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#![no_std]
#![feature(allocator_api)]
#![feature(ptr_offset_from)]
mod allocator;
mod raw;
pub use allocator::BuddyAllocator;
use alloc_wg::alloc::{AllocRef, Global, ReallocPlacement};
use raw::RawBuddies;
pub struct Buddies<A: AllocRef = Global> {
raw: RawBuddies<A>,
}
impl Buddies<Global> {
/// create a new instance
///
/// `max_order` determines how many different orders there are.
///
/// `multiplier` multiplies all indices by a certain value. eg if `multiplier` was 4 it would return 0, 4, 8, 12 instead of 0, 1, 2, 3
///
/// # Panics
/// panics if:
/// - `max_order` is zero
/// - `multiplier` is not a power of two
/// - `max_ids` is not a valid index
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(3, 1, None);
/// buddies.allocate(2, 2).unwrap();
/// ```
pub fn new(max_order: usize, multiplier: usize, max_idx: Option<usize>) -> Self {
Buddies::new_in(max_order, multiplier, max_idx, Global)
}
/// create a new instance with the appropriate `max_order` to fit `capacity`
///
/// `capacity` must not be zero and be divisable by `multiplier`
///
/// see [Buddies::new](Buddies::new)
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::with_capacity(500, 1);
/// assert_eq!(buddies.capacity(), 500);
/// buddies.allocate(2, 2).unwrap();
/// ```
pub fn with_capacity(capacity: usize, multiplier: usize) -> Self {
Buddies {
raw: RawBuddies::with_capacity(capacity, multiplier, Global),
}
}
}
impl<A: AllocRef> Buddies<A> {
/// see [Buddies::new](Buddies::new)
pub fn new_in(max_order: usize, multiplier: usize, max_idx: Option<usize>, a: A) -> Self {
Buddies {
raw: RawBuddies::new_in(max_order, multiplier, max_idx, a),
}
}
/// see [Buddies::with_capacity](Buddies::with_capacity)
pub fn with_capacity_in(capacity: usize, multiplier: usize, a: A) -> Self {
Buddies {
raw: RawBuddies::with_capacity(capacity, multiplier, a),
}
}
/// return the capacity
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(3, 1, None);
/// assert_eq!(buddies.capacity(), 4);
/// let buddies = Buddies::new(3, 4, None);
/// assert_eq!(buddies.capacity(), 16);
/// let buddies = Buddies::new(3, 4, Some(12));
/// assert_eq!(buddies.capacity(), 12);
/// ```
pub fn capacity(&self) -> usize {
self.raw.capacity()
}
/// check if there are any allocations
/// # Safety
/// calling this method is equivalent to trying to allocate the entire memory inside at once thus rendering it useless after it returned true
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(3, 1, None);
/// let idx = buddies.allocate(1, 1).unwrap();
/// assert!(!buddies.is_unused());
/// buddies.deallocate(idx, 1);
/// assert!(buddies.is_unused());
/// ```
pub fn is_unused(&self) -> bool {
self.raw.is_unused()
}
/// get the real size of an allocation for a given size
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(3, 1, None);
/// assert_eq!(buddies.real_size_for_allocation(0), 1);
/// assert_eq!(buddies.real_size_for_allocation(1), 1);
/// assert_eq!(buddies.real_size_for_allocation(2), 2);
/// assert_eq!(buddies.real_size_for_allocation(3), 4);
/// assert_eq!(buddies.real_size_for_allocation(4), 4);
///
/// let buddies = Buddies::new(3, 4, None);
/// assert_eq!(buddies.real_size_for_allocation(0), 4);
/// assert_eq!(buddies.real_size_for_allocation(4), 4);
/// assert_eq!(buddies.real_size_for_allocation(8), 8);
