#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.Collections;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
using System.Security;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace Google.Protobuf
{
/// <summary>
/// Immutable array of bytes.
/// </summary>
[SecuritySafeCritical]
public sealed class ByteString : IEnumerable<byte>, IEquatable<ByteString>
{
private static readonly ByteString empty = new ByteString(new byte[0]);
private readonly ReadOnlyMemory<byte> bytes;
/// <summary>
/// Internal use only. Ensure that the provided memory is not mutated and belongs to this instance.
/// </summary>
internal static ByteString AttachBytes(ReadOnlyMemory<byte> bytes)
{
return new ByteString(bytes);
}
/// <summary>
/// Internal use only. Ensure that the provided memory is not mutated and belongs to this instance.
/// This method encapsulates converting array to memory. Reduces need for SecuritySafeCritical
/// in .NET Framework.
/// </summary>
internal static ByteString AttachBytes(byte[] bytes)
{
return AttachBytes(bytes.AsMemory());
}
/// <summary>
/// Constructs a new ByteString from the given memory. The memory is
/// *not* copied, and must not be modified after this constructor is called.
/// </summary>
private ByteString(ReadOnlyMemory<byte> bytes)
{
this.bytes = bytes;
}
/// <summary>
/// Returns an empty ByteString.
/// </summary>
public static ByteString Empty
{
get { return empty; }
}
/// <summary>
/// Returns the length of this ByteString in bytes.
/// </summary>
public int Length
{
get { return bytes.Length; }
}
/// <summary>
/// Returns <c>true</c> if this byte string is empty, <c>false</c> otherwise.
/// </summary>
public bool IsEmpty
{
get { return Length == 0; }
}
/// <summary>
/// Provides read-only access to the data of this <see cref="ByteString"/>.
/// No data is copied so this is the most efficient way of accessing.
/// </summary>
public ReadOnlySpan<byte> Span
{
get { return bytes.Span; }
}
/// <summary>
/// Provides read-only access to the data of this <see cref="ByteString"/>.
/// No data is copied so this is the most efficient way of accessing.
/// </summary>
public ReadOnlyMemory<byte> Memory
{
get { return bytes; }
}
/// <summary>
/// Converts this <see cref="ByteString"/> into a byte array.
/// </summary>
/// <remarks>The data is copied - changes to the returned array will not be reflected in this <c>ByteString</c>.</remarks>
/// <returns>A byte array with the same data as this <c>ByteString</c>.</returns>
public byte[] ToByteArray()
{
return bytes.ToArray();
}
/// <summary>
/// Converts this <see cref="ByteString"/> into a standard base64 representation.
/// </summary>
/// <returns>A base64 representation of this <c>ByteString</c>.</returns>
public string ToBase64()
{
if (MemoryMarshal.TryGetArray(bytes, out ArraySegment<byte> segment))
{
// Fast path. ByteString was created with an array, so pass the underlying array.
return Convert.ToBase64String(segment.Array, segment.Offset, segment.Count);
}
else
{
// Slow path. BytesString is not an array. Convert memory and pass result to ToBase64String.
return Convert.ToBase64String(bytes.ToArray());
}
}
/// <summary>
/// Constructs a <see cref="ByteString" /> from the Base64 Encoded String.
/// </summary>
public static ByteString FromBase64(string bytes)
{
// By handling the empty string explicitly, we not only optimize but we fix a
// problem on CF 2.0. See issue 61 for details.
return bytes == "" ? Empty : new ByteString(Convert.FromBase64String(bytes));
}
/// <summary>
/// Constructs a <see cref="ByteString"/> from data in the given stream, synchronously.
/// </summary>
/// <remarks>If successful, <paramref name="stream"/> will be read completely, from the position
/// at the start of the call.</remarks>
/// <param name="stream">The stream to copy into a ByteString.</param>
/// <returns>A ByteString with content read from the given stream.</returns>
public static ByteString FromStream(Stream stream)
{
ProtoPreconditions.CheckNotNull(stream, nameof(stream));
int capacity = stream.CanSeek ? checked((int) (stream.Length - stream.Position)) : 0;
var memoryStream = new MemoryStream(capacity);
stream.CopyTo(memoryStream);
#if NETSTANDARD1_1 || NETSTANDARD2_0
byte[] bytes = memoryStream.ToArray();
#else
// Avoid an extra copy if we can.
byte[] bytes = memoryStream.Length == memoryStream.Capacity ? memoryStream.GetBuffer() : memoryStream.ToArray();
#endif
return AttachBytes(bytes);
}
/// <summary>
/// Constructs a <see cref="ByteString"/> from data in the given stream, asynchronously.
