628 lines
24 KiB
C#
628 lines
24 KiB
C#
#region Copyright notice and license
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// Protocol Buffers - Google's data interchange format
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// Copyright 2008 Google Inc. All rights reserved.
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// https://developers.google.com/protocol-buffers/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#endregion
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using System;
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using System.Buffers.Binary;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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using System.Security;
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using System.Text;
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namespace LC.Google.Protobuf
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{
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/// <summary>
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/// Primitives for encoding protobuf wire format.
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/// </summary>
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[SecuritySafeCritical]
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internal static class WritingPrimitives
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{
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// "Local" copy of Encoding.UTF8, for efficiency. (Yes, it makes a difference.)
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internal static readonly Encoding Utf8Encoding = Encoding.UTF8;
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#region Writing of values (not including tags)
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/// <summary>
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/// Writes a double field value, without a tag, to the stream.
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/// </summary>
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public static void WriteDouble(ref Span<byte> buffer, ref WriterInternalState state, double value)
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{
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WriteRawLittleEndian64(ref buffer, ref state, (ulong)BitConverter.DoubleToInt64Bits(value));
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}
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/// <summary>
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/// Writes a float field value, without a tag, to the stream.
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/// </summary>
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public static unsafe void WriteFloat(ref Span<byte> buffer, ref WriterInternalState state, float value)
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{
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const int length = sizeof(float);
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if (buffer.Length - state.position >= length)
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{
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// if there's enough space in the buffer, write the float directly into the buffer
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var floatSpan = buffer.Slice(state.position, length);
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Unsafe.WriteUnaligned(ref MemoryMarshal.GetReference(floatSpan), value);
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if (!BitConverter.IsLittleEndian)
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{
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floatSpan.Reverse();
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}
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state.position += length;
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}
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else
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{
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WriteFloatSlowPath(ref buffer, ref state, value);
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}
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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private static unsafe void WriteFloatSlowPath(ref Span<byte> buffer, ref WriterInternalState state, float value)
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{
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const int length = sizeof(float);
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// TODO(jtattermusch): deduplicate the code. Populating the span is the same as for the fastpath.
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Span<byte> floatSpan = stackalloc byte[length];
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Unsafe.WriteUnaligned(ref MemoryMarshal.GetReference(floatSpan), value);
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if (!BitConverter.IsLittleEndian)
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{
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floatSpan.Reverse();
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}
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WriteRawByte(ref buffer, ref state, floatSpan[0]);
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WriteRawByte(ref buffer, ref state, floatSpan[1]);
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WriteRawByte(ref buffer, ref state, floatSpan[2]);
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WriteRawByte(ref buffer, ref state, floatSpan[3]);
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}
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/// <summary>
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/// Writes a uint64 field value, without a tag, to the stream.
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/// </summary>
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public static void WriteUInt64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
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{
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WriteRawVarint64(ref buffer, ref state, value);
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}
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/// <summary>
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/// Writes an int64 field value, without a tag, to the stream.
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/// </summary>
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public static void WriteInt64(ref Span<byte> buffer, ref WriterInternalState state, long value)
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{
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WriteRawVarint64(ref buffer, ref state, (ulong)value);
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}
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/// <summary>
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/// Writes an int32 field value, without a tag, to the stream.
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/// </summary>
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public static void WriteInt32(ref Span<byte> buffer, ref WriterInternalState state, int value)
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{
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if (value >= 0)
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{
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WriteRawVarint32(ref buffer, ref state, (uint)value);
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}
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else
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{
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// Must sign-extend.
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WriteRawVarint64(ref buffer, ref state, (ulong)value);
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}
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}
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/// <summary>
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/// Writes a fixed64 field value, without a tag, to the stream.
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/// </summary>
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public static void WriteFixed64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
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{
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WriteRawLittleEndian64(ref buffer, ref state, value);
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}
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/// <summary>
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/// Writes a fixed32 field value, without a tag, to the stream.
