csharp/src/Google.Protobuf.Test/ByteStringTest.cs - third_party/github/protocolbuffers/protobuf - Git at Google

 #region Copyright notice and license
 // Protocol Buffers - Google's data interchange format
 // Copyright 2008 Google Inc.  All rights reserved.
 // https://developers.google.com/protocol-buffers/
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion

 using System;
 using System.Text;
 using NUnit.Framework;
 using System.IO;
 using System.Collections.Generic;
 using System.Collections;
 using System.Linq;
 using System.Buffers;
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Runtime.CompilerServices;
 using System.Threading.Tasks;

 namespace Google.Protobuf
 {
     public class ByteStringTest
     {
         [Test]
         public void Equality()
         {
             ByteString b1 = ByteString.CopyFrom(1, 2, 3);
             ByteString b2 = ByteString.CopyFrom(1, 2, 3);
             ByteString b3 = ByteString.CopyFrom(1, 2, 4);
             ByteString b4 = ByteString.CopyFrom(1, 2, 3, 4);
             EqualityTester.AssertEquality(b1, b1);
             EqualityTester.AssertEquality(b1, b2);
             EqualityTester.AssertInequality(b1, b3);
             EqualityTester.AssertInequality(b1, b4);
             EqualityTester.AssertInequality(b1, null);
             EqualityTester.AssertEquality(ByteString.Empty, ByteString.Empty);
 #pragma warning disable 1718 // Deliberately calling ==(b1, b1) and !=(b1, b1)
             Assert.IsTrue(b1 == b1);
             Assert.IsTrue(b1 == b2);
             Assert.IsFalse(b1 == b3);
             Assert.IsFalse(b1 == b4);
             Assert.IsFalse(b1 == null);
             Assert.IsTrue((ByteString) null == null);
             Assert.IsFalse(b1 != b1);
             Assert.IsFalse(b1 != b2);
             Assert.IsTrue(ByteString.Empty == ByteString.Empty);
 #pragma warning disable 1718
             Assert.IsTrue(b1 != b3);
             Assert.IsTrue(b1 != b4);
             Assert.IsTrue(b1 != null);
             Assert.IsFalse((ByteString) null != null);
         }

         [Test]
         public void EmptyByteStringHasZeroSize()
         {
             Assert.AreEqual(0, ByteString.Empty.Length);
         }

         [Test]
         public void CopyFromStringWithExplicitEncoding()
         {
             ByteString bs = ByteString.CopyFrom("AB", Encoding.Unicode);
             Assert.AreEqual(4, bs.Length);
             Assert.AreEqual(65, bs[0]);
             Assert.AreEqual(0, bs[1]);
             Assert.AreEqual(66, bs[2]);
             Assert.AreEqual(0, bs[3]);
         }

         [Test]
         public void IsEmptyWhenEmpty()
         {
             Assert.IsTrue(ByteString.CopyFromUtf8("").IsEmpty);
         }

         [Test]
         public void IsEmptyWhenNotEmpty()
         {
             Assert.IsFalse(ByteString.CopyFromUtf8("X").IsEmpty);
         }

         [Test]
         public void CopyFromByteArrayCopiesContents()
         {
             byte[] data = new byte[1];
             data[0] = 10;
             ByteString bs = ByteString.CopyFrom(data);
             Assert.AreEqual(10, bs[0]);
             data[0] = 5;
             Assert.AreEqual(10, bs[0]);
         }

         [Test]
         public void CopyFromReadOnlySpanCopiesContents()
         {
             byte[] data = new byte[1];
             data[0] = 10;
             ReadOnlySpan<byte> byteSpan = data;
             var bs = ByteString.CopyFrom(byteSpan);
             Assert.AreEqual(10, bs[0]);
             data[0] = 5;
             Assert.AreEqual(10, bs[0]);
         }

