1use serde::de::DeserializeOwned;
2use serde::Serialize;
3use serde_cbor::{from_slice, to_vec};
4use std::convert::TryInto;
5use std::mem;
6use std::mem::ManuallyDrop;
7use std::slice;
8
9pub type Pointer = *const u8;
10pub const LENGTH_BYTE_COUNT: isize = 4;
11
12pub unsafe fn free(ptr: *mut u8) {
13 let length = ptr_to_u32(ptr) as usize;
14 Vec::from_raw_parts(ptr.offset(LENGTH_BYTE_COUNT), length, length);
15}
16
17pub fn ptr_to_u32(ptr: *const u8) -> u32 {
18 let length_slice = unsafe { slice::from_raw_parts(ptr, LENGTH_BYTE_COUNT as usize) };
19 u32::from_le_bytes(length_slice.try_into().unwrap())
20}
21
22pub fn malloc(size: usize) -> *mut u8 {
23 ptr_from_vec(Vec::with_capacity(size))
24}
25#[inline]
26pub fn ptr_from_vec(mut buf: Vec<u8>) -> *mut u8 {
27 let ptr = buf.as_mut_ptr();
28 mem::forget(buf);
29
30 ptr
31}
32
33pub fn to_value<T: DeserializeOwned>(ptr: Pointer) -> Result<T, serde_cbor::Error> {
34 from_slice::<T>(to_bytes(ptr))
35}
36
37pub fn to_bytes<'a>(ptr: Pointer) -> &'a [u8] {
38 let length = ptr_to_u32(ptr) as usize;
39 unsafe { slice::from_raw_parts(ptr.offset(LENGTH_BYTE_COUNT), length) }
40}
41
42pub fn from_value<V: Serialize>(value: &V) -> Pointer {
43 from_bytes(&to_vec(&value).unwrap())
44}
45
46pub fn from_bytes(bytes: &[u8]) -> Pointer {
47 let value_and_length = [&(bytes.len() as i32).to_le_bytes()[..], bytes].concat();
48 ManuallyDrop::new(value_and_length).as_mut_ptr()
49}