| #region Copyright notice and license |
| // Protocol Buffers - Google's data interchange format |
| // Copyright 2015 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.Generic; |
| |
| namespace Google.Protobuf |
| { |
| /// <summary> |
| /// Factory methods for <see cref="FieldCodec{T}"/>. |
| /// </summary> |
| public static class FieldCodec |
| { |
| // TODO: Avoid the "dual hit" of lambda expressions: create open delegates instead. (At least test...) |
| public static FieldCodec<string> ForString(uint tag) |
| { |
| return new FieldCodec<string>(input => input.ReadString(), (output, value) => output.WriteString(value), CodedOutputStream.ComputeStringSize, tag); |
| } |
| |
| public static FieldCodec<ByteString> ForBytes(uint tag) |
| { |
| return new FieldCodec<ByteString>(input => input.ReadBytes(), (output, value) => output.WriteBytes(value), CodedOutputStream.ComputeBytesSize, tag); |
| } |
| |
| public static FieldCodec<bool> ForBool(uint tag) |
| { |
| return new FieldCodec<bool>(input => input.ReadBool(), (output, value) => output.WriteBool(value), CodedOutputStream.ComputeBoolSize, tag); |
| } |
| |
| public static FieldCodec<int> ForInt32(uint tag) |
| { |
| return new FieldCodec<int>(input => input.ReadInt32(), (output, value) => output.WriteInt32(value), CodedOutputStream.ComputeInt32Size, tag); |
| } |
| |
| public static FieldCodec<int> ForSInt32(uint tag) |
| { |
| return new FieldCodec<int>(input => input.ReadSInt32(), (output, value) => output.WriteSInt32(value), CodedOutputStream.ComputeSInt32Size, tag); |
| } |
| |
| public static FieldCodec<uint> ForFixed32(uint tag) |
| { |
| return new FieldCodec<uint>(input => input.ReadFixed32(), (output, value) => output.WriteFixed32(value), 4, tag); |
| } |
| |
| public static FieldCodec<int> ForSFixed32(uint tag) |
| { |
| return new FieldCodec<int>(input => input.ReadSFixed32(), (output, value) => output.WriteSFixed32(value), 4, tag); |
| } |
| |
| public static FieldCodec<uint> ForUInt32(uint tag) |
| { |
| return new FieldCodec<uint>(input => input.ReadUInt32(), (output, value) => output.WriteUInt32(value), CodedOutputStream.ComputeUInt32Size, tag); |
| } |
| |
| public static FieldCodec<long> ForInt64(uint tag) |
| { |
| return new FieldCodec<long>(input => input.ReadInt64(), (output, value) => output.WriteInt64(value), CodedOutputStream.ComputeInt64Size, tag); |
| } |
| |
| public static FieldCodec<long> ForSInt64(uint tag) |
| { |
| return new FieldCodec<long>(input => input.ReadSInt64(), (output, value) => output.WriteSInt64(value), CodedOutputStream.ComputeSInt64Size, tag); |
| } |
| |
| public static FieldCodec<ulong> ForFixed64(uint tag) |
| { |
| return new FieldCodec<ulong>(input => input.ReadFixed64(), (output, value) => output.WriteFixed64(value), 8, tag); |
| } |
| |
| public static FieldCodec<long> ForSFixed64(uint tag) |
| { |
| return new FieldCodec<long>(input => input.ReadSFixed64(), (output, value) => output.WriteSFixed64(value), 8, tag); |
| } |
| |
| public static FieldCodec<ulong> ForUInt64(uint tag) |
| { |
| return new FieldCodec<ulong>(input => input.ReadUInt64(), (output, value) => output.WriteUInt64(value), CodedOutputStream.ComputeUInt64Size, tag); |
| } |
| |
| public static FieldCodec<float> ForFloat(uint tag) |
| { |
| return new FieldCodec<float>(input => input.ReadFloat(), (output, value) => output.WriteFloat(value), CodedOutputStream.ComputeFloatSize, tag); |
| } |
| |
| public static FieldCodec<double> ForDouble(uint tag) |
| { |
| return new FieldCodec<double>(input => input.ReadDouble(), (output, value) => output.WriteDouble(value), CodedOutputStream.ComputeDoubleSize, tag); |
| } |
| |
| // Enums are tricky. We can probably use expression trees to build these delegates automatically, |
| // but it's easy to generate the code for it. |
| public static FieldCodec<T> ForEnum<T>(uint tag, Func<T, int> toInt32, Func<int, T> fromInt32) |
| { |
| return new FieldCodec<T>(input => fromInt32( |
| input.ReadEnum()), |
| (output, value) => output.WriteEnum(toInt32(value)), |
| value => CodedOutputStream.ComputeEnumSize(toInt32(value)), tag); |
| } |
| |
| public static FieldCodec<T> ForMessage<T>(uint tag, MessageParser<T> parser) where T : IMessage<T> |
