public override int Read(byte[] buffer, int bufferOffset, int count)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (bufferOffset + count > buffer.LongLength)
{
throw new ArgumentOutOfRangeException("bufferOffset");
}
if (count == 0)
{
return(0);
}
lock (locker)
{
// If the stream is used for both reading and writing, make sure we're reading everything that was written
WriteAnyUnwrittenData();
if (Position >= underlyingStream.Footer.TotalLength)
{
return(0);
}
long startingBlock = underlyingStream.Header.GetBlockNumberFromLogicalPosition(Position);
long blockOffset = underlyingStream.Header.GetBlockOffsetFromLogicalPosition(Position);
if (currentReadingBlock == null || currentReadingBlock.BlockNumber != startingBlock)
{
currentReadingBlock = underlyingStream.ReadBlock(startingBlock);
}
int blockRead = (int)Math.Min(currentReadingBlock.TotalStreamLength - Position, currentBlockSize - bufferOffset);
int actualRead = Math.Min(count, blockRead);
Array.Copy(currentReadingBlock.Data, blockOffset, buffer, bufferOffset, actualRead);
// We use the fact that a stream doesn't have to read all data in one go to avoid a loop here.
Position += actualRead;
return(actualRead);
}
}
public override int Read(byte[] buffer, int bufferOffset, int count)
{
//precaution, should never be true
if (underlyingStream.Header.MagicNumber != EncryptedFile.WithTotalSizeMagicNumber &&
underlyingStream.Header.MagicNumber != EncryptedFile.DefaultMagicNumber)
{
throw new ApplicationException("Invalid magic number in the encrypted file. Cannot proceed with reading.");
}
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (bufferOffset + count > buffer.LongLength)
{
throw new ArgumentOutOfRangeException("bufferOffset");
}
if (count == 0)
{
return(0);
}
lock (locker)
{
// If the stream is used for both reading and writing, make sure we're reading everything that was written
WriteAnyUnwrittenData();
if (Position >= underlyingStream.Footer.TotalLength &&
underlyingStream.Header.MagicNumber == EncryptedFile.DefaultMagicNumber)
{
return(0);
}
if (Position >= underlyingStream.Header.TotalUnencryptedSize &&
underlyingStream.Header.MagicNumber == EncryptedFile.WithTotalSizeMagicNumber)
{
return(0);
}
if (underlyingStream.Header.MagicNumber != EncryptedFile.WithTotalSizeMagicNumber &&
underlyingStream.Header.MagicNumber != EncryptedFile.DefaultMagicNumber)
{
throw new ApplicationException("Invalid magic number in the encrypted file. Cannot proceed with reading.");
}
var startingBlock = underlyingStream.Header.GetBlockNumberFromLogicalPosition(Position);
var blockOffset = underlyingStream.Header.GetBlockOffsetFromLogicalPosition(Position);
if (currentReadingBlock == null || currentReadingBlock.BlockNumber != startingBlock)
{
currentReadingBlock = underlyingStream.ReadBlock(startingBlock);
}
var blockRead = (int)Math.Min(underlyingStream.Header.TotalUnencryptedSize - Position, currentBlockSize - blockOffset);
var actualRead = Math.Min(count, blockRead);
Array.Copy(currentReadingBlock.Data, blockOffset, buffer, bufferOffset, actualRead);
// We use the fact that a stream doesn't have to read all data in one go to avoid a loop here.
Position += actualRead;
return(actualRead);
}
}
