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use std::fmt;
use wasmer::{Array, Memory, WasmPtr};
pub type AsmScriptStringPtr = WasmPtr<u16, Array>;
pub trait AsmScriptRead<T> {
fn read(self, memory: &Memory) -> Result<T, Error>;
fn size(offset: u32, memory: &Memory) -> Result<u32, Error>;
}
impl AsmScriptRead<String> for AsmScriptStringPtr {
fn read(self, memory: &Memory) -> Result<String, Error> {
let offset = self.offset();
let size = Self::size(offset, memory)?;
if let Some(buf) = self.deref(memory, 0, size / 2) {
let input: Vec<u16> = buf.iter().map(|b| b.get()).collect();
Ok(String::from_utf16_lossy(&input))
} else {
Err(Error::Mem("Wrong offset: can't read buf"))
}
}
fn size(offset: u32, memory: &Memory) -> Result<u32, Error> {
if offset < 4 {
return Err(Error::Mem("Wrong offset: less than 2"));
}
if let Some(cell) = memory.view::<u32>().get(offset as usize / (32 / 8) - 1) {
Ok(cell.get())
} else {
Err(Error::Mem("Wrong offset: can't read size"))
}
}
}
#[derive(Debug)]
pub enum Error {
Mem(&'static str),
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Error::Mem(err) => write!(f, "{}", err),
}
}
}
impl std::error::Error for Error {}