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/// </summary>
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public static void WriteFixed32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
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{
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WriteRawLittleEndian32(ref buffer, ref state, value);
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}
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/// <summary>
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/// Writes a bool field value, without a tag, to the stream.
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/// </summary>
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public static void WriteBool(ref Span<byte> buffer, ref WriterInternalState state, bool value)
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{
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WriteRawByte(ref buffer, ref state, value ? (byte)1 : (byte)0);
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}
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/// <summary>
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/// Writes a string field value, without a tag, to the stream.
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/// The data is length-prefixed.
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/// </summary>
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public static void WriteString(ref Span<byte> buffer, ref WriterInternalState state, string value)
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{
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// Optimise the case where we have enough space to write
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// the string directly to the buffer, which should be common.
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int length = Utf8Encoding.GetByteCount(value);
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WriteLength(ref buffer, ref state, length);
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if (buffer.Length - state.position >= length)
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{
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if (length == value.Length) // Must be all ASCII...
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{
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for (int i = 0; i < length; i++)
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{
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buffer[state.position + i] = (byte)value[i];
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}
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state.position += length;
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}
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else
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{
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#if NETSTANDARD1_1
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// slowpath when Encoding.GetBytes(Char*, Int32, Byte*, Int32) is not available
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byte[] bytes = Utf8Encoding.GetBytes(value);
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WriteRawBytes(ref buffer, ref state, bytes);
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#else
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ReadOnlySpan<char> source = value.AsSpan();
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int bytesUsed;
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unsafe
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{
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fixed (char* sourceChars = &MemoryMarshal.GetReference(source))
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fixed (byte* destinationBytes = &MemoryMarshal.GetReference(buffer.Slice(state.position)))
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{
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bytesUsed = Utf8Encoding.GetBytes(sourceChars, source.Length, destinationBytes, buffer.Length);
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}
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}
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state.position += bytesUsed;
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#endif
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}
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}
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else
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{
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// Opportunity for future optimization:
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// Large strings that don't fit into the current buffer segment
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// can probably be optimized by using Utf8Encoding.GetEncoder()
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// but more benchmarks would need to be added as evidence.
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byte[] bytes = Utf8Encoding.GetBytes(value);
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WriteRawBytes(ref buffer, ref state, bytes);
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}
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}
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/// <summary>
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/// Write a byte string, without a tag, to the stream.
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/// The data is length-prefixed.
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/// </summary>
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public static void WriteBytes(ref Span<byte> buffer, ref WriterInternalState state, ByteString value)
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{
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WriteLength(ref buffer, ref state, value.Length);
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WriteRawBytes(ref buffer, ref state, value.Span);
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}
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/// <summary>
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/// Writes a uint32 value, without a tag, to the stream.
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/// </summary>
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public static void WriteUInt32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
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{
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WriteRawVarint32(ref buffer, ref state, value);
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}
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/// <summary>
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/// Writes an enum value, without a tag, to the stream.
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/// </summary>
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public static void WriteEnum(ref Span<byte> buffer, ref WriterInternalState state, int value)
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{
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WriteInt32(ref buffer, ref state, value);
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}
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/// <summary>
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/// Writes an sfixed32 value, without a tag, to the stream.
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/// </summary>
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public static void WriteSFixed32(ref Span<byte> buffer, ref WriterInternalState state, int value)
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{
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WriteRawLittleEndian32(ref buffer, ref state, (uint)value);
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}
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/// <summary>
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/// Writes an sfixed64 value, without a tag, to the stream.
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/// </summary>
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public static void WriteSFixed64(ref Span<byte> buffer, ref WriterInternalState state, long value)
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{
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WriteRawLittleEndian64(ref buffer, ref state, (ulong)value);
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}
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/// <summary>
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/// Writes an sint32 value, without a tag, to the stream.
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/// </summary>
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public static void WriteSInt32(ref Span<byte> buffer, ref WriterInternalState state, int value)
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{
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WriteRawVarint32(ref buffer, ref state, EncodeZigZag32(value));
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}
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/// <summary>
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/// Writes an sint64 value, without a tag, to the stream.
