/// <summary>Writes the contents of the buffer to the VarBinary column and clears the buffer.</summary>
public override void Flush()
{
//If we're in read mode (or no mode), then we don't want to flush the data.
if (!this.IsReading.HasValue || this.IsReading.Value)
{
return;
}
//If there is nothing to flush then don't do anything.
if (this.BufferPosition == 0)
{
return;
}
byte[] bytesToWrite = new byte[this.BufferPosition];
//Copy from the buffer.
System.Buffer.BlockCopy(Buffer, 0, bytesToWrite, 0, this.BufferPosition);
//Write the bytes to the column and update the position.
this.Position += SqlVarBinaryMaxHelper.WritePartOfVarBinaryColumn(this.Connection, this.TableName, this.ColumnName, this.PrimaryKeyColumnName, this.PrimaryKeyValue, this.Position, bytesToWrite);
//Clear the buffer.
this.Buffer = new byte[SqlVarBinaryStream.BufferSize];
this.BufferPosition = 0;
}
/// <summary>Sets the column's data to 0x0. Otherwise, if you were to write a smaller file to the column than the existing data,the existing data would still remain after the smaller data is written.</summary>
private void ClearColumnData()
{
//Initialize (clear) the column.
SqlVarBinaryMaxHelper.InitializeVarBinaryColumn(this.Connection, this.TableName, this.ColumnName, this.PrimaryKeyColumnName, this.PrimaryKeyValue);
//Indicate that the data no longer needs to be cleared.
this.ClearData = false;
}
/// <summary>Reads data from the VarBinary column into the supplied buffer.</summary>
public override int Read(byte[] buffer, int offset, int count)
{
if (!this.IsReading.HasValue)
{
this.IsReading = true;
}
else if (!this.IsReading.Value)
{
throw new InvalidOperationException("The stream is already being used to write data; it cannot be used to read data as well.");
}
int bytesToWrite = count;
int bytesWritten = 0;
do
{
int bytesToCopy = 0;
//If the buffer is empty, read another chunk of data.
if (Buffer == null || (this.Buffer.Length - this.BufferPosition) == 0)
{
byte[] newBytes = SqlVarBinaryMaxHelper.ReadPartOfVarbinaryColumn(this.Connection, this.TableName, this.ColumnName, this.PrimaryKeyColumnName, this.PrimaryKeyValue, this.Position, SqlVarBinaryStream.BufferSize);
int bytesRead = (newBytes == null ? 0 : newBytes.Length);
if (bytesRead > 0)
{
this.Buffer = new byte[newBytes.Length];
this.BufferPosition = 0;
newBytes.CopyTo(Buffer, 0);
this.Position += bytesRead;
}
else
{
break;
}
}
//Copy to the output buffer.
bytesToCopy = System.Math.Min(bytesToWrite, this.Buffer.Length - this.BufferPosition);
System.Buffer.BlockCopy(this.Buffer, this.BufferPosition, buffer, offset + bytesWritten, bytesToCopy);
//Update the counters.
bytesToWrite -= bytesToCopy;
bytesWritten += bytesToCopy;
this.BufferPosition += bytesToCopy;
} while (bytesWritten < count);
return(bytesWritten);
}
private SqlVarBinaryStream(SqlConnection connection, string tableName, string columnName, string primaryKeyColumnName, int primaryKeyValue)
{
if (string.IsNullOrEmpty(tableName))
{
throw new ArgumentNullException("tableName");
}
if (string.IsNullOrEmpty(columnName))
{
throw new ArgumentNullException("columnName");
}
this.Connection = connection;
this.TableName = tableName;
this.ColumnName = columnName;
this.PrimaryKeyColumnName = primaryKeyColumnName;
this.PrimaryKeyValue = primaryKeyValue;
this.LengthInternal = SqlVarBinaryMaxHelper.GetLengthOfVarbinaryColumn(this.Connection, this.TableName, this.ColumnName, this.PrimaryKeyColumnName, this.PrimaryKeyValue);
this.ClearData = true;
}