| { |
| return new FieldCodec<T>(input => { T message = parser.CreateTemplate(); input.ReadMessage(message); return message; }, |
| (output, value) => output.WriteMessage(value), message => CodedOutputStream.ComputeMessageSize(message), tag); |
| } |
| } |
| |
| /// <summary> |
| /// An encode/decode pair for a single field. This effectively encapsulates |
| /// all the information needed to read or write the field value from/to a coded |
| /// stream. |
| /// </summary> |
| /// <remarks> |
| /// This never writes default values to the stream, and is not currently designed |
| /// to play well with packed arrays. |
| /// </remarks> |
| public sealed class FieldCodec<T> |
| { |
| private static readonly Func<T, bool> IsDefault; |
| private static readonly T Default; |
| |
| static FieldCodec() |
| { |
| if (typeof(T) == typeof(string)) |
| { |
| Default = (T)(object)""; |
| IsDefault = CreateDefaultValueCheck<string>(x => x.Length == 0); |
| } |
| else if (typeof(T) == typeof(ByteString)) |
| { |
| Default = (T)(object)ByteString.Empty; |
| IsDefault = CreateDefaultValueCheck<ByteString>(x => x.Length == 0); |
| } |
| else if (!typeof(T).IsValueType) |
| { |
| // Default default |
| IsDefault = CreateDefaultValueCheck<T>(x => x == null); |
| } |
| else |
| { |
| // Default default |
| IsDefault = CreateDefaultValueCheck<T>(x => EqualityComparer<T>.Default.Equals(x, default(T))); |
| } |
| } |
| |
| private static Func<T, bool> CreateDefaultValueCheck<TTmp>(Func<TTmp, bool> check) |
| { |
| return (Func<T, bool>)(object)check; |
| } |
| |
| private readonly Func<CodedInputStream, T> reader; |
| private readonly Action<CodedOutputStream, T> writer; |
| private readonly Func<T, int> sizeCalculator; |
| private readonly uint tag; |
| private readonly int tagSize; |
| private readonly int fixedSize; |
| |
| internal FieldCodec( |
| Func<CodedInputStream, T> reader, |
| Action<CodedOutputStream, T> writer, |
| Func<T, int> sizeCalculator, |
| uint tag) |
| { |
| this.reader = reader; |
| this.writer = writer; |
| this.sizeCalculator = sizeCalculator; |
| this.fixedSize = 0; |
| this.tag = tag; |
| tagSize = CodedOutputStream.ComputeRawVarint32Size(tag); |
| } |
| |
| internal FieldCodec( |
| Func<CodedInputStream, T> reader, |
| Action<CodedOutputStream, T> writer, |
| int fixedSize, |
| uint tag) |
| { |
| this.reader = reader; |
| this.writer = writer; |
| this.sizeCalculator = _ => fixedSize; |
| this.fixedSize = fixedSize; |
| this.tag = tag; |
| tagSize = CodedOutputStream.ComputeRawVarint32Size(tag); |
| } |
| |
| /// <summary> |
| /// Returns the size calculator for just a value. |
| /// </summary> |
| internal Func<T, int> ValueSizeCalculator { get { return sizeCalculator; } } |
| |
| /// <summary> |
| /// Returns a delegate to write a value (unconditionally) to a coded output stream. |
| /// </summary> |
| internal Action<CodedOutputStream, T> ValueWriter { get { return writer; } } |
| |
| /// <summary> |
| /// Returns a delegate to read a value from a coded input stream. It is assumed that |
| /// the stream is already positioned on the appropriate tag. |
| /// </summary> |
| internal Func<CodedInputStream, T> ValueReader { get { return reader; } } |
| |
| /// <summary> |
| /// Returns the fixed size for an entry, or 0 if sizes vary. |
| /// </summary> |
| internal int FixedSize { get { return fixedSize; } } |
| |
| public uint Tag { get { return tag; } } |
| |
| public T DefaultValue { get { return Default; } } |
| |
| /// <summary> |
| /// Write a tag and the given value, *if* the value is not the default. |
| /// </summary> |
| public void WriteTagAndValue(CodedOutputStream output, T value) |
| { |
| if (!IsDefault(value)) |
| { |
| output.WriteTag(tag); |
| writer(output, value); |
| } |
| } |
| |
| public T Read(CodedInputStream input) |
| { |
| return reader(input); |
| } |
| |
| /// <summary> |
| /// Calculates the size required to write the given value, with a tag, |
| /// if the value is not the default. |
| /// </summary> |
| public int CalculateSizeWithTag(T value) |
| { |
| return IsDefault(value) ? 0 : sizeCalculator(value) + tagSize; |
| } |
| } |
| } |