// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use core::ptr::Unique;
+use allocator::{Alloc, Layout};
+use core::ptr::{self, Unique};
use core::mem;
use core::slice;
-use heap;
-use super::oom;
+use heap::{HeapAlloc};
use super::boxed::Box;
use core::ops::Drop;
use core::cmp;
/// field. This allows zero-sized types to not be special-cased by consumers of
/// this type.
#[allow(missing_debug_implementations)]
-pub struct RawVec<T> {
+pub struct RawVec<T, A: Alloc = HeapAlloc> {
ptr: Unique<T>,
cap: usize,
+ a: A,
}
-impl<T> RawVec<T> {
- /// Creates the biggest possible RawVec without allocating. If T has positive
- /// size, then this makes a RawVec with capacity 0. If T has 0 size, then it
- /// it makes a RawVec with capacity `usize::MAX`. Useful for implementing
- /// delayed allocation.
- pub fn new() -> Self {
+impl<T, A: Alloc> RawVec<T, A> {
+ /// Like `new` but parameterized over the choice of allocator for
+ /// the returned RawVec.
+ pub fn new_in(a: A) -> Self {
// !0 is usize::MAX. This branch should be stripped at compile time.
let cap = if mem::size_of::<T>() == 0 { !0 } else { 0 };
RawVec {
ptr: Unique::empty(),
cap: cap,
+ a: a,
}
}
- /// Creates a RawVec with exactly the capacity and alignment requirements
- /// for a `[T; cap]`. This is equivalent to calling RawVec::new when `cap` is 0
- /// or T is zero-sized. Note that if `T` is zero-sized this means you will *not*
- /// get a RawVec with the requested capacity!
- ///
- /// # Panics
- ///
- /// * Panics if the requested capacity exceeds `usize::MAX` bytes.
- /// * Panics on 32-bit platforms if the requested capacity exceeds
- /// `isize::MAX` bytes.
- ///
- /// # Aborts
- ///
- /// Aborts on OOM
+ /// Like `with_capacity` but parameterized over the choice of
+ /// allocator for the returned RawVec.
#[inline]
- pub fn with_capacity(cap: usize) -> Self {
- RawVec::allocate(cap, false)
+ pub fn with_capacity_in(cap: usize, a: A) -> Self {
+ RawVec::allocate_in(cap, false, a)
}
- /// Like `with_capacity` but guarantees the buffer is zeroed.
+ /// Like `with_capacity_zeroed` but parameterized over the choice
+ /// of allocator for the returned RawVec.
#[inline]
- pub fn with_capacity_zeroed(cap: usize) -> Self {
- RawVec::allocate(cap, true)
+ pub fn with_capacity_zeroed_in(cap: usize, a: A) -> Self {
+ RawVec::allocate_in(cap, true, a)
}
- fn allocate(cap: usize, zeroed: bool) -> Self {
+ fn allocate_in(cap: usize, zeroed: bool, mut a: A) -> Self {
unsafe {
let elem_size = mem::size_of::<T>();
mem::align_of::<T>() as *mut u8
} else {
let align = mem::align_of::<T>();
- let ptr = if zeroed {
- heap::allocate_zeroed(alloc_size, align)
+ let result = if zeroed {
+ a.alloc_zeroed(Layout::from_size_align(alloc_size, align).unwrap())
} else {
- heap::allocate(alloc_size, align)
+ a.alloc(Layout::from_size_align(alloc_size, align).unwrap())
};
- if ptr.is_null() {
- oom()
+ match result {
+ Ok(ptr) => ptr,
+ Err(err) => a.oom(err),
}
- ptr
};
RawVec {
ptr: Unique::new(ptr as *mut _),
cap: cap,
+ a: a,
}
}
}
+}
+
+impl<T> RawVec<T, HeapAlloc> {
+ /// Creates the biggest possible RawVec (on the system heap)
+ /// without allocating. If T has positive size, then this makes a
+ /// RawVec with capacity 0. If T has 0 size, then it it makes a
+ /// RawVec with capacity `usize::MAX`. Useful for implementing
+ /// delayed allocation.
+ pub fn new() -> Self {
+ Self::new_in(HeapAlloc)
+ }
+
+ /// Creates a RawVec (on the system heap) with exactly the
+ /// capacity and alignment requirements for a `[T; cap]`. This is
+ /// equivalent to calling RawVec::new when `cap` is 0 or T is
+ /// zero-sized. Note that if `T` is zero-sized this means you will
+ /// *not* get a RawVec with the requested capacity!
+ ///
+ /// # Panics
+ ///
+ /// * Panics if the requested capacity exceeds `usize::MAX` bytes.
