common: add more methods to SectionRange

common/rust/src/section_range.rs

@@ -81,6 +81,40 @@ impl<T: Ord + Copy> SectionRange<T> {
         };
         intersection == *other
     }
+
+    /// Returns the start of the range.
+    #[must_use]
+    pub fn start(&self) -> &T {
+        &self.start
+    }
+
+    /// Returns the end of the range.
+    #[must_use]
+    pub fn end(&self) -> &T {
+        &self.end
+    }
+}
+
+impl<T: Add<Output = T> + Clone> SectionRange<T> {
+    /// Offsets both the start and end of the range by the given offset.
+    #[must_use]
+    pub fn offset_by(self, offset: T) -> SectionRange<T> {
+        Self {
+            start: self.start + offset.clone(),
+            end: self.end + offset,
+        }
+    }
+}
+
+impl<T: Sub<Output = T> + Clone> SectionRange<T> {
+    /// Offsets both the start and end of the range by the given offset in the negative direction.
+    #[must_use]
+    pub fn offset_by_neg(self, offset: T) -> SectionRange<T> {
+        Self {
+            start: self.start - offset.clone(),
+            end: self.end - offset,
+        }
+    }
 }
 
 impl<T: Ord + Copy + Sub<Output = L>, L: TryInto<usize>> SectionRange<T> {