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/*
* Copyright 2018 The Starlark in Rust Authors.
* Copyright (c) Facebook, Inc. and its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#[inline(always)]
pub(crate) fn ptr_to_usize<T: ?Sized>(x: &T) -> usize {
x as *const T as *const () as usize
}
/// Undefined behaviour if the argument is zero, or does not satisfy the alignment
/// of type `T`.
#[inline(always)]
pub(crate) unsafe fn usize_to_ptr<'a, T>(x: usize) -> &'a T {
debug_assert!(x != 0, "Zero is not a valid pointer");
debug_assert!(x % std::mem::align_of::<T>() == 0, "Pointer is not aligned");
&*(x as *const T)
}
#[inline(always)]
pub(crate) unsafe fn ptr_lifetime<'a, 'b, T: ?Sized>(x: &'a T) -> &'b T {
&*(x as *const T)
}
/// `transmute!(from-type, to-type, value)` will do a [`transmute`](std::mem::transmute),
/// but the original and result types must be specified.
macro_rules! transmute {
($from:ty, $to:ty, $e:expr) => {
std::mem::transmute::<$from, $to>($e)
};
}
pub(crate) use transmute;