         [Test]
         public void ToByteArrayCopiesContents()
         {
             ByteString bs = ByteString.CopyFromUtf8("Hello");
             byte[] data = bs.ToByteArray();
             Assert.AreEqual((byte)'H', data[0]);
             Assert.AreEqual((byte)'H', bs[0]);
             data[0] = 0;
             Assert.AreEqual(0, data[0]);
             Assert.AreEqual((byte)'H', bs[0]);
         }

         [Test]
         public void CopyFromUtf8UsesUtf8()
         {
             ByteString bs = ByteString.CopyFromUtf8("\u20ac");
             Assert.AreEqual(3, bs.Length);
             Assert.AreEqual(0xe2, bs[0]);
             Assert.AreEqual(0x82, bs[1]);
             Assert.AreEqual(0xac, bs[2]);
         }

         [Test]
         public void CopyFromPortion()
         {
             byte[] data = new byte[] {0, 1, 2, 3, 4, 5, 6};
             ByteString bs = ByteString.CopyFrom(data, 2, 3);
             Assert.AreEqual(3, bs.Length);
             Assert.AreEqual(2, bs[0]);
             Assert.AreEqual(3, bs[1]);
         }

         [Test]
         public void CopyTo()
         {
             byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
             ByteString bs = ByteString.CopyFrom(data);

             byte[] dest = new byte[data.Length];
             bs.CopyTo(dest, 0);

             CollectionAssert.AreEqual(data, dest);
         }

         [Test]
         public void GetEnumerator()
         {
             byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
             ByteString bs = ByteString.CopyFrom(data);

             IEnumerator<byte> genericEnumerator = bs.GetEnumerator();
             Assert.IsTrue(genericEnumerator.MoveNext());
             Assert.AreEqual(0, genericEnumerator.Current);

             IEnumerator enumerator = ((IEnumerable)bs).GetEnumerator();
             Assert.IsTrue(enumerator.MoveNext());
             Assert.AreEqual(0, enumerator.Current);

             // Call via LINQ
             CollectionAssert.AreEqual(bs.Span.ToArray(), bs.ToArray());
         }

         [Test]
         public void UnsafeWrap()
         {
             byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
             ByteString bs = UnsafeByteOperations.UnsafeWrap(data.AsMemory(2, 3));
             ReadOnlySpan<byte> s = bs.Span;

             Assert.AreEqual(3, s.Length);
             Assert.AreEqual(2, s[0]);
             Assert.AreEqual(3, s[1]);
             Assert.AreEqual(4, s[2]);

             // Check that the value is not a copy
             data[2] = byte.MaxValue;
             Assert.AreEqual(byte.MaxValue, s[0]);
         }

         [Test]
         public void CreateCodedInput_FromArraySegment()
         {
             byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
             ByteString bs = UnsafeByteOperations.UnsafeWrap(data.AsMemory(2, 3));
             CodedInputStream codedInputStream = bs.CreateCodedInput();

             byte[] bytes = codedInputStream.ReadRawBytes(3);

             Assert.AreEqual(3, bytes.Length);
             Assert.AreEqual(2, bytes[0]);
             Assert.AreEqual(3, bytes[1]);
             Assert.AreEqual(4, bytes[2]);
             Assert.IsTrue(codedInputStream.IsAtEnd);
         }

         [Test]
         public void WriteToStream()
         {
             byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
             ByteString bs = ByteString.CopyFrom(data);

             MemoryStream ms = new MemoryStream();
             bs.WriteTo(ms);

             CollectionAssert.AreEqual(data, ms.ToArray());
         }

         [Test]
         public void WriteToStream_Stackalloc()
         {
             byte[] data = Encoding.UTF8.GetBytes("Hello world");
             Span<byte> s = stackalloc byte[data.Length];
             data.CopyTo(s);

             MemoryStream ms = new MemoryStream();

             using (UnmanagedMemoryManager<byte> manager = new UnmanagedMemoryManager<byte>(s))
             {
                 ByteString bs = ByteString.AttachBytes(manager.Memory);

                 bs.WriteTo(ms);
             }

             CollectionAssert.AreEqual(data, ms.ToArray());
         }

         [Test]
         public void ToStringUtf8()
         {
             ByteString bs = ByteString.CopyFromUtf8("\u20ac");
             Assert.AreEqual("\u20ac", bs.ToStringUtf8());
         }

