#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.Buffers.Binary;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
#if GOOGLE_PROTOBUF_SIMD
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.Arm;
using System.Runtime.Intrinsics.X86;
#endif
using System.Security;
using System.Text;
namespace Google.Protobuf
{
/// <summary>
/// Primitives for encoding protobuf wire format.
/// </summary>
[SecuritySafeCritical]
internal static class WritingPrimitives
{
#if NET5_0
internal static Encoding Utf8Encoding => Encoding.UTF8; // allows JIT to devirtualize
#else
internal static readonly Encoding Utf8Encoding = Encoding.UTF8; // "Local" copy of Encoding.UTF8, for efficiency. (Yes, it makes a difference.)
#endif
#region Writing of values (not including tags)
/// <summary>
/// Writes a double field value, without a tag, to the stream.
/// </summary>
public static void WriteDouble(ref Span<byte> buffer, ref WriterInternalState state, double value)
{
WriteRawLittleEndian64(ref buffer, ref state, (ulong)BitConverter.DoubleToInt64Bits(value));
}
/// <summary>
/// Writes a float field value, without a tag, to the stream.
/// </summary>
public static unsafe void WriteFloat(ref Span<byte> buffer, ref WriterInternalState state, float value)
{
const int length = sizeof(float);
if (buffer.Length - state.position >= length)
{
// if there's enough space in the buffer, write the float directly into the buffer
var floatSpan = buffer.Slice(state.position, length);
Unsafe.WriteUnaligned(ref MemoryMarshal.GetReference(floatSpan), value);
if (!BitConverter.IsLittleEndian)
{
floatSpan.Reverse();
}
state.position += length;
}
else
{
WriteFloatSlowPath(ref buffer, ref state, value);
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
private static unsafe void WriteFloatSlowPath(ref Span<byte> buffer, ref WriterInternalState state, float value)
{
const int length = sizeof(float);
// TODO(jtattermusch): deduplicate the code. Populating the span is the same as for the fastpath.
Span<byte> floatSpan = stackalloc byte[length];
Unsafe.WriteUnaligned(ref MemoryMarshal.GetReference(floatSpan), value);
if (!BitConverter.IsLittleEndian)
{
floatSpan.Reverse();
}
WriteRawByte(ref buffer, ref state, floatSpan[0]);
WriteRawByte(ref buffer, ref state, floatSpan[1]);
WriteRawByte(ref buffer, ref state, floatSpan[2]);
WriteRawByte(ref buffer, ref state, floatSpan[3]);
}
/// <summary>
/// Writes a uint64 field value, without a tag, to the stream.
/// </summary>
public static void WriteUInt64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
{
WriteRawVarint64(ref buffer, ref state, value);
}
/// <summary>
/// Writes an int64 field value, without a tag, to the stream.
/// </summary>
public static void WriteInt64(ref Span<byte> buffer, ref WriterInternalState state, long value)
{
WriteRawVarint64(ref buffer, ref state, (ulong)value);
}
/// <summary>
/// Writes an int32 field value, without a tag, to the stream.
/// </summary>
public static void WriteInt32(ref Span<byte> buffer, ref WriterInternalState state, int value)
{
if (value >= 0)
{
WriteRawVarint32(ref buffer, ref state, (uint)value);
}
else
{
// Must sign-extend.
WriteRawVarint64(ref buffer, ref state, (ulong)value);
}
}
/// <summary>
/// Writes a fixed64 field value, without a tag, to the stream.
/// </summary>
public static void WriteFixed64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
{
WriteRawLittleEndian64(ref buffer, ref state, value);
}
/// <summary>
/// Writes a fixed32 field value, without a tag, to the stream.
/// </summary>
public static void WriteFixed32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
{
WriteRawLittleEndian32(ref buffer, ref state, value);
}
/// <summary>
/// Writes a bool field value, without a tag, to the stream.
/// </summary>
public static void WriteBool(ref Span<byte> buffer, ref WriterInternalState state, bool value)
{
WriteRawByte(ref buffer, ref state, value ? (byte)1 : (byte)0);
}
/// <summary>
/// Writes a string field value, without a tag, to the stream.
