`.
+    /// Negative values with therefore wrap.
+    pub fn as_usize(&self) -> usize {
+        self.0 as usize
+    }
+}
+
 impl std::fmt::Display for SizeType {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(f, "{}", self.0)