         [Test]
         public void ToStringWithExplicitEncoding()
         {
             ByteString bs = ByteString.CopyFrom("\u20ac", Encoding.Unicode);
             Assert.AreEqual("\u20ac", bs.ToString(Encoding.Unicode));
         }

         [Test]
         public void ToString_Stackalloc()
         {
             byte[] data = Encoding.UTF8.GetBytes("Hello world");
             Span<byte> s = stackalloc byte[data.Length];
             data.CopyTo(s);

             using (UnmanagedMemoryManager<byte> manager = new UnmanagedMemoryManager<byte>(s))
             {
                 ByteString bs = ByteString.AttachBytes(manager.Memory);

                 Assert.AreEqual("Hello world", bs.ToString(Encoding.UTF8));
             }
         }

         [Test]
         public void FromBase64_WithText()
         {
             byte[] data = new byte[] {0, 1, 2, 3, 4, 5, 6};
             string base64 = Convert.ToBase64String(data);
             ByteString bs = ByteString.FromBase64(base64);
             Assert.AreEqual(data, bs.ToByteArray());
         }

         [Test]
         public void FromBase64_Empty()
         {
             // Optimization which also fixes issue 61.
             Assert.AreSame(ByteString.Empty, ByteString.FromBase64(""));
         }

         [Test]
         public void ToBase64_Array()
         {
             ByteString bs = ByteString.CopyFrom(Encoding.UTF8.GetBytes("Hello world"));

             Assert.AreEqual("SGVsbG8gd29ybGQ=", bs.ToBase64());
         }

         [Test]
         public void ToBase64_Stackalloc()
         {
             byte[] data = Encoding.UTF8.GetBytes("Hello world");
             Span<byte> s = stackalloc byte[data.Length];
             data.CopyTo(s);

             using (UnmanagedMemoryManager<byte> manager = new UnmanagedMemoryManager<byte>(s))
             {
                 ByteString bs = ByteString.AttachBytes(manager.Memory);

                 Assert.AreEqual("SGVsbG8gd29ybGQ=", bs.ToBase64());
             }
         }

         [Test]
         public void FromStream_Seekable()
         {
             var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
             // Consume the first byte, just to test that it's "from current position"
             stream.ReadByte();
             var actual = ByteString.FromStream(stream);
             ByteString expected = ByteString.CopyFrom(2, 3, 4, 5);
             Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
         }

         [Test]
         public void FromStream_NotSeekable()
         {
             var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
             // Consume the first byte, just to test that it's "from current position"
             stream.ReadByte();
             // Wrap the original stream in LimitedInputStream, which has CanSeek=false
             var limitedStream = new LimitedInputStream(stream, 3);
             var actual = ByteString.FromStream(limitedStream);
             ByteString expected = ByteString.CopyFrom(2, 3, 4);
             Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
         }

         [Test]
         public async Task FromStreamAsync_Seekable()
         {
             var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
             // Consume the first byte, just to test that it's "from current position"
             stream.ReadByte();
             var actual = await ByteString.FromStreamAsync(stream);
             ByteString expected = ByteString.CopyFrom(2, 3, 4, 5);
             Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
         }

         [Test]
         public async Task FromStreamAsync_NotSeekable()
         {
             var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
             // Consume the first byte, just to test that it's "from current position"
             stream.ReadByte();
             // Wrap the original stream in LimitedInputStream, which has CanSeek=false
             var limitedStream = new LimitedInputStream(stream, 3);
             var actual = await ByteString.FromStreamAsync(limitedStream);
             ByteString expected = ByteString.CopyFrom(2, 3, 4);
             Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
         }

         [Test]
         public void GetHashCode_Regression()
         {
             // We used to have an awful hash algorithm where only the last four
             // bytes were relevant. This is a regression test for
             // https://github.com/protocolbuffers/protobuf/issues/2511

