Implement a Base64 codec

test/base64_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Library tag to allow the test to run on Dartium.
 library base64_test;
 
 import 'dart:math';
+import 'dart:async';
 
 import "package:crypto/crypto.dart";
 import "package:test/test.dart";
 
 void main() {
   test('encoder', _testEncoder);
   test('decoder', _testDecoder);
   test('decoder for malformed input', _testDecoderForMalformedInput);
   test('encode decode lists', _testEncodeDecodeLists);
   test('url safe encode-decode', _testUrlSafeEncodeDecode);
+  test('streaming encoder', _testStreamingEncoder);
+  test('streaming decoder', _testStreamingDecoder);
+  test('streaming decoder for malformed input', _testStreamingDecoderForMalformedInput);
+  test('streaming encoder for different decompositions of a list of bytes',
+       _testStreamingEncoderForDecompositions);
+  test('streaming decoder for different decompositions of a string',
+       _testStreamingDecoderForDecompositions);
+  test('url safe streaming encoder/decoder', _testUrlSafeStreaming);
   test('performance', _testPerformance);
+
+
 }
 
 // Data from http://tools.ietf.org/html/rfc4648.
 const _INPUTS =
     const [ '', 'f', 'fo', 'foo', 'foob', 'fooba', 'foobar'];
 const _RESULTS =
     const [ '', 'Zg==', 'Zm8=', 'Zm9v', 'Zm9vYg==', 'Zm9vYmE=', 'Zm9vYmFy'];
+var _STREAMING_ENCODER_INPUT =
+    [[102, 102], [111, 102],
+     [111, 111, 102, 111, 111, 98, 102, 111,
+      111, 98, 97, 102, 111, 111, 98, 97, 114]];
+
+const _STREAMING_ENCODED = 'ZmZvZm9vZm9vYmZvb2JhZm9vYmFy';
+const _STREAMING_DECODER_INPUT =
+    const ['YmFz', 'ZTY', '0I', 'GRlY29kZXI='];
+const _STREAMING_DECODED =
+    const [98, 97, 115, 101, 54, 52, 32, 100, 101, 99, 111, 100, 101, 114];
+const _STREAMING_DECODER_INPUT_FOR_ZEROES =
+    const ['AAAA', 'AAA=', 'AA==', ''];
+var _STREAMING_DECODED_ZEROES = [0, 0, 0, 0, 0, 0];
+
+var _DECOMPOSITIONS_FOR_DECODING = [
+    ["A", "", "BCD"], ["A", "BCD", "", ""], ["A", "B", "", "", "CD", ""],
+    ["", "A", "BC", "", "D"], ["", "AB", "C", "", "", "D"], ["AB", "CD", ""],
+    ["", "ABC", "", "D"], ["", "ABC", "D", ""], ["", "", "ABCD", ""],
+    ["A", "B", "C", "D"], ["", "A", "B", "C", "D", ""],
+    ["", "A", "B", "", "", "C", "", "D", ""]];
+
+const _DECOMPOSITION_DECODED = const [0, 16, 131];
+
+var _DECOMPOSITIONS_FOR_ENCODING = [
+    [[196, 16], [], [158], [196]],
+    [[196, 16], [158, 196], [], []],
+    [[196], [], [16], [], [], [158], [], [196]],
+    [[196], [], [16], [158, 196], [], []],
+    [[], [196], [], [], [16, 158], [], [196]],
+    [[], [196], [16, 158, 196], []],
+    [[196, 16, 158], [], [], [196]],
+    [[196, 16, 158], [], [196], []],
+    [[196, 16, 158, 196], [], [], []]];
+
+const _DECOMPOSITION_ENCODED = 'xBCexA==';
 
 // Test data with only zeroes.
 var inputsWithZeroes = [[0, 0, 0], [0, 0], [0], []];
 const _RESULTS_WITH_ZEROS = const ['AAAA', 'AAA=', 'AA==', ''];
 
 const _LONG_LINE =
     "Man is distinguished, not only by his reason, but by this singular "
     "passion from other animals, which is a lust of the mind, that by a "
     "perseverance of delight in the continued and indefatigable generation "
     "of knowledge, exceeds the short vehemence of any carnal pleasure.";
@@ skipping 17 matching lines @@
     "BhbmltYWxzLCB3aGljaCBpcyBhIGx1c3Qgb2Yg"
     "dGhlIG1pbmQsIHRoYXQgYnkgYSBwZXJzZXZlcm"
     "FuY2Ugb2YgZGVsaWdodCBpbiB0aGUgY29udGlu"
     "dWVkIGFuZCBpbmRlZmF0aWdhYmxlIGdlbmVyYX"
     "Rpb24gb2Yga25vd2xlZGdlLCBleGNlZWRzIHRo"
     "ZSBzaG9ydCB2ZWhlbWVuY2Ugb2YgYW55IGNhcm"
     "5hbCBwbGVhc3VyZS4=";
 
