Add Base64 codec to dart:convert.

tests/lib/convert/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.
+
+import 'dart:convert';
+import "dart:typed_data";
+import "package:expect/expect.dart";
+
+main() {
+  for (var list in [[],
+                    [0x00],
+                    [0xff, 0x00],
+                    [0xff, 0xaa, 0x55],
+                    [0x00, 0x01, 0x02, 0x03],
+                    new Iterable.generate(13).toList(),
+                    new Iterable.generate(254).toList(),
+                    new Iterable.generate(255).toList(),
+                    new Iterable.generate(256).toList()]) {
+    testRoundtrip(list, "List#${list.length}");
+    testRoundtrip(new Uint8List.fromList(list), "Uint8List#${list.length}");
+  }
+  testErrors();
+}
+
+void testRoundtrip(list, name) {
+  // Direct.
+  String encoded = BASE64.encode(list);
+  List result = BASE64.decode(encoded);
+  Expect.listEquals(list, result, name);
+
+  int increment = list.length ~/ 7 + 1;
+  // Chunked.
+  for (int i = 0; i < list.length; i += increment) {
+    for (int j = i; j < list.length; j += increment) {
+      {
+        // Using add/close
+        var results;
+        var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
+        var encoder = BASE64.encoder.startChunkedConversion(sink);
+        encoder.add(list.sublist(0, i));
+        encoder.add(list.sublist(i, j));
+        encoder.add(list.sublist(j, list.length));
+        encoder.close();
+        var name = "0-$i-$j-${list.length}: list";
+        Expect.equals(encoded, results.join(""), name);
+      }
+      {
+        // Using addSlice
+        var results;
+        var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
+        var encoder = BASE64.encoder.startChunkedConversion(sink);
+        encoder.addSlice(list, 0, i, false);
+        encoder.addSlice(list, i, j, false);
+        encoder.addSlice(list, j, list.length, true);
+        var name = "0-$i-$j-${list.length}: $list";
+        Expect.equals(encoded, results.join(""), name);
+      }
+    }
+  }
+
+  increment = encoded.length ~/ 7 + 1;
+  for (int i = 0; i < encoded.length; i += increment) {
+    for (int j = i; j < encoded.length; j += increment) {
+      {
+        // Using add/close
+        var results;
+        var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
+        var decoder = BASE64.decoder.startChunkedConversion(sink);
+        decoder.add(encoded.substring(0, i));
+        decoder.add(encoded.substring(i, j));
+        decoder.add(encoded.substring(j, encoded.length));
+        decoder.close();
+        var name = "0-$i-$j-${encoded.length}: $encoded";
+        Expect.listEquals(list, results.expand((x)=>x).toList(), name);
+      }
+      {
+        // Using addSlice
+        var results;
+        var sink = new ChunkedConversionSink.withCallback((v) { results = v; });
+        var decoder = BASE64.decoder.startChunkedConversion(sink);
+        decoder.addSlice(encoded, 0, i, false);
+        decoder.addSlice(encoded, i, j, false);
+        decoder.addSlice(encoded, j, encoded.length, true);
+        var name = "0-$i-$j-${encoded.length}: $encoded";
+        Expect.listEquals(list, results.expand((x)=>x).toList(), name);
+      }
+    }
+  }
+}
+
+bool isFormatException(e) => e is FormatException;
+bool isArgumentError(e) => e is ArgumentError;
+
+void testErrors() {
+  void badChunkDecode(List<String> list) {
+    Expect.throws(() {
+      var sink = new ChunkedConversionSink.withCallback((v) {