             ByteString b1 = ByteString.CopyFrom(100, 1, 2, 3, 4);
             ByteString b2 = ByteString.CopyFrom(200, 1, 2, 3, 4);
             Assert.AreNotEqual(b1.GetHashCode(), b2.GetHashCode());
         }

         [Test]
         public void GetContentsAsReadOnlySpan()
         {
             var byteString = ByteString.CopyFrom(1, 2, 3, 4, 5);
             var copied = byteString.Span.ToArray();
             CollectionAssert.AreEqual(byteString, copied);
         }

         [Test]
         public void GetContentsAsReadOnlyMemory()
         {
             var byteString = ByteString.CopyFrom(1, 2, 3, 4, 5);
             var copied = byteString.Memory.ToArray();
             CollectionAssert.AreEqual(byteString, copied);
         }

         // Create Memory<byte> from non-array source.
         // Use by ByteString tests that have optimized path for array backed Memory<byte>.
         private sealed unsafe class UnmanagedMemoryManager<T> : MemoryManager<T> where T : unmanaged
         {
             private readonly T* _pointer;
             private readonly int _length;

             public UnmanagedMemoryManager(Span<T> span)
             {
                 fixed (T* ptr = &MemoryMarshal.GetReference(span))
                 {
                     _pointer = ptr;
                     _length = span.Length;
                 }
             }

             public override Span<T> GetSpan() => new Span<T>(_pointer, _length);

             public override MemoryHandle Pin(int elementIndex = 0)
             {
                 if (elementIndex < 0 || elementIndex >= _length)
                 {
                     throw new ArgumentOutOfRangeException(nameof(elementIndex));
                 }

                 return new MemoryHandle(_pointer + elementIndex);
             }

             public override void Unpin() { }

             protected override void Dispose(bool disposing) { }
         }
     }
 }
	#region Copyright notice and license
	// Protocol Buffers - Google's data interchange format
	// Copyright 2008 Google Inc. All rights reserved.
	// https://developers.google.com/protocol-buffers/
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are
	// met:
	//
	// * Redistributions of source code must retain the above copyright
	// notice, this list of conditions and the following disclaimer.
	// * Redistributions in binary form must reproduce the above
	// copyright notice, this list of conditions and the following disclaimer
	// in the documentation and/or other materials provided with the
	// distribution.
	// * Neither the name of Google Inc. nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	#endregion

	using System;
	using System.Text;
	using NUnit.Framework;
	using System.IO;
	using System.Collections.Generic;
	using System.Collections;
	using System.Linq;
	using System.Buffers;
	using System.Runtime.InteropServices;
	using System.Threading;
	using System.Runtime.CompilerServices;
	using System.Threading.Tasks;

	namespace Google.Protobuf
	{
	public class ByteStringTest
	{
	[Test]
	public void Equality()
	{
	ByteString b1 = ByteString.CopyFrom(1, 2, 3);
	ByteString b2 = ByteString.CopyFrom(1, 2, 3);
	ByteString b3 = ByteString.CopyFrom(1, 2, 4);
	ByteString b4 = ByteString.CopyFrom(1, 2, 3, 4);
	EqualityTester.AssertEquality(b1, b1);
	EqualityTester.AssertEquality(b1, b2);
	EqualityTester.AssertInequality(b1, b3);
	EqualityTester.AssertInequality(b1, b4);
	EqualityTester.AssertInequality(b1, null);
	EqualityTester.AssertEquality(ByteString.Empty, ByteString.Empty);
	#pragma warning disable 1718 // Deliberately calling ==(b1, b1) and !=(b1, b1)
	Assert.IsTrue(b1 == b1);
	Assert.IsTrue(b1 == b2);
	Assert.IsFalse(b1 == b3);
	Assert.IsFalse(b1 == b4);
	Assert.IsFalse(b1 == null);
	Assert.IsTrue((ByteString) null == null);
	Assert.IsFalse(b1 != b1);
	Assert.IsFalse(b1 != b2);
	Assert.IsTrue(ByteString.Empty == ByteString.Empty);
	#pragma warning disable 1718
	Assert.IsTrue(b1 != b3);
	Assert.IsTrue(b1 != b4);
	Assert.IsTrue(b1 != null);
	Assert.IsFalse((ByteString) null != null);
	}

