From 8adce672578683dcc7ab62e5492e0f5dbc07a0b4 Mon Sep 17 00:00:00 2001
From: Henry Gressmann <mail@henrygressmann.de>
Date: Fri, 26 Jan 2024 18:03:59 +0100
Subject: docs: string example

Signed-off-by: Henry Gressmann <mail@henrygressmann.de>
---
 examples/wasm-rust.rs | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

(limited to 'examples/wasm-rust.rs')

diff --git a/examples/wasm-rust.rs b/examples/wasm-rust.rs
index 3b26863..6580bd5 100644
--- a/examples/wasm-rust.rs
+++ b/examples/wasm-rust.rs
@@ -7,12 +7,15 @@ fn main() -> Result<()> {
         println!("Usage: cargo run --example wasm-rust <rust_example>");
         println!("Available examples:");
         println!("  hello");
-        println!("  tinywasm");
+        println!("  printi32");
+        println!("  fibonacci - calculate fibonacci(30)");
+        println!("  tinywasm - run printi32 inside of tinywasm inside of itself");
         return Ok(());
     }
 
     match args[1].as_str() {
         "hello" => hello()?,
+        "printi32" => printi32()?,
         "fibonacci" => fibonacci()?,
         "tinywasm" => tinywasm()?,
         _ => {}
@@ -48,6 +51,36 @@ fn hello() -> Result<()> {
     let module = Module::parse_bytes(&HELLO_WASM)?;
     let mut store = Store::default();
 
+    let mut imports = Imports::new();
+    imports.define(
+        "env",
+        "print_utf8",
+        Extern::typed_func(|mut ctx: FuncContext<'_>, args: (i32, i32)| {
+            let mem = ctx.memory("memory")?;
+            let ptr = args.1 as usize;
+            let len = args.0 as usize;
+            let string = mem.load_string(ptr, len)?;
+            println!("{}", string);
+            Ok(())
+        }),
+    )?;
+
+    let instance = module.instantiate(&mut store, Some(imports))?;
+    let arg_ptr = instance.exported_func::<(), i32>(&mut store, "arg_ptr")?.call(&mut store, ())?;
+    let arg = b"world";
+
+    instance.exported_memory(&mut store, "memory")?.store(arg_ptr as usize, arg.len(), arg)?;
+    let hello = instance.exported_func::<i32, ()>(&mut store, "hello")?;
+    hello.call(&mut store, arg.len() as i32)?;
+
+    Ok(())
+}
+
+fn printi32() -> Result<()> {
+    const HELLO_WASM: &[u8] = include_bytes!("./rust/out/print.wasm");
+    let module = Module::parse_bytes(&HELLO_WASM)?;
+    let mut store = Store::default();
+
     let mut imports = Imports::new();
     imports.define(
         "env",
-- 
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