// Copyright 2023 The Fuchsia Authors

//

// Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0

// <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT

// license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option.

// This file may not be copied, modified, or distributed except according to

// those terms.

//! Abstractions over raw pointers.

mod inner;

#[doc(hidden)]

pub mod invariant;

mod ptr;

mod transmute;

#[doc(hidden)]

pub use {inner::PtrInner, transmute::*};

#[doc(hidden)]

pub use {

    invariant::{BecauseExclusive, BecauseImmutable, Read},

    ptr::Ptr,

};

/// A shorthand for a maybe-valid, maybe-aligned reference. Used as the argument

/// to [`TryFromBytes::is_bit_valid`].

///

/// [`TryFromBytes::is_bit_valid`]: crate::TryFromBytes::is_bit_valid

pub type Maybe<'a, T, Aliasing = invariant::Shared, Alignment = invariant::Unaligned> =

    Ptr<'a, T, (Aliasing, Alignment, invariant::Initialized)>;

/// Checks if the referent is zeroed.

pub(crate) fn is_zeroed<T, I>(ptr: Ptr<'_, T, I>) -> bool

where

    T: crate::Immutable + crate::KnownLayout,

    I: invariant::Invariants<Validity = invariant::Initialized>,

    I::Aliasing: invariant::Reference,

{

    ptr.as_bytes::<BecauseImmutable>().as_ref().iter().all(|&byte| byte == 0)

}