// Enums are tricky. We can probably use expression trees to build these delegates automatically,
// but it's easy to generate the code for it.
/// <summary>
/// Retrieves a codec suitable for an enum field with the given tag.
/// </summary>
/// <param name="tag">The tag.</param>
/// <param name="toInt32">A conversion function from <see cref="Int32"/> to the enum type.</param>
/// <param name="fromInt32">A conversion function from the enum type to <see cref="Int32"/>.</param>
/// <returns>A codec for the given tag.</returns>
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> ForEnum <T>(uint tag, Func <T, int> toInt32, Func <int, T> fromInt32)
{
return(new FieldCodec <T>((CodedInputStream input) => fromInt32(input.ReadEnum()), delegate(CodedOutputStream output, T value)
{
output.WriteEnum(toInt32(value));
}, (T value) => CodedOutputStream.ComputeEnumSize(toInt32(value)), 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.
/// <summary>
/// Retrieves a codec suitable for an enum field with the given tag.
/// </summary>
/// <param name="tag">The tag.</param>
/// <param name="toInt32">A conversion function from <see cref="Int32"/> to the enum type.</param>
/// <param name="fromInt32">A conversion function from the enum type to <see cref="Int32"/>.</param>
/// <param name="defaultValue">The default value.</param>
/// <returns>A codec for the given tag.</returns>
public static FieldCodec <T> ForEnum <T>(uint tag, Func <T, int> toInt32, Func <int, T> fromInt32, T defaultValue)
{
return(new FieldCodec <T>((ref ParseContext ctx) => fromInt32(
ctx.ReadEnum()),
(ref WriteContext output, T value) => output.WriteEnum(toInt32(value)),
value => CodedOutputStream.ComputeEnumSize(toInt32(value)), tag, defaultValue));
}
public void TestNegativeEnumNoTag()
{
Assert.AreEqual(10, CodedOutputStream.ComputeInt32Size(-2));
Assert.AreEqual(10, CodedOutputStream.ComputeEnumSize((int) SampleEnum.NegativeValue));
byte[] bytes = new byte[10];
CodedOutputStream output = CodedOutputStream.CreateInstance(bytes);
output.WriteEnum((int) SampleEnum.NegativeValue);
Assert.AreEqual(0, output.SpaceLeft);
Assert.AreEqual("FE-FF-FF-FF-FF-FF-FF-FF-FF-01", BitConverter.ToString(bytes));
}