react-native-snarkjs/src/wtns_calculate.js

zkSNARKs implementation in JavaScript

/*
    Copyright 2018 0KIMS association.

    This file is part of snarkJS.

    snarkJS is a free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    snarkJS is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
    License for more details.

    You should have received a copy of the GNU General Public License
    along with snarkJS. If not, see <https://www.gnu.org/licenses/>.
*/

import * as fastFile from "fastfile";
import { WitnessCalculatorBuilder } from "react-native-circom_runtime";
import * as wtnsUtils from "./wtns_utils.js";
import * as binFileUtils from "react-native-binfileutils";

export default async function wtnsCalculate(input, wasmFileName, wtnsFileName, options) {


    console.log("wtnsCalculate")

    const wasmFileBuff = await get(wasmFileName).then( function(res) {
        return res
    }).then(function (ab) {
        return new Uint8Array(ab);
    }).catch(err => {
        console.log("err wtnsCalculate")
        console.log(err)
    });
    const o = {
        type: "mem",
        data: wasmFileBuff
    };
    const fdWasm = await fastFile.readExisting(o);
    const wasm = await fdWasm.read(fdWasm.totalSize);

    console.log("WitnessCalculatorBuilder start")
    const wc = await WitnessCalculatorBuilder(wasm);

    const w = await wc.calculateBinWitness(input);

    const fdWtns = await binFileUtils.createBinFile(wtnsFileName, "wtns", 2, 2);

    await wtnsUtils.writeBin(fdWtns, w, wc.prime);
    await fdWtns.close();

}

export function readExisting(o) {
    const fd = new MemFile();
    fd.o = o;
    fd.allocSize = o.data.byteLength;
    fd.totalSize = o.data.byteLength;
    fd.readOnly = true;
    fd.pos = 0;
    return fd;
}

export function get(url) {
    return new Promise((accept, reject) => {
        var req = new XMLHttpRequest();
        req.open("GET", url, true);
        req.responseType = "arraybuffer";

        req.onload = function(event) {
            var resp = req.response;
            if(resp) {
                accept(resp);
            }
        };

        req.send(null);
    });
}