Files
simple-rust-tests/__wasm/wasmtime-serde-demo/crates/guest/src/lib.rs

61 lines
1.5 KiB
Rust

//! Simple library for serializing complex types to the wasmtime runtime using serde
pub use bincode::{deserialize, serialize};
pub use wasmtime_serde_guest_macro::*;
#[inline]
#[no_mangle]
pub extern "C" fn alloc(len: u32) -> *mut u8 {
let mut buf = Vec::with_capacity(len as _);
let ptr = buf.as_mut_ptr();
std::mem::forget(buf);
return ptr;
}
#[inline]
#[no_mangle]
pub unsafe extern "C" fn dealloc(value: u64) {
let (ptr, len) = from_bitwise(value);
let ptr = std::mem::transmute::<usize, *mut u8>(ptr as _);
let buffer = Vec::from_raw_parts(ptr, len as _, len as _);
std::mem::drop(buffer);
}
pub fn write_msg<T: serde::ser::Serialize>(value: &T) -> u64 {
let mut buffer = bincode::serialize(value).unwrap();
let len = buffer.len();
let ptr = buffer.as_mut_ptr();
std::mem::forget(buffer);
into_bitwise(ptr as _, len as _)
}
pub unsafe fn read_msg<T: serde::de::DeserializeOwned>(value: u64) -> T {
let (ptr, len) = from_bitwise(value);
let ptr = std::mem::transmute::<usize, *mut u8>(ptr as _);
let buffer = Vec::from_raw_parts(ptr, len as _, len as _);
bincode::deserialize(&buffer).unwrap()
}
#[inline(always)]
const fn from_bitwise(value: u64) -> (u32, u32) {
((value << 32 >> 32) as u32, (value >> 32) as u32)
}
#[inline(always)]
const fn into_bitwise(a: u32, b: u32) -> u64 {
(a as u64) | (b as u64) << 32
}
#[cfg(test)]
mod test {
use crate::*;
#[test]
fn bitwise() {
const DATA: (u32, u32) = (10, 20);
const INTO: u64 = into_bitwise(DATA.0, DATA.1);
const FROM: (u32, u32) = from_bitwise(INTO);
assert_eq!(DATA, FROM)
}
}