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// Copyright 2014-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use alloc::allocator::{Alloc,Layout,AllocErr,Excess,CannotReallocInPlace};
use alloc::heap;
/// Heap allocator that delegates to the default liballoc heap allocator.
/// Its purpose is to override methods while still using the standard alloc api.
#[derive(Copy, Clone, Default, Debug)]
pub struct Heap;
unsafe impl Alloc for Heap {
#[inline]
unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
heap::Heap.alloc(layout)
}
// A nicer handler for out-of-memory situations than the default one. This
// one prints a message to stderr before aborting. It is critical that this
// code does not allocate any memory since we are in an OOM situation. Any
// errors are ignored while printing since there's nothing we can do about
// them and we are about to exit anyways.
#[inline]
fn oom(&mut self, err: AllocErr) -> ! {
use intrinsics;
use libc::{self, STDERR_FILENO, c_void};
let msg = err.description();
unsafe {
libc::write(STDERR_FILENO, msg.as_ptr() as *const c_void, msg.len());
libc::write(STDERR_FILENO, "\n".as_ptr() as *const c_void, 1);
intrinsics::abort();
}
}
#[inline]
unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout) {
heap::Heap.dealloc(ptr, layout)
}
#[inline]
fn usable_size(&self, layout: &Layout) -> (usize, usize) {
heap::Heap.usable_size(layout)
}
#[inline]
unsafe fn realloc(&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout)
-> Result<*mut u8, AllocErr>
{
heap::Heap.realloc(ptr, layout, new_layout)
}
#[inline]
unsafe fn alloc_zeroed(&mut self, layout: Layout) -> Result<*mut u8, AllocErr> {
heap::Heap.alloc_zeroed(layout)
}
#[inline]
unsafe fn alloc_excess(&mut self, layout: Layout) -> Result<Excess, AllocErr> {
heap::Heap.alloc_excess(layout)
}
#[inline]
unsafe fn realloc_excess(&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout) -> Result<Excess, AllocErr>
{
heap::Heap.realloc_excess(ptr, layout, new_layout)
}
#[inline]
unsafe fn grow_in_place(&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout)
-> Result<(), CannotReallocInPlace>
{
heap::Heap.grow_in_place(ptr, layout, new_layout)
}
#[inline]
unsafe fn shrink_in_place(&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout) -> Result<(), CannotReallocInPlace>
{
heap::Heap.shrink_in_place(ptr, layout, new_layout)
}
}
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