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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Buffers;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.AspNetCore.Internal;
using Microsoft.AspNetCore.SignalR.Internal;
using Xunit;
namespace Microsoft.AspNetCore.SignalR.Common.Tests.Internal.Protocol;
public class Utf8BufferTextWriterTests
{
[Fact]
public void WriteChar_Unicode()
{
var bufferWriter = new TestMemoryBufferWriter(4096);
var textWriter = new Utf8BufferTextWriter();
textWriter.SetWriter(bufferWriter);
textWriter.Write('[');
textWriter.Flush();
Assert.Equal(1, bufferWriter.Position);
Assert.Equal((byte)'[', bufferWriter.CurrentSegment.Span[0]);
textWriter.Write('"');
textWriter.Flush();
Assert.Equal(2, bufferWriter.Position);
Assert.Equal((byte)'"', bufferWriter.CurrentSegment.Span[1]);
textWriter.Write('\u00A3');
textWriter.Flush();
Assert.Equal(4, bufferWriter.Position);
textWriter.Write('\u00A3');
textWriter.Flush();
Assert.Equal(6, bufferWriter.Position);
textWriter.Write('"');
textWriter.Flush();
Assert.Equal(7, bufferWriter.Position);
Assert.Equal((byte)0xC2, bufferWriter.CurrentSegment.Span[2]);
Assert.Equal((byte)0xA3, bufferWriter.CurrentSegment.Span[3]);
Assert.Equal((byte)0xC2, bufferWriter.CurrentSegment.Span[4]);
Assert.Equal((byte)0xA3, bufferWriter.CurrentSegment.Span[5]);
Assert.Equal((byte)'"', bufferWriter.CurrentSegment.Span[6]);
textWriter.Write(']');
textWriter.Flush();
Assert.Equal(8, bufferWriter.Position);
Assert.Equal((byte)']', bufferWriter.CurrentSegment.Span[7]);
}
[Fact]
public void WriteChar_UnicodeLastChar()
{
var bufferWriter = new TestMemoryBufferWriter(4096);
using (var textWriter = new Utf8BufferTextWriter())
{
textWriter.SetWriter(bufferWriter);
textWriter.Write('\u00A3');
}
Assert.Equal(2, bufferWriter.Position);
Assert.Equal((byte)0xC2, bufferWriter.CurrentSegment.Span[0]);
Assert.Equal((byte)0xA3, bufferWriter.CurrentSegment.Span[1]);
}
[Fact]
public void WriteChar_UnicodeAndRunOutOfBufferSpace()
{
var bufferWriter = new TestMemoryBufferWriter(4096);
var textWriter = new Utf8BufferTextWriter();
textWriter.SetWriter(bufferWriter);
textWriter.Write('[');
textWriter.Flush();
Assert.Equal(1, bufferWriter.Position);
Assert.Equal((byte)'[', bufferWriter.CurrentSegment.Span[0]);
textWriter.Write('"');
textWriter.Flush();
Assert.Equal(2, bufferWriter.Position);
Assert.Equal((byte)'"', bufferWriter.CurrentSegment.Span[1]);
for (var i = 0; i < 2000; i++)
{
textWriter.Write('\u00A3');
}
textWriter.Flush();
textWriter.Write('"');
textWriter.Flush();
Assert.Equal(4003, bufferWriter.Position);
Assert.Equal((byte)'"', bufferWriter.CurrentSegment.Span[4002]);
textWriter.Write(']');
textWriter.Flush();
Assert.Equal(4004, bufferWriter.Position);
var result = Encoding.UTF8.GetString(bufferWriter.CurrentSegment.Slice(0, bufferWriter.Position).ToArray());
Assert.Equal(2004, result.Length);
Assert.Equal('[', result[0]);
Assert.Equal('"', result[1]);
for (var i = 0; i < 2000; i++)
{
Assert.Equal('\u00A3', result[i + 2]);
}
Assert.Equal('"', result[2002]);
Assert.Equal(']', result[2003]);
}
[Fact]
public void WriteCharArray_SurrogatePairInMultipleCalls()
{
var fourCircles = char.ConvertFromUtf32(0x1F01C);
var chars = fourCircles.ToCharArray();
var bufferWriter = new TestMemoryBufferWriter(4096);
var textWriter = new Utf8BufferTextWriter();
textWriter.SetWriter(bufferWriter);
textWriter.Write(chars, 0, 1);
textWriter.Flush();
// Surrogate buffered
Assert.Equal(0, bufferWriter.Position);
textWriter.Write(chars, 1, 1);
