Merge pull request #46 from gzsombor/helper-functions

Add intersection/translate and size to the interval type

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "discrete_range_map"
-version = "0.6.0"
+version = "0.6.1"
 authors = ["James Forster <james.forsterer@gmail.com>"]
 edition = "2021"
 description = """

src/discrete_range_map.rs

@@ -1486,7 +1486,7 @@ pub trait InclusiveRange<I> {
 		self.start() <= self.end()
 	}
 
-	///requires that self comes before other and they don't overlap
+	/// requires that self comes before other and they don't overlap
 	fn touches_ordered(&self, other: &Self) -> bool
 	where
 		I: PointType,
@@ -1494,7 +1494,7 @@ pub trait InclusiveRange<I> {
 		self.end() == other.start().down().unwrap()
 	}
 
-	///requires that self comes before other
+	/// requires that self comes before other
 	fn overlaps_ordered(&self, other: &Self) -> bool
 	where
 		I: PointType,
@@ -1502,7 +1502,47 @@ pub trait InclusiveRange<I> {
 		self.contains(other.start()) || self.contains(other.end())
 	}
 
-	///requires that self comes before other
+	/// Intersect the range with the other one, and return Some if the intersection is not empty.
+	fn intersect(&self, other: &Self) -> Option<Self>
+	where
+		I: PointType,
+		Self: From<InclusiveInterval<I>>,
+	{
+		let intersect_start = I::max(self.start(), other.start());
+		let intersect_end = I::min(self.end(), other.end());
+		if intersect_start <= intersect_end {
+			Some(Self::from(InclusiveInterval {
+				start: intersect_start,
+				end: intersect_end,
+			}))
+		} else {
+			None
+		}
+	}
+
+	/// Move the entire range by the given amount.
+	fn translate(&self, delta: I) -> Self
+	where
+		I: PointType,
+		I: core::ops::Add<Output = I>,
+		Self: From<InclusiveInterval<I>>,
+	{
+		Self::from(InclusiveInterval {
+			start: self.start() + delta,
+			end: self.end() + delta,
+		})
+	}
+
+	/// The amount between the start and the end points of the range.
+	fn size(&self) -> I
+	where
+		I: PointType,
+		I: core::ops::Sub<Output = I>,
+	{
+		(self.end() - self.start()).up().unwrap()
+	}
+
+	/// requires that self comes before other
 	fn merge_ordered(&self, other: &Self) -> Self
 	where
 		Self: From<InclusiveInterval<I>>,
@@ -2272,6 +2312,36 @@ mod tests {
 		}
 	}
 
+	#[test]
+	fn test_intersection() {
+		let input = InclusiveInterval { start: 5, end: 10 };
+		assert_eq!(
+			input.intersect(&InclusiveInterval { start: 8, end: 13 }),
+			Some(InclusiveInterval { start: 8, end: 10 })
+		);
+		assert_eq!(
+			input.intersect(&InclusiveInterval { start: 10, end: 13 }),
+			Some(InclusiveInterval { start: 10, end: 10 })
+		);
+		assert_eq!(
+			input.intersect(&InclusiveInterval { start: 11, end: 13 }),
+			None
+		);
+	}
+
+	#[test]
+	fn test_translate() {
+		let input = InclusiveInterval { start: 5, end: 10 };
+		assert_eq!(input.translate(3), InclusiveInterval { start: 8, end: 13 });
+		assert_eq!(input.translate(-2), InclusiveInterval { start: 3, end: 8 });
+	}
+
+	#[test]
+	fn test_size() {
+		assert_eq!(InclusiveInterval { start: 5, end: 10 }.size(), 6);
+		assert_eq!(InclusiveInterval { start: 6, end: 6 }.size(), 1);
+	}
+
 	// Test Helper Functions
 	//======================
 	fn all_non_overlapping_test_bound_entries()