matrixmultiply_mt 0.2.1

// Copyright 2016 bluss
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::cmp::min;

pub struct RangeChunk {
	i: usize,
	n: usize,
	chunk: usize,
}

/// Create an iterator that splits `n` in chunks of size `chunk`;
/// the last item can be an uneven chunk.
pub fn range_chunk(n: usize, chunk: usize) -> RangeChunk {
	RangeChunk { i: 0, n, chunk }
}

impl Iterator for RangeChunk {
	type Item = (usize, usize);

	#[inline]
	fn next(&mut self) -> Option<Self::Item> {
		if self.n == 0 {
			None
		} else {
			let i = self.i;
			let rem = min(self.n, self.chunk);
			self.i += 1;
			self.n -= rem;
			Some((i, rem))
		}
	}
}

#[inline]
pub fn round_up_to(x: usize, multiple_of: usize) -> usize {
	round_up_div(x, multiple_of) * multiple_of
}

#[inline]
pub fn round_up_div(n: usize, d: usize) -> usize {
	(n + d - 1) / d
}