Create string efficiently from Uint16List/View.

tests/corelib/string_fromcharcodes_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 "package:expect/expect.dart";
 import "dart:typed_data";
 
 main() {
   iter(count, [values]) => values is List
                                ? new Iterable.generate(count, (x) => values[x])
                                : new Iterable.generate(count, (x) => values);
   test(expect, iter, [start = 0, end]) {
-    Expect.equals(expect, new String.fromCharCodes(iter, start, end));
+    var actual = new String.fromCharCodes(iter, start, end);
+    Expect.equals(expect, actual);
   }
   testThrows(iterable, [start = 0, end]) {
     Expect.throws(() { new String.fromCharCodes(iterable, start, end); });
   }
 
   test("", iter(0));
   test("", []);
   test("", const []);
   test("", new List(0));
   test("", new Uint8List(0));
@@ skipping 162 matching lines @@
     }
   }
 
   testSubstring("");
   testSubstring("ABCDEFGH");
   // length > 128
   testSubstring("ABCDEFGH" * 33);
   testSubstring("\x00" * 357);
   // length > 128 and non-ASCII.
   testSubstring("\uFFFD\uFFFE\u{10000}\u{10ffff}c\x00" * 37);
+
+  const cLatin1      = const [0x00, 0xff];
+  const cUtf16       = const [0x00, 0xffff, 0xdfff, 0xdbff, 0xdfff, 0xdbff];
+  const cCodepoints  = const [0x00, 0xffff, 0xdfff, 0x10ffff, 0xdbff];
+  List  gLatin1      = cLatin1.toList(growable: true);
+  List  gUtf16       = cUtf16.toList(growable: true);
+  List  gCodepoints  = cCodepoints.toList(growable: true);
+  List  fLatin1      = cLatin1.toList(growable: false);
+  List  fUtf16       = cUtf16.toList(growable: false);
+  List  fCodepoints  = cCodepoints.toList(growable: false);
+  Uint8List  bLatin1 = new Uint8List(2)..setRange(0, 2, cLatin1);
+  Uint16List wLatin1 = new Uint16List(2)..setRange(0, 2, cLatin1);
+  Uint16List wUtf16  = new Uint16List(6)..setRange(0, 6, cUtf16);
+  Uint32List lLatin1 = new Uint32List(2)..setRange(0, 2, cLatin1);
+  Uint32List lUtf16  = new Uint32List(6)..setRange(0, 6, cUtf16);
+  Uint32List lCodepoints = new Uint32List(5)..setRange(0, 5, cCodepoints);
+  String sLatin1     = "\x00\xff";
+  String sUnicode    =
+      "\x00\uffff$tailSurrogate$leadSurrogate$tailSurrogate$leadSurrogate";
+  for (int i = 0; i < 2; i++) {
+    for (int j = i + 1; j < 2; j++) {
+      test(sLatin1.substring(i, j), cLatin1, i, j);
+      test(sLatin1.substring(i, j), gLatin1, i, j);
+      test(sLatin1.substring(i, j), fLatin1, i, j);
+      test(sLatin1.substring(i, j), bLatin1, i, j);
+      test(sLatin1.substring(i, j), wLatin1, i, j);
+      test(sLatin1.substring(i, j), lLatin1, i, j);
+    }
+  }
+  for (int i = 0; i < 6; i++) {
+    for (int j = i + 1; j < 6; j++) {
+      test(sUnicode.substring(i, j), cUtf16, i, j);
+      test(sUnicode.substring(i, j), gUtf16, i, j);
+      test(sUnicode.substring(i, j), fUtf16, i, j);
+      test(sUnicode.substring(i, j), wUtf16, i, j);
+      test(sUnicode.substring(i, j), lUtf16, i, j);
+    }
+  }
+  for (int i = 0; i < 5; i++) {
+    for (int j = i + 1; j < 5; j++) {
+      int stringEnd = j < 4 ? j : j + 1;
+      test(sUnicode.substring(i, stringEnd), cCodepoints, i, j);
+      test(sUnicode.substring(i, stringEnd), gCodepoints, i, j);
+      test(sUnicode.substring(i, stringEnd), fCodepoints, i, j);
+      test(sUnicode.substring(i, stringEnd), lCodepoints, i, j);
+    }
+  }

[siva, 2015/01/20 23:50:26]

Does this also test the ExternalTypedData and Uint16ListView cases?

[Lasse Reichstein Nielsen, 2015/01/22 07:16:33]

No. I'll add Uint16ListViev. Is there a way to create an ExtrenalTypedData from
Dart code? 

[siva, 2015/01/23 01:06:33]

You would have to create it in native code and pass it back to dart, there are
some examples in dart_api_impl_test.cc (e.g: ExternalByteDataAccess test)

 }