arrayvec/src/lib.rs at arraystring-wip · Simteract/arrayvec · GitHub

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extern crate odds;

extern crate nodrop;

use std::cmp;

use std::io;

use std::iter;

use std::mem;

use std::ptr;

use std::ops::{

Deref,

DerefMut,

};

use std::slice;

use nodrop::NoDrop;

// extra traits

use std::borrow::{Borrow, BorrowMut};

use std::hash::{Hash, Hasher};

use std::fmt;

mod array;

mod array_string;

pub use array::Array;

pub use odds::IndexRange as RangeArgument;

use array::Index;

pub use array_string::ArrayString;

unsafe fn new_array<A: Array>() -> A {

// Note: Returning an uninitialized value here only works

// if we can be sure the data is never used. The nullable pointer

// inside enum optimization conflicts with this this for example,

// so we need to be extra careful. See `NoDrop` enum.

mem::uninitialized()

}

/// A vector with a fixed capacity.

///

/// The `ArrayVec` is a vector backed by a fixed size array. It keeps track of

/// the number of initialized elements.

///

/// The vector is a contiguous value that you can store directly on the stack

/// if needed.

///

/// It offers a simple API but also dereferences to a slice, so

/// that the full slice API is available.

///

/// ArrayVec can be converted into a by value iterator.

pub struct ArrayVec<A: Array> {

xs: NoDrop<A>,

len: A::Index,

}

impl<A: Array> Drop for ArrayVec<A> {

fn drop(&mut self) {

// clear all elements

while let Some(_) = self.pop() {

}

// NoDrop inhibits array's drop

// panic safety: NoDrop::drop will trigger on panic, so the inner

// array will not drop even after panic.

}

impl<A: Array> ArrayVec<A> {

/// Create a new empty `ArrayVec`.

///

/// Capacity is inferred from the type parameter.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::<[_; 16]>::new();

/// array.push(1);

/// array.push(2);

/// assert_eq!(&array[..], &[1, 2]);

/// assert_eq!(array.capacity(), 16);

/// ```

pub fn new() -> ArrayVec<A> {

unsafe {

ArrayVec { xs: NoDrop::new(new_array()), len: Index::zero() }

}

/// Return the number of elements in the `ArrayVec`.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::from([1, 2, 3]);

/// array.pop();

/// assert_eq!(array.len(), 2);

/// ```

#[inline]

pub fn len(&self) -> usize { self.len.to_usize() }

/// Return the capacity of the `ArrayVec`.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let array = ArrayVec::from([1, 2, 3]);

/// assert_eq!(array.capacity(), 3);

/// ```

#[inline]

pub fn capacity(&self) -> usize { A::capacity() }

/// Push `element` to the end of the vector.

///

/// Return `None` if the push succeeds, or and return `Some(` *element* `)`

/// if the vector is full.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::<[_; 2]>::new();

///

/// array.push(1);

/// array.push(2);

/// let overflow = array.push(3);

///

/// assert_eq!(&array[..], &[1, 2]);

/// assert_eq!(overflow, Some(3));

/// ```

pub fn push(&mut self, element: A::Item) -> Option<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);

}

None

} else {

Some(element)

}

/// Remove the last element in the vector.

///

/// Return `Some(` *element* `)` if the vector is non-empty, else `None`.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::<[_; 2]>::new();

///

/// array.push(1);

///

/// assert_eq!(array.pop(), Some(1));

/// assert_eq!(array.pop(), None);

/// ```

pub fn pop(&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)))

}

/// Insert `element` in position `index`.

///

/// Shift up all elements after `index`. If any is pushed out, it is returned.

///

/// Return `None` if no element is shifted out.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::<[_; 2]>::new();

///

/// assert_eq!(array.insert(0, "x"), None);

/// assert_eq!(array.insert(0, "y"), None);

/// assert_eq!(array.insert(0, "z"), Some("x"));

/// assert_eq!(array.insert(1, "w"), Some("y"));

/// assert_eq!(&array[..], &["z", "w"]);

///

/// ```

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

if index >= self.capacity() {

return Some(element);

}

let mut ret = None;

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

ret = self.pop();

}

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

}

/// Remove the element at `index` and swap the last element into its place.

