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#![feature(thread_local)]
#![feature(const_fn)]
#![feature(placement_new_protocol)]
#![feature(placement_in_syntax)]
#![feature(nonzero)]
#![cfg_attr(not(feature = "std"), no_std)]
#![cfg_attr(feature = "alloc", feature(alloc, heap_api))]
#[cfg(feature = "std")]
extern crate core;
#[cfg(feature = "alloc")]
extern crate alloc;
#[cfg(feature = "std")]
use std::io;
use core::{cell, mem, slice, ptr, ops, marker, fmt, nonzero, str};
use cell::{RefCell, RefMut};
use ops::{Deref, DerefMut, Placer, Place, InPlace};
use marker::{PhantomData};
use nonzero::NonZero;
#[derive(Debug)]
pub struct InitError {}
#[derive(Debug)]
pub struct OutOfMemory {}
pub struct Frame<'a> {
top: usize,
cap: usize,
_m: PhantomData<&'a ()>
}
struct Root(RefCell<Frame<'static>>);
impl Root {
#[inline(always)]
fn get_mut(&self) -> RefMut<Frame<'static>> {
let mut frame = self.0.borrow_mut();
if frame.top == 0 {
#[cold]
#[cfg(feature = "alloc")]
frame.init(DEFAULT_SIZE);
#[cfg(not(feature = "alloc"))]
panic!("Root frame not initialized");
}
assert!(frame.top != 0);
frame
}
}
unsafe impl Sync for Root {}
#[thread_local]
static mut ROOT: Root = Root(RefCell::new(Frame { top: 0, cap: 0, _m: PhantomData }));
const DEFAULT_SIZE: usize = 1 << 20;
fn get_root() -> RefMut<'static, Frame<'static>> {
unsafe { ROOT.get_mut() }
}
#[cfg(feature = "alloc")]
pub fn init_with_capacity(size: usize) -> Result<(), InitError> {
let mut root = unsafe { ROOT.0.borrow_mut() };
if root.top == 0 {
Ok(root.init(size))
} else {
Err(InitError{})
}
}
#[inline(always)]
fn padding_for<T>(ptr: usize) -> usize {
let align = mem::align_of::<T>();
align - (ptr - 1) % align - 1
}
impl<'a> Frame<'a> {
#[cfg(feature = "alloc")]
fn init(&mut self, size: usize) {
use alloc;
assert_eq!(self.top, 0);
let base = unsafe { alloc::heap::allocate(size, 64) } as usize;
self.top = base;
self.cap = base + size;
}
pub fn from_slice(s: &'a mut [u8]) -> Frame<'a> {
let ptr = s.as_mut_ptr() as usize;
let len = s.len();
Frame {
top: ptr,
cap: ptr + len,
_m: PhantomData
}
}
#[inline]
pub fn try_place<T>(&mut self, count: usize)
-> Result<FArray<'a, T>, OutOfMemory> where T: Default
{
let ptr = try!(unsafe { self.try_place_raw(count) });
Ok(FArray::init(ptr.get(), count))
}
#[inline]
pub fn place<T>(&mut self, count: usize) -> FArray<'a, T> where T: Default
{
let ptr = unsafe { self.place_raw(count) };
FArray::init(ptr, count)
}
#[inline(always)]
pub unsafe fn try_place_raw<T>(&mut self, count: usize)
-> Result<NonZero<*mut T>, OutOfMemory>
{
let size = count * mem::size_of::<T>();
let pad = padding_for::<T>(self.top);
let ptr = self.top + pad;
let new_top = ptr + size;
if new_top < self.cap {
self.top = new_top;
Ok(NonZero::new(ptr as *mut T))
} else {
#[cold]
Err(OutOfMemory{})
}
}
#[inline(always)]
pub unsafe fn place_raw<T>(&mut self, count: usize) -> *mut T {
let size = count * mem::size_of::<T>();
let pad = padding_for::<T>(self.top);
let ptr = self.top + pad;
let new_top = ptr + size;
