67 lines
1.8 KiB
Rust
67 lines
1.8 KiB
Rust
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use wasmi::{
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Error as InterpreterError, Externals, FuncInstance, FuncRef, HostError, ImportsBuilder,
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ModuleImportResolver, ModuleInstance, ModuleRef, RuntimeArgs, RuntimeValue, Signature, Trap,
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ValueType,
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};
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use crate::{print, println};
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pub fn run() {
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use alloc::vec::Vec;
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let bytes = include_bytes!("../../data/h.wasm");
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let b: Vec<u8> = bytes.iter().cloned().collect();
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println!("loaded wasm into a Vec");
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let module = wasmi::Module::from_buffer(&b).unwrap();
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let mut imports = ImportsBuilder::new();
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imports.push_resolver("h", &H);
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let instance = ModuleInstance::new(&module, &imports)
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.expect("failed to load wasm module")
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.assert_no_start();
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println!("invoking export");
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let _ = instance.invoke_export("h", &[], &mut H);
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}
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struct H;
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const H_FUNC: usize = 0;
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impl Externals for H {
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fn invoke_index(
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&mut self,
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index: usize,
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args: RuntimeArgs,
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) -> Result<Option<RuntimeValue>, Trap> {
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use core::char::from_u32;
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match index {
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H_FUNC => {
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let ch_t: i32 = args.nth(0);
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let ch = from_u32(ch_t as u32);
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print!("{}", ch.unwrap());
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Ok(None)
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}
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_ => panic!("unknown function called"),
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}
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}
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}
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impl ModuleImportResolver for H {
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fn resolve_func(
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&self,
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field_name: &str,
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_signature: &Signature,
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) -> Result<FuncRef, InterpreterError> {
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let func_ref = match field_name {
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"h" => FuncInstance::alloc_host(
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Signature::new(&[ValueType::I32][..], None),
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H_FUNC,
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),
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_ => panic!("unknwon function asked for"),
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};
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Ok(func_ref)
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}
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}
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