/// The data is length-prefixed.
/// </summary>
public static void WriteString(ref Span<byte> buffer, ref WriterInternalState state, string value)
{
const int MaxBytesPerChar = 3;
const int MaxSmallStringLength = 128 / MaxBytesPerChar;
// The string is small enough that the length will always be a 1 byte varint.
// Also there is enough space to write length + bytes to buffer.
// Write string directly to the buffer, and then write length.
// This saves calling GetByteCount on the string. We get the string length from GetBytes.
if (value.Length <= MaxSmallStringLength && buffer.Length - state.position - 1 >= value.Length * MaxBytesPerChar)
{
int indexOfLengthDelimiter = state.position++;
buffer[indexOfLengthDelimiter] = (byte)WriteStringToBuffer(buffer, ref state, value);
return;
}
int length = Utf8Encoding.GetByteCount(value);
WriteLength(ref buffer, ref state, length);
// Optimise the case where we have enough space to write
// the string directly to the buffer, which should be common.
if (buffer.Length - state.position >= length)
{
if (length == value.Length) // Must be all ASCII...
{
WriteAsciiStringToBuffer(buffer, ref state, value, length);
}
else
{
WriteStringToBuffer(buffer, ref state, value);
}
}
else
{
// Opportunity for future optimization:
// Large strings that don't fit into the current buffer segment
// can probably be optimized by using Utf8Encoding.GetEncoder()
// but more benchmarks would need to be added as evidence.
byte[] bytes = Utf8Encoding.GetBytes(value);
WriteRawBytes(ref buffer, ref state, bytes);
}
}
// Calling this method with non-ASCII content will break.
// Content must be verified to be all ASCII before using this method.
private static void WriteAsciiStringToBuffer(Span<byte> buffer, ref WriterInternalState state, string value, int length)
{
ref char sourceChars = ref MemoryMarshal.GetReference(value.AsSpan());
ref byte destinationBytes = ref MemoryMarshal.GetReference(buffer.Slice(state.position));
int currentIndex = 0;
// If 64bit, process 4 chars at a time.
// The logic inside this check will be elided by JIT in 32bit programs.
if (IntPtr.Size == 8)
{
// Need at least 4 chars available to use this optimization.
if (length >= 4)
{
ref byte sourceBytes = ref Unsafe.As<char, byte>(ref sourceChars);
// Process 4 chars at a time until there are less than 4 remaining.
// We already know all characters are ASCII so there is no need to validate the source.
int lastIndexWhereCanReadFourChars = value.Length - 4;
do
{
NarrowFourUtf16CharsToAsciiAndWriteToBuffer(
ref Unsafe.AddByteOffset(ref destinationBytes, (IntPtr)currentIndex),
Unsafe.ReadUnaligned<ulong>(ref Unsafe.AddByteOffset(ref sourceBytes, (IntPtr)(currentIndex * 2))));
} while ((currentIndex += 4) <= lastIndexWhereCanReadFourChars);
}
}
// Process any remaining, 1 char at a time.
// Avoid bounds checking with ref + Unsafe
for (; currentIndex < length; currentIndex++)
{
Unsafe.AddByteOffset(ref destinationBytes, (IntPtr)currentIndex) = (byte)Unsafe.AddByteOffset(ref sourceChars, (IntPtr)(currentIndex * 2));
}
state.position += length;
}
// Copied with permission from https://github.com/dotnet/runtime/blob/1cdafd27e4afd2c916af5df949c13f8b373c4335/src/libraries/System.Private.CoreLib/src/System/Text/ASCIIUtility.cs#L1119-L1171
//
/// <summary>
/// Given a QWORD which represents a buffer of 4 ASCII chars in machine-endian order,
/// narrows each WORD to a BYTE, then writes the 4-byte result to the output buffer
/// also in machine-endian order.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void NarrowFourUtf16CharsToAsciiAndWriteToBuffer(ref byte outputBuffer, ulong value)
{
#if GOOGLE_PROTOBUF_SIMD
if (Sse2.X64.IsSupported)
{
// Narrows a vector of words [ w0 w1 w2 w3 ] to a vector of bytes
// [ b0 b1 b2 b3 b0 b1 b2 b3 ], then writes 4 bytes (32 bits) to the destination.
