tustvold commented on code in PR #5897:
URL: https://github.com/apache/arrow-datafusion/pull/5897#discussion_r1162453846
##########
datafusion/core/src/physical_plan/sorts/cursor.rs:
##########
@@ -93,3 +96,232 @@ impl Cursor for RowCursor {
t
}
}
+
+/// A cursor over sorted, nullable [`ArrowNativeTypeOp`]
+///
+/// Note: comparing cursors with different `SortOptions` will yield an
arbitrary ordering
+#[derive(Debug)]
+pub struct PrimitiveCursor<T: ArrowNativeTypeOp> {
+ values: ScalarBuffer<T>,
+ offset: usize,
+ // If nulls first, the first non-null index
+ // Otherwise, the first null index
+ null_threshold: usize,
+ options: SortOptions,
+}
+
+impl<T: ArrowNativeTypeOp> PrimitiveCursor<T> {
+ /// Create a new [`PrimitiveCursor`] from the provided `values` sorted
according to `options`
+ pub fn new(options: SortOptions, values: ScalarBuffer<T>, null_count:
usize) -> Self {
+ assert!(null_count <= values.len());
+
+ let null_threshold = match options.nulls_first {
+ true => null_count,
+ false => values.len() - null_count,
+ };
+
+ Self {
+ values,
+ offset: 0,
+ null_threshold,
+ options,
+ }
+ }
+
+ fn is_null(&self) -> bool {
+ (self.offset < self.null_threshold) == self.options.nulls_first
+ }
+
+ fn value(&self) -> T {
+ self.values[self.offset]
+ }
+}
+
+impl<T: ArrowNativeTypeOp> PartialEq for PrimitiveCursor<T> {
+ fn eq(&self, other: &Self) -> bool {
+ self.cmp(other).is_eq()
+ }
+}
+
+impl<T: ArrowNativeTypeOp> Eq for PrimitiveCursor<T> {}
+impl<T: ArrowNativeTypeOp> PartialOrd for PrimitiveCursor<T> {
+ fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+ Some(self.cmp(other))
+ }
+}
+
+impl<T: ArrowNativeTypeOp> Ord for PrimitiveCursor<T> {
+ fn cmp(&self, other: &Self) -> Ordering {
+ match (self.is_null(), other.is_null()) {
+ (true, true) => Ordering::Equal,
+ (true, false) => match self.options.nulls_first {
+ true => Ordering::Less,
+ false => Ordering::Greater,
+ },
+ (false, true) => match self.options.nulls_first {
+ true => Ordering::Greater,
+ false => Ordering::Less,
+ },
+ (false, false) => {
+ let s_v = self.value();
+ let o_v = other.value();
+
+ match self.options.descending {
Review Comment:
It's definitely something we could experiment, my expectation is that it
won't make a huge difference given how branch heavy merging inherently is
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