/// assert_eq!(buddies.real_size_for_allocation(12), 16);
/// assert_eq!(buddies.real_size_for_allocation(16), 16);
/// ```
pub fn real_size_for_allocation(&self, size: usize) -> usize {
self.raw.real_size_for_allocation(size)
}
/// try to allocate a buddy with a given size at a given index
/// # Panics
/// panics if:
/// - `idx + size` is too big
/// - `idx` is not properly aligned
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(5, 1, None);
/// assert_eq!(buddies.allocate_at(1, 0), true);
/// assert_eq!(buddies.allocate_at(2, 2), true);
/// assert_eq!(buddies.allocate_at(1, 3), false);
/// assert_eq!(buddies.allocate_at(2, 4), true);
/// assert_eq!(buddies.allocate_at(2, 4), false);
/// assert_eq!(buddies.allocate_at(1, 5), false);
/// assert_eq!(buddies.allocate_at(2, 8), true);
/// ```
pub fn allocate_at(&self, size: usize, idx: usize) -> bool {
self.raw.allocate_at_with_size(size, idx)
}
/// allocate a buddy with a given size
/// # Panics
/// panics if:
/// - `size` or `align` are too big
/// - `align` is not a power of two
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(5, 1, None);
/// assert_eq!(buddies.allocate(1, 1).unwrap(), 0);
/// assert_eq!(buddies.allocate(2, 1).unwrap(), 2);
/// assert_eq!(buddies.allocate(2, 1).unwrap(), 4);
/// assert_eq!(buddies.allocate(2, 4).unwrap(), 8);
/// ```
pub fn allocate(&self, size: usize, align: usize) -> Option<usize> {
self.raw.allocate_with_size(size, align)
}
/// deallocate a buddy with a given size
/// # Panics
/// panics if:
/// - there is no buddy with that size allocated at that index
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(5, 1, None);
/// let idx1 = buddies.allocate(1, 1).unwrap();
/// let idx2 = buddies.allocate(2, 1).unwrap();
/// let idx3 = buddies.allocate(2, 1).unwrap();
/// let idx4 = buddies.allocate(2, 4).unwrap();
/// buddies.deallocate(idx1, 1);
/// buddies.deallocate(idx4, 2);
/// buddies.deallocate(idx2, 2);
/// buddies.deallocate(idx3, 2);
/// ```
pub fn deallocate(&self, idx: usize, size: usize) {
self.raw.deallocate_with_size(idx, size)
}
/// shrink a buddy
/// # Panics
/// panics if:
/// - there is no buddy with that size allocated at that index
/// - `new_size` is greater that `old_size`
/// ```
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(3, 1, None);
/// let idx = buddies.allocate(3, 1).unwrap();
/// buddies.shrink(idx, 3, 2);
/// buddies.shrink(idx, 2, 1);
/// buddies.shrink(idx, 1, 0);
/// ```
pub fn shrink(&self, idx: usize, old_size: usize, new_size: usize) {
self.raw.shrink_with_size(idx, old_size, new_size)
}
/// grow a buddy
/// # Panics
/// panics if:
/// - there is no buddy with that size allocated at that index
/// - `new_size` is smaller that `old_size`
/// - `new_size` is too big
/// ```
/// #![feature(allocator_api)]
/// use alloc_wg::alloc::ReallocPlacement;
/// use buddy_allocator::Buddies;
///
/// let buddies = Buddies::new(3, 1, None);
/// let idx = buddies.allocate(0, 1).unwrap();
/// let idx = buddies.grow(idx, 0, 1, ReallocPlacement::InPlace).unwrap();
/// let idx = buddies.grow(idx, 1, 2, ReallocPlacement::MayMove).unwrap();
/// buddies.grow(idx, 2, 3, ReallocPlacement::InPlace).unwrap();
/// ```
pub fn grow(
&self,
idx: usize,
old_size: usize,
new_size: usize,
placement: ReallocPlacement,
) -> Option<usize> {
self.raw.grow_with_size(idx, old_size, new_size, placement)
}
}