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