+ /// * Panics on 32-bit platforms if the requested capacity exceeds
+ /// `isize::MAX` bytes.
+ ///
+ /// # Aborts
+ ///
+ /// Aborts on OOM
+ #[inline]
+ pub fn with_capacity(cap: usize) -> Self {
+ RawVec::allocate_in(cap, false, HeapAlloc)
+ }
+
+ /// Like `with_capacity` but guarantees the buffer is zeroed.
+ #[inline]
+ pub fn with_capacity_zeroed(cap: usize) -> Self {
+ RawVec::allocate_in(cap, true, HeapAlloc)
+ }
+}
+
+impl<T, A: Alloc> RawVec<T, A> {
+ /// Reconstitutes a RawVec from a pointer, capacity, and allocator.
+ ///
+ /// # Undefined Behavior
+ ///
+ /// The ptr must be allocated (via the given allocator `a`), and with the given capacity. The
+ /// capacity cannot exceed `isize::MAX` (only a concern on 32-bit systems).
+ /// If the ptr and capacity come from a RawVec created via `a`, then this is guaranteed.
+ pub unsafe fn from_raw_parts_in(ptr: *mut T, cap: usize, a: A) -> Self {
+ RawVec {
+ ptr: Unique::new(ptr),
+ cap: cap,
+ a: a,
+ }
+ }
+}
- /// Reconstitutes a RawVec from a pointer and capacity.
+impl<T> RawVec<T, HeapAlloc> {
+ /// Reconstitutes a RawVec from a pointer, capacity.
///
/// # Undefined Behavior
///
- /// The ptr must be allocated, and with the given capacity. The
+ /// The ptr must be allocated (on the system heap), and with the given capacity. The
/// capacity cannot exceed `isize::MAX` (only a concern on 32-bit systems).
/// If the ptr and capacity come from a RawVec, then this is guaranteed.
pub unsafe fn from_raw_parts(ptr: *mut T, cap: usize) -> Self {
RawVec {
ptr: Unique::new(ptr),
cap: cap,
+ a: HeapAlloc,
}
}
}
}
-impl<T> RawVec<T> {
+impl<T, A: Alloc> RawVec<T, A> {
/// Gets a raw pointer to the start of the allocation. Note that this is
/// Unique::empty() if `cap = 0` or T is zero-sized. In the former case, you must
/// be careful.
}
}
+ /// Returns a shared reference to the allocator backing this RawVec.
+ pub fn alloc(&self) -> &A {
+ &self.a
+ }
+
+ /// Returns a mutable reference to the allocator backing this RawVec.
+ pub fn alloc_mut(&mut self) -> &mut A {
+ &mut self.a
+ }
+
/// Doubles the size of the type's backing allocation. This is common enough
/// to want to do that it's easiest to just have a dedicated method. Slightly
/// more efficient logic can be provided for this than the general case.
// 0, getting to here necessarily means the RawVec is overfull.
assert!(elem_size != 0, "capacity overflow");
- let align = mem::align_of::<T>();
-
- let (new_cap, ptr) = if self.cap == 0 {
+ let (new_cap, ptr_res) = if self.cap == 0 {
// skip to 4 because tiny Vec's are dumb; but not if that would cause overflow
let new_cap = if elem_size > (!0) / 8 { 1 } else { 4 };
- let ptr = heap::allocate(new_cap * elem_size, align);
- (new_cap, ptr)
+ let ptr_res = self.a.alloc_array::<T>(new_cap);
+ (new_cap, ptr_res)
} else {
// Since we guarantee that we never allocate more than isize::MAX bytes,
// `elem_size * self.cap <= isize::MAX` as a precondition, so this can't overflow
let new_cap = 2 * self.cap;
let new_alloc_size = new_cap * elem_size;
alloc_guard(new_alloc_size);
- let ptr = heap::reallocate(self.ptr() as *mut _,
- self.cap * elem_size,
- new_alloc_size,
- align);
- (new_cap, ptr)
+ let ptr_res = self.a.realloc_array(self.ptr, self.cap, new_cap);
+ (new_cap, ptr_res)
};
// If allocate or reallocate fail, we'll get `null` back
- if ptr.is_null() {
- oom()
- }
+ let uniq = match ptr_res {
+ Err(err) => self.a.oom(err),
+ Ok(uniq) => uniq,
+ };
- self.ptr = Unique::new(ptr as *mut _);
+ self.ptr = uniq;
self.cap = new_cap;
}
}
pub fn double_in_place(&mut self) -> bool {
unsafe {
let elem_size = mem::size_of::<T>();
- let align = mem::align_of::<T>();
// since we set the capacity to usize::MAX when elem_size is
// 0, getting to here necessarily means the RawVec is overfull.
let new_alloc_size = new_cap * elem_size;
alloc_guard(new_alloc_size);
- let size = heap::reallocate_inplace(self.ptr() as *mut _,
- self.cap * elem_size,
- new_alloc_size,
- align);
- if size >= new_alloc_size {
- // We can't directly divide `size`.
