| use super::plumbing::*; |
| use super::ParallelIterator; |
| |
| pub(super) fn reduce<PI, R, ID, T>(pi: PI, identity: ID, reduce_op: R) -> T |
| where |
| PI: ParallelIterator<Item = T>, |
| R: Fn(T, T) -> T + Sync, |
| ID: Fn() -> T + Sync, |
| T: Send, |
| { |
| let consumer = ReduceConsumer { |
| identity: &identity, |
| reduce_op: &reduce_op, |
| }; |
| pi.drive_unindexed(consumer) |
| } |
| |
| struct ReduceConsumer<'r, R, ID> { |
| identity: &'r ID, |
| reduce_op: &'r R, |
| } |
| |
| impl<'r, R, ID> Copy for ReduceConsumer<'r, R, ID> {} |
| |
| impl<'r, R, ID> Clone for ReduceConsumer<'r, R, ID> { |
| fn clone(&self) -> Self { |
| *self |
| } |
| } |
| |
| impl<'r, R, ID, T> Consumer<T> for ReduceConsumer<'r, R, ID> |
| where |
| R: Fn(T, T) -> T + Sync, |
| ID: Fn() -> T + Sync, |
| T: Send, |
| { |
| type Folder = ReduceFolder<'r, R, T>; |
| type Reducer = Self; |
| type Result = T; |
| |
| fn split_at(self, _index: usize) -> (Self, Self, Self) { |
| (self, self, self) |
| } |
| |
| fn into_folder(self) -> Self::Folder { |
| ReduceFolder { |
| reduce_op: self.reduce_op, |
| item: (self.identity)(), |
| } |
| } |
| |
| fn full(&self) -> bool { |
| false |
| } |
| } |
| |
| impl<'r, R, ID, T> UnindexedConsumer<T> for ReduceConsumer<'r, R, ID> |
| where |
| R: Fn(T, T) -> T + Sync, |
| ID: Fn() -> T + Sync, |
| T: Send, |
| { |
| fn split_off_left(&self) -> Self { |
| *self |
| } |
| |
| fn to_reducer(&self) -> Self::Reducer { |
| *self |
| } |
| } |
| |
| impl<'r, R, ID, T> Reducer<T> for ReduceConsumer<'r, R, ID> |
| where |
| R: Fn(T, T) -> T + Sync, |
| { |
| fn reduce(self, left: T, right: T) -> T { |
| (self.reduce_op)(left, right) |
| } |
| } |
| |
| struct ReduceFolder<'r, R, T> { |
| reduce_op: &'r R, |
| item: T, |
| } |
| |
| impl<'r, R, T> Folder<T> for ReduceFolder<'r, R, T> |
| where |
| R: Fn(T, T) -> T, |
| { |
| type Result = T; |
| |
| fn consume(self, item: T) -> Self { |
| ReduceFolder { |
| reduce_op: self.reduce_op, |
| item: (self.reduce_op)(self.item, item), |
| } |
| } |
| |
| fn consume_iter<I>(self, iter: I) -> Self |
| where |
| I: IntoIterator<Item = T>, |
| { |
| ReduceFolder { |
| reduce_op: self.reduce_op, |
| item: iter.into_iter().fold(self.item, self.reduce_op), |
| } |
| } |
| |
| fn complete(self) -> T { |
| self.item |
| } |
| |
| fn full(&self) -> bool { |
| false |
| } |
| } |