arrayvec/src/raw.rs at arrayvec-copy-2 · Simteract/arrayvec · GitHub

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use CapacityError;

use RangeArgument;

use array::Array;

use std::cmp;

use std::ops::{DerefMut};

use std::ptr;

use std::slice;

#[cfg(feature="std")]

use std::io;

use array::Index;

pub trait RawArrayVec<A: Array> : DerefMut<Target=[A::Item]> {

fn len(&self) -> usize;

fn capacity(&self) -> usize;

fn is_full_impl(&self) -> bool { self.len() == self.capacity() }

unsafe fn set_len(&mut self, length: usize);

fn len_ref(&mut self) -> &mut A::Index;

fn push_impl(&mut self, element: A::Item) -> Result<(), CapacityError<A::Item>> {

if self.len() < A::capacity() {

let len = self.len();

unsafe {

ptr::write(self.get_unchecked_mut(len), element);

self.set_len(len + 1);

}

Ok(())

} else {

Err(CapacityError::new(element))

}

fn insert_impl(&mut self, index: usize, element: A::Item)

-> Result<(), CapacityError<A::Item>>

{

assert!(index <= self.len());

if index == self.capacity() {

return Err(CapacityError::new(element));

}

let ret = if self.len() == self.capacity() {

Err(CapacityError::new(self.pop_impl().unwrap()))

} else {

Ok(())

};

let len = self.len();

// follows is just like Vec<T>

unsafe { // infallible

// The spot to put the new value

{

let p = self.get_unchecked_mut(index) as *mut _;

// Shift everything over to make space. (Duplicating the

// `index`th element into two consecutive places.)

ptr::copy(p, p.offset(1), len - index);

// Write it in, overwriting the first copy of the `index`th

// element.

ptr::write(p, element);

}

self.set_len(len + 1);

}

ret

}

fn pop_impl(&mut self) -> Option<A::Item> {

if self.len() == 0 {

return None

}

unsafe {

let new_len = self.len() - 1;

self.set_len(new_len);

Some(ptr::read(self.get_unchecked_mut(new_len)))

}

fn swap_remove_impl(&mut self, index: usize) -> Option<A::Item> {

let len = self.len();

if index >= len {

return None

}

self.swap(index, len - 1);

self.pop_impl()

}

fn remove_impl(&mut self, index: usize) -> Option<A::Item> {

if index >= self.len() {

None

} else {

self.drain_impl(index..index + 1).next()

}

fn clear_impl(&mut self) {

while let Some(_) = self.pop_impl() { }

}

fn retain_impl<F>(&mut self, mut f: F)

where F: FnMut(&mut A::Item) -> bool

{

let len = self.len();

let mut del = 0;

{

let v = &mut **self;

for i in 0..len {

if !f(&mut v[i]) {

del += 1;

} else if del > 0 {

v.swap(i - del, i);

}

if del > 0 {

self.drain_impl(len - del..);

}

fn extend_impl<T: IntoIterator<Item=A::Item>>(&mut self, iter: T) {

let take = self.capacity() - self.len();

for elt in iter.into_iter().take(take) {

let _ = self.push_impl(elt);

}

#[cfg(feature="std")]

fn write_impl(&mut self, data: &[u8]) -> io::Result<usize>

where A: Array<Item=u8>

{

use std::io::Write;

unsafe {

let len = self.len();

let mut tail = slice::from_raw_parts_mut(self.get_unchecked_mut(len),

A::capacity() - len);

let result = tail.write(data);

if let Ok(written) = result {

self.set_len(len + written);

}

result

}

fn drain_impl<R: RangeArgument>(&mut self, range: R) -> Drain<A> {

// Memory safety

// When the Drain is first created, it shortens the length of

// the source vector to make sure no uninitalized or moved-from elements

// are accessible at all if the Drain's destructor never gets to run.

// Drain will ptr::read out the values to remove.

