internal bool TryPlpBytesLeft(TdsParserStateObject stateObj, out ulong left)
{
if ((stateObj._longlen != 0) && (stateObj._longlenleft == 0))
{
if (!stateObj.TryReadPlpLength(false, out left))
{
return false;
}
}
left = stateObj._longlenleft;
return true;
}
// Reads the requested number of chars from a plp data stream, or the entire data if
// requested length is -1 or larger than the actual length of data. First call to this method
// should be preceeded by a call to ReadPlpLength or ReadDataLength.
// Returns the actual chars read.
internal bool TryReadPlpUnicodeChars(ref char[] buff, int offst, int len, TdsParserStateObject stateObj, out int totalCharsRead)
{
int charsRead = 0;
int charsLeft = 0;
char[] newbuf;
if (stateObj._longlen == 0)
{
Debug.Assert(stateObj._longlenleft == 0);
totalCharsRead = 0;
return true; // No data
}
Debug.Assert(((ulong)stateObj._longlen != TdsEnums.SQL_PLP_NULL),
"Out of sync plp read request");
Debug.Assert((buff == null && offst == 0) || (buff.Length >= offst + len), "Invalid length sent to ReadPlpUnicodeChars()!");
charsLeft = len;
// If total length is known up front, allocate the whole buffer in one shot instead of realloc'ing and copying over each time
if (buff == null && stateObj._longlen != TdsEnums.SQL_PLP_UNKNOWNLEN)
{
buff = new char[(int)Math.Min((int)stateObj._longlen, len)];
}
if (stateObj._longlenleft == 0)
{
ulong ignored;
if (!stateObj.TryReadPlpLength(false, out ignored))
{
totalCharsRead = 0;
return false;
}
if (stateObj._longlenleft == 0)
{ // Data read complete
totalCharsRead = 0;
return true;
}
}
totalCharsRead = 0;
while (charsLeft > 0)
{
charsRead = (int)Math.Min((stateObj._longlenleft + 1) >> 1, (ulong)charsLeft);
if ((buff == null) || (buff.Length < (offst + charsRead)))
{
// Grow the array
newbuf = new char[offst + charsRead];
if (buff != null)
{
Buffer.BlockCopy(buff, 0, newbuf, 0, offst * 2);
}
buff = newbuf;
}
if (charsRead > 0)
{
if (!TryReadPlpUnicodeCharsChunk(buff, offst, charsRead, stateObj, out charsRead))
{
return false;
}
charsLeft -= charsRead;
offst += charsRead;
totalCharsRead += charsRead;
}
// Special case single byte left
if (stateObj._longlenleft == 1 && (charsLeft > 0))
{
byte b1;
if (!stateObj.TryReadByte(out b1))
{
return false;
}
stateObj._longlenleft--;
ulong ignored;
if (!stateObj.TryReadPlpLength(false, out ignored))
{
return false;
}
Debug.Assert((stateObj._longlenleft != 0), "ReadPlpUnicodeChars: Odd byte left at the end!");
byte b2;
if (!stateObj.TryReadByte(out b2))
{
return false;
}
stateObj._longlenleft--;
// Put it at the end of the array. At this point we know we have an extra byte.
buff[offst] = (char)(((b2 & 0xff) << 8) + (b1 & 0xff));
offst = checked((int)offst + 1);
charsRead++;
charsLeft--;
totalCharsRead++;
}
if (stateObj._longlenleft == 0)
{ // Read the next chunk or cleanup state if hit the end
ulong ignored;
if (!stateObj.TryReadPlpLength(false, out ignored))
{
return false;
}
}
if (stateObj._longlenleft == 0) // Data read complete
break;
}
return true;
}
internal bool TrySkipPlpValue(ulong cb, TdsParserStateObject stateObj, out ulong totalBytesSkipped)
{
// Read and skip cb bytes or until ReadPlpLength returns 0.
int bytesSkipped;
totalBytesSkipped = 0;
if (stateObj._longlenleft == 0)
{
ulong ignored;
if (!stateObj.TryReadPlpLength(false, out ignored))
{
return false;
}
}
while ((totalBytesSkipped < cb) &&
(stateObj._longlenleft > 0))
{
if (stateObj._longlenleft > Int32.MaxValue)
bytesSkipped = Int32.MaxValue;
else
bytesSkipped = (int)stateObj._longlenleft;
bytesSkipped = ((cb - totalBytesSkipped) < (ulong)bytesSkipped) ? (int)(cb - totalBytesSkipped) : bytesSkipped;
if (!stateObj.TrySkipBytes(bytesSkipped))
{
return false;
}
stateObj._longlenleft -= (ulong)bytesSkipped;
totalBytesSkipped += (ulong)bytesSkipped;
if (stateObj._longlenleft == 0)
{
ulong ignored;
if (!stateObj.TryReadPlpLength(false, out ignored))
{
return false;
}
}
}
return true;
}
//
// Returns the data stream length of the data identified by tds type or SqlMetaData returns
// Returns either the total size or the size of the first chunk for partially length prefixed types.
//
internal bool TryGetDataLength(SqlMetaDataPriv colmeta, TdsParserStateObject stateObj, out ulong length)
{
// Handle Yukon specific tokens
if (colmeta.metaType.IsPlp)
{
Debug.Assert(colmeta.tdsType == TdsEnums.SQLXMLTYPE ||
colmeta.tdsType == TdsEnums.SQLBIGVARCHAR ||
colmeta.tdsType == TdsEnums.SQLBIGVARBINARY ||
colmeta.tdsType == TdsEnums.SQLNVARCHAR ||
// Large UDTs is WinFS-only
colmeta.tdsType == TdsEnums.SQLUDT,
"GetDataLength:Invalid streaming datatype");
return stateObj.TryReadPlpLength(true, out length);
}
else
{
int intLength;
if (!TryGetTokenLength(colmeta.tdsType, stateObj, out intLength))
{
length = 0;
return false;
}
length = (ulong)intLength;
return true;
}
}