WAZM

A wrapper and accompanying preamble for emscripten's emcc. Meant for code doing computation only. If you're accessing the filesystem or doing some kind of IO, this module is not for you (you should use the regular emscripten preamble). If you are doing cryptography or some other form of pure computation, this module might suit you.

Example

Build file:

{
  "output": "keccak",
  "input": [
    "src/keccak.c"
  ],
  "exports": [
    "keccak_init",
    "keccak_update",
    "keccak_final",
    "keccak_digest"
  ],
  "memory": {
    "total": 3,
    "stack": 1,
    "max": null,
    "grow": false
  },
  "base64": true,
  "wat": true,
  "args": [
    "-O2"
  ]
}

On the command line:

$ ls
./  ../  src/  build.json
$ wazm ./build.json
...
$ ls
./  ../  src/  build.json  keccak.wasm  keccak.wasm.js  keccak.wat

Usage:

const WASM = require('wazm');
const wasm = new WASM(require('./keccak.wasm.js'));

const data = Buffer.alloc(100, 0xaa); // Our data to hash with SHA-3.

const save = wasm.save(); // Save the stack pointer.
const out = wasm.alloc(32); // Allocate a buffer for the output.

wasm.call('keccak_digest', out, data, data.length, 32, 0x06);

const result = wasm.read(out, 32); // Read the output.

wasm.restore(save); // Restore the stack pointer.

console.log(result.toString('hex')); // Print our SHA-3 hash.

Contribution and License Agreement

If you contribute code to this project, you are implicitly allowing your code to be distributed under the MIT license. You are also implicitly verifying that all code is your original work. </legalese>

License

• Copyright (c) 2019, Christopher Jeffrey (MIT License).

See LICENSE for more info.