arrayvec/src/arrayvec_impl.rs at master · sugar700/arrayvec · GitHub

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use std::ptr;

use std::slice;

use crate::CapacityError;

/// Implements basic arrayvec methods - based on a few required methods

/// for length and element access.

pub(crate) trait ArrayVecImpl {

type Item;

const CAPACITY: usize;

fn len(&self) -> usize;

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

/// Return a slice containing all elements of the vector.

fn as_slice(&self) -> &[Self::Item] {

let len = self.len();

unsafe {

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

}

/// Return a mutable slice containing all elements of the vector.

fn as_mut_slice(&mut self) -> &mut [Self::Item] {

let len = self.len();

unsafe {

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

}

/// Return a raw pointer to the vector's buffer.

fn as_ptr(&self) -> *const Self::Item;

/// Return a raw mutable pointer to the vector's buffer.

fn as_mut_ptr(&mut self) -> *mut Self::Item;

fn push(&mut self, element: Self::Item) {

self.try_push(element).unwrap()

}

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

if self.len() < Self::CAPACITY {

unsafe {

self.push_unchecked(element);

}

Ok(())

} else {

Err(CapacityError::new(element))

}

unsafe fn push_unchecked(&mut self, element: Self::Item) {

let len = self.len();

debug_assert!(len < Self::CAPACITY);

ptr::write(self.as_mut_ptr().add(len), element);

self.set_len(len + 1);

}

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

if self.len() == 0 {

return None;

}

unsafe {

let new_len = self.len() - 1;

self.set_len(new_len);

Some(ptr::read(self.as_ptr().add(new_len)))

}

fn clear(&mut self) {

self.truncate(0)

}

fn truncate(&mut self, new_len: usize) {

unsafe {

let len = self.len();

if new_len < len {

self.set_len(new_len);

let tail = slice::from_raw_parts_mut(self.as_mut_ptr().add(new_len), len - new_len);

ptr::drop_in_place(tail);

}

arrayvec/src/arrayvec_impl.rs at master · sugar700/arrayvec · GitHub

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