[JavaScript] Simple SHA256 implementation with TypedArray

main.js

#!/usr/bin/env node
"use strict";

const fs = require("fs");
const Hash = require(".");
function main() {
    if (process.argv[2] === "-c") {
        const names = process.argv.slice(3);
        check(names).then(({fails, sumerror}) => {
            if (fails > 0) {
                console.error(`${process.argv[1]}: WARNING: ${fails
                  } computed checksum${fails > 1 ? "s" : ""} did NOT match`);
            }
            process.exit(fails > 0 || sumerror > 0 ? 1 : 0);
        }).catch(err => {
            console.error(err);
            process.exit(1);
        });
    } else {
        const names = process.argv.slice(2);
        generate(names).then(_ => process.exit(0)).catch(err => {
            console.error(err);
            process.exit(1);
        });
    }
}
main();

function digestFile(name) {
    return new Promise((resolve, reject) => {
        const h = new Hash(), bufsize = 64 * 1024;
        const rs = fs.createReadStream(name);
        rs.on("readable", _ => {
            let chunk;
            while ((chunk = rs.read(bufsize)) !== null) {
                h.update(chunk);
            }
        });
        rs.on("end", _ => {
            resolve(Buffer.from(h.digest()));
        });
        rs.on("error", error => {
            reject(error);
        });
    });
}

async function generate(names) {
    for (const name of names) {
        const digest = await digestFile(name);
        console.log(`${digest.toString("hex")} ${name}`);        
    }
}
async function check(names) {
    let fails = 0, sumerror = 0;
    for (const name of names) {
        try {
            const r = await checkFile(name);
            fails += r.fails;
        } catch (err) {
            sumerror++;
            console.error(`${process.argv[1]}: ${name
              }: No such file or directory`);
        }
    }
    return {fails, sumerror};
}
async function checkFile(name) {
    const sumReg = /^\s*([\da-fA-F]{64})[\t ][ ]?(.+)$/;
    let fails = 0;
    for (const sum of fs.readFileSync(name, "utf8").split(/\n/)) {
        const match = sum.match(sumReg);
        if (!match) continue;
        const expected = Buffer.from(match[1], "hex");
        try {
            const digest = await digestFile(match[2]);
            if (digest.compare(expected) === 0) {
                console.log(`${match[2]}: OK`);
            } else {
                fails++;
                console.log(`${match[2]}: FAILED`);
            }
        } catch (err) {
            fails++;
            console.log(`${match[2]}: FAILED open or read`);            
        }
    }
    return {fails};
}

package.json

{"name": "sha256", "version": "1.0.0", "main": "sha256.js", "bin": "main.js"}

sha256.js

"use strict";

// see: https://en.wikipedia.org/wiki/SHA-2#Pseudocode
const K = Uint32Array.from([
    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
    0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
    0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
    0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
    0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
    0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
    0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
    0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
]);
const H = Uint32Array.from([
    0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
    0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19,
]);

class sha256 {
    constructor() {
        this.hv = H.slice();
        this.total = 0;
        this.chunk = new Uint8Array(64);
        this.filled = 0;
    }
    update(buffer) {
        let {filled} = this;
        if (filled < 0) return this;
        const {hv, chunk} = this;
        const buf = new Uint8Array(buffer);
        const bytes = buf.byteLength;
        let offs = 0;
        for (let next = 64 - filled; next <= bytes; next += 64) {
            chunk.set(buf.subarray(offs, next), filled);
            update(hv, chunk);
            filled = 0;
            offs = next;
        }
        chunk.set(buf.subarray(offs), filled);
        this.filled = filled + bytes - offs;
        this.total += bytes;
        return this;
    }
    digest() {
        if (this.filled >= 0) {
            last(this);
            this.filled = -1;
        }
        const digest = new DataView(new ArrayBuffer(32));
        this.hv.forEach((v, i) => {digest.setUint32(i * 4, v, false);});
        return digest.buffer;
    }
}

