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// FORK NOTE: Copied from liballoc_system, removed unnecessary APIs,
// APIs take size/align directly instead of Layout
// The minimum alignment guaranteed by the architecture. This value is used to
// add fast paths for low alignment values. In practice, the alignment is a
// constant at the call site and the branch will be optimized out.
#[cfg(all(any(
target_arch = "x86",
target_arch = "arm",
target_arch = "mips",
target_arch = "powerpc",
target_arch = "powerpc64",
target_arch = "asmjs",
target_arch = "wasm32"
)))]
const MIN_ALIGN: usize = 8;
#[cfg(all(any(
target_arch = "x86_64",
target_arch = "aarch64",
target_arch = "mips64",
target_arch = "s390x",
target_arch = "sparc64"
)))]
const MIN_ALIGN: usize = 16;
pub use self::platform::{alloc, dealloc, realloc};
#[cfg(any(unix, target_os = "redox"))]
mod platform {
extern crate libc;
#[cfg(not(any(target_os = "android")))]
use std::ptr;
use super::MIN_ALIGN;
#[inline]
pub unsafe fn alloc(size: usize, align: usize) -> *mut u8 {
let ptr = if align <= MIN_ALIGN {
libc::malloc(size) as *mut u8
} else {
aligned_malloc(size, align)
};
ptr
}
#[inline]
pub unsafe fn dealloc(ptr: *mut u8, _align: usize) {
libc::free(ptr as *mut libc::c_void)
}
#[inline]
pub unsafe fn realloc(ptr: *mut u8, new_size: usize) -> *mut u8 {
libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8
}
#[cfg(any(target_os = "android", target_os = "redox"))]
#[inline]
unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
// On android we currently target API level 9 which unfortunately
// doesn't have the `posix_memalign` API used below. Instead we use
// `memalign`, but this unfortunately has the property on some systems
// where the memory returned cannot be deallocated by `free`!
//
// Upon closer inspection, however, this appears to work just fine with
// Android, so for this platform we should be fine to call `memalign`
// (which is present in API level 9). Some helpful references could
// possibly be chromium using memalign [1], attempts at documenting that
// memalign + free is ok [2] [3], or the current source of chromium
// which still uses memalign on android [4].
//
// [1]: https://codereview.chromium.org/10796020/
// [2]: https://code.google.com/p/android/issues/detail?id=35391
// [3]: https://bugs.chromium.org/p/chromium/issues/detail?id=138579
// [4]: https://chromium.googlesource.com/chromium/src/base/+/master/
// /memory/aligned_memory.cc
libc::memalign(align, size) as *mut u8
}
#[cfg(not(any(target_os = "android", target_os = "redox")))]
#[inline]
unsafe fn aligned_malloc(size: usize, align: usize) -> *mut u8 {
let mut out = ptr::null_mut();
let ret = libc::posix_memalign(&mut out, align, size);
if ret != 0 {
ptr::null_mut()
} else {
out as *mut u8
}
}
}
#[cfg(windows)]
#[allow(bad_style)]
mod platform {
use super::MIN_ALIGN;
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);
unsafe fn get_header<'a>(ptr: *mut u8) -> &'a mut Header {
&mut *(ptr as *mut Header).offset(-1)
}
unsafe fn align_ptr(ptr: *mut u8, align: usize) -> *mut u8 {
let aligned = ptr.offset((align - (ptr as usize & (align - 1))) as isize);
*get_header(aligned) = Header(ptr);
aligned
}
#[inline]
unsafe fn allocate_with_flags(size: usize, align: usize, flags: DWORD) -> *mut u8 {
if align <= MIN_ALIGN {
HeapAlloc(GetProcessHeap(), flags, size)
} else {
let size = size + align;
let ptr = HeapAlloc(GetProcessHeap(), flags, size);
if ptr.is_null() {
ptr
} else {
align_ptr(ptr, align)
}
}
}
#[inline]
pub unsafe fn alloc(size: usize, align: usize) -> *mut u8 {
allocate_with_flags(size, align, 0)
}
#[inline]
pub unsafe fn dealloc(ptr: *mut u8, align: usize) {
if align <= MIN_ALIGN {
let err = HeapFree(GetProcessHeap(), 0, ptr as LPVOID);
debug_assert!(err != 0, "Failed to free heap memory: {}", GetLastError());
} else {
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]
pub unsafe fn realloc(ptr: *mut u8, new_size: usize) -> *mut u8 {
HeapReAlloc(GetProcessHeap(), 0, ptr as LPVOID, new_size) as *mut u8
}
}
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