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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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
//
// http://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.
//! Defines memory-related functions, such as allocate/deallocate/reallocate memory
//! regions, cache and allocation alignments.
use std::alloc::{handle_alloc_error, Layout};
use std::fmt::{Debug, Formatter};
use std::mem::size_of;
use std::panic::RefUnwindSafe;
use std::ptr::NonNull;
use std::sync::Arc;
mod alignment;
mod types;
pub use alignment::ALIGNMENT;
pub use types::NativeType;
#[inline]
unsafe fn null_pointer<T: NativeType>() -> NonNull<T> {
NonNull::new_unchecked(ALIGNMENT as *mut T)
}
/// Allocates a cache-aligned memory region of `size` bytes with uninitialized values.
/// This is more performant than using [allocate_aligned_zeroed] when all bytes will have
/// an unknown or non-zero value and is semantically similar to `malloc`.
pub fn allocate_aligned<T: NativeType>(size: usize) -> NonNull<T> {
unsafe {
if size == 0 {
null_pointer()
} else {
let size = size * size_of::<T>();
let layout = Layout::from_size_align_unchecked(size, ALIGNMENT);
let raw_ptr = std::alloc::alloc(layout) as *mut T;
NonNull::new(raw_ptr).unwrap_or_else(|| handle_alloc_error(layout))
}
}
}
/// Allocates a cache-aligned memory region of `size` bytes with `0` on all of them.
/// This is more performant than using [allocate_aligned] and setting all bytes to zero
/// and is semantically similar to `calloc`.
pub fn allocate_aligned_zeroed<T: NativeType>(size: usize) -> NonNull<T> {
unsafe {
if size == 0 {
null_pointer()
} else {
let size = size * size_of::<T>();
let layout = Layout::from_size_align_unchecked(size, ALIGNMENT);
let raw_ptr = std::alloc::alloc_zeroed(layout) as *mut T;
NonNull::new(raw_ptr).unwrap_or_else(|| handle_alloc_error(layout))
}
}
}
/// # Safety
///
/// This function is unsafe because undefined behavior can result if the caller does not ensure all
/// of the following:
///
/// * ptr must denote a block of memory currently allocated via this allocator,
///
/// * size must be the same size that was used to allocate that block of memory,
pub unsafe fn free_aligned<T: NativeType>(ptr: NonNull<T>, size: usize) {
if ptr != null_pointer() {
let size = size * size_of::<T>();
std::alloc::dealloc(
ptr.as_ptr() as *mut u8,
Layout::from_size_align_unchecked(size, ALIGNMENT),
);
}
}
/// # Safety
///
/// This function is unsafe because undefined behavior can result if the caller does not ensure all
/// of the following:
///
/// * ptr must be currently allocated via this allocator,
///
/// * new_size must be greater than zero.
///
/// * new_size, when rounded up to the nearest multiple of [ALIGNMENT], must not overflow (i.e.,
/// the rounded value must be less than usize::MAX).
pub unsafe fn reallocate<T: NativeType>(
ptr: NonNull<T>,
old_size: usize,
new_size: usize,
) -> NonNull<T> {
let old_size = old_size * size_of::<T>();
let new_size = new_size * size_of::<T>();
if ptr == null_pointer() {
return allocate_aligned(new_size);
}
if new_size == 0 {
free_aligned(ptr, old_size);
return null_pointer();
}
let raw_ptr = std::alloc::realloc(
ptr.as_ptr() as *mut u8,
Layout::from_size_align_unchecked(old_size, ALIGNMENT),
new_size,
) as *mut T;
NonNull::new(raw_ptr).unwrap_or_else(|| {
handle_alloc_error(Layout::from_size_align_unchecked(new_size, ALIGNMENT))
})
}
/// The owner of an allocation.
/// The trait implementation is responsible for dropping the allocations once no more references exist.
pub trait Allocation: RefUnwindSafe {}
impl<T: RefUnwindSafe> Allocation for T {}
/// Mode of deallocating memory regions
pub(crate) enum Deallocation {
/// An allocation of the given capacity that needs to be deallocated using arrows's cache aligned allocator.
/// See [allocate_aligned] and [free_aligned].
Arrow(usize),
/// An allocation from an external source like the FFI interface or a Rust Vec.
/// Deallocation will happen
Custom(Arc<dyn Allocation>),
}
impl Debug for Deallocation {
fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
match self {
Deallocation::Arrow(capacity) => {
write!(f, "Deallocation::Arrow {{ capacity: {} }}", capacity)
}
Deallocation::Custom(_) => {
write!(f, "Deallocation::Custom {{ capacity: unknown }}")
}
}
}
}