Tiny Typescript implementation of Sha1

Sha1.ts

/**
 * // hash content
 * // content must be an uint8 typed array
 * const hash = new Sha1();
 * hash.update(content)
 * // get digest as uint8 typed array
 * const digest = hash.digest();
 * // or get digest as hex string
 * const hex = hash.hexDigest();
 */

const EXTRA = [-2147483648, 8388608, 32768, 128];

const SHIFT = [24, 16, 8, 0];

export class Sha1 {

  public start = 0;
  public bytes = 0;
  public hBytes = 0;

  public finalized = false;
  public hashed = false;

  public lastByteIndex: number;
  
  public block = 0;
  public blocks = new Array(17).fill(0);

  public h = new Uint32Array([0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0]);

  public hash() {
    let a = this.h[0];
    let b = this.h[1];
    let c = this.h[2];
    let d = this.h[3];
    let e = this.h[4];
    var f, j, t, blocks = this.blocks;

    for (j = 16; j < 80; ++j) {
      t = blocks[j - 3] ^ blocks[j - 8] ^ blocks[j - 14] ^ blocks[j - 16];
      blocks[j] =  (t << 1) | (t >>> 31);
    }

    for (j = 0; j < 20; j += 5) {
      f = (b & c) | ((~b) & d);
      t = (a << 5) | (a >>> 27);
      e = t + f + e + 1518500249 + blocks[j] << 0;
      b = (b << 30) | (b >>> 2);

      f = (a & b) | ((~a) & c);
      t = (e << 5) | (e >>> 27);
      d = t + f + d + 1518500249 + blocks[j + 1] << 0;
      a = (a << 30) | (a >>> 2);

      f = (e & a) | ((~e) & b);
      t = (d << 5) | (d >>> 27);
      c = t + f + c + 1518500249 + blocks[j + 2] << 0;
      e = (e << 30) | (e >>> 2);

      f = (d & e) | ((~d) & a);
      t = (c << 5) | (c >>> 27);
      b = t + f + b + 1518500249 + blocks[j + 3] << 0;
      d = (d << 30) | (d >>> 2);

      f = (c & d) | ((~c) & e);
      t = (b << 5) | (b >>> 27);
      a = t + f + a + 1518500249 + blocks[j + 4] << 0;
      c = (c << 30) | (c >>> 2);
    }

    for (; j < 40; j += 5) {
      f = b ^ c ^ d;
      t = (a << 5) | (a >>> 27);
      e = t + f + e + 1859775393 + blocks[j] << 0;
      b = (b << 30) | (b >>> 2);

      f = a ^ b ^ c;
      t = (e << 5) | (e >>> 27);
      d = t + f + d + 1859775393 + blocks[j + 1] << 0;
      a = (a << 30) | (a >>> 2);

      f = e ^ a ^ b;
      t = (d << 5) | (d >>> 27);
      c = t + f + c + 1859775393 + blocks[j + 2] << 0;
      e = (e << 30) | (e >>> 2);

      f = d ^ e ^ a;
      t = (c << 5) | (c >>> 27);
      b = t + f + b + 1859775393 + blocks[j + 3] << 0;
      d = (d << 30) | (d >>> 2);

      f = c ^ d ^ e;
      t = (b << 5) | (b >>> 27);
      a = t + f + a + 1859775393 + blocks[j + 4] << 0;
      c = (c << 30) | (c >>> 2);
    }

    for (; j < 60; j += 5) {
      f = (b & c) | (b & d) | (c & d);
      t = (a << 5) | (a >>> 27);
      e = t + f + e - 1894007588 + blocks[j] << 0;
      b = (b << 30) | (b >>> 2);

      f = (a & b) | (a & c) | (b & c);
      t = (e << 5) | (e >>> 27);
      d = t + f + d - 1894007588 + blocks[j + 1] << 0;
      a = (a << 30) | (a >>> 2);

      f = (e & a) | (e & b) | (a & b);
      t = (d << 5) | (d >>> 27);
      c = t + f + c - 1894007588 + blocks[j + 2] << 0;
      e = (e << 30) | (e >>> 2);

