internal int WriteLengthPrefixed <TValue>(TValue value, uint underEstimatedLength, ILengthProperty <TValue> property)
{
Flush(); // commit to the stream before monkeying with the buffers...
MemoryStream ms = stream as MemoryStream;
if (ms != null)
{
// we'll write to out current stream, optimising
// for the case when the length-prefix is 1-byte;
// if not we'll have to BlockCopy
int startIndex = (int)ms.Position;
uint guessLength = underEstimatedLength,
guessPrefixLength = (uint)this.EncodeUInt32(guessLength),
actualLength = (uint)property.Serialize(value, this);
if (guessLength == actualLength)
{ // good guess! nothing to do...
return((int)(guessPrefixLength + actualLength));
}
uint actualPrefixLength = (uint)SerializationContext.GetLength(actualLength);
Flush(); // commit to the stream before we start messing with it...
if (actualPrefixLength < guessPrefixLength)
{
throw new ProtoException("Internal error; the serializer over-estimated the length. Sorry, but this shouldn't have happened.");
}
else if (actualPrefixLength > guessPrefixLength)
{
// our guess of the length turned out to be bad; we need to
// fix things...
// extend the buffer to ensure we have space
for (uint i = actualPrefixLength - guessPrefixLength; i > 0; i--)
{
ms.WriteByte(0);
position++;
}
// move the data
// (note; we MUST call GetBuffer *after* extending it,
// otherwise there the buffer might change if we extend
// over a boundary)
byte[] buffer = ms.GetBuffer();
Buffer.BlockCopy(buffer, (int)(startIndex + guessPrefixLength),
buffer, (int)(startIndex + actualPrefixLength), (int)actualLength);
}
// back-fill the actual length into the buffer
SerializationContext.EncodeUInt32(actualLength, ms.GetBuffer(), startIndex);
return((int)(actualPrefixLength + actualLength));
}
else
{
// create a temporary stream and write the final result
using (ms = new MemoryStream())
{
SerializationContext ctx = new SerializationContext(ms, this);
int len = property.Serialize(value, ctx);
ctx.Flush();
this.ReadFrom(ctx);
int preambleLen = this.EncodeInt32(len);
byte[] buffer = ms.GetBuffer();
this.WriteBlock(buffer, 0, len);
return(preambleLen + len);
}
}
}
