Files
nethack/sys/lib/npm-package/src/nethackShim.js
2020-08-30 12:00:39 -07:00

128 lines
4.3 KiB
JavaScript

const path = require("path");
let Module;
let userCallback;
let savedOnRuntimeInitialized;
function nethackStart(cb, inputModule = {}) {
console.log("cb is", cb);
if(typeof cb !== "function") throw new TypeError("expected first argument to be callback function");
if(typeof inputModule !== "object") throw new TypeError("expected second argument to be object");
// Emscripten Module config
Module = inputModule;
userCallback = cb;
savedOnRuntimeInitialized = Module.onRuntimeInitialized;
Module.onRuntimeInitialized = function (... args) {
// after the WASM is loaded, add the shim graphics callback function
let cb = Module.addFunction(windowCallback, "viiii");
Module.ccall(
"shim_graphics_set_callback", // C function name
null, // return type
["number"], // arg types
[cb], // arg values
{async: true} // options
);
/* TODO: Module.removeFunction() */
// if the user had their own onRuntimeInitialized(), call it now
if (savedOnRuntimeInitialized) savedOnRuntimeInitialized(... args);
};
// load and run the module
var factory = require(path.join(__dirname, "../build/nethack.js"));
factory(Module);
}
function windowCallback(name, retPtr, fmt, args) {
name = Module.UTF8ToString(name);
fmt = Module.UTF8ToString(fmt);
let argTypes = fmt.split("");
let retType = argTypes.shift();
// build array of JavaScript args from WASM parameters
let jsArgs = [];
for (let i = 0; i < argTypes.length; i++) {
let ptr = args + (4*i);
let val = typeLookup(argTypes[i], ptr);
jsArgs.push(val);
}
let retVal = userCallback(name, ... jsArgs);
setReturn(name, retPtr, retType, retVal);
}
function typeLookup(type, ptr) {
switch(type) {
case "s": // string
return Module.UTF8ToString(Module.getValue(ptr, "*"));
case "p": // pointer
ptr = Module.getValue(ptr, "*");
if(!ptr) return 0; // null pointer
return Module.getValue(ptr, "*");
case "c": // char
return String.fromCharCode(Module.getValue(Module.getValue(ptr, "*"), "i8"));
case "0": /* 2^0 = 1 byte */
return Module.getValue(Module.getValue(ptr, "*"), "i8");
case "1": /* 2^1 = 2 bytes */
return Module.getValue(Module.getValue(ptr, "*"), "i16");
case "2": /* 2^2 = 4 bytes */
case "i": // integer
case "n": // number
return Module.getValue(Module.getValue(ptr, "*"), "i32");
case "f": // float
return Module.getValue(Module.getValue(ptr, "*"), "float");
case "d": // double
return Module.getValue(Module.getValue(ptr, "*"), "double");
default:
throw new TypeError ("unknown type:" + type);
}
}
function setReturn(name, ptr, type, value = 0) {
switch (type) {
case "p":
throw new Error("not implemented");
case "s":
if(typeof value !== "string")
throw new TypeError(`expected ${name} return type to be string`);
value=value?value:"(no value)";
var strPtr = Module.getValue(ptr, "i32");
Module.stringToUTF8(value, strPtr, 1024);
break;
case "i":
if(typeof value !== "number" || !Number.isInteger(value))
throw new TypeError(`expected ${name} return type to be integer`);
Module.setValue(ptr, value, "i32");
break;
case "c":
if(typeof value !== "number" || value < 0 || value > 128)
throw new TypeError(`expected ${name} return type to be integer representing an ASCII character`);
Module.setValue(ptr, value, "i8");
break;
case "f":
if(typeof value !== "number" || isFloat(value))
throw new TypeError(`expected ${name} return type to be float`);
// XXX: I'm not sure why 'double' works and 'float' doesn't
Module.setValue(ptr, value, "double");
break;
case "d":
if(typeof value !== "number" || isFloat(value))
throw new TypeError(`expected ${name} return type to be float`);
Module.setValue(ptr, value, "double");
break;
case "v":
break;
default:
throw new Error("unknown type");
}
function isFloat(n){
return n === +n && n !== (n|0) && !Number.isInteger(n);
}
}
// TODO: ES6 'import' style module
module.exports = nethackStart;