      f = (d & e) | (d & a) | (e & a);
      t = (c << 5) | (c >>> 27);
      b = t + f + b - 1894007588 + blocks[j + 3] << 0;
      d = (d << 30) | (d >>> 2);

      f = (c & d) | (c & e) | (d & e);
      t = (b << 5) | (b >>> 27);
      a = t + f + a - 1894007588 + blocks[j + 4] << 0;
      c = (c << 30) | (c >>> 2);
    }

    for (; j < 80; j += 5) {
      f = b ^ c ^ d;
      t = (a << 5) | (a >>> 27);
      e = t + f + e - 899497514 + blocks[j] << 0;
      b = (b << 30) | (b >>> 2);

      f = a ^ b ^ c;
      t = (e << 5) | (e >>> 27);
      d = t + f + d - 899497514 + blocks[j + 1] << 0;
      a = (a << 30) | (a >>> 2);

      f = e ^ a ^ b;
      t = (d << 5) | (d >>> 27);
      c = t + f + c - 899497514 + blocks[j + 2] << 0;
      e = (e << 30) | (e >>> 2);

      f = d ^ e ^ a;
      t = (c << 5) | (c >>> 27);
      b = t + f + b - 899497514 + blocks[j + 3] << 0;
      d = (d << 30) | (d >>> 2);

      f = c ^ d ^ e;
      t = (b << 5) | (b >>> 27);
      a = t + f + a - 899497514 + blocks[j + 4] << 0;
      c = (c << 30) | (c >>> 2);
    }

    this.h[0] += a;
    this.h[1] += b;
    this.h[2] += c;
    this.h[3] += d;
    this.h[4] += e;
  }

  public update(bytes: Uint8Array) {
    if (this.finalized) {
      return;
    }

    const nBytes = bytes.length;
    const blocks = this.blocks;
    let ptr = 0;
    let i = 0;

    while (ptr < nBytes) {
      if (this.hashed) {
        this.hashed = false;
        blocks[0] = this.block;
        blocks.fill(0);
      }

      for (i = this.start; ptr < nBytes && i < 64; ++ptr) {
        blocks[i >> 2] |= bytes[ptr] << SHIFT[i++ & 3];
      }

      this.lastByteIndex = i;
      this.bytes += i - this.start;
      if (i >= 64) {
        this.block = blocks[16];
        this.start = i - 64;
        this.hash();
        this.hashed = true;
      } else {
        this.start = i;
      }
    }

    if (this.bytes > 4294967295) {
      this.hBytes += this.bytes / 4294967296 << 0;
      this.bytes = this.bytes % 4294967296;
    }

    return this;
  }

  public finalize() {
    if (this.finalized) {
      return;
    }
    this.finalized = true;
    var blocks = this.blocks, i = this.lastByteIndex;
    blocks[16] = this.block;
    blocks[i >> 2] |= EXTRA[i & 3];
    this.block = blocks[16];
    if (i >= 56) {
      if (!this.hashed) {
        this.hash();
      }
      blocks[0] = this.block;
      blocks.fill(0);
    }
    blocks[14] = this.hBytes << 3 | this.bytes >>> 29;
    blocks[15] = this.bytes << 3;
    this.hash();
  }

  public digest() {
    this.finalize();
    const b = new Uint8Array(this.h.byteLength);
    for (let i = 0, ptr = 0; i < this.h.length; i++, ptr += 4) {
      const chunk = this.h[i];
      b[ptr + 0] = (chunk >> 24) & 0xff;
      b[ptr + 1] = (chunk >> 16) & 0xff;
      b[ptr + 2] = (chunk >> 8) & 0xff;
      b[ptr + 3] = chunk & 0xff;
    }
    return b;
  }

  public hexDigest() {
    this.finalize();
    return this.h.reduce((hex, chunk) => hex + chunk.toString(16).padStart(8, '0'), '')
  }

  public toString() {
    return this.hexDigest();
  }
}