- self.cap = new_cap;
+
+ let ptr = self.ptr() as *mut _;
+ let old_layout = Layout::new::<T>().repeat(self.cap).unwrap().0;
+ let new_layout = Layout::new::<T>().repeat(new_cap).unwrap().0;
+ match self.a.grow_in_place(ptr, old_layout, new_layout) {
+ Ok(_) => {
+ // We can't directly divide `size`.
+ self.cap = new_cap;
+ true
+ }
+ Err(_) => {
+ false
+ }
}
- size >= new_alloc_size
}
}
pub fn reserve_exact(&mut self, used_cap: usize, needed_extra_cap: usize) {
unsafe {
let elem_size = mem::size_of::<T>();
- let align = mem::align_of::<T>();
// NOTE: we don't early branch on ZSTs here because we want this
// to actually catch "asking for more than usize::MAX" in that case.
let new_alloc_size = new_cap.checked_mul(elem_size).expect("capacity overflow");
alloc_guard(new_alloc_size);
- let ptr = if self.cap == 0 {
- heap::allocate(new_alloc_size, align)
+ let result = if self.cap == 0 {
+ self.a.alloc_array::<T>(new_cap)
} else {
- heap::reallocate(self.ptr() as *mut _,
- self.cap * elem_size,
- new_alloc_size,
- align)
+ self.a.realloc_array(self.ptr, self.cap, new_cap)
};
// If allocate or reallocate fail, we'll get `null` back
- if ptr.is_null() {
- oom()
- }
+ let uniq = match result {
+ Err(err) => self.a.oom(err),
+ Ok(uniq) => uniq,
+ };
- self.ptr = Unique::new(ptr as *mut _);
+ self.ptr = uniq;
self.cap = new_cap;
}
}
/// ```
pub fn reserve(&mut self, used_cap: usize, needed_extra_cap: usize) {
unsafe {
- let elem_size = mem::size_of::<T>();
- let align = mem::align_of::<T>();
-
// NOTE: we don't early branch on ZSTs here because we want this
// to actually catch "asking for more than usize::MAX" in that case.
// If we make it past the first branch then we are guaranteed to
// FIXME: may crash and burn on over-reserve
alloc_guard(new_alloc_size);
- let ptr = if self.cap == 0 {
- heap::allocate(new_alloc_size, align)
+ let result = if self.cap == 0 {
+ self.a.alloc_array::<T>(new_cap)
} else {
- heap::reallocate(self.ptr() as *mut _,
- self.cap * elem_size,
- new_alloc_size,
- align)
+ self.a.realloc_array(self.ptr, self.cap, new_cap)
};
- // If allocate or reallocate fail, we'll get `null` back
- if ptr.is_null() {
- oom()
- }
+ let uniq = match result {
+ Err(err) => self.a.oom(err),
+ Ok(uniq) => uniq,
+ };
- self.ptr = Unique::new(ptr as *mut _);
+ self.ptr = uniq;
self.cap = new_cap;
}
}
/// `isize::MAX` bytes.
pub fn reserve_in_place(&mut self, used_cap: usize, needed_extra_cap: usize) -> bool {
unsafe {
- let elem_size = mem::size_of::<T>();
- let align = mem::align_of::<T>();
-
// NOTE: we don't early branch on ZSTs here because we want this
// to actually catch "asking for more than usize::MAX" in that case.
// If we make it past the first branch then we are guaranteed to
return false;
}
- let (_, new_alloc_size) = self.amortized_new_size(used_cap, needed_extra_cap);
+ let (new_cap, new_alloc_size) = self.amortized_new_size(used_cap, needed_extra_cap);
// FIXME: may crash and burn on over-reserve
alloc_guard(new_alloc_size);
- let size = heap::reallocate_inplace(self.ptr() as *mut _,
- self.cap * elem_size,
- new_alloc_size,
- align);
- if size >= new_alloc_size {
- self.cap = new_alloc_size / elem_size;
+ // Here, `cap < used_cap + needed_extra_cap <= new_cap`
+ // (regardless of whether `self.cap - used_cap` wrapped).
+ // Therefore we can safely call grow_in_place.