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/// </summary>
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public static void WriteSInt64(ref Span<byte> buffer, ref WriterInternalState state, long value)
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{
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WriteRawVarint64(ref buffer, ref state, EncodeZigZag64(value));
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}
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/// <summary>
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/// Writes a length (in bytes) for length-delimited data.
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/// </summary>
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/// <remarks>
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/// This method simply writes a rawint, but exists for clarity in calling code.
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/// </remarks>
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public static void WriteLength(ref Span<byte> buffer, ref WriterInternalState state, int length)
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{
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WriteRawVarint32(ref buffer, ref state, (uint)length);
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}
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#endregion
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#region Writing primitives
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/// <summary>
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/// Writes a 32 bit value as a varint. The fast route is taken when
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/// there's enough buffer space left to whizz through without checking
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/// for each byte; otherwise, we resort to calling WriteRawByte each time.
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/// </summary>
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public static void WriteRawVarint32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
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{
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// Optimize for the common case of a single byte value
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if (value < 128 && state.position < buffer.Length)
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{
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buffer[state.position++] = (byte)value;
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return;
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}
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// Fast path when capacity is available
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while (state.position < buffer.Length)
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{
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if (value > 127)
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{
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buffer[state.position++] = (byte)((value & 0x7F) | 0x80);
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value >>= 7;
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}
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else
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{
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buffer[state.position++] = (byte)value;
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return;
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}
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}
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while (value > 127)
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{
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WriteRawByte(ref buffer, ref state, (byte)((value & 0x7F) | 0x80));
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value >>= 7;
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}
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WriteRawByte(ref buffer, ref state, (byte)value);
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}
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public static void WriteRawVarint64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
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{
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// Optimize for the common case of a single byte value
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if (value < 128 && state.position < buffer.Length)
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{
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buffer[state.position++] = (byte)value;
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return;
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}
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// Fast path when capacity is available
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while (state.position < buffer.Length)
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{
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if (value > 127)
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{
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buffer[state.position++] = (byte)((value & 0x7F) | 0x80);
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value >>= 7;
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}
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else
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{
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buffer[state.position++] = (byte)value;
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return;
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}
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}
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while (value > 127)
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{
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WriteRawByte(ref buffer, ref state, (byte)((value & 0x7F) | 0x80));
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value >>= 7;
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}
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WriteRawByte(ref buffer, ref state, (byte)value);
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}
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public static void WriteRawLittleEndian32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
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{
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const int length = sizeof(uint);
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if (state.position + length > buffer.Length)
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{
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WriteRawLittleEndian32SlowPath(ref buffer, ref state, value);
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}
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else
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{
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BinaryPrimitives.WriteUInt32LittleEndian(buffer.Slice(state.position), value);
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state.position += length;
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}
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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private static void WriteRawLittleEndian32SlowPath(ref Span<byte> buffer, ref WriterInternalState state, uint value)
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{
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WriteRawByte(ref buffer, ref state, (byte)value);
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WriteRawByte(ref buffer, ref state, (byte)(value >> 8));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 16));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 24));
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}
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public static void WriteRawLittleEndian64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
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{
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const int length = sizeof(ulong);
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if (state.position + length > buffer.Length)
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{
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WriteRawLittleEndian64SlowPath(ref buffer, ref state, value);
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}
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else
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{
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BinaryPrimitives.WriteUInt64LittleEndian(buffer.Slice(state.position), value);
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state.position += length;
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}
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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public static void WriteRawLittleEndian64SlowPath(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
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{
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WriteRawByte(ref buffer, ref state, (byte)value);
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WriteRawByte(ref buffer, ref state, (byte)(value >> 8));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 16));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 24));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 32));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 40));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 48));
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WriteRawByte(ref buffer, ref state, (byte)(value >> 56));
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}
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private static void WriteRawByte(ref Span<byte> buffer, ref WriterInternalState state, byte value)
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{
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if (state.position == buffer.Length)
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{
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WriteBufferHelper.RefreshBuffer(ref buffer, ref state);
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}
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buffer[state.position++] = value;
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}
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/// <summary>
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/// Writes out an array of bytes.
