pushgen 0.0.2

Push-style design pattern for processing of ranges and data-streams.
Documentation 
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use crate::{Generator, GeneratorResult, SliceGenerator, ValueResult};

pub struct StoppingGen<'a, T> {
    stop_at: i32,
    stopped_data: Option<&'a T>,
    data: SliceGenerator<'a, T>,
}

impl<'a, T> StoppingGen<'a, T> {
    pub fn new(stop_at: i32, data: &'a [T]) -> Self {
        Self {
            stop_at,
            stopped_data: None,
            data: SliceGenerator::new(data),
        }
    }
}

impl<'a, T> Generator for StoppingGen<'a, T> {
    type Output = &'a T;

    fn run(&mut self, mut output: impl FnMut(Self::Output) -> ValueResult) -> GeneratorResult {
        if self.stop_at == 0 {
            self.stop_at -= 1;
            return GeneratorResult::Stopped;
        }

        if let Some(x) = self.stopped_data.take() {
            if output(x) == ValueResult::Stop {
                return GeneratorResult::Stopped;
            }
        }

        let stored_stop = &mut self.stopped_data;
        let stop_at = &mut self.stop_at;
        let result = self.data.run(|x| {
            let old_stop_at = *stop_at;
            *stop_at -= 1;
            if old_stop_at == 0 {
                *stored_stop = Some(x);
                ValueResult::Stop
            } else {
                output(x)
            }
        });
        if result == GeneratorResult::Complete {
            *stop_at = -1;
        }
        result
    }
}

pub struct MultiStoppingGen<'a, T> {
    stop_at: &'a [usize],
    stop_at_index: usize,
    index: usize,
    data: &'a [T],
}

impl<'a, T> MultiStoppingGen<'a, T> {
    pub fn new(stop_at: &'a [usize], data: &'a [T]) -> Self {
        Self {
            stop_at,
            stop_at_index: 0,
            index: 0,
            data,
        }
    }
}

impl<'a, T> Generator for MultiStoppingGen<'a, T> {
    type Output = &'a T;

    fn run(&mut self, mut output: impl FnMut(Self::Output) -> ValueResult) -> GeneratorResult {
        while self.data.len() > 0 {
            if self.stop_at_index < self.stop_at.len()
                && self.index == self.stop_at[self.stop_at_index]
            {
                self.index += 1;
                self.stop_at_index += 1;
                return GeneratorResult::Stopped;
            }

            let data = &self.data[0];
            let out_result = output(data);
            self.data = self.data.split_at(1).1;
            self.index += 1;

            if out_result == ValueResult::Stop {
                return GeneratorResult::Stopped;
            }
        }

        GeneratorResult::Complete
    }
}