+
+ let ptr = self.ptr() as *mut _;
+ let old_layout = Layout::new::<T>().repeat(self.cap).unwrap().0;
+ let new_layout = Layout::new::<T>().repeat(new_cap).unwrap().0;
+ match self.a.grow_in_place(ptr, old_layout, new_layout) {
+ Ok(_) => {
+ self.cap = new_cap;
+ true
+ }
+ Err(_) => {
+ false
+ }
}
- size >= new_alloc_size
}
}
/// Aborts on OOM.
pub fn shrink_to_fit(&mut self, amount: usize) {
let elem_size = mem::size_of::<T>();
- let align = mem::align_of::<T>();
// Set the `cap` because they might be about to promote to a `Box<[T]>`
if elem_size == 0 {
assert!(self.cap >= amount, "Tried to shrink to a larger capacity");
if amount == 0 {
- mem::replace(self, RawVec::new());
+ // We want to create a new zero-length vector within the
+ // same allocator. We use ptr::write to avoid an
+ // erroneous attempt to drop the contents, and we use
+ // ptr::read to sidestep condition against destructuring
+ // types that implement Drop.
+
+ unsafe {
+ let a = ptr::read(&self.a as *const A);
+ self.dealloc_buffer();
+ ptr::write(self, RawVec::new_in(a));
+ }
} else if self.cap != amount {
unsafe {
- // Overflow check is unnecessary as the vector is already at
- // least this large.
- let ptr = heap::reallocate(self.ptr() as *mut _,
- self.cap * elem_size,
- amount * elem_size,
- align);
- if ptr.is_null() {
- oom()
+ match self.a.realloc_array(self.ptr, self.cap, amount) {
+ Err(err) => self.a.oom(err),
+ Ok(uniq) => self.ptr = uniq,
}
- self.ptr = Unique::new(ptr as *mut _);
}
self.cap = amount;
}
}
+}
+impl<T> RawVec<T, HeapAlloc> {
/// Converts the entire buffer into `Box<[T]>`.
///
/// While it is not *strictly* Undefined Behavior to call
}
}
-unsafe impl<#[may_dangle] T> Drop for RawVec<T> {
+impl<T, A: Alloc> RawVec<T, A> {
/// Frees the memory owned by the RawVec *without* trying to Drop its contents.
- fn drop(&mut self) {
+ pub unsafe fn dealloc_buffer(&mut self) {
let elem_size = mem::size_of::<T>();
if elem_size != 0 && self.cap != 0 {
- let align = mem::align_of::<T>();
-
- let num_bytes = elem_size * self.cap;
- unsafe {
- heap::deallocate(self.ptr() as *mut u8, num_bytes, align);
- }
+ let ptr = self.ptr() as *mut u8;
+ let layout = Layout::new::<T>().repeat(self.cap).unwrap().0;
+ self.a.dealloc(ptr, layout);
}
}
}
+unsafe impl<#[may_dangle] T, A: Alloc> Drop for RawVec<T, A> {
+ /// Frees the memory owned by the RawVec *without* trying to Drop its contents.
+ fn drop(&mut self) {
+ unsafe { self.dealloc_buffer(); }
+ }
+}
+
// We need to guarantee the following:
mod tests {
use super::*;
+ #[test]
+ fn allocator_param() {
+ use allocator::{Alloc, AllocErr};
+
+ // Writing a test of integration between third-party
+ // allocators and RawVec is a little tricky because the RawVec
+ // API does not expose fallible allocation methods, so we
+ // cannot check what happens when allocator is exhausted
+ // (beyond detecting a panic).
+ //
+ // Instead, this just checks that the RawVec methods do at
+ // least go through the Allocator API when it reserves
+ // storage.
+
+ // A dumb allocator that consumes a fixed amount of fuel
+ // before allocation attempts start failing.
+ struct BoundedAlloc { fuel: usize }
+ unsafe impl Alloc for BoundedAlloc {
+ unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
+ let size = layout.size();
+ if size > self.fuel {
+ return Err(AllocErr::Unsupported { details: "fuel exhausted" });
+ }
+ match HeapAlloc.alloc(layout) {
+ ok @ Ok(_) => { self.fuel -= size; ok }
+ err @ Err(_) => err,
+ }
+ }
+ unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout) {
+ HeapAlloc.dealloc(ptr, layout)
+ }
+ }
+
+ let a = BoundedAlloc { fuel: 500 };
+ let mut v: RawVec<u8, _> = RawVec::with_capacity_in(50, a);
+ assert_eq!(v.a.fuel, 450);
+ v.reserve(50, 150); // (causes a realloc, thus using 50 + 150 = 200 units of fuel)
+ assert_eq!(v.a.fuel, 250);
+ }
+
#[test]
fn reserve_does_not_overallocate() {
{
}
}
+
}
projects / rust.git / commitdiff