/// </summary>
/// <remarks>If successful, <paramref name="stream"/> will be read completely, from the position
/// at the start of the call.</remarks>
/// <param name="stream">The stream to copy into a ByteString.</param>
/// <param name="cancellationToken">The cancellation token to use when reading from the stream, if any.</param>
/// <returns>A ByteString with content read from the given stream.</returns>
public static Task<ByteString> FromStreamAsync(Stream stream, CancellationToken cancellationToken = default(CancellationToken))
{
ProtoPreconditions.CheckNotNull(stream, nameof(stream));
return ByteStringAsync.FromStreamAsyncCore(stream, cancellationToken);
}
/// <summary>
/// Constructs a <see cref="ByteString" /> from the given array. The contents
/// are copied, so further modifications to the array will not
/// be reflected in the returned ByteString.
/// This method can also be invoked in <c>ByteString.CopyFrom(0xaa, 0xbb, ...)</c> form
/// which is primarily useful for testing.
/// </summary>
public static ByteString CopyFrom(params byte[] bytes)
{
return new ByteString((byte[]) bytes.Clone());
}
/// <summary>
/// Constructs a <see cref="ByteString" /> from a portion of a byte array.
/// </summary>
public static ByteString CopyFrom(byte[] bytes, int offset, int count)
{
byte[] portion = new byte[count];
ByteArray.Copy(bytes, offset, portion, 0, count);
return new ByteString(portion);
}
/// <summary>
/// Constructs a <see cref="ByteString" /> from a read only span. The contents
/// are copied, so further modifications to the span will not
/// be reflected in the returned <see cref="ByteString" />.
/// </summary>
public static ByteString CopyFrom(ReadOnlySpan<byte> bytes)
{
return new ByteString(bytes.ToArray());
}
/// <summary>
/// Creates a new <see cref="ByteString" /> by encoding the specified text with
/// the given encoding.
/// </summary>
public static ByteString CopyFrom(string text, Encoding encoding)
{
return new ByteString(encoding.GetBytes(text));
}
/// <summary>
/// Creates a new <see cref="ByteString" /> by encoding the specified text in UTF-8.
/// </summary>
public static ByteString CopyFromUtf8(string text)
{
return CopyFrom(text, Encoding.UTF8);
}
/// <summary>
/// Returns the byte at the given index.
/// </summary>
public byte this[int index]
{
get { return bytes.Span[index]; }
}
/// <summary>
/// Converts this <see cref="ByteString"/> into a string by applying the given encoding.
/// </summary>
/// <remarks>
/// This method should only be used to convert binary data which was the result of encoding
/// text with the given encoding.
/// </remarks>
/// <param name="encoding">The encoding to use to decode the binary data into text.</param>
/// <returns>The result of decoding the binary data with the given decoding.</returns>
public string ToString(Encoding encoding)
{
if (MemoryMarshal.TryGetArray(bytes, out ArraySegment<byte> segment))
{
// Fast path. ByteString was created with an array.
return encoding.GetString(segment.Array, segment.Offset, segment.Count);
}
else
{
// Slow path. BytesString is not an array. Convert memory and pass result to GetString.
// TODO: Consider using GetString overload that takes a pointer.
byte[] array = bytes.ToArray();
return encoding.GetString(array, 0, array.Length);
}
}
/// <summary>
/// Converts this <see cref="ByteString"/> into a string by applying the UTF-8 encoding.
/// </summary>
/// <remarks>
/// This method should only be used to convert binary data which was the result of encoding
/// text with UTF-8.
