This crate implements a structure that can be used as a generic array type.

**Requires minimum Rust version of 1.65.0

Documentation on GH Pages may be required to view certain types on foreign crates.

generic-array 0.14 has been officially deprecated, so here's a quick guide on how to upgrade from generic-array 0.14 to 1.x. Note that libraries depending on generic-array will need to update their usage as well. Some libraries are moving to hybrid-array 0.4 instead, which we provide interoperability with generic-array 1.x via the hybrid-array-0_4 feature flag.

[dependencies]
generic-array = "1"

[dependencies]
generic-array = { version = "1", features = ["compat-0_14"] }

let array = arr![i32; 1, 2, 3];
// to
let array = arr![1, 2, 3];

[dependencies]
generic-array = { version = "1", features = ["hybrid-array-0_4"] }

Before Rust 1.51, arrays [T; N] were problematic in that they couldn't be generic with respect to the length N, so this wouldn't work:

struct Foo<N> {
    data: [i32; N],
}

Since 1.51, the below syntax is valid:

struct Foo<const N: usize> {
    data: [i32; N],
}

However, the const-generics we have as of writing this are still the minimum-viable product (min_const_generics), so many situations still result in errors, such as this example:

trait Bar {
    const LEN: usize;

    // Error: cannot perform const operation using `Self`
    fn bar(&self) -> Foo<{ Self::LEN }>;
}

generic-array defines a new trait ArrayLength and a struct GenericArray<T, N: ArrayLength>, which lets the above be implemented as:

struct Foo<N: ArrayLength> {
    data: GenericArray<i32, N>
}

trait Bar {
    type LEN: ArrayLength;
    fn bar(&self) -> Foo<Self::LEN>;
}

The ArrayLength trait is implemented for unsigned integer types from typenum crate. For example, GenericArray<T, U5> would work almost like [T; 5]:

use generic_array::typenum::U5;

struct Foo<T, N: ArrayLength> {
    data: GenericArray<T, N>
}

let foo = Foo::<i32, U5> { data: GenericArray::default() };

The arr! macro is provided to allow easier creation of literal arrays, as shown below:

let array = arr![1, 2, 3];
//  array: GenericArray<i32, typenum::U3>
assert_eq!(array[2], 3);

[dependencies.generic-array]
features = [
    "serde",            # Serialize/Deserialize implementation
    "zeroize",          # Zeroize implementation for setting array elements to zero
    "const-default",    # Compile-time const default value support via trait
    "alloc",            # Enables From/TryFrom implementations between GenericArray and Vec<T>/Box<[T]>
    "faster-hex",       # Enables internal use of the `faster-hex` crate for faster hex encoding via SIMD
    "subtle",           # Enables `subtle` crate support for constant-time equality checks and conditional selection
    "arbitrary",        # Enables `arbitrary` crate support for fuzzing
    "bytemuck",         # Enables `bytemuck` crate support
    "bitvec",           # Enables `bitvec` crate support to use GenericArray as a storage backend for bit arrays
    "compat-0_14",      # Enables interoperability with `generic-array` 0.14
    "hybrid-array-0_4"  # Enables interoperability with `hybrid-array` 0.4
]