///

/// This operation is O(1).

///

/// Return `Some(` *element* `)` if the index is in bounds, else `None`.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::from([1, 2, 3]);

///

/// assert_eq!(array.swap_remove(0), Some(1));

/// assert_eq!(&array[..], &[3, 2]);

///

/// assert_eq!(array.swap_remove(10), None);

/// ```

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

let len = self.len();

if index >= len {

return None

}

self.swap(index, len - 1);

self.pop()

}

/// Remove the element at `index` and shift down the following elements.

///

/// Return `Some(` *element* `)` if the index is in bounds, else `None`.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::from([1, 2, 3]);

///

/// assert_eq!(array.remove(0), Some(1));

/// assert_eq!(&array[..], &[2, 3]);

///

/// assert_eq!(array.remove(10), None);

/// ```

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

if index >= self.len() {

None

} else {

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

}

/// Remove all elements in the vector.

pub fn clear(&mut self) {

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

}

/// Set the vector's length without dropping or moving out elements

///

/// May panic if `length` is greater than the capacity.

///

/// This function is `unsafe` because it changes the notion of the

/// number of “valid” elements in the vector. Use with care.

#[inline]

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

debug_assert!(length <= self.capacity());

self.len = Index::from(length);

}

/// Create a draining iterator that removes the specified range in the vector

/// and yields the removed items from start to end. The element range is

/// removed even if the iterator is not consumed until the end.

///

/// Note: It is unspecified how many elements are removed from the vector,

/// if the `Drain` value is leaked.

///

/// **Panics** if the starting point is greater than the end point or if

/// the end point is greater than the length of the vector.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut v = ArrayVec::from([1, 2, 3]);

/// let u: Vec<_> = v.drain(0..2).collect();

/// assert_eq!(&v[..], &[3]);

/// assert_eq!(&u[..], &[1, 2]);

/// ```

pub fn drain<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(),

vec: self as *mut _,

}

/// Return the inner fixed size array, if it is full to its capacity.

///

/// Return an `Ok` value with the array if length equals capacity,

/// return an `Err` with self otherwise.

///

/// `Note:` This function may incur unproportionally large overhead

/// to move the array out, its performance is not optimal.

pub fn into_inner(self) -> Result<A, Self> {

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

Err(self)

} else {

unsafe {

let array = ptr::read(&*self.xs);

mem::forget(self);

Ok(array)

}

impl<A: Array> Deref for ArrayVec<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 ArrayVec<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)

}

/// Create an `ArrayVec` from an array.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::from([1, 2, 3]);

/// assert_eq!(array.len(), 3);

/// assert_eq!(array.capacity(), 3);

/// ```

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

fn from(array: A) -> Self {

ArrayVec { xs: NoDrop::new(array), len: Index::from(A::capacity()) }

}

/// Iterate the `ArrayVec` with references to each element.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let array = ArrayVec::from([1, 2, 3]);

///

/// for elt in &array {

/// // ...

/// }

/// ```

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

type Item = &'a A::Item;

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

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

}

/// Iterate the `ArrayVec` with mutable references to each element.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// let mut array = ArrayVec::from([1, 2, 3]);

///

/// for elt in &mut array {

/// // ...

/// }

/// ```

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

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

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

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

}

/// Iterate the `ArrayVec` with each element by value.

///

/// The vector is consumed by this operation.

///

/// ```

/// use arrayvec::ArrayVec;

///

/// for elt in ArrayVec::from([1, 2, 3]) {

/// // ...

/// }

/// ```

impl<A: Array> IntoIterator for ArrayVec<A> {

type Item = A::Item;

type IntoIter = IntoIter<A>;

fn into_iter(self) -> IntoIter<A> {

IntoIter { index: Index::zero(), v: self, }

}

/// By-value iterator for `ArrayVec`.

pub struct IntoIter<A: Array> {

index: A::Index,

v: ArrayVec<A>,

}

impl<A: Array> Iterator for IntoIter<A> {

type Item = A::Item;

#[inline]

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

if self.index == self.v.len {

None

} else {

unsafe {

let index = self.index.to_usize();

self.index = Index::from(index + 1);

Some(ptr::read(self.v.get_unchecked_mut(index)))