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/// </summary>
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public static void WriteRawBytes(ref Span<byte> buffer, ref WriterInternalState state, byte[] value)
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{
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WriteRawBytes(ref buffer, ref state, new ReadOnlySpan<byte>(value));
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}
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/// <summary>
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/// Writes out part of an array of bytes.
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/// </summary>
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public static void WriteRawBytes(ref Span<byte> buffer, ref WriterInternalState state, byte[] value, int offset, int length)
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{
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WriteRawBytes(ref buffer, ref state, new ReadOnlySpan<byte>(value, offset, length));
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}
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/// <summary>
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/// Writes out part of an array of bytes.
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/// </summary>
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public static void WriteRawBytes(ref Span<byte> buffer, ref WriterInternalState state, ReadOnlySpan<byte> value)
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{
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if (buffer.Length - state.position >= value.Length)
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{
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// We have room in the current buffer.
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value.CopyTo(buffer.Slice(state.position, value.Length));
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state.position += value.Length;
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}
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else
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{
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// When writing to a CodedOutputStream backed by a Stream, we could avoid
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// copying the data twice (first copying to the current buffer and
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// and later writing from the current buffer to the underlying Stream)
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// in some circumstances by writing the data directly to the underlying Stream.
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// Current this is not being done to avoid specialcasing the code for
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// CodedOutputStream vs IBufferWriter<byte>.
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int bytesWritten = 0;
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while (buffer.Length - state.position < value.Length - bytesWritten)
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{
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int length = buffer.Length - state.position;
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value.Slice(bytesWritten, length).CopyTo(buffer.Slice(state.position, length));
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bytesWritten += length;
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state.position += length;
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WriteBufferHelper.RefreshBuffer(ref buffer, ref state);
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}
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// copy the remaining data
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int remainderLength = value.Length - bytesWritten;
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value.Slice(bytesWritten, remainderLength).CopyTo(buffer.Slice(state.position, remainderLength));
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state.position += remainderLength;
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}
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}
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#endregion
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#region Raw tag writing
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/// <summary>
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/// Encodes and writes a tag.
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/// </summary>
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public static void WriteTag(ref Span<byte> buffer, ref WriterInternalState state, int fieldNumber, WireFormat.WireType type)
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{
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WriteRawVarint32(ref buffer, ref state, WireFormat.MakeTag(fieldNumber, type));
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}
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/// <summary>
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/// Writes an already-encoded tag.
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/// </summary>
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public static void WriteTag(ref Span<byte> buffer, ref WriterInternalState state, uint tag)
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{
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WriteRawVarint32(ref buffer, ref state, tag);
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}
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/// <summary>
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/// Writes the given single-byte tag directly to the stream.
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/// </summary>
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public static void WriteRawTag(ref Span<byte> buffer, ref WriterInternalState state, byte b1)
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{
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WriteRawByte(ref buffer, ref state, b1);
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}
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/// <summary>
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/// Writes the given two-byte tag directly to the stream.
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/// </summary>
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public static void WriteRawTag(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2)
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{
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if (state.position + 2 > buffer.Length)
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{
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WriteRawTagSlowPath(ref buffer, ref state, b1, b2);
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}
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else
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{
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buffer[state.position++] = b1;
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buffer[state.position++] = b2;
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}
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}
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[MethodImpl(MethodImplOptions.NoInlining)]
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private static void WriteRawTagSlowPath(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2)
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{
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WriteRawByte(ref buffer, ref state, b1);
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WriteRawByte(ref buffer, ref state, b2);
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}
|
|
|
|
/// <summary>
|
|
/// Writes the given three-byte tag directly to the stream.