+        Expect.fail("Should have thrown: chunk $list");
+      });
+      var c = BASE64.decoder.startChunkedConversion(sink);
+      for (String string in list) {
+        c.add(string);
+      }
+      c.close();
+    }, isFormatException, "chunk $list");
+  }
+  void badDecode(String string) {
+    Expect.throws(() => BASE64.decode(string), isFormatException, string);
+    badChunkDecode([string]);
+    badChunkDecode(["", string]);
+    badChunkDecode([string, ""]);
+    badChunkDecode([string, "", ""]);
+    badChunkDecode(["", string, ""]);
+  }
+
+  badDecode("A");
+  badDecode("AA");
+  badDecode("AAA");
+  badDecode("AAAAA");
+  badDecode("AAAAAA");
+  badDecode("AAAAAAA");
+  badDecode("AAAA=");
+  badDecode("AAAA==");
+  badDecode("AAAA===");
+  badDecode("AAAA====");
+  badDecode("A=");
+  badDecode("A=A");
+  badDecode("A==");
+  badDecode("A==A");
+  badDecode("A===");
+  badDecode("====");
+  badDecode("AA=");
+  badDecode("AA===");
+  badDecode("AAA==");
+  badDecode("AAA=AAAA");
+  badDecode("AAA-");
+  badDecode("AAA_");
+  badDecode("AAA\x00");
+  badDecode("AAA=\x00");
+  badDecode("AAA\x80");
+  badDecode("AAA\xFF");
+  badDecode("AAA\u{141}");
+  badDecode("AAA\u{1041}");
+  badDecode("AAA\u{10041}");
+
+  var alphabet =
+    "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+/";
+  var units = alphabet.codeUnits;
+  for (int i = 0; i < 128; i++) {
+    if (!units.contains(i)) {
+      badDecode(new String.fromCharCode(i) * 4);
+    }
+  }
+
+  badChunkDecode(["A", "A"]);
+  badChunkDecode(["A", "A", "A"]);
+  badChunkDecode(["A", "A", "="]);
+  badChunkDecode(["A", "A", "=", ""]);
+  badChunkDecode(["A", "A", "=", "=", "="]);
+  badChunkDecode(["AAA", "=="]);
+  badChunkDecode(["A", "A", "A"]);
+  badChunkDecode(["AAA", ""]);
+  badChunkDecode(["AA=", ""]);
+  badChunkDecode(["AB==", ""]);
+
+
+  badChunkEncode(list) {
+    for (int i = 0; i < list.length; i++) {
+      for (int j = 0; j < list.length; j++) {
+        Expect.throws(() {
+          var sink = new ChunkedConversionSink.withCallback((v) {
+            Expect.fail("Should have thrown: chunked $list");
+          });
+          var c = BASE64.encoder.startChunkedConversion(sink);
+          c.add(list.sublist(0, i));
+          c.add(list.sublist(i, j));
+          c.add(list.sublist(j, list.length));
+          c.close();
+        }, isArgumentError, "chunk $list");
+      }
+    }
+    for (int i = 0; i < list.length; i++) {
+      for (int j = 0; j < list.length; j++) {
+        Expect.throws(() {
+          var sink = new ChunkedConversionSink.withCallback((v) {
+            Expect.fail("Should have thrown: chunked $list");
+          });
+          var c = BASE64.encoder.startChunkedConversion(sink);
+          c.addSlice(list, 0, i, false);
+          c.addSlice(list, i, j, false);
+          c.addSlice(list, j, list.length, true);
+        }, isArgumentError, "chunk $list");
+      }
+    }
+  }
+
+  void badEncode(int invalid) {
+    Expect.throws(() {
+      BASE64.encode([invalid]);
+    }, isArgumentError, "$invalid");
+    Expect.throws(() {
+      BASE64.encode([0, invalid, 0]);
+    }, isArgumentError, "$invalid");
+    badChunkEncode([invalid]);
+    badChunkEncode([0, invalid]);
+    badChunkEncode([0, 0, invalid]);
+    badChunkEncode([0, invalid, 0]);
+    badChunkEncode([invalid, 0, 0]);
+  }
+
+  badEncode(-1);
+  badEncode(0x100);
+  badEncode(0x1000);
+  badEncode(0x10000);
+  badEncode(0x100000000);          /// 01: ok
+  badEncode(0x10000000000000000);  /// 01: continued
+}