Vector128<short> vecWide = Sse2.X64.ConvertScalarToVector128UInt64(value).AsInt16();
Vector128<uint> vecNarrow = Sse2.PackUnsignedSaturate(vecWide, vecWide).AsUInt32();
Unsafe.WriteUnaligned<uint>(ref outputBuffer, Sse2.ConvertToUInt32(vecNarrow));
}
else if (AdvSimd.IsSupported)
{
// Narrows a vector of words [ w0 w1 w2 w3 ] to a vector of bytes
// [ b0 b1 b2 b3 * * * * ], then writes 4 bytes (32 bits) to the destination.
Vector128<short> vecWide = Vector128.CreateScalarUnsafe(value).AsInt16();
Vector64<byte> lower = AdvSimd.ExtractNarrowingSaturateUnsignedLower(vecWide);
Unsafe.WriteUnaligned<uint>(ref outputBuffer, lower.AsUInt32().ToScalar());
}
else
#endif
{
// Fallback to non-SIMD approach when SIMD is not available.
// This could happen either because the APIs are not available, or hardware doesn't support it.
// Processing 4 chars at a time in this fallback is still faster than casting one char at a time.
if (BitConverter.IsLittleEndian)
{
outputBuffer = (byte)value;
value >>= 16;
Unsafe.Add(ref outputBuffer, 1) = (byte)value;
value >>= 16;
Unsafe.Add(ref outputBuffer, 2) = (byte)value;
value >>= 16;
Unsafe.Add(ref outputBuffer, 3) = (byte)value;
}
else
{
Unsafe.Add(ref outputBuffer, 3) = (byte)value;
value >>= 16;
Unsafe.Add(ref outputBuffer, 2) = (byte)value;
value >>= 16;
Unsafe.Add(ref outputBuffer, 1) = (byte)value;
value >>= 16;
outputBuffer = (byte)value;
}
}
}
private static int WriteStringToBuffer(Span<byte> buffer, ref WriterInternalState state, string value)
{
#if NETSTANDARD1_1
// slowpath when Encoding.GetBytes(Char*, Int32, Byte*, Int32) is not available
byte[] bytes = Utf8Encoding.GetBytes(value);
WriteRawBytes(ref buffer, ref state, bytes);
return bytes.Length;
#else
ReadOnlySpan<char> source = value.AsSpan();
int bytesUsed;
unsafe
{
fixed (char* sourceChars = &MemoryMarshal.GetReference(source))
fixed (byte* destinationBytes = &MemoryMarshal.GetReference(buffer))
{
bytesUsed = Utf8Encoding.GetBytes(
sourceChars,
source.Length,
destinationBytes + state.position,
buffer.Length - state.position);
}
}
state.position += bytesUsed;
return bytesUsed;
#endif
}
/// <summary>
/// Write a byte string, without a tag, to the stream.
/// The data is length-prefixed.
/// </summary>
public static void WriteBytes(ref Span<byte> buffer, ref WriterInternalState state, ByteString value)
{
WriteLength(ref buffer, ref state, value.Length);
WriteRawBytes(ref buffer, ref state, value.Span);
}
/// <summary>
/// Writes a uint32 value, without a tag, to the stream.
/// </summary>
public static void WriteUInt32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
{
WriteRawVarint32(ref buffer, ref state, value);
}
/// <summary>
/// Writes an enum value, without a tag, to the stream.
/// </summary>
public static void WriteEnum(ref Span<byte> buffer, ref WriterInternalState state, int value)
{
WriteInt32(ref buffer, ref state, value);
}
/// <summary>
/// Writes an sfixed32 value, without a tag, to the stream.
/// </summary>
public static void WriteSFixed32(ref Span<byte> buffer, ref WriterInternalState state, int value)
{
WriteRawLittleEndian32(ref buffer, ref state, (uint)value);
}
/// <summary>
/// Writes an sfixed64 value, without a tag, to the stream.
