first

.eslintrc

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+{
+  "extends": ["standard"]
+}

index.js

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+var Transform = require('stream').Transform
+var inherits = require('inherits')
+var StringDecoder = require('string_decoder').StringDecoder
+module.exports = CipherBase
+inherits(CipherBase, Transform)
+function CipherBase (hashMode) {
+  Transform.call(this)
+  this.hashMode = typeof hashMode === 'string';
+  if (this.hashMode) {
+    this[hashMode] = this._finalOrDigest
+  } else {
+    this.final = this._finalOrDigest
+  }
+  this._decoder = null
+  this._encoding = null
+}
+CipherBase.prototype.update = function (data, inputEnc, outputEnc) {
+  if (typeof data === 'string') {
+    data = new Buffer(data, inputEnc)
+  }
+  var outData = this._update(data)
+  if (this.hashMode) {
+    return this
+  }
+  if (outputEnc) {
+    outData = this._toString(outData, outputEnc)
+  }
+  return outData
+}
+CipherBase.prototype._transform = function (data, _, next) {
+  var err
+  try {
+    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
+  } finally {
+    done(err)
+  }
+}
+CipherBase.prototype._finalOrDigest = function (outputEnc) {
+  var outData = this._final() || new Buffer('')
+  if (outputEnc) {
+    outData = this._toString(outData, outputEnc, true)
+  }
+  return outData
+}
+
+CipherBase.prototype._toString = function (value, enc, final) {
+  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 (final) {
+    out += this._decoder.end()
+  }
+  return out
+}

package.json

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+{
+  "name": "cipher-base",
+  "version": "1.0.0",
+  "description": "abstract base class for crypto-streams",
+  "main": "index.js",
+  "scripts": {
+    "test": "node test.js | tspec"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/crypto-browserify/cipher-base.git"
+  },
+  "keywords": [
+    "cipher",
+    "stream"
+  ],
+  "author": "Calvin Metcalf <[email protected]>",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/crypto-browserify/cipher-base/issues"
+  },
+  "homepage": "https://github.com/crypto-browserify/cipher-base#readme",
+  "dependencies": {
+    "inherits": "^2.0.1"
+  },
+  "devDependencies": {
+    "tap-spec": "^4.1.0",
+    "tape": "^4.2.0"
+  }
+}

readme.md

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+cipher-base
+===
+
+Abstract base class to inherit from if you want to create streams implementing
+the same api as node crypto streams.
+
+Requires you to implement 2 methods `_final` and `_update`. `_final` takes a
+buffer and should return a buffer, `_final` takes no arguments and should return
+a buffer.
+
+
+The constructor takes one argument and that is a string which if present switches
+it into hash mode, i.e. the object you get from crypto.createHash or
+crypto.createSign, this switches the name of the final method to be the string
+you passed instead of `final` and returns `this` from update.

test.js

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+var test = require('tape')
+var CipherBase = require('./')
+var inherits = require('inherits')
+
+test('basic version', function (t) {
+  inherits(Cipher, CipherBase)
+  function Cipher () {
+    CipherBase.call(this)
+  }
+  Cipher.prototype._update = function (input) {
+    t.ok(Buffer.isBuffer(input))
+    return input
+  }
+  Cipher.prototype._final = function () {
+    // noop
+  }
+  var cipher = new Cipher()
+  var utf8 = 'abc123abcd'
+  var update = cipher.update(utf8, 'utf8', 'base64') + cipher.final('base64')
+  var string = (new Buffer(update, 'base64')).toString()
+  t.equals(utf8, string)
+  t.end()
+})
+test('hash mode', function (t) {
+  inherits(Cipher, CipherBase)
+  function Cipher () {
+    CipherBase.call(this, 'finalName')
+    this._cache = []
+  }
+  Cipher.prototype._update = function (input) {
+    t.ok(Buffer.isBuffer(input))
+    this._cache.push(input)
+  }
+  Cipher.prototype._final = function () {
+    return Buffer.concat(this._cache)
+  }
+  var cipher = new Cipher()
+  var utf8 = 'abc123abcd'
+  var update = cipher.update(utf8, 'utf8').finalName('base64')
+  var string = (new Buffer(update, 'base64')).toString()
+
+  t.equals(utf8, string)
+  t.end()
+})
+test('encodings', function (t) {
+  inherits(Cipher, CipherBase)
+  function Cipher () {
+    CipherBase.call(this)
+  }
+  Cipher.prototype._update = function (input) {
+    return input
+  }
+  Cipher.prototype._final = function () {
+    // noop
+  }
+  t.test('mix and match encoding', function (t) {
+    t.plan(2)
+
+    var cipher = new Cipher()
+    cipher.update('foo', 'utf8', 'utf8')
+    t.throws(function () {
+      cipher.update('foo', 'utf8', 'base64')
+    })
+    cipher = new Cipher()
+    cipher.update('foo', 'utf8', 'base64')
+    t.doesNotThrow(function () {
+      cipher.update('foo', 'utf8')
+      cipher.final('base64')
+    })
+  })
+  t.test('handle long uft8 plaintexts', function (t) {
+    t.plan(1)
+    var txt = 'ふっかつ　あきる　すぶり　はやい　つける　まゆげ　たんさん　みんぞく　ねほりはほり　せまい　たいまつばな　ひはん'
+
+    var cipher = new Cipher()
+    var decipher = new Cipher()
+    var enc = decipher.update(cipher.update(txt, 'utf8', 'base64'), 'base64', 'utf8')
+    enc += decipher.update(cipher.final('base64'), 'base64', 'utf8')
+    enc += decipher.final('utf8')
+
+    t.equals(txt, enc)
+  })
+})