private static bool TryReadPrefixLength(Stream source, PrefixStyle style, int tag, out uint length, Getter <int, bool> processField)
{
MethodStart:
switch (style)
{
case PrefixStyle.None:
length = uint.MaxValue;
return(true);
case PrefixStyle.Base128:
if (tag <= 0)
{
return(SerializationContext.TryDecodeUInt32(source, out length));
}
uint expected = GetFieldToken(tag, WireType.String), actual;
if (!SerializationContext.TryDecodeUInt32(source, out actual))
{
length = 0;
return(false);
}
WireType wireType;
int actualTag;
ParseFieldToken(actual, out wireType, out actualTag);
if (processField != null)
{
if (processField(actualTag))
{
length = SerializationContext.DecodeUInt32(source);
return(true);
}
}
else if (expected == actual)
{
length = SerializationContext.DecodeUInt32(source);
return(true);
}
switch (wireType)
{
case WireType.String:
SerializationContext.SkipStringData(source);
goto MethodStart;
default:
throw new ProtoException("A record with a different tag could not be jumped because of the wire-type: " + wireType);
}
case PrefixStyle.Fixed32:
return(SerializationContext.TryDecodeUInt32Fixed(source, out length));
default:
throw new NotSupportedException("Invalid prefix style: " + style);
}
}
/// <summary>
/// Jump a block of data using a base-128 length prefix.
/// </summary>
/// <param name="source">The input stream.</param>
public static void SkipStringData(Stream source)
{
int bytesRead, bytesRemaining = (int)SerializationContext.DecodeUInt32(source);
while (bytesRemaining > trashBuffer.Length && (bytesRead = source.Read(trashBuffer, 0, trashBuffer.Length)) > 0)
{
bytesRemaining -= bytesRead;
}
while (bytesRemaining > 0 && (bytesRead = source.Read(trashBuffer, 0, bytesRemaining)) > 0)
{
bytesRemaining -= bytesRead;
}
if (bytesRemaining != 0)
{
throw new EndOfStreamException();
}
}
private static bool TryReadPrefixLength(SerializationContext context, PrefixStyle style, int tag, out uint length)
{
MethodStart:
switch (style)
{
case PrefixStyle.None:
length = uint.MaxValue;
return(true);
case PrefixStyle.Base128:
if (tag <= 0)
{
return(context.TryDecodeUInt32(out length));
}
uint expected = GetFieldToken(tag, WireType.String), actual;
if (!context.TryDecodeUInt32(out actual))
{
length = 0;
return(false);
}
if (expected == actual)
{
length = context.DecodeUInt32();
return(true);
}
WireType wireType;
int actualTag;
ParseFieldToken(actual, out wireType, out actualTag);
SkipData(context, actualTag, wireType);
goto MethodStart;
case PrefixStyle.Fixed32:
return(context.TryDecodeUInt32Fixed(out length));
default:
throw new NotSupportedException("Invalid prefix style: " + style);
}
}
