add BSeries struct and conversion implementations for FSeries and ISeries

src/core/xseries.rs

@@ -161,3 +161,63 @@ impl_iseries_scalar_op!(Add, add, +);
 impl_iseries_scalar_op!(Sub, sub, -);
 impl_iseries_scalar_op!(Mul, mul, *);
 impl_iseries_scalar_op!(Div, div, /); // floor/trunc division by scalar
+
+/// A boolean series: BSeries
+///
+#[derive(Debug, Clone)]
+pub struct BSeries {
+    data: Vec<bool>,
+}
+
+impl BSeries {
+    pub fn new(data: Vec<bool>) -> Self {
+        Self { data }
+    }
+
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn data(&self) -> &[bool] {
+        &self.data
+    }
+}
+
+/// Convert an FSeries to ISeries by truncation (floor cast).
+impl From<FSeries> for ISeries {
+    fn from(fseries: FSeries) -> Self {
+        let data = fseries
+            .data
+            .into_iter()
+            .map(|val| val as i64) // trunc cast
+            .collect();
+        ISeries::new(data)
+    }
+}
+
+/// Implement conversion from ISeries to FSeries by casting to f64.
+impl From<ISeries> for FSeries {
+    fn from(iseries: ISeries) -> Self {
+        let data = iseries.data.into_iter().map(|val| val as f64).collect();
+        FSeries::new(data)
+    }
+}
+
+/// Convert an ISeries to BSeries by checking if each value is non-zero.
+impl From<ISeries> for BSeries {
+    fn from(iseries: ISeries) -> Self {
+        let data = iseries.data.into_iter().map(|val| val != 0).collect();
+        BSeries::new(data)
+    }
+}
+
+impl From<BSeries> for ISeries {
+    fn from(bseries: BSeries) -> Self {
+        let data = bseries
+            .data
+            .into_iter()
+            .map(|val| if val { 1 } else { 0 })
+            .collect();
+        ISeries::new(data)
+    }
+}