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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// Copyright 2014-2017 browserify-aes contributors. All rights reserved. MIT license.// Copyright 2013 Maxwell Krohn. All rights reserved. MIT license.// Copyright 2009-2013 Jeff Mott. All rights reserved. MIT license.
// deno-lint-ignore-file no-var no-inner-declarations
import { Buffer } from "../../../buffer.ts";import * as aes from "./aes.js";import Transform from "../cipher_base.js";import { GHASH } from "./ghash.js";import { xor } from "./xor.ts";import { incr32 } from "./incr32.js";
function xorTest(a, b) {  var out = 0;  if (a.length !== b.length) out++;
  var len = Math.min(a.length, b.length);  for (var i = 0; i < len; ++i) {    out += a[i] ^ b[i];  }
  return out;}
function calcIv(self, iv, ck) {  if (iv.length === 12) {    self._finID = Buffer.concat([iv, Buffer.from([0, 0, 0, 1])]);    return Buffer.concat([iv, Buffer.from([0, 0, 0, 2])]);  }  var ghash = new GHASH(ck);  var len = iv.length;  var toPad = len % 16;  ghash.update(iv);  if (toPad) {    toPad = 16 - toPad;    ghash.update(Buffer.alloc(toPad, 0));  }  ghash.update(Buffer.alloc(8, 0));  var ivBits = len * 8;  var tail = Buffer.alloc(8);  // Fixed from the original  // https://github.com/crypto-browserify/browserify-aes/issues/58#issuecomment-451778917  tail.writeUIntBE(ivBits, 2, 6);  ghash.update(tail);  self._finID = ghash.state;  var out = Buffer.from(self._finID);  incr32(out);  return out;}export function StreamCipher(mode, key, iv, decrypt) {  Transform.call(this);
  var h = Buffer.alloc(4, 0);
  this._cipher = new aes.AES(key);  var ck = this._cipher.encryptBlock(h);  this._ghash = new GHASH(ck);  iv = calcIv(this, iv, ck);
  this._prev = Buffer.from(iv);  this._cache = Buffer.allocUnsafe(0);  this._secCache = Buffer.allocUnsafe(0);  this._decrypt = decrypt;  this._alen = 0;  this._len = 0;  this._mode = mode;
  this._authTag = null;  this._called = false;}
// StreamCipher inherts TransformStreamCipher.prototype = Object.create(Transform.prototype, {  constructor: {    value: StreamCipher,    enumerable: false,    writable: true,    configurable: true,  },});
StreamCipher.prototype._update = function (chunk) {  if (!this._called && this._alen) {    var rump = 16 - (this._alen % 16);    if (rump < 16) {      rump = Buffer.alloc(rump, 0);      this._ghash.update(rump);    }  }
  this._called = true;  var out = this._mode.encrypt(this, chunk);  if (this._decrypt) {    this._ghash.update(chunk);  } else {    this._ghash.update(out);  }  this._len += chunk.length;  return out;};
StreamCipher.prototype._final = function () {  if (this._decrypt && !this._authTag) {    throw new Error("Unsupported state or unable to authenticate data");  }
  var tag = xor(    this._ghash.final(this._alen * 8, this._len * 8),    this._cipher.encryptBlock(this._finID),  );  if (this._decrypt && xorTest(tag, this._authTag)) {    throw new Error("Unsupported state or unable to authenticate data");  }
  this._authTag = tag;  this._cipher.scrub();};
StreamCipher.prototype.getAuthTag = function getAuthTag() {  if (this._decrypt || !Buffer.isBuffer(this._authTag)) {    throw new Error("Attempting to get auth tag in unsupported state");  }
  return this._authTag;};
StreamCipher.prototype.setAuthTag = function setAuthTag(tag) {  if (!this._decrypt) {    throw new Error("Attempting to set auth tag in unsupported state");  }
  this._authTag = tag;};
StreamCipher.prototype.setAAD = function setAAD(buf) {  if (this._called) {    throw new Error("Attempting to set AAD in unsupported state");  }
  this._ghash.update(buf);  this._alen += buf.length;};
export default StreamCipher;