/// </remarks>
/// <returns>The result of decoding the binary data with the given decoding.</returns>
public string ToStringUtf8()
{
return ToString(Encoding.UTF8);
}
/// <summary>
/// Returns an iterator over the bytes in this <see cref="ByteString"/>.
/// </summary>
/// <returns>An iterator over the bytes in this object.</returns>
[SecuritySafeCritical]
public IEnumerator<byte> GetEnumerator()
{
return MemoryMarshal.ToEnumerable(bytes).GetEnumerator();
}
/// <summary>
/// Returns an iterator over the bytes in this <see cref="ByteString"/>.
/// </summary>
/// <returns>An iterator over the bytes in this object.</returns>
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
/// <summary>
/// Creates a CodedInputStream from this ByteString's data.
/// </summary>
public CodedInputStream CreateCodedInput()
{
// We trust CodedInputStream not to reveal the provided byte array or modify it
if (MemoryMarshal.TryGetArray(bytes, out ArraySegment<byte> segment) && segment.Count == bytes.Length)
{
// Fast path. ByteString was created with a complete array.
return new CodedInputStream(segment.Array, segment.Offset, segment.Count);
}
else
{
// Slow path. BytesString is not an array, or is a slice of an array.
// Convert memory and pass result to WriteRawBytes.
return new CodedInputStream(bytes.ToArray());
}
}
/// <summary>
/// Compares two byte strings for equality.
/// </summary>
/// <param name="lhs">The first byte string to compare.</param>
/// <param name="rhs">The second byte string to compare.</param>
/// <returns><c>true</c> if the byte strings are equal; false otherwise.</returns>
public static bool operator ==(ByteString lhs, ByteString rhs)
{
if (ReferenceEquals(lhs, rhs))
{
return true;
}
if (ReferenceEquals(lhs, null) || ReferenceEquals(rhs, null))
{
return false;
}
return lhs.bytes.Span.SequenceEqual(rhs.bytes.Span);
}
/// <summary>
/// Compares two byte strings for inequality.
/// </summary>
/// <param name="lhs">The first byte string to compare.</param>
/// <param name="rhs">The second byte string to compare.</param>
/// <returns><c>false</c> if the byte strings are equal; true otherwise.</returns>
public static bool operator !=(ByteString lhs, ByteString rhs)
{
return !(lhs == rhs);
}
/// <summary>
/// Compares this byte string with another object.
/// </summary>
/// <param name="obj">The object to compare this with.</param>
/// <returns><c>true</c> if <paramref name="obj"/> refers to an equal <see cref="ByteString"/>; <c>false</c> otherwise.</returns>
[SecuritySafeCritical]
public override bool Equals(object obj)
{
return this == (obj as ByteString);
}
/// <summary>
/// Returns a hash code for this object. Two equal byte strings
/// will return the same hash code.
/// </summary>
/// <returns>A hash code for this object.</returns>
[SecuritySafeCritical]
public override int GetHashCode()
{
ReadOnlySpan<byte> b = bytes.Span;
int ret = 23;
for (int i = 0; i < b.Length; i++)
{
ret = (ret * 31) + b[i];
}
return ret;
}
/// <summary>
/// Compares this byte string with another.
/// </summary>
/// <param name="other">The <see cref="ByteString"/> to compare this with.</param>
/// <returns><c>true</c> if <paramref name="other"/> refers to an equal byte string; <c>false</c> otherwise.</returns>
public bool Equals(ByteString other)
{
return this == other;
}
/// <summary>
/// Copies the entire byte array to the destination array provided at the offset specified.
/// </summary>
public void CopyTo(byte[] array, int position)
{
bytes.CopyTo(array.AsMemory(position));
}
/// <summary>
/// Writes the entire byte array to the provided stream
/// </summary>
public void WriteTo(Stream outputStream)
{
if (MemoryMarshal.TryGetArray(bytes, out ArraySegment<byte> segment))
{
// Fast path. ByteString was created with an array, so pass the underlying array.
outputStream.Write(segment.Array, segment.Offset, segment.Count);
}
else
{
// Slow path. BytesString is not an array. Convert memory and pass result to WriteRawBytes.
var array = bytes.ToArray();
outputStream.Write(array, 0, array.Length);
}
}
}
}