 void _testEncoder() {
   for (var i = 0; i < _INPUTS.length; i++) {
-    expect(CryptoUtils.bytesToBase64(_INPUTS[i].codeUnits), _RESULTS[i]);
+    expect(BASE64.encode(_INPUTS[i].codeUnits), _RESULTS[i]);
   }
   for (var i = 0; i < inputsWithZeroes.length; i++) {
-    expect(CryptoUtils.bytesToBase64(inputsWithZeroes[i]),
-        _RESULTS_WITH_ZEROS[i]);
+    expect(BASE64.encode(inputsWithZeroes[i]),
+           _RESULTS_WITH_ZEROS[i]);
   }
   expect(
-      CryptoUtils.bytesToBase64(_LONG_LINE.codeUnits, addLineSeparator : true),
+      BASE64.encode(_LONG_LINE.codeUnits, addLineSeparator : true),

[Lasse Reichstein Nielsen, 2015/05/29 14:15:42]

This may now fit on the previous line.

[Alexander Ivanov, 2015/06/03 09:14:58]

Done.

       _LONG_LINE_RESULT);
-  expect(CryptoUtils.bytesToBase64(_LONG_LINE.codeUnits),
+  expect(BASE64.encode(_LONG_LINE.codeUnits),
       _LONG_LINE_RESULT_NO_BREAK);
 }
 
 void _testDecoder() {
   for (var i = 0; i < _RESULTS.length; i++) {
     expect(
-        new String.fromCharCodes(CryptoUtils.base64StringToBytes(_RESULTS[i])),
+        new String.fromCharCodes(BASE64.decode(_RESULTS[i])),
         _INPUTS[i]);
   }
+
   for (var i = 0; i < _RESULTS_WITH_ZEROS.length; i++) {
-    expect(CryptoUtils.base64StringToBytes(_RESULTS_WITH_ZEROS[i]),
+    expect(BASE64.decode(_RESULTS_WITH_ZEROS[i]),
         inputsWithZeroes[i]);
   }
-  var longLineDecoded = CryptoUtils.base64StringToBytes(_LONG_LINE_RESULT);
+
+  var longLineDecoded = BASE64.decode(_LONG_LINE_RESULT);
   expect(new String.fromCharCodes(longLineDecoded), _LONG_LINE);
-  var longLineResultNoBreak =
-      CryptoUtils.base64StringToBytes(_LONG_LINE_RESULT);
+
+  var longLineResultNoBreak = BASE64.decode(_LONG_LINE_RESULT);
   expect(new String.fromCharCodes(longLineResultNoBreak), _LONG_LINE);
 }
 
+Future _testStreamingEncoder() async {
+  expect(await new Stream.fromIterable(_STREAMING_ENCODER_INPUT)
+                         .transform(BASE64.encoder)
+                         .join(),
+         _STREAMING_ENCODED);
+}
+
+Future _testStreamingDecoder() async {
+  expect(
+    await new Stream.fromIterable(_STREAMING_DECODER_INPUT)

[Lasse Reichstein Nielsen, 2015/05/29 14:15:42]

Indent "await" by four.

[Alexander Ivanov, 2015/06/03 09:14:58]

Done.

+        .transform(BASE64.decoder)
+        .expand((l) => l)
+        .toList(),
+       _STREAMING_DECODED);

[Lasse Reichstein Nielsen, 2015/05/29 14:15:42]

Indent this line to match the await.
Ditto for expect below.

[Alexander Ivanov, 2015/06/03 09:14:58]

Done.

+
+  expect(
+    await new Stream.fromIterable(_STREAMING_DECODER_INPUT_FOR_ZEROES)
+        .transform(BASE64.decoder)
+        .expand((l) => l)
+        .toList(),
+        _STREAMING_DECODED_ZEROES);
+}
+
+Future _testStreamingDecoderForMalformedInput() async {
+  expect(() async {
+    await new Stream.fromIterable(['ABz'])
+        .transform(BASE64.decoder).toList();
+  }(), throwsFormatException);

[Lasse Reichstein Nielsen, 2015/05/29 14:15:42]

I think the value for the expect can be just:
  new Stream.fromIterable(['ABz']).transform(BASE64.decoder).toList()
That itself returns a future, so there is no need to wrap it in an async
function that returns a future with the same error.