if new_top >= self.cap {
panic!("Out of Memory");
}
self.top = new_top;
ptr as *mut T
}
#[inline]
pub fn place_iter<I, T>(&mut self, mut iter: I) -> Result<FArray<'a, T>, OutOfMemory>
where I: Iterator<Item=T>
{
let old_top = self.top;
let pad = padding_for::<T>(old_top);
let mut p = old_top + pad;
let mut arr = FArray { ptr: p as *mut T, len: 0, _m: PhantomData };
while let Some(e) = iter.next() {
if p + mem::size_of::<T>() > self.cap {
self.top = old_top;
#[cold]
return Err(OutOfMemory{});
}
unsafe {
ptr::write(p as *mut T, e);
}
p += mem::size_of::<T>();
arr.len += 1;
}
Ok(arr)
}
#[inline(always)]
pub fn push<T>(&mut self) -> FramePlacer<'a, T> {
let ptr = unsafe { self.place_raw(1) };
FramePlacer { ptr: ptr, _m: PhantomData }
}
#[inline(always)]
pub fn subframe(&mut self) -> Frame {
Frame {
top: self.top,
cap: self.cap,
_m: PhantomData
}
}
#[cfg(feature = "std")]
#[inline(always)]
pub fn cursor<'b>(&'b mut self) -> Cursor<'a, 'b> {
Cursor {
ptr: self.top as *mut u8,
len: 0,
cap: self.cap - self.top,
frame: self
}
}
#[inline(always)]
pub fn writer<'b>(&'b mut self) -> Writer<'a, 'b> {
Writer {
ptr: self.top as *mut u8,
len: 0,
cap: self.cap - self.top,
frame: self
}
}
}
#[cfg(feature = "std")]
pub struct Cursor<'a, 'b> where 'a: 'b {
ptr: *mut u8,
len: usize,
cap: usize,
frame: &'b mut Frame<'a>
}
#[cfg(feature = "std")]
impl<'a, 'b> Cursor<'a, 'b> {
pub fn finish(self) -> &'a mut [u8] {
self.frame.top += self.len;
unsafe {
slice::from_raw_parts_mut(self.ptr, self.len)
}
}
}
#[cfg(feature = "std")]
impl<'a, 'b> io::Write for Cursor<'a, 'b> {
#[inline(always)]
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
if self.len + buf.len() <= self.cap {
unsafe {
ptr::copy(
buf.as_ptr(),
self.ptr.offset(self.len as isize),
buf.len()
);
}
self.len += buf.len();
Ok(buf.len())
} else {
Err(io::ErrorKind::Other.into())
}
}
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}
pub struct Writer<'a, 'b> where 'a: 'b {
ptr: *mut u8,
len: usize,
cap: usize,
frame: &'b mut Frame<'a>
}
impl<'a, 'b> Writer<'a, 'b> {
pub fn finish(self) -> &'a str {
self.frame.top += self.len;
unsafe {
let slice = slice::from_raw_parts(self.ptr, self.len);
str::from_utf8_unchecked(slice)
}
}
}
impl<'a, 'b> fmt::Write for Writer<'a, 'b> {
#[inline(always)]
fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> {
if self.len + s.len() <= self.cap {
unsafe {
ptr::copy(s.as_ptr(), self.ptr.offset(self.len as isize), s.len());
}
self.len += s.len();
Ok(())
} else {
Err(fmt::Error::default())
}
}
#[inline(always)]
fn write_char(&mut self, c: char) -> Result<(), fmt::Error> {
if self.len + 4 <= self.cap {
let mut slice = unsafe {
slice::from_raw_parts_mut(
self.ptr.offset(self.len as isize),
self.cap
)
};
self.len += c.encode_utf8(slice).len();
Ok(())
} else {
Err(fmt::Error::default())
}
}
}
pub struct FArray<'a, T: 'a> {
ptr: *mut T,
len: usize,
_m: PhantomData<&'a T>
}
impl<'a, T: Default + 'a> FArray<'a, T> {
#[inline(always)]
fn init(ptr: *mut T, len: usize) -> FArray<'a, T> {
for i in 0 .. len {