	[Test]
	public void EmptyByteStringHasZeroSize()
	{
	Assert.AreEqual(0, ByteString.Empty.Length);
	}

	[Test]
	public void CopyFromStringWithExplicitEncoding()
	{
	ByteString bs = ByteString.CopyFrom("AB", Encoding.Unicode);
	Assert.AreEqual(4, bs.Length);
	Assert.AreEqual(65, bs[0]);
	Assert.AreEqual(0, bs[1]);
	Assert.AreEqual(66, bs[2]);
	Assert.AreEqual(0, bs[3]);
	}

	[Test]
	public void IsEmptyWhenEmpty()
	{
	Assert.IsTrue(ByteString.CopyFromUtf8("").IsEmpty);
	}

	[Test]
	public void IsEmptyWhenNotEmpty()
	{
	Assert.IsFalse(ByteString.CopyFromUtf8("X").IsEmpty);
	}

	[Test]
	public void CopyFromByteArrayCopiesContents()
	{
	byte[] data = new byte[1];
	data[0] = 10;
	ByteString bs = ByteString.CopyFrom(data);
	Assert.AreEqual(10, bs[0]);
	data[0] = 5;
	Assert.AreEqual(10, bs[0]);
	}

	[Test]
	public void CopyFromReadOnlySpanCopiesContents()
	{
	byte[] data = new byte[1];
	data[0] = 10;
	ReadOnlySpan<byte> byteSpan = data;
	var bs = ByteString.CopyFrom(byteSpan);
	Assert.AreEqual(10, bs[0]);
	data[0] = 5;
	Assert.AreEqual(10, bs[0]);
	}

	[Test]
	public void ToByteArrayCopiesContents()
	{
	ByteString bs = ByteString.CopyFromUtf8("Hello");
	byte[] data = bs.ToByteArray();
	Assert.AreEqual((byte)'H', data[0]);
	Assert.AreEqual((byte)'H', bs[0]);
	data[0] = 0;
	Assert.AreEqual(0, data[0]);
	Assert.AreEqual((byte)'H', bs[0]);
	}

	[Test]
	public void CopyFromUtf8UsesUtf8()
	{
	ByteString bs = ByteString.CopyFromUtf8("\u20ac");
	Assert.AreEqual(3, bs.Length);
	Assert.AreEqual(0xe2, bs[0]);
	Assert.AreEqual(0x82, bs[1]);
	Assert.AreEqual(0xac, bs[2]);
	}

	[Test]
	public void CopyFromPortion()
	{
	byte[] data = new byte[] {0, 1, 2, 3, 4, 5, 6};
	ByteString bs = ByteString.CopyFrom(data, 2, 3);
	Assert.AreEqual(3, bs.Length);
	Assert.AreEqual(2, bs[0]);
	Assert.AreEqual(3, bs[1]);
	}

	[Test]
	public void CopyTo()
	{
	byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
	ByteString bs = ByteString.CopyFrom(data);

	byte[] dest = new byte[data.Length];
	bs.CopyTo(dest, 0);

	CollectionAssert.AreEqual(data, dest);
	}

	[Test]
	public void GetEnumerator()
	{
	byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
	ByteString bs = ByteString.CopyFrom(data);

	IEnumerator<byte> genericEnumerator = bs.GetEnumerator();
	Assert.IsTrue(genericEnumerator.MoveNext());
	Assert.AreEqual(0, genericEnumerator.Current);

	IEnumerator enumerator = ((IEnumerable)bs).GetEnumerator();
	Assert.IsTrue(enumerator.MoveNext());
	Assert.AreEqual(0, enumerator.Current);

	// Call via LINQ
	CollectionAssert.AreEqual(bs.Span.ToArray(), bs.ToArray());
	}

	[Test]
	public void UnsafeWrap()
	{
	byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
	ByteString bs = UnsafeByteOperations.UnsafeWrap(data.AsMemory(2, 3));
	ReadOnlySpan<byte> s = bs.Span;

