55 lines
1.4 KiB
Rust
55 lines
1.4 KiB
Rust
#[no_mangle]
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pub unsafe fn malloc_1(len: usize) -> *mut u8 {
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let mut buffer: std::mem::ManuallyDrop<Vec<u8>> = std::mem::ManuallyDrop::new(Vec::with_capacity(len as usize));
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buffer.as_mut_ptr() as *mut u8
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}
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#[no_mangle]
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pub unsafe fn free_1(ptr: *mut u8, len: usize) {
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std::mem::drop(Vec::from_raw_parts(ptr as *mut u8, 0, len as usize))
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}
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#[no_mangle]
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pub unsafe fn malloc_2(len: usize) -> *mut u8 {
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let mut buf = Vec::with_capacity(len);
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let ptr = buf.as_mut_ptr();
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std::mem::forget(buf);
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return ptr;
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}
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#[no_mangle]
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pub unsafe fn free_2(ptr: *mut u8, len: usize) {
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let data = Vec::from_raw_parts(ptr, len, len);
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std::mem::drop(data);
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}
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#[no_mangle]
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pub unsafe fn malloc_3(len: usize) -> *mut u8 {
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let align = std::mem::align_of::<usize>();
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let layout = std::alloc::Layout::from_size_align_unchecked(len, align);
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std::alloc::alloc(layout)
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}
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#[no_mangle]
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pub unsafe fn free_3(ptr: *mut u8, len: usize) {
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let align = std::mem::align_of::<usize>();
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let layout = std::alloc::Layout::from_size_align_unchecked(len, align);
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std::alloc::dealloc(ptr, layout)
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}
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fn main() {
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unsafe {
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println!("Malloc & Free - 1");
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let p = malloc_1(1024);
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free_1(p, 1024);
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println!("Malloc & Free - 2");
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let p = malloc_2(1024);
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free_2(p, 1024);
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println!("Malloc & Free - 3");
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let p = malloc_3(1024);
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free_3(p, 1024);
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}
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}
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