[Alexander Ivanov, 2015/06/03 09:14:58]

oh, absolutely

+
+  expect(() async {
+    await new Stream.fromIterable(['AB', 'Lx', 'z', 'xx'])
+       .transform(BASE64.decoder).toList();
+  }(), throwsFormatException);
+}
+
+Future _testStreamingEncoderForDecompositions() async {
+  for(var decomposition in _DECOMPOSITIONS_FOR_ENCODING) {
+    expect(
+      await new Stream.fromIterable(decomposition)
+                      .transform(BASE64.encoder)
+                      .join(),
+      _DECOMPOSITION_ENCODED);
+  }
+}
+
+Future _testStreamingDecoderForDecompositions() async {
+  for(var decomposition in _DECOMPOSITIONS_FOR_DECODING) {
+    expect(
+      await new Stream.fromIterable(decomposition)
+                      .transform(BASE64.decoder)
+                      .expand((x) => x)
+                      .toList(),
+      _DECOMPOSITION_DECODED);
+  }
+}
+
 void _testDecoderForMalformedInput() {
   expect(() {
-    CryptoUtils.base64StringToBytes('AB~');
+    BASE64.decode('AB~');
   }, throwsFormatException);
 
   expect(() {
-    CryptoUtils.base64StringToBytes('A');
+    BASE64.decode('A');
   }, throwsFormatException);
 }
 
+Future _testUrlSafeStreaming() async {
+  String encUrlSafe = '-_A=';
+  List<List<int>> dec = [BASE64.decode('+/A=')];
+  var streamed_result = await new Stream.fromIterable(dec)

[Lasse Reichstein Nielsen, 2015/05/29 14:15:42]

streamedResult :)

[Alexander Ivanov, 2015/06/03 09:14:58]

Done.

+      .transform(new Base64Encoder(urlSafe: true)).join();
+
+  expect(streamed_result, encUrlSafe);
+}
+
 void _testUrlSafeEncodeDecode() {
-  List<int> decUrlSafe = CryptoUtils.base64StringToBytes('-_A=');
-  List<int> dec = CryptoUtils.base64StringToBytes('+/A=');
+  List<int> decUrlSafe = BASE64.decode('-_A=');
+  List<int> dec = BASE64.decode('+/A=');
   expect(decUrlSafe, orderedEquals(dec));
-  expect(CryptoUtils.bytesToBase64(dec, urlSafe: true), '-_A=');
-  expect(CryptoUtils.bytesToBase64(dec), '+/A=');
+  expect(BASE64.encode(dec, urlSafe: true), '-_A=');
+  expect(BASE64.encode(dec), '+/A=');
 }
 
 void _testEncodeDecodeLists() {
   for (int i = 0; i < 10; i++) {
     for (int j = 0; j < 256 - i; j++) {
       List<int> x = new List<int>(i);
       for (int k = 0; k < i; k++) {
         x[k] = j;
       }
-      var enc = CryptoUtils.bytesToBase64(x);
-      var dec = CryptoUtils.base64StringToBytes(enc);
+      var enc = BASE64.encode(x);
+      var dec = BASE64.decode(enc);
       expect(dec, orderedEquals(x));
     }
   }
 }
 
 void _fillRandom(List<int> l) {
   var random = new Random(0xBABE);
   for (int j = 0; j < l.length; j++) {
     l[j] = random.nextInt(255);
   }
 }
 
 void _testPerformance() {
     var l = new List<int>(1024);
     var iters = 5000;
     _fillRandom(l);
     String enc;
     var w = new Stopwatch()..start();
     for( int i = 0; i < iters; ++i ) {
-      enc = CryptoUtils.bytesToBase64(l);
+      enc = BASE64.encode(l);
     }
     int ms = w.elapsedMilliseconds;
     int perSec = (iters * l.length) * 1000 ~/ ms;
     // print("Encode 1024 bytes for $iters times: $ms msec. $perSec b/s");
     w..reset();
     for( int i = 0; i < iters; ++i ) {
-      CryptoUtils.base64StringToBytes(enc);
+      BASE64.decode(enc);
     }
     ms = w.elapsedMilliseconds;
     perSec = (iters * l.length) * 1000 ~/ ms;
-    // print('''Decode into ${l.length} bytes for $iters
+    // ('''Decode into ${l.length} bytes for $iters
     //     times: $ms msec. $perSec b/s''');
 }