89 lines
2.5 KiB
Rust
89 lines
2.5 KiB
Rust
#[repr(C)]
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pub struct BlobVec {
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pub data: *mut u8,
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pub len: usize,
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pub cap: usize,
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pub elem_size: usize,
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pub drop: Option<extern "C" fn(*mut u8)>,
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}
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#[unsafe(no_mangle)]
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extern "C" fn panic() -> ! {
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panic!("Called panic from external code.");
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}
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unsafe impl Send for BlobVec {}
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unsafe impl Sync for BlobVec {}
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unsafe extern "C" {
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unsafe fn vec_init(vec: *mut BlobVec, elem_size: usize, drop: Option<extern "C" fn(*mut u8)>);
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unsafe fn vec_push(vec: *mut BlobVec, elem: *const u8, size: usize);
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unsafe fn vec_pop(vec: *mut BlobVec);
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unsafe fn vec_get(vec: *mut BlobVec, index: usize) -> *mut u8;
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#[allow(dead_code)]
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unsafe fn vec_remove(vec: *mut BlobVec, index: usize);
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#[allow(dead_code)]
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unsafe fn vec_drop(vec: *mut BlobVec);
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}
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fn main() {
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static mut DROPS: usize = 1;
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fn get_drops() -> usize {
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unsafe { (&raw const DROPS).read() }
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}
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unsafe fn update_drops(f: impl FnOnce(&mut usize)) {
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unsafe {
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let drops = &raw mut DROPS;
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f(&mut *drops);
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}
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}
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let mut vec = BlobVec {
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data: core::ptr::null_mut(),
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len: 0,
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cap: 0,
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elem_size: 1,
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drop: None,
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};
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fn as_slice<T>(vec: &BlobVec) -> &[T] {
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assert_eq!(vec.elem_size, core::mem::size_of::<T>());
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unsafe { core::slice::from_raw_parts(vec.data as *const T, vec.len) }
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}
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extern "C" fn drop(ptr: *mut u8) {
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unsafe {
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update_drops(|drops| {
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*drops *= ptr.cast::<u32>().read() as usize;
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});
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}
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}
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unsafe {
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vec_init(&mut vec, 4, Some(drop));
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let mut value: u32 = 2;
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assert_eq!(vec.len, 0);
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vec_push(&mut vec, &value as *const u32 as *const u8, 4);
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assert_eq!(vec.len, 1);
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assert_eq!(as_slice::<u32>(&vec), &[2]);
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let retrieved = *(vec_get(&mut vec, 0) as *mut u32);
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assert_eq!(retrieved, 2);
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assert_eq!(get_drops(), 1);
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vec_pop(&mut vec);
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assert_eq!(vec.len, 0);
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assert_eq!(get_drops(), 2);
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value = 3;
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vec_push(&mut vec, &value as *const u32 as *const u8, 4);
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assert_eq!(as_slice::<u32>(&vec), &[3]);
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value = 5;
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vec_push(&mut vec, &value as *const u32 as *const u8, 4);
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assert_eq!(as_slice::<u32>(&vec), &[3, 5]);
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assert_eq!(vec.len, 2);
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vec_pop(&mut vec);
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vec_pop(&mut vec);
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assert_eq!(get_drops(), 2 * 3 * 5);
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eprintln!("Push/pop test passed\n");
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}
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}
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