}

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

let len = self.v.len() - self.index.to_usize();

(len, Some(len))

}

impl<A: Array> DoubleEndedIterator for IntoIter<A> {

#[inline]

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

if self.index == self.v.len {

None

} else {

unsafe {

let new_len = self.v.len() - 1;

self.v.set_len(new_len);

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

}

impl<A: Array> ExactSizeIterator for IntoIter<A> { }

impl<A: Array> Drop for IntoIter<A> {

fn drop(&mut self) {

// panic safety: Set length to 0 before dropping elements.

let index = self.index.to_usize();

let len = self.v.len();

unsafe {

self.v.set_len(0);

let elements = slice::from_raw_parts(self.v.get_unchecked_mut(index),

len - index);

for elt in elements {

ptr::read(elt);

}

/// 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>,

vec: *mut ArrayVec<A>,

}

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 source_vec = &mut *self.vec;

// memmove back untouched tail, update to new length

let start = source_vec.len();

let tail = self.tail_start;

let src = source_vec.as_ptr().offset(tail as isize);

let dst = source_vec.as_mut_ptr().offset(start as isize);

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

source_vec.set_len(start + self.tail_len);

}

/// Extend the `ArrayVec` with an iterator.

///

/// Does not extract more items than there is space for. No error

/// occurs if there are more iterator elements.

impl<A: Array> Extend<A::Item> for ArrayVec<A> {

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

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

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

self.push(elt);

}

/// Create an `ArrayVec` from an iterator.

///

/// Does not extract more items than there is space for. No error

/// occurs if there are more iterator elements.

impl<A: Array> iter::FromIterator<A::Item> for ArrayVec<A> {

fn from_iter<T: IntoIterator<Item=A::Item>>(iter: T) -> Self {

let mut array = ArrayVec::new();

array.extend(iter);

array

}

impl<A: Array> Clone for ArrayVec<A>

where A::Item: Clone

{

fn clone(&self) -> Self {

self.iter().cloned().collect()

}

impl<A: Array> Hash for ArrayVec<A>

where A::Item: Hash

{

fn hash<H: Hasher>(&self, state: &mut H) {

Hash::hash(&**self, state)

}

impl<A: Array> PartialEq for ArrayVec<A>

where A::Item: PartialEq

{

fn eq(&self, other: &Self) -> bool {

**self == **other

}

impl<A: Array> Eq for ArrayVec<A> where A::Item: Eq { }

impl<A: Array> Borrow<[A::Item]> for ArrayVec<A> {

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

}

impl<A: Array> BorrowMut<[A::Item]> for ArrayVec<A> {

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

}

impl<A: Array> AsRef<[A::Item]> for ArrayVec<A> {

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

}

impl<A: Array> AsMut<[A::Item]> for ArrayVec<A> {

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

}

impl<A: Array> fmt::Debug for ArrayVec<A> where A::Item: fmt::Debug {

fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { (**self).fmt(f) }

}

impl<A: Array> Default for ArrayVec<A> {

fn default() -> ArrayVec<A> {

ArrayVec::new()

}

impl<A: Array> PartialOrd for ArrayVec<A> where A::Item: PartialOrd {

#[inline]

fn partial_cmp(&self, other: &ArrayVec<A>) -> Option<cmp::Ordering> {

(**self).partial_cmp(other)

}

#[inline]

fn lt(&self, other: &Self) -> bool {

(**self).lt(other)

}

#[inline]

fn le(&self, other: &Self) -> bool {

(**self).le(other)

}

#[inline]

fn ge(&self, other: &Self) -> bool {

(**self).ge(other)

}

#[inline]

fn gt(&self, other: &Self) -> bool {

(**self).gt(other)

}

impl<A: Array> Ord for ArrayVec<A> where A::Item: Ord {

fn cmp(&self, other: &ArrayVec<A>) -> cmp::Ordering {

(**self).cmp(other)

}

/// `Write` appends written data to the end of the vector.

impl<A: Array<Item=u8>> io::Write for ArrayVec<A> {

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

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 flush(&mut self) -> io::Result<()> { Ok(()) }

}

arrayvec/src/lib.rs at arraystring-wip · Simteract/arrayvec · GitHub

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