1 use crate::alloc::{GlobalAlloc, Layout, System};
3 use crate::sys_common::alloc::{realloc_fallback, MIN_ALIGN};
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);
26 if ptr.is_null() { ptr as *mut u8 } else { align_ptr(ptr as *mut u8, layout.align()) }
29 #[stable(feature = "alloc_system_type", since = "1.28.0")]
30 unsafe impl GlobalAlloc for System {
32 unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
33 allocate_with_flags(layout, 0)
37 unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
38 allocate_with_flags(layout, c::HEAP_ZERO_MEMORY)
42 unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
43 if layout.align() <= MIN_ALIGN {
44 let err = c::HeapFree(c::GetProcessHeap(), 0, ptr as c::LPVOID);
45 debug_assert!(err != 0, "Failed to free heap memory: {}", c::GetLastError());
47 let header = get_header(ptr);
48 let err = c::HeapFree(c::GetProcessHeap(), 0, header.0 as c::LPVOID);
49 debug_assert!(err != 0, "Failed to free heap memory: {}", c::GetLastError());
54 unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
55 if layout.align() <= MIN_ALIGN {
56 c::HeapReAlloc(c::GetProcessHeap(), 0, ptr as c::LPVOID, new_size) as *mut u8
58 realloc_fallback(self, ptr, layout, new_size)