#no-std #no-std #data #structure #map

macro no-std array_map_derive

Map backed array for fixed size keys with O(1) performance

3 releases (breaking)

0.3.0 Jul 7, 2021
0.2.0 May 25, 2021
0.1.0 May 19, 2021

#11 in #structure

Download history 4/week @ 2021-10-02 6/week @ 2021-10-09 3/week @ 2021-10-16 18/week @ 2021-10-23 48/week @ 2021-10-30 214/week @ 2021-11-06 111/week @ 2021-11-13 40/week @ 2021-11-20 57/week @ 2021-11-27 45/week @ 2021-12-04 25/week @ 2021-12-11 19/week @ 2021-12-18 2/week @ 2021-12-25 58/week @ 2022-01-01 44/week @ 2022-01-08 30/week @ 2022-01-15

134 downloads per month
Used in array_map

MIT/Apache

13KB
258 lines

array_map

no_std compatible Map and Set backed by arrays.

This crate will evolve as more const-generic features become available.

This is especially useful if you have a bare enum where you want to treat each key as a field

use array_map::*;
#[repr(u8)]
#[derive(Indexable)]
enum DetectionType {
  Person,
  Vehicle,
  Bicycle,
}
let thresholds = ArrayMap::<DetectionType, f32, {DetectionType::count()}>::from_closure(|dt| match dt {
    DetectionType::Person => 0.8,
    DetectionType::Vehicle => 0.9,
    DetectionType::Bicycle => 0.7,
  });
let person_threshold = thresholds[DetectionType::Person];

This can also be used to memoize some common computations. (this is 2x as fast as doing the computation on aarch64)

use array_map::*;
let u8_to_f32_cache = ArrayMap::<u8, f32, {u8::SIZE}>::from_closure(|u|f32::from(*u) / 255.0);
let bytes = vec![0_u8; 1024];
// take some bytes and convert them to f32
let floats = bytes.iter().copied().map(|b|u8_to_f32_cache[b]).collect::<Vec<_>>();

Dependencies

~275–680KB
~17K SLoC

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