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// SPDX-License-Identifier: MIT OR Apache-2.0
// SPDX-FileCopyrightText: The Rust Project Developers (see https://thanks.rust-lang.org)
#![no_std]
pub struct System;
#[cfg(any(windows, unix, target_os = "redox"))]
mod realloc_fallback {
use core::alloc::{GlobalAlloc, Layout};
use core::cmp;
use core::ptr;
impl super::System {
pub(crate) unsafe fn realloc_fallback(
&self,
ptr: *mut u8,
old_layout: Layout,
new_size: usize,
) -> *mut u8 {
// Docs for GlobalAlloc::realloc require this to be valid:
let new_layout = Layout::from_size_align_unchecked(new_size, old_layout.align());
let new_ptr = GlobalAlloc::alloc(self, new_layout);
if !new_ptr.is_null() {
let size = cmp::min(old_layout.size(), new_size);
ptr::copy_nonoverlapping(ptr, new_ptr, size);
GlobalAlloc::dealloc(self, ptr, old_layout);
}
new_ptr
}
}
}
#[cfg(any(unix, target_os = "redox"))]
mod platform {
use core::alloc::{GlobalAlloc, Layout};
use core::ffi::c_void;
use core::ptr;
use System;
extern "C" {
fn posix_memalign(memptr: *mut *mut c_void, align: usize, size: usize) -> i32;
fn free(p: *mut c_void);
}
unsafe impl GlobalAlloc for System {
#[inline]
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
aligned_malloc(&layout)
}
#[inline]
unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
let ptr = self.alloc(layout.clone());
if !ptr.is_null() {
ptr::write_bytes(ptr, 0, layout.size());
}
ptr
}
#[inline]
unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
free(ptr as *mut c_void)
}
#[inline]
unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
self.realloc_fallback(ptr, layout, new_size)
}
}
unsafe fn aligned_malloc(layout: &Layout) -> *mut u8 {
let mut out = ptr::null_mut();
let ret = posix_memalign(&mut out, layout.align(), layout.size());
if ret != 0 { ptr::null_mut() } else { out as *mut u8 }
}
}
#[cfg(windows)]
#[allow(nonstandard_style)]
mod platform {
use core::alloc::{GlobalAlloc, Layout};
use System;
type LPVOID = *mut u8;
type HANDLE = LPVOID;
type SIZE_T = usize;
type DWORD = u32;
type BOOL = i32;
extern "system" {
fn GetProcessHeap() -> HANDLE;
fn HeapAlloc(hHeap: HANDLE, dwFlags: DWORD, dwBytes: SIZE_T) -> LPVOID;
fn HeapReAlloc(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID, dwBytes: SIZE_T) -> LPVOID;
fn HeapFree(hHeap: HANDLE, dwFlags: DWORD, lpMem: LPVOID) -> BOOL;
fn GetLastError() -> DWORD;
}
#[repr(C)]
struct Header(*mut u8);
const HEAP_ZERO_MEMORY: DWORD = 0x00000008;
unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
&mut *(ptr as *mut Header).sub(1)
}
unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
let aligned = ptr.add(align - (ptr as usize & (align - 1)));
*get_header(aligned) = Header(ptr);
aligned
}
#[inline]
unsafe fn allocate_with_flags(layout: Layout, flags: DWORD) -> *mut u8 {
let size = layout.size() + layout.align();
let ptr = HeapAlloc(GetProcessHeap(), flags, size);
(if ptr.is_null() { ptr } else { align_ptr(ptr, layout.align()) }) as *mut u8
}
unsafe impl GlobalAlloc for System {
#[inline]
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
allocate_with_flags(layout, 0)
}
#[inline]
unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
allocate_with_flags(layout, HEAP_ZERO_MEMORY)
}
#[inline]
unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
let header = get_header(ptr);
let err = HeapFree(GetProcessHeap(), 0, header.0 as LPVOID);
debug_assert!(err != 0, "Failed to free heap memory: {}", GetLastError());
}
#[inline]
unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
self.realloc_fallback(ptr, layout, new_size)
}
}
}
|
