README.md

wasm-java-easybind

wasm-java-easybind enables developers write Java programs with WebAssembly libraries easily. This library has APIs like JNA (Java Native Access).

Features

• Automatic mapping from Java to WebAssembly functions, with simple mappings for all primitive data types
• Automatic conversion between C and Java strings, with customizable encoding/decoding
• Structure and Union arguments/return values, by reference and by value
• By-reference (pointer-to-type) arguments
• Java array and NIO Buffer arguments (primitive types and pointers) as pointer-to-buffer
• Nested structures and arrays
• Wide (wchar_t-based) strings
• Customizable marshalling/unmarshalling (argument and return value conversions)
• Customizable mapping from Java method to native function name, and customizable invocation to simulate C preprocessor function macros
• Support for automatic Windows ASCII/UNICODE function mappings
• Type-safety for native pointers

Example

• Write C code and save it as 'hello.c'

#include <stdio.h>
#include <stdlib.h>

void hello(char *name) {
 	printf("Hello, %s!\n", name);
}

• Compile 'hello.c' to 'hello.wasm' with Emscripten on your shell

docker run -it --rm -v $(pwd):/src emscripten/emsdk:2.0.20 emcc --no-entry -s EXPORTED_FUNCTIONS="['_hello', '_malloc', '_free']" -s WASM=1 -o hello.wasm hello.c

• Write Java code and run it

import jp.hisano.wasm.easybind.Library;
import jp.hisano.wasm.easybind.Native;

public class HelloMain {
	public static void main(String[] args) {
		Hello library = Native.load("hello.wasm", Hello.class);
		library.hello("World");
	}

	public interface Hello extends Library {
		void hello(String name);
	}
}

License

This library is licensed under the Apache Software License.