slice_map 0.1.4

SliceMap provides a container that allows iterating directly all of its items, or iterating slices of uneven sizes.

Examples

A good use would be storing the points for polygons of different point counts, but in a way where all those points are laid out continuously in memory. Each slice is effectively a new polygon, and drawing all polygons at once can be very CPU cache-friendly.

Here's the code for a simpler example with i32 values:

let mut slicemap = slice_map::SliceVec::default();

// Adding items can fail when using SliceArray and the capacity is reached,
// but is unlikely to fail with SliceVec.
slicemap.add_items([1, 2, 3, 4, 5]).ok();
slicemap.add_items([6, 7]).ok();
slicemap.add_items([8, 9, 10]).ok();

// Iterating over slices
let mut slices = slicemap.iter_slices();
assert_eq!(slices.next().unwrap(), [1, 2, 3, 4, 5]);
assert_eq!(slices.next().unwrap(), [6, 7]);
assert_eq!(slices.next().unwrap(), [8, 9, 10]);
assert_eq!(slices.next(), None);

// Iterating over all items
let mut i = 1;
for item in slicemap.iter_items(){
    assert_eq!(i, *item);
    i += 1
}

Features:

"vec"

Enables [SliceVec], which is a SliceMap implementation using Vecs for all its storage. This is the easiest to use option.

"array"

Enables [SliceArray], which is a "no_std" option that uses a simple ArrayVec with const generics for storage. This is more cumbersome to use, since the user has to provide the capacity for both the item storage and the slice range storage.

"default"

The "vec" feature is enabled by default. Make sure you use default-features = false, features = ["array"] in your cargo.toml if you wish to use slice_map in a no_std environment.