function rotr(v, n) {
    // note: `>>>` result casts unint32, e.g. -1 >>> 0 is UINT32_MAX 
    return ((v >>> n) | (v << (32 - n))) >>> 0;
}
function step(i, w, a, b, c, d, e, f, g, h) {
    if (i === 64) return [a, b, c, d, e, f, g, h];
    // t1 from e, f, g, h (and K[i], w[i])
    const s1 = (rotr(e, 6) ^ rotr(e, 11) ^ rotr(e, 25)) >>> 0;
    const ch = ((e & f) ^ ((~e >>> 0) & g)) >>> 0;
    const t1 = (h + s1 + ch + K[i] + w[i]) >>> 0;
    // t2 from a, b, c
    const s0 = (rotr(a, 2) ^ rotr(a, 13) ^ rotr(a, 22)) >>> 0;
    const maj = ((a & b) ^ (a & c) ^ (b & c)) >>> 0;
    const t2 = (s0 + maj) >>> 0;
    // rotating vars a,b,c,d,e,f,g,h with mixed d and h
    return step(i + 1, w, (t1 + t2) >>> 0, a, b, c, (d + t1) >>> 0, e, f, g);
}
function update(hv, chunk) {
    const w = new Uint32Array(64);
    const cd = new DataView(chunk.buffer, chunk.byteOffset, chunk.byteLength);
    for (let i = 0; i < 16; i++) {
        w[i] = cd.getUint32(i * 4, false);
    }
    for (let i = 16; i < 64; i++) {
        const w16 = w[i - 16], w15 = w[i - 15], w7 = w[i - 7], w2 = w[i - 2];
        const s0 = (rotr(w15, 7) ^ rotr(w15, 18) ^ (w15 >>> 3)) >>> 0;
        const s1 = (rotr(w2, 17) ^ rotr(w2, 19) ^ (w2 >>> 10)) >>> 0;
        w[i] = (w16 + s0 + w7 + s1) >>> 0;
    }
    // note: tailcall recursive function is faster than loop
    const data = step(0, w, ...hv);
    hv.set(hv.map((v, i) => (v + data[i]) >>> 0));
}
function last(ctx) {
    const {hv, total, chunk, filled} = ctx;
    chunk[filled] = 0x80;
    let start0 = filled + 1;
    if (start0 + 8 > 64) {
        chunk.fill(0, start0);
        update(hv, chunk);
        start0 = 0;
    }
    chunk.fill(0, start0, -8);
    
    const dv = new DataView(chunk.buffer, chunk.byteLength - 8);
    const b30 = 1 << 29; // note: bits is bytes * 8, lowwer use 29bit
    const low = total % b30;
    const high = (total - low) / b30;
    dv.setUint32(0, high, false);
    dv.setUint32(4, (low << 3) >>> 0, false);
    update(hv, chunk);        
}


if (typeof require === "function" && require.main === module) {
    const fs = require("fs");
    const digestFile = name => new Promise((resolve, reject) => {
        //const hash = require("crypto").createHash("sha256");
        const hash = new sha256();
        const rs = fs.createReadStream(name);
        rs.on("readable", _ => {
            const buf = rs.read();
            if (buf) hash.update(buf);
        });
        rs.on("end", () => {resolve(hash.digest());});
        rs.on("error", error => {reject(error);});
    });
    
    const names = process.argv.slice(process.argv[0].includes("node") ? 2 : 1);
    (async function () {
        for (const name of names) {
            const hex = Buffer.from(await digestFile(name)).toString("hex");
            console.log(`${hex}  ${name}`);
        }
    })().catch(console.log);
} else if (typeof module !== "undefined") {
    module.exports = sha256;
}

sha256constants.js

"use strict";

function fractop32(v) {
    const [b0, b1, b2, b3, b4, b5, b6, b7] =
          new Uint8Array(Float64Array.of(v).buffer);
    const e = (((b7 & 0x7f) << 4) | (b6 >> 4)) - 1023;
    const upper = (((b6 & 0x0f) << 28) | (b5 << 20) | (b4 << 12) |
                   (b3 << 4) | (b2 >>> 4)) >>> 0;
    const lower = ((b2 & 0x0f) << 16) | (b1 << 8) | b0;
    if (e < 0) return (((1 << 31) >>> (-e - 1)) | (upper >>> -e)) >>> 0;
    return ((upper << e) | (lower >>> (20 - e))) >>> 0;
}

function primes(len) {
    const ps = [2];
    for (let n = 3; ps.length < len; n += 2) {
        if (ps.every(p => n % p !== 0)) ps.push(n);
    }
    return ps.slice(0, len);
}

// constants of SHA-256 as https://en.wikipedia.org/wiki/SHA-2#Pseudocode
const K = Uint32Array.from(primes(64), p => fractop32(Math.cbrt(p)));
const H = Uint32Array.from(primes(8), p => fractop32(Math.sqrt(p)));
console.log("K", Array.from(K, n => `0x${n.toString(16).padStart(8, "0")}`));
console.log("H", Array.from(H, n => `0x${n.toString(16).padStart(8, "0")}`));

with npx:

$ npx https://gist.github.com/bellbind/1cfcc96514099fcebd455259b7249525 /bin/bash | tee sum
295fbc2356e8605e804f95cb6d6f992335e247dbf11767fe8781e2a7f889978a /bin/bash
$ npx https://gist.github.com/bellbind/1cfcc96514099fcebd455259b7249525 -c sum
/bin/bash: OK