textWriter.Flush();
Assert.Equal(4, bufferWriter.Position);
var expectedData = Encoding.UTF8.GetBytes(fourCircles);
var actualData = bufferWriter.CurrentSegment.Slice(0, 4).ToArray();
Assert.Equal(expectedData, actualData);
}
[Fact]
public void WriteChar_SurrogatePairInMultipleCalls()
{
var fourCircles = char.ConvertFromUtf32(0x1F01C);
var chars = fourCircles.ToCharArray();
var bufferWriter = new TestMemoryBufferWriter(4096);
var textWriter = new Utf8BufferTextWriter();
textWriter.SetWriter(bufferWriter);
textWriter.Write(chars[0]);
textWriter.Flush();
// Surrogate buffered
Assert.Equal(0, bufferWriter.Position);
textWriter.Write(chars[1]);
textWriter.Flush();
Assert.Equal(4, bufferWriter.Position);
var expectedData = Encoding.UTF8.GetBytes(fourCircles);
var actualData = bufferWriter.CurrentSegment.Slice(0, 4).ToArray();
Assert.Equal(expectedData, actualData);
}
[Fact]
public void WriteCharArray_NonZeroStart()
{
var bufferWriter = new TestMemoryBufferWriter(4096);
var textWriter = new Utf8BufferTextWriter();
textWriter.SetWriter(bufferWriter);
var chars = "Hello world".ToCharArray();
textWriter.Write(chars, 6, 1);
textWriter.Flush();
Assert.Equal(1, bufferWriter.Position);
Assert.Equal((byte)'w', bufferWriter.CurrentSegment.Span[0]);
}
[Fact]
public void WriteCharArray_AcrossMultipleBuffers()
{
var bufferWriter = new TestMemoryBufferWriter(2);
var textWriter = new Utf8BufferTextWriter();
textWriter.SetWriter(bufferWriter);
var chars = "Hello world".ToCharArray();
textWriter.Write(chars);
textWriter.Flush();
var segments = bufferWriter.GetSegments();
Assert.Equal(6, segments.Count);
Assert.Equal(1, bufferWriter.Position);
Assert.Equal((byte)'H', segments[0].Span[0]);
Assert.Equal((byte)'e', segments[0].Span[1]);
Assert.Equal((byte)'l', segments[1].Span[0]);
Assert.Equal((byte)'l', segments[1].Span[1]);
Assert.Equal((byte)'o', segments[2].Span[0]);
Assert.Equal((byte)' ', segments[2].Span[1]);
Assert.Equal((byte)'w', segments[3].Span[0]);
Assert.Equal((byte)'o', segments[3].Span[1]);
Assert.Equal((byte)'r', segments[4].Span[0]);
Assert.Equal((byte)'l', segments[4].Span[1]);
Assert.Equal((byte)'d', segments[5].Span[0]);
}
[Fact]
public void GetAndReturnCachedBufferTextWriter()
{
var bufferWriter1 = new TestMemoryBufferWriter();
var textWriter1 = Utf8BufferTextWriter.Get(bufferWriter1);
textWriter1.Write("Hello");
textWriter1.Flush();
Utf8BufferTextWriter.Return(textWriter1);
Assert.Equal("Hello", Encoding.UTF8.GetString(bufferWriter1.ToArray()));
var bufferWriter2 = new TestMemoryBufferWriter();
var textWriter2 = Utf8BufferTextWriter.Get(bufferWriter2);
textWriter2.Write("World");
textWriter2.Flush();
Utf8BufferTextWriter.Return(textWriter2);
Assert.Equal("World", Encoding.UTF8.GetString(bufferWriter2.ToArray()));
Assert.Same(textWriter1, textWriter2);
}
[Fact]
public void WriteMultiByteCharactersToSmallBuffers()
{
// Test string breakdown (char => UTF-8 hex values):
// a => 61
// い => E3-81-84
// b => 62
// ろ => E3-82-8D
// c => 63
// d => 64
// は => E3-81-AF
// に => E3-81-AB
// e => 65
// ほ => E3-81-BB
// f => 66
// へ => E3-81-B8
// ど => E3-81-A9
// g => 67
// h => 68
// i => 69
// \uD800\uDC00 => F0-90-80-80 (this is a surrogate pair that is represented as a single 4-byte UTF-8 encoding)
const string testString = "aいbろcdはにeほfへどghi\uD800\uDC00";
// By mixing single byte and multi-byte characters, we know that there will
// be spaces in the active segment that cannot fit the current character. This
// means we'll be testing the GetMemory(minimumSize) logic.
