cipher_base.js

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
// Copyright 2017 crypto-browserify. All rights reserved. MIT license.
// deno-lint-ignore-file no-var

import { Buffer } from "../../buffer.ts";
import { Transform } from "../../stream.ts";
import { StringDecoder } from "../../string_decoder.ts";

export function CipherBase(hashMode) {
  Transform.call(this);
  this.hashMode = typeof hashMode === "string";
  if (this.hashMode) {
    this[hashMode] = this._finalOrDigest;
  } else {
    this.final = this._finalOrDigest;
  }
  if (this._final) {
    this.__final = this._final;
    this._final = null;
  }
  this._decoder = null;
  this._encoding = null;
}
// inherits(CipherBase, Transform)
CipherBase.prototype = Object.create(Transform.prototype, {
  constructor: {
    value: CipherBase,
    enumerable: false,
    writable: true,
    configurable: true,
  },
});

CipherBase.prototype.update = function (data, inputEnc, outputEnc) {
  if (typeof data === "string") {
    data = Buffer.from(data, inputEnc);
  }

  var outData = this._update(data);
  if (this.hashMode) return this;

  if (outputEnc) {
    outData = this._toString(outData, outputEnc);
  }

  return outData;
};

CipherBase.prototype.setAutoPadding = function () {};
CipherBase.prototype.getAuthTag = function () {
  throw new Error("trying to get auth tag in unsupported state");
};

CipherBase.prototype.setAuthTag = function () {
  throw new Error("trying to set auth tag in unsupported state");
};

CipherBase.prototype.setAAD = function () {
  throw new Error("trying to set aad in unsupported state");
};

CipherBase.prototype._transform = function (data, _, next) {
  var err;
  try {
    if (this.hashMode) {
      this._update(data);
    } else {
      this.push(this._update(data));
    }
  } catch (e) {
    err = e;
  } finally {
    next(err);
  }
};
CipherBase.prototype._flush = function (done) {
  var err;
  try {
    this.push(this.__final());
  } catch (e) {
    err = e;
  }

  done(err);
};
CipherBase.prototype._finalOrDigest = function (outputEnc) {
  var outData = this.__final() || Buffer.alloc(0);
  if (outputEnc) {
    outData = this._toString(outData, outputEnc, true);
  }
  return outData;
};

CipherBase.prototype._toString = function (value, enc, fin) {
  if (!this._decoder) {
    this._decoder = new StringDecoder(enc);
    this._encoding = enc;
  }

  if (this._encoding !== enc) throw new Error("can't switch encodings");

  var out = this._decoder.write(value);
  if (fin) {
    out += this._decoder.end();
  }

  return out;
};

export default CipherBase;