unsafe { ptr::write(ptr.offset(i as isize), T::default()) };
}
FArray { ptr, len, _m: PhantomData }
}
}
impl<'a, T> Drop for FArray<'a, T> {
#[inline(always)]
fn drop(&mut self) {
for i in 0 .. self.len {
unsafe { ptr::drop_in_place(self.ptr.offset(i as isize)) };
}
}
}
impl<'a, T> Deref for FArray<'a, T> {
type Target = [T];
#[inline(always)]
fn deref(&self) -> &[T] {
unsafe { slice::from_raw_parts(self.ptr, self.len) }
}
}
impl<'a, T> DerefMut for FArray<'a, T> {
#[inline(always)]
fn deref_mut(&mut self) -> &mut [T] {
unsafe { slice::from_raw_parts_mut(self.ptr, self.len) }
}
}
impl<'a, T: fmt::Debug> fmt::Debug for FArray<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
(self as &[T]).fmt(f)
}
}
pub struct FBox<'a, T: 'a> {
ptr: *mut T,
_m: PhantomData<&'a T>
}
impl<'a, T: 'a> Drop for FBox<'a, T> {
#[inline(always)]
fn drop(&mut self) {
unsafe { ptr::drop_in_place(self.ptr) }
}
}
impl<'a, T> Deref for FBox<'a, T> {
type Target = T;
#[inline(always)]
fn deref(&self) -> &T {
unsafe { &*self.ptr }
}
}
impl<'a, T> DerefMut for FBox<'a, T> {
#[inline(always)]
fn deref_mut(&mut self) -> &mut T {
unsafe { &mut *self.ptr }
}
}
impl<'a, T, U> PartialEq<U> for FBox<'a, T> where T: PartialEq<U> {
fn eq(&self, rhs: &U) -> bool {
(self as &T).eq(rhs)
}
}
impl<'a, T: fmt::Debug> fmt::Debug for FBox<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
(self as &T).fmt(f)
}
}
pub struct FramePlacer<'a, T: 'a> {
ptr: *mut T,
_m: PhantomData<&'a T>
}
pub struct FramePlace<'a, T: 'a> {
ptr: *mut T,
_m: PhantomData<&'a T>
}
impl<'a, T> Placer<T> for FramePlacer<'a, T> {
type Place = FramePlace<'a, T>;
#[inline(always)]
fn make_place(self) -> Self::Place {
FramePlace { ptr: self.ptr, _m: PhantomData }
}
}
impl<'a, T> Place<T> for FramePlace<'a, T> {
#[inline(always)]
fn pointer(&mut self) -> *mut T {
self.ptr
}
}
impl<'a, T> InPlace<T> for FramePlace<'a, T> {
type Owner = FBox<'a, T>;
#[inline(always)]
unsafe fn finalize(self) -> FBox<'a, T> {
FBox { ptr: self.ptr, _m: PhantomData }
}
}
#[inline(always)]
pub unsafe fn place_raw<F, O, T>(count: usize, f: F) -> Result<O, OutOfMemory>
where F: FnOnce(*mut T) -> O
{
let mut root = ROOT.get_mut();
let mut sub = root.subframe();
Ok(f(sub.try_place_raw(count)?.get()))
}
#[inline]
pub fn place<F, O, T>(count: usize, f: F) -> Result<O, OutOfMemory>
where F: FnOnce(&mut [T]) -> O, T: Default
{
let mut root = get_root();
let mut sub = root.subframe();
let mut arr = sub.try_place(count)?;
Ok(f(&mut arr))
}
#[inline]
pub fn place_iter<T, I, O, F>(it: I, f: F) -> Result<O, OutOfMemory>
where I: Iterator<Item=T>, F: FnOnce(&mut FArray<T>) -> O
{
let mut root = get_root();
let mut sub = root.subframe();
let mut arr = sub.place_iter(it)?;
Ok(f(&mut arr))
}
pub fn frame<F, O>(f: F) -> O
where F: FnOnce(&mut Frame) -> O
{
let mut root = get_root();
let mut sub = root.subframe();
f(&mut sub)
}
#[test]
fn test_place() {
frame(|f| {
let p1 = f.push();
let p2 = f.push();
let a = p1 <- "hi";
let b = p2 <- 42;
assert_eq!(a, "hi");
assert_eq!(b, 42);
})
}