var bufferWriter = new TestMemoryBufferWriter(segmentSize: 5);
var writer = new Utf8BufferTextWriter();
writer.SetWriter(bufferWriter);
writer.Write(testString);
writer.Flush();
// Verify the output
var allSegments = bufferWriter.GetSegments().Select(s => s.ToArray()).ToArray();
Assert.Collection(allSegments,
seg => Assert.Equal(new byte[] { 0x61, 0xE3, 0x81, 0x84, 0x62 }, seg), // "aいb"
seg => Assert.Equal(new byte[] { 0xE3, 0x82, 0x8D, 0x63, 0x64 }, seg), // "ろcd"
seg => Assert.Equal(new byte[] { 0xE3, 0x81, 0xAF }, seg), // "は"
seg => Assert.Equal(new byte[] { 0xE3, 0x81, 0xAB, 0x65 }, seg), // "にe"
seg => Assert.Equal(new byte[] { 0xE3, 0x81, 0xBB, 0x66 }, seg), // "ほf"
seg => Assert.Equal(new byte[] { 0xE3, 0x81, 0xB8 }, seg), // "へ"
seg => Assert.Equal(new byte[] { 0xE3, 0x81, 0xA9, 0x67, 0x68 }, seg), // "どgh"
seg => Assert.Equal(new byte[] { 0x69, 0xF0, 0x90, 0x80, 0x80 }, seg)); // "i\uD800\uDC00"
Assert.Equal(testString, Encoding.UTF8.GetString(bufferWriter.ToArray()));
}
public static IEnumerable<object[]> CharAndSegmentSizes
{
get
{
foreach (var singleChar in new[] { '"', 'い' })
{
for (int i = 4; i <= 16; i++)
{
yield return new object[] { singleChar, i };
}
}
}
}
[Theory]
[MemberData(nameof(CharAndSegmentSizes))]
public void WriteUnicodeStringAndCharsWithVaryingSegmentSizes(char singleChar, int segmentSize)
{
const string testString = "aいbろ";
const int iterations = 10;
var testBufferWriter = new TestMemoryBufferWriter(segmentSize);
var sb = new StringBuilder();
using (var textWriter = new Utf8BufferTextWriter())
{
textWriter.SetWriter(testBufferWriter);
for (int i = 0; i < iterations; i++)
{
textWriter.Write(singleChar);
textWriter.Write(testString);
textWriter.Write(singleChar);
sb.Append(singleChar);
sb.Append(testString);
sb.Append(singleChar);
}
}
var expected = sb.ToString();
var data = testBufferWriter.ToArray();
var result = Encoding.UTF8.GetString(data);
Assert.Equal(expected, result);
}
private sealed class TestMemoryBufferWriter : IBufferWriter<byte>
{
private readonly int _segmentSize;
private readonly List<Memory<byte>> _completedSegments = new List<Memory<byte>>();
private int _totalLength;
public Memory<byte> CurrentSegment { get; private set; }
internal int Position { get; private set; }
public TestMemoryBufferWriter(int segmentSize = 2048)
{
_segmentSize = segmentSize;
CurrentSegment = Memory<byte>.Empty;
}
public void Advance(int count)
{
Position += count;
_totalLength += count;
}
public Memory<byte> GetMemory(int sizeHint = 0)
{
// Need special handling for sizeHint == 0, because for that we want to enter the if even if there are "sizeHint" (i.e. 0) bytes left :).
if ((sizeHint == 0 && CurrentSegment.Length == Position) || (CurrentSegment.Length - Position < sizeHint))
{
if (Position > 0)
{
// Complete the current segment
_completedSegments.Add(CurrentSegment.Slice(0, Position));
}
// Allocate a new segment and reset the position.
CurrentSegment = new Memory<byte>(new byte[_segmentSize]);
Position = 0;
}
return CurrentSegment.Slice(Position, CurrentSegment.Length - Position);
}
public Span<byte> GetSpan(int sizeHint = 0)
{
return GetMemory(sizeHint).Span;
}
public byte[] ToArray()
{
if (CurrentSegment.IsEmpty && _completedSegments.Count == 0)
{
return Array.Empty<byte>();
}
var result = new byte[_totalLength];
var totalWritten = 0;
// Copy completed segments
foreach (var segment in _completedSegments)
{
segment.CopyTo(result.AsMemory(totalWritten, segment.Length));
totalWritten += segment.Length;
}
// Copy current segment
CurrentSegment.Slice(0, Position).CopyTo(result.AsMemory(totalWritten, Position));
return result;
}
public IList<Memory<byte>> GetSegments()
{
var list = new List<Memory<byte>>();
foreach (var segment in _completedSegments)
{
list.Add(segment);
}
if (CurrentSegment.Length > 0)
{
list.Add(CurrentSegment.Slice(0, Position));
}
return list;
}
}
}
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