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| 1 | +// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file |
| 2 | +// for details. All rights reserved. Use of this source code is governed by a |
| 3 | +// BSD-style license that can be found in the LICENSE file. |
| 4 | + |
| 5 | +import "dart:async"; |
| 6 | +import "dart:io"; |
| 7 | +import "dart:typed_data"; |
| 8 | + |
| 9 | +import "package:expect/expect.dart"; |
| 10 | +import "test_utils.dart" show withTempDir; |
| 11 | + |
| 12 | +const chunkCount = 8192; |
| 13 | +const chunkSize = 8192; |
| 14 | + |
| 15 | +Future<int> timeWrite(File file, chunks) async { |
| 16 | + final sink = file.openWrite(); |
| 17 | + |
| 18 | + final Stopwatch stopwatch = new Stopwatch()..start(); |
| 19 | + for (var chunk in chunks) { |
| 20 | + sink.add(chunk); |
| 21 | + } |
| 22 | + await sink.close(); |
| 23 | + stopwatch.stop(); |
| 24 | + |
| 25 | + Expect.equals(chunkCount * chunkSize, await file.length()); |
| 26 | + |
| 27 | + await file.delete(); |
| 28 | + |
| 29 | + return stopwatch.elapsedMilliseconds; |
| 30 | +} |
| 31 | + |
| 32 | +main() async { |
| 33 | + await withTempDir("regress50206", (Directory tempDir) async { |
| 34 | + File file = new File("${tempDir.path}/file.tmp"); |
| 35 | + |
| 36 | + int arrayTime = 0; |
| 37 | + { |
| 38 | + var chunks = []; |
| 39 | + for (var i = 0; i < chunkCount; i++) { |
| 40 | + var chunk = new Uint8List(chunkSize); |
| 41 | + chunks.add(chunk); |
| 42 | + } |
| 43 | + arrayTime = await timeWrite(file, chunks); |
| 44 | + print("arrays: $arrayTime ms"); |
| 45 | + } |
| 46 | + |
| 47 | + int unmodifiableArrayTime = 0; |
| 48 | + { |
| 49 | + var chunks = []; |
| 50 | + for (var i = 0; i < chunkCount; i++) { |
| 51 | + var chunk = new UnmodifiableUint8ListView(new Uint8List(chunkSize)); |
| 52 | + chunks.add(chunk); |
| 53 | + } |
| 54 | + unmodifiableArrayTime = await timeWrite(file, chunks); |
| 55 | + print("unmodifiable arrays: $unmodifiableArrayTime ms"); |
| 56 | + } |
| 57 | + |
| 58 | + int viewTime = 0; |
| 59 | + { |
| 60 | + var chunks = []; |
| 61 | + var backing = new Uint8List(chunkSize * chunkCount); |
| 62 | + for (var i = 0; i < chunkCount; i++) { |
| 63 | + var chunk = |
| 64 | + new Uint8List.view(backing.buffer, i * chunkSize, chunkSize); |
| 65 | + chunks.add(chunk); |
| 66 | + } |
| 67 | + viewTime = await timeWrite(file, chunks); |
| 68 | + print("views: $viewTime ms"); |
| 69 | + } |
| 70 | + |
| 71 | + int unmodifiableViewTime = 0; |
| 72 | + { |
| 73 | + var chunks = []; |
| 74 | + var backing = new Uint8List(chunkSize * chunkCount); |
| 75 | + for (var i = 0; i < chunkCount; i++) { |
| 76 | + var chunk = new UnmodifiableUint8ListView( |
| 77 | + new Uint8List.view(backing.buffer, i * chunkSize, chunkSize)); |
| 78 | + chunks.add(chunk); |
| 79 | + } |
| 80 | + unmodifiableViewTime = await timeWrite(file, chunks); |
| 81 | + print("unmodifiable views: $unmodifiableViewTime ms"); |
| 82 | + } |
| 83 | + |
| 84 | + // Assert with factor a 1000 to avoid the test being flaky from I/O |
| 85 | + // variance. If we copy the whole backing store for each view chunk, things |
| 86 | + // will be quadratically slower, i.e. more than a factor of 1000. |
| 87 | + Expect.isTrue(unmodifiableArrayTime / arrayTime < 1000); |
| 88 | + Expect.isTrue(viewTime / arrayTime < 1000); |
| 89 | + Expect.isTrue(unmodifiableViewTime / arrayTime < 1000); |
| 90 | + }); |
| 91 | +} |
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