1 use crate::alloc::{GlobalAlloc, Layout, System};
3 use crate::sys_common::alloc::{MIN_ALIGN, realloc_fallback};
6 struct Header(*mut u8);
8 unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
9 &mut *(ptr as *mut Header).offset(-1)
12 unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
13 let aligned = ptr.add(align - (ptr as usize & (align - 1)));
14 *get_header(aligned) = Header(ptr);
19 unsafe fn allocate_with_flags(layout: Layout, flags: c::DWORD) -> *mut u8 {
20 if layout.align() <= MIN_ALIGN {
21 return c::HeapAlloc(c::GetProcessHeap(), flags, layout.size()) as *mut u8
24 let size = layout.size() + layout.align();
25 let ptr = c::HeapAlloc(c::GetProcessHeap(), flags, size);
29 align_ptr(ptr as *mut u8, layout.align())
33 #[stable(feature = "alloc_system_type", since = "1.28.0")]
34 unsafe impl GlobalAlloc for System {
36 unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
37 allocate_with_flags(layout, 0)
41 unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
42 allocate_with_flags(layout, c::HEAP_ZERO_MEMORY)
46 unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
47 if layout.align() <= MIN_ALIGN {
48 let err = c::HeapFree(c::GetProcessHeap(), 0, ptr as c::LPVOID);
49 debug_assert!(err != 0, "Failed to free heap memory: {}",
52 let header = get_header(ptr);
53 let err = c::HeapFree(c::GetProcessHeap(), 0, header.0 as c::LPVOID);
54 debug_assert!(err != 0, "Failed to free heap memory: {}",
60 unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
61 if layout.align() <= MIN_ALIGN {
62 c::HeapReAlloc(c::GetProcessHeap(), 0, ptr as c::LPVOID, new_size) as *mut u8
64 realloc_fallback(self, ptr, layout, new_size)