10 releases (6 breaking)
0.7.0 | Oct 7, 2023 |
---|---|
0.6.0 | Oct 7, 2023 |
0.5.0 | Oct 7, 2023 |
0.4.0 | Oct 7, 2023 |
0.1.0 | Sep 24, 2023 |
#1189 in Algorithms
63 downloads per month
30KB
515 lines
Ribbon - tape for Iterators
Ribbon
is meant to provide API for holding (and thus making available) some
number of items returned by iterators.
This is meant for cases where using iterators is convenient, but some context around the item returned by an iterator is needed. This is especially useful when look-ahead is necessary (we need to know what values come after the current one before deciding what to do with it).
This crate provides two types that implement the Ribbon
trait:
Tape
: a dynamically sizedRibbon
that can hold varying number of items and can grow and shrink as necessary. It is backed up by aVecDeque
, and allocates memory on the heap (as is customary by dynamically sized collections)Band
: a fix-sizedRibbon
backed up by an array ofN
elements. It cannot grow over the given fixed length, and instead drops the first element if no space is available at the given moment.
Examples:
Using Tape
use ribbon::Tape;
let mut tape = Tape::new(0..10);
tape.expand_n(5);
assert_eq!(tape.len(), 5);
assert_eq!(tape.peek_front(), Some(&0));
assert_eq!(tape.peek_back(), Some(&4));
Using Band
use ribbon::Band;
use ribbon::Ribbon;
// Band with capacity for 5 items
let mut band: Band<3, _, _> = Band::new(0..4);
band.expand_n(2); // consume 0, 1 from iterator
assert_eq!(band.len(), 2);
assert_eq!(band.peek_front(), Some(&0));
assert_eq!(band.peek_back(), Some(&1));
// "slides" over the items from iterator -> returns first and expands by 1
assert_eq!(band.progress(), Some(0)); // consume 3 from iterator
assert_eq!(band.progress(), Some(1)); // consumes 4 from iterator, iterator has no more values
// iterator does not produce more values, progress becomes no-op.
assert_eq!(band.progress(), None);