|
|
/// </summary>
|
|
public static void WriteRawTag(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2, byte b3)
|
|
{
|
|
if (state.position + 3 > buffer.Length)
|
|
{
|
|
WriteRawTagSlowPath(ref buffer, ref state, b1, b2, b3);
|
|
}
|
|
else
|
|
{
|
|
buffer[state.position++] = b1;
|
|
buffer[state.position++] = b2;
|
|
buffer[state.position++] = b3;
|
|
}
|
|
}
|
|
|
|
[MethodImpl(MethodImplOptions.NoInlining)]
|
|
private static void WriteRawTagSlowPath(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2, byte b3)
|
|
{
|
|
WriteRawByte(ref buffer, ref state, b1);
|
|
WriteRawByte(ref buffer, ref state, b2);
|
|
WriteRawByte(ref buffer, ref state, b3);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Writes the given four-byte tag directly to the stream.
|
|
/// </summary>
|
|
public static void WriteRawTag(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2, byte b3, byte b4)
|
|
{
|
|
if (state.position + 4 > buffer.Length)
|
|
{
|
|
WriteRawTagSlowPath(ref buffer, ref state, b1, b2, b3, b4);
|
|
}
|
|
else
|
|
{
|
|
buffer[state.position++] = b1;
|
|
buffer[state.position++] = b2;
|
|
buffer[state.position++] = b3;
|
|
buffer[state.position++] = b4;
|
|
}
|
|
}
|
|
|
|
[MethodImpl(MethodImplOptions.NoInlining)]
|
|
|
|
private static void WriteRawTagSlowPath(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2, byte b3, byte b4)
|
|
{
|
|
WriteRawByte(ref buffer, ref state, b1);
|
|
WriteRawByte(ref buffer, ref state, b2);
|
|
WriteRawByte(ref buffer, ref state, b3);
|
|
WriteRawByte(ref buffer, ref state, b4);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Writes the given five-byte tag directly to the stream.
|
|
/// </summary>
|
|
public static void WriteRawTag(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2, byte b3, byte b4, byte b5)
|
|
{
|
|
if (state.position + 5 > buffer.Length)
|
|
{
|
|
WriteRawTagSlowPath(ref buffer, ref state, b1, b2, b3, b4, b5);
|
|
}
|
|
else
|
|
{
|
|
buffer[state.position++] = b1;
|
|
buffer[state.position++] = b2;
|
|
buffer[state.position++] = b3;
|
|
buffer[state.position++] = b4;
|
|
buffer[state.position++] = b5;
|
|
}
|
|
}
|
|
|
|
[MethodImpl(MethodImplOptions.NoInlining)]
|
|
private static void WriteRawTagSlowPath(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2, byte b3, byte b4, byte b5)
|
|
{
|
|
WriteRawByte(ref buffer, ref state, b1);
|
|
WriteRawByte(ref buffer, ref state, b2);
|
|
WriteRawByte(ref buffer, ref state, b3);
|
|
WriteRawByte(ref buffer, ref state, b4);
|
|
WriteRawByte(ref buffer, ref state, b5);
|
|
}
|
|
#endregion
|
|
|
|
/// <summary>
|
|
/// Encode a 32-bit value with ZigZag encoding.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// ZigZag encodes signed integers into values that can be efficiently
|
|
/// encoded with varint. (Otherwise, negative values must be
|
|
/// sign-extended to 64 bits to be varint encoded, thus always taking
|
|
/// 10 bytes on the wire.)
|
|
/// </remarks>
|
|
public static uint EncodeZigZag32(int n)
|
|
{
|
|
// Note: the right-shift must be arithmetic
|
|
return (uint)((n << 1) ^ (n >> 31));
|
|
}
|
|
|
|
/// <summary>
|
|
/// Encode a 64-bit value with ZigZag encoding.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// ZigZag encodes signed integers into values that can be efficiently
|
|
/// encoded with varint. (Otherwise, negative values must be
|
|
/// sign-extended to 64 bits to be varint encoded, thus always taking
|
|
/// 10 bytes on the wire.)
|
|
/// </remarks>
|
|
public static ulong EncodeZigZag64(long n)
|
|
{
|
|
return (ulong)((n << 1) ^ (n >> 63));
|
|
}
|
|
}
|
|
} |