/// </summary>
public static void WriteSFixed64(ref Span<byte> buffer, ref WriterInternalState state, long value)
{
WriteRawLittleEndian64(ref buffer, ref state, (ulong)value);
}
/// <summary>
/// Writes an sint32 value, without a tag, to the stream.
/// </summary>
public static void WriteSInt32(ref Span<byte> buffer, ref WriterInternalState state, int value)
{
WriteRawVarint32(ref buffer, ref state, EncodeZigZag32(value));
}
/// <summary>
/// Writes an sint64 value, without a tag, to the stream.
/// </summary>
public static void WriteSInt64(ref Span<byte> buffer, ref WriterInternalState state, long value)
{
WriteRawVarint64(ref buffer, ref state, EncodeZigZag64(value));
}
/// <summary>
/// Writes a length (in bytes) for length-delimited data.
/// </summary>
/// <remarks>
/// This method simply writes a rawint, but exists for clarity in calling code.
/// </remarks>
public static void WriteLength(ref Span<byte> buffer, ref WriterInternalState state, int length)
{
WriteRawVarint32(ref buffer, ref state, (uint)length);
}
#endregion
#region Writing primitives
/// <summary>
/// Writes a 32 bit value as a varint. The fast route is taken when
/// there's enough buffer space left to whizz through without checking
/// for each byte; otherwise, we resort to calling WriteRawByte each time.
/// </summary>
public static void WriteRawVarint32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
{
// Optimize for the common case of a single byte value
if (value < 128 && state.position < buffer.Length)
{
buffer[state.position++] = (byte)value;
return;
}
// Fast path when capacity is available
while (state.position < buffer.Length)
{
if (value > 127)
{
buffer[state.position++] = (byte)((value & 0x7F) | 0x80);
value >>= 7;
}
else
{
buffer[state.position++] = (byte)value;
return;
}
}
while (value > 127)
{
WriteRawByte(ref buffer, ref state, (byte)((value & 0x7F) | 0x80));
value >>= 7;
}
WriteRawByte(ref buffer, ref state, (byte)value);
}
public static void WriteRawVarint64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
{
// Optimize for the common case of a single byte value
if (value < 128 && state.position < buffer.Length)
{
buffer[state.position++] = (byte)value;
return;
}
// Fast path when capacity is available
while (state.position < buffer.Length)
{
if (value > 127)
{
buffer[state.position++] = (byte)((value & 0x7F) | 0x80);
value >>= 7;
}
else
{
buffer[state.position++] = (byte)value;
return;
}
}
while (value > 127)
{
WriteRawByte(ref buffer, ref state, (byte)((value & 0x7F) | 0x80));
value >>= 7;
}
WriteRawByte(ref buffer, ref state, (byte)value);
}
public static void WriteRawLittleEndian32(ref Span<byte> buffer, ref WriterInternalState state, uint value)
{
const int length = sizeof(uint);
if (state.position + length > buffer.Length)
{
WriteRawLittleEndian32SlowPath(ref buffer, ref state, value);
}
else
{
BinaryPrimitives.WriteUInt32LittleEndian(buffer.Slice(state.position), value);
state.position += length;
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
private static void WriteRawLittleEndian32SlowPath(ref Span<byte> buffer, ref WriterInternalState state, uint value)
{
WriteRawByte(ref buffer, ref state, (byte)value);
WriteRawByte(ref buffer, ref state, (byte)(value >> 8));
WriteRawByte(ref buffer, ref state, (byte)(value >> 16));
WriteRawByte(ref buffer, ref state, (byte)(value >> 24));
}
public static void WriteRawLittleEndian64(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
{
const int length = sizeof(ulong);
if (state.position + length > buffer.Length)
{
WriteRawLittleEndian64SlowPath(ref buffer, ref state, value);
}
else
{
BinaryPrimitives.WriteUInt64LittleEndian(buffer.Slice(state.position), value);
state.position += length;
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
public static void WriteRawLittleEndian64SlowPath(ref Span<byte> buffer, ref WriterInternalState state, ulong value)
{
WriteRawByte(ref buffer, ref state, (byte)value);
WriteRawByte(ref buffer, ref state, (byte)(value >> 8));
WriteRawByte(ref buffer, ref state, (byte)(value >> 16));
WriteRawByte(ref buffer, ref state, (byte)(value >> 24));
WriteRawByte(ref buffer, ref state, (byte)(value >> 32));
WriteRawByte(ref buffer, ref state, (byte)(value >> 40));
WriteRawByte(ref buffer, ref state, (byte)(value >> 48));
WriteRawByte(ref buffer, ref state, (byte)(value >> 56));
}
private static void WriteRawByte(ref Span<byte> buffer, ref WriterInternalState state, byte value)
{
if (state.position == buffer.Length)
{
WriteBufferHelper.RefreshBuffer(ref buffer, ref state);
}
buffer[state.position++] = value;
}
/// <summary>
/// Writes out an array of bytes.