	Assert.AreEqual(3, s.Length);
	Assert.AreEqual(2, s[0]);
	Assert.AreEqual(3, s[1]);
	Assert.AreEqual(4, s[2]);

	// Check that the value is not a copy
	data[2] = byte.MaxValue;
	Assert.AreEqual(byte.MaxValue, s[0]);
	}

	[Test]
	public void CreateCodedInput_FromArraySegment()
	{
	byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
	ByteString bs = UnsafeByteOperations.UnsafeWrap(data.AsMemory(2, 3));
	CodedInputStream codedInputStream = bs.CreateCodedInput();

	byte[] bytes = codedInputStream.ReadRawBytes(3);

	Assert.AreEqual(3, bytes.Length);
	Assert.AreEqual(2, bytes[0]);
	Assert.AreEqual(3, bytes[1]);
	Assert.AreEqual(4, bytes[2]);
	Assert.IsTrue(codedInputStream.IsAtEnd);
	}

	[Test]
	public void WriteToStream()
	{
	byte[] data = new byte[] { 0, 1, 2, 3, 4, 5, 6 };
	ByteString bs = ByteString.CopyFrom(data);

	MemoryStream ms = new MemoryStream();
	bs.WriteTo(ms);

	CollectionAssert.AreEqual(data, ms.ToArray());
	}

	[Test]
	public void WriteToStream_Stackalloc()
	{
	byte[] data = Encoding.UTF8.GetBytes("Hello world");
	Span<byte> s = stackalloc byte[data.Length];
	data.CopyTo(s);

	MemoryStream ms = new MemoryStream();

	using (UnmanagedMemoryManager<byte> manager = new UnmanagedMemoryManager<byte>(s))
	{
	ByteString bs = ByteString.AttachBytes(manager.Memory);

	bs.WriteTo(ms);
	}

	CollectionAssert.AreEqual(data, ms.ToArray());
	}

	[Test]
	public void ToStringUtf8()
	{
	ByteString bs = ByteString.CopyFromUtf8("\u20ac");
	Assert.AreEqual("\u20ac", bs.ToStringUtf8());
	}

	[Test]
	public void ToStringWithExplicitEncoding()
	{
	ByteString bs = ByteString.CopyFrom("\u20ac", Encoding.Unicode);
	Assert.AreEqual("\u20ac", bs.ToString(Encoding.Unicode));
	}

	[Test]
	public void ToString_Stackalloc()
	{
	byte[] data = Encoding.UTF8.GetBytes("Hello world");
	Span<byte> s = stackalloc byte[data.Length];
	data.CopyTo(s);

	using (UnmanagedMemoryManager<byte> manager = new UnmanagedMemoryManager<byte>(s))
	{
	ByteString bs = ByteString.AttachBytes(manager.Memory);

	Assert.AreEqual("Hello world", bs.ToString(Encoding.UTF8));
	}
	}

	[Test]
	public void FromBase64_WithText()
	{
	byte[] data = new byte[] {0, 1, 2, 3, 4, 5, 6};
	string base64 = Convert.ToBase64String(data);
	ByteString bs = ByteString.FromBase64(base64);
	Assert.AreEqual(data, bs.ToByteArray());
	}

	[Test]
	public void FromBase64_Empty()
	{
	// Optimization which also fixes issue 61.
	Assert.AreSame(ByteString.Empty, ByteString.FromBase64(""));
	}

	[Test]
	public void ToBase64_Array()
	{
	ByteString bs = ByteString.CopyFrom(Encoding.UTF8.GetBytes("Hello world"));

	Assert.AreEqual("SGVsbG8gd29ybGQ=", bs.ToBase64());
	}

	[Test]
	public void ToBase64_Stackalloc()
	{
	byte[] data = Encoding.UTF8.GetBytes("Hello world");
	Span<byte> s = stackalloc byte[data.Length];
	data.CopyTo(s);

	using (UnmanagedMemoryManager<byte> manager = new UnmanagedMemoryManager<byte>(s))
	{
	ByteString bs = ByteString.AttachBytes(manager.Memory);