// When finished, remaining tail of the vec is copied back to cover

// the hole, and the vector length is restored to the new length.

let len = self.len();

let start = range.start().unwrap_or(0);

let end = range.end().unwrap_or(len);

// bounds check happens here

let range_slice: *const _ = &self[start..end];

unsafe {

// set self.vec length's to start, to be safe in case Drain is leaked

self.set_len(start);

Drain {

tail_start: end,

tail_len: len - end,

iter: (*range_slice).iter(),

source_ptr: self.as_mut_ptr(),

source_len: self.len_ref() as *mut _

}

fn clone_from_impl(&mut self, rhs: &Self)

where A::Item: Clone

{

// recursive case for the common prefix

let prefix = cmp::min(self.len(), rhs.len());

{

let a = &mut self[..prefix];

let b = &rhs[..prefix];

for i in 0..prefix {

a[i].clone_from(&b[i]);

}

if prefix < self.len() {

// rhs was shorter

for _ in 0..self.len() - prefix {

self.pop_impl();

}

} else {

for elt in &rhs[self.len()..] {

let _ = self.push_impl(elt.clone());

}

impl<A: Array> Deref for RawArrayVec<A> {

type Target = [A::Item];

#[inline]

fn deref(&self) -> &[A::Item] {

unsafe {

slice::from_raw_parts(self.xs.as_ptr(), self.len())

}

impl<A: Array> DerefMut for RawArrayVec<A> {

#[inline]

fn deref_mut(&mut self) -> &mut [A::Item] {

let len = self.len();

unsafe {

slice::from_raw_parts_mut(self.xs.as_mut_ptr(), len)

}

impl<A: Array> From<A> for RawArrayVec<A> {

fn from(array: A) -> Self {

RawArrayVec {

xs: array,

len: Index::from(A::capacity()),

}

impl<'a, A: Array> IntoIterator for &'a RawArrayVec<A> {

type Item = &'a A::Item;

type IntoIter = slice::Iter<'a, A::Item>;

fn into_iter(self) -> Self::IntoIter { self.iter() }

}

impl<'a, A: Array> IntoIterator for &'a mut RawArrayVec<A> {

type Item = &'a mut A::Item;

type IntoIter = slice::IterMut<'a, A::Item>;

fn into_iter(self) -> Self::IntoIter { self.iter_mut() }

}

/// A draining iterator for `ArrayVec`.

pub struct Drain<'a, A>

where A: Array,

A::Item: 'a,

{

/// Index of tail to preserve

tail_start: usize,

/// Length of tail

tail_len: usize,

/// Current remaining range to remove

iter: slice::Iter<'a, A::Item>,

source_ptr: *mut A::Item,

source_len: *mut A::Index,

}

unsafe impl<'a, A: Array + Sync> Sync for Drain<'a, A> {}

unsafe impl<'a, A: Array + Send> Send for Drain<'a, A> {}

impl<'a, A: Array> Iterator for Drain<'a, A>

where A::Item: 'a,

{

type Item = A::Item;

#[inline]

fn next(&mut self) -> Option<Self::Item> {

self.iter.next().map(|elt|

unsafe {

ptr::read(elt as *const _)

}

)

}

#[inline]

fn size_hint(&self) -> (usize, Option<usize>) {

self.iter.size_hint()

}

impl<'a, A: Array> DoubleEndedIterator for Drain<'a, A>

where A::Item: 'a,

{

#[inline]

fn next_back(&mut self) -> Option<Self::Item> {

self.iter.next_back().map(|elt|

unsafe {

ptr::read(elt as *const _)

}

)

}

impl<'a, A: Array> ExactSizeIterator for Drain<'a, A> where A::Item: 'a {}

impl<'a, A: Array> Drop for Drain<'a, A>

where A::Item: 'a

{

fn drop(&mut self) {

// len is currently 0 so panicking while dropping will not cause a double drop.

// exhaust self first

while let Some(_) = self.next() { }

if self.tail_len > 0 {

unsafe {

let ptr = self.source_ptr;

let source_len = &mut *self.source_len;

// memmove back untouched tail, update to new length

let start = source_len.to_usize();

let tail = self.tail_start;

let src = ptr.offset(tail as isize);

let dst = ptr.offset(start as isize);

ptr::copy(src, dst, self.tail_len);

*source_len = Index::from(start + self.tail_len);

}

arrayvec/src/raw.rs at arrayvec-copy-2 · Simteract/arrayvec · GitHub

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