/// </summary>
public static void WriteRawBytes(ref Span<byte> buffer, ref WriterInternalState state, byte[] value)
{
WriteRawBytes(ref buffer, ref state, new ReadOnlySpan<byte>(value));
}
/// <summary>
/// Writes out part of an array of bytes.
/// </summary>
public static void WriteRawBytes(ref Span<byte> buffer, ref WriterInternalState state, byte[] value, int offset, int length)
{
WriteRawBytes(ref buffer, ref state, new ReadOnlySpan<byte>(value, offset, length));
}
/// <summary>
/// Writes out part of an array of bytes.
/// </summary>
public static void WriteRawBytes(ref Span<byte> buffer, ref WriterInternalState state, ReadOnlySpan<byte> value)
{
if (buffer.Length - state.position >= value.Length)
{
// We have room in the current buffer.
value.CopyTo(buffer.Slice(state.position, value.Length));
state.position += value.Length;
}
else
{
// When writing to a CodedOutputStream backed by a Stream, we could avoid
// copying the data twice (first copying to the current buffer and
// and later writing from the current buffer to the underlying Stream)
// in some circumstances by writing the data directly to the underlying Stream.
// Current this is not being done to avoid specialcasing the code for
// CodedOutputStream vs IBufferWriter<byte>.
int bytesWritten = 0;
while (buffer.Length - state.position < value.Length - bytesWritten)
{
int length = buffer.Length - state.position;
value.Slice(bytesWritten, length).CopyTo(buffer.Slice(state.position, length));
bytesWritten += length;
state.position += length;
WriteBufferHelper.RefreshBuffer(ref buffer, ref state);
}
// copy the remaining data
int remainderLength = value.Length - bytesWritten;
value.Slice(bytesWritten, remainderLength).CopyTo(buffer.Slice(state.position, remainderLength));
state.position += remainderLength;
}
}
#endregion
#region Raw tag writing
/// <summary>
/// Encodes and writes a tag.
/// </summary>
public static void WriteTag(ref Span<byte> buffer, ref WriterInternalState state, int fieldNumber, WireFormat.WireType type)
{
WriteRawVarint32(ref buffer, ref state, WireFormat.MakeTag(fieldNumber, type));
}
/// <summary>
/// Writes an already-encoded tag.
/// </summary>
public static void WriteTag(ref Span<byte> buffer, ref WriterInternalState state, uint tag)
{
WriteRawVarint32(ref buffer, ref state, tag);
}
/// <summary>
/// Writes the given single-byte tag directly to the stream.
/// </summary>
public static void WriteRawTag(ref Span<byte> buffer, ref WriterInternalState state, byte b1)
{
WriteRawByte(ref buffer, ref state, b1);
}
/// <summary>
/// Writes the given two-byte tag directly to the stream.
/// </summary>
public static void WriteRawTag(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2)
{
if (state.position + 2 > buffer.Length)
{
WriteRawTagSlowPath(ref buffer, ref state, b1, b2);
}
else
{
buffer[state.position++] = b1;
buffer[state.position++] = b2;
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
private static void WriteRawTagSlowPath(ref Span<byte> buffer, ref WriterInternalState state, byte b1, byte b2)
{
WriteRawByte(ref buffer, ref state, b1);
WriteRawByte(ref buffer, ref state, b2);
}
/// <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));
}
}
}
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