Liam Appelbe
5c58113405
Bug: https://github.com/dart-lang/sdk/issues/37882 Change-Id: Ia1a268aeb08f8775573287a025b91182ca621766 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/179062 Commit-Queue: Liam Appelbe <liama@google.com> Reviewed-by: Siva Annamalai <asiva@google.com>
84 lines
3.1 KiB
Dart
84 lines
3.1 KiB
Dart
// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Example of using package:wasm to run a wasm build of the Brotli compression
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// library. Usage:
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// dart brotli.dart input.txt
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import 'dart:convert';
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import "dart:io";
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import "dart:typed_data";
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import "package:wasm/wasm.dart";
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// Brotli compression parameters.
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const int kDefaultQuality = 11;
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const int kDefaultWindow = 22;
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const int kDefaultMode = 0;
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main(List<String> args) {
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var brotliPath = Platform.script.resolve('libbrotli.wasm');
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var moduleData = File(brotliPath.path).readAsBytesSync();
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var module = WasmModule(moduleData);
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print(module.describe());
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var instance = module.instantiate().enableWasi().build();
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var memory = instance.memory;
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var compress = instance.lookupFunction("BrotliEncoderCompress");
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var decompress = instance.lookupFunction("BrotliDecoderDecompress");
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print("Loading ${args[0]}");
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var inputData = File(args[0]).readAsBytesSync();
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print("Input size: ${inputData.length} bytes");
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// Grow the module's memory to get unused space to put our data.
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// [initial memory][input data][output data][size][decoded data][size]
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var inputPtr = memory.lengthInBytes;
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memory.grow((3 * inputData.length / WasmMemory.kPageSizeInBytes).ceil());
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var memoryView = memory.view;
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var outputPtr = inputPtr + inputData.length;
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var outSizePtr = outputPtr + inputData.length;
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var decodedPtr = outSizePtr + 4;
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var decSizePtr = decodedPtr + inputData.length;
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memoryView.setRange(inputPtr, inputPtr + inputData.length, inputData);
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var sizeBytes = ByteData(4);
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sizeBytes.setUint32(0, inputData.length, Endian.host);
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memoryView.setRange(
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outSizePtr, outSizePtr + 4, sizeBytes.buffer.asUint8List());
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print("\nCompressing...");
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var status = compress(kDefaultQuality, kDefaultWindow, kDefaultMode,
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inputData.length, inputPtr, outSizePtr, outputPtr);
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print("Compression status: $status");
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var compressedSize =
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ByteData.sublistView(memoryView, outSizePtr, outSizePtr + 4)
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.getUint32(0, Endian.host);
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print("Compressed size: $compressedSize bytes");
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var spaceSaving = 100 * (1 - compressedSize / inputData.length);
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print("Space saving: ${spaceSaving.toStringAsFixed(2)}%");
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var decSizeBytes = ByteData(4);
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decSizeBytes.setUint32(0, inputData.length, Endian.host);
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memoryView.setRange(
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decSizePtr, decSizePtr + 4, decSizeBytes.buffer.asUint8List());
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print("\nDecompressing...");
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status = decompress(compressedSize, outputPtr, decSizePtr, decodedPtr);
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print("Decompression status: $status");
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var decompressedSize =
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ByteData.sublistView(memoryView, decSizePtr, decSizePtr + 4)
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.getUint32(0, Endian.host);
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print("Decompressed size: $decompressedSize bytes");
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print("\nVerifying decompression...");
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assert(inputData.length == decompressedSize);
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for (var i = 0; i < inputData.length; ++i) {
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assert(inputData[i] == memoryView[decodedPtr + i]);
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}
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print("Decompression succeeded :)");
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}
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