public override int Serialize(TSource source, SerializationContext context)
{
string value = GetValue(source);
if (value == null || (IsOptional && value == DefaultValue))
{
return(0);
}
int charCount = value.Length;
uint underEstimate = (uint)charCount;
if (charCount == 0)
{
int prefixLen = WritePrefix(context);
context.WriteByte(0);
return(prefixLen + 1);
}
else if (charCount <= 42)
{
// guaranteed to have a byte length at most 127, so single byte;
// any text up to 42 chars will take at most 126 bytes
context.CheckSpace((3 * charCount) + 1);
int prefixLen = WritePrefix(context),
byteCount = utf8.GetBytes(value, 0, charCount, context.Workspace, 1);
context.Workspace[0] = (byte)byteCount;
context.WriteBlock(context.Workspace, 0, ++byteCount);
return(prefixLen + byteCount);
}
else if (charCount <= 127)
{
// common text in many locales will /tend/ to be single-byte. We'll
// absorb the cost of checking the actual length, since we know it
// is only a short string.
underEstimate = (uint)utf8.GetByteCount(value);
if (underEstimate <= 127)
{
context.CheckSpace((int)(underEstimate + 1));
int prefixLen = WritePrefix(context),
byteCount = utf8.GetBytes(value, 0, charCount, context.Workspace, 1);
context.Workspace[0] = (byte)byteCount;
context.WriteBlock(context.Workspace, 0, ++byteCount);
return(prefixLen + byteCount);
}
// note also that we update "underEstimate"; this means that even
// if we find a 100-char string actually needs multiple bytes
// (and so we'll use the callback below), we at least start the
// callback with the correct length, avoiding the need to
// encode it twice.
}
// when all else fails (longer strings), use a callback
// to to a length prefix using our estimated length...
return(WritePrefix(context)
+ context.WriteLengthPrefixed(value, underEstimate, this));
}
int ILengthProperty <string> .Serialize(string value, SerializationContext context)
{
context.CheckSpace(Encoding.UTF8.GetMaxByteCount(value.Length));
int len = utf8.GetBytes(value, 0, value.Length, context.Workspace, 0);
context.WriteBlock(context.Workspace, 0, len);
return(len);
}
public override string DeserializeImpl(TSource source, SerializationContext context)
{
int len = (int)context.DecodeUInt32();
string value;
if (len == 0)
{
value = "";
}
else
{
if (len > SerializationContext.InitialBufferLength)
{
context.CheckSpace(len);
}
context.ReadBlock(len);
value = context.Intern(utf8.GetString(context.Workspace, 0, len));
}
return(value);
}