	Assert.AreEqual("SGVsbG8gd29ybGQ=", bs.ToBase64());
	}
	}

	[Test]
	public void FromStream_Seekable()
	{
	var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
	// Consume the first byte, just to test that it's "from current position"
	stream.ReadByte();
	var actual = ByteString.FromStream(stream);
	ByteString expected = ByteString.CopyFrom(2, 3, 4, 5);
	Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
	}

	[Test]
	public void FromStream_NotSeekable()
	{
	var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
	// Consume the first byte, just to test that it's "from current position"
	stream.ReadByte();
	// Wrap the original stream in LimitedInputStream, which has CanSeek=false
	var limitedStream = new LimitedInputStream(stream, 3);
	var actual = ByteString.FromStream(limitedStream);
	ByteString expected = ByteString.CopyFrom(2, 3, 4);
	Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
	}

	[Test]
	public async Task FromStreamAsync_Seekable()
	{
	var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
	// Consume the first byte, just to test that it's "from current position"
	stream.ReadByte();
	var actual = await ByteString.FromStreamAsync(stream);
	ByteString expected = ByteString.CopyFrom(2, 3, 4, 5);
	Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
	}

	[Test]
	public async Task FromStreamAsync_NotSeekable()
	{
	var stream = new MemoryStream(new byte[] { 1, 2, 3, 4, 5 });
	// Consume the first byte, just to test that it's "from current position"
	stream.ReadByte();
	// Wrap the original stream in LimitedInputStream, which has CanSeek=false
	var limitedStream = new LimitedInputStream(stream, 3);
	var actual = await ByteString.FromStreamAsync(limitedStream);
	ByteString expected = ByteString.CopyFrom(2, 3, 4);
	Assert.AreEqual(expected, actual, $"{expected.ToBase64()} != {actual.ToBase64()}");
	}

	[Test]
	public void GetHashCode_Regression()
	{
	// We used to have an awful hash algorithm where only the last four
	// bytes were relevant. This is a regression test for
	// https://github.com/protocolbuffers/protobuf/issues/2511

	ByteString b1 = ByteString.CopyFrom(100, 1, 2, 3, 4);
	ByteString b2 = ByteString.CopyFrom(200, 1, 2, 3, 4);
	Assert.AreNotEqual(b1.GetHashCode(), b2.GetHashCode());
	}

	[Test]
	public void GetContentsAsReadOnlySpan()
	{
	var byteString = ByteString.CopyFrom(1, 2, 3, 4, 5);
	var copied = byteString.Span.ToArray();
	CollectionAssert.AreEqual(byteString, copied);
	}

	[Test]
	public void GetContentsAsReadOnlyMemory()
	{
	var byteString = ByteString.CopyFrom(1, 2, 3, 4, 5);
	var copied = byteString.Memory.ToArray();
	CollectionAssert.AreEqual(byteString, copied);
	}

	// Create Memory<byte> from non-array source.
	// Use by ByteString tests that have optimized path for array backed Memory<byte>.
	private sealed unsafe class UnmanagedMemoryManager<T> : MemoryManager<T> where T : unmanaged
	{
	private readonly T* _pointer;
	private readonly int _length;

	public UnmanagedMemoryManager(Span<T> span)
	{
	fixed (T* ptr = &MemoryMarshal.GetReference(span))
	{
	_pointer = ptr;
	_length = span.Length;
	}
	}

	public override Span<T> GetSpan() => new Span<T>(_pointer, _length);

	public override MemoryHandle Pin(int elementIndex = 0)
	{
	if (elementIndex < 0 \|\| elementIndex >= _length)
	{
	throw new ArgumentOutOfRangeException(nameof(elementIndex));
	}

	return new MemoryHandle(_pointer + elementIndex);
	}

	public override void Unpin() { }

	protected override void Dispose(bool disposing) { }
	}
	}
	}