| static private BCryptGenRandom_PinnedBuffer ( byte pbBuffer, int obBuffer, int cbBuffer ) : NTSTATUS | ||
| pbBuffer | byte | |
| obBuffer | int | |
| cbBuffer | int | |
| return | NTSTATUS | |
}//NextBytes()
void NextBytesInternal(ArraySegment<byte> bufferSegment)
{
BCrypt.NTSTATUS status;
var buffer = bufferSegment.Array;
var offset = bufferSegment.Offset;
var count = bufferSegment.Count;
if (count > CACHE_THRESHOLD)
{
status = (offset == 0) ? BCrypt.BCryptGenRandom(buffer, count) : BCrypt.BCryptGenRandom_PinnedBuffer(buffer, offset, count);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS) return;
throw new CryptographicException((int)status);
}
lock (_byteCache)
{
if (_byteCachePosition + count <= BYTE_CACHE_SIZE)
{
Utils.BlockCopy(_byteCache, _byteCachePosition, buffer, offset, count);
_byteCachePosition += count;
return;
}
status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = count;
Utils.BlockCopy(_byteCache, 0, buffer, offset, count);
return;
}
throw new CryptographicException((int)status);
}// lock
}//NextBytesInternal()
void NextBytesInternal(ArraySegment<byte> bufferSegment)
{
BCrypt.NTSTATUS status;
var buffer = bufferSegment.Array;
var offset = bufferSegment.Offset;
var count = bufferSegment.Count;
if (count > CACHE_THRESHOLD)
{
status = (offset == 0) ? BCrypt.BCryptGenRandom(buffer, count) : BCrypt.BCryptGenRandom_PinnedBuffer(buffer, offset, count);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS) return;
throw new CryptographicException((int)status);
}
while (true)
{
int currentByteCachePosition = Interlocked.Add(ref _byteCachePosition, count);
if (currentByteCachePosition <= BYTE_CACHE_SIZE && currentByteCachePosition > 0)
{
Utils.BlockCopy(_byteCache, currentByteCachePosition - count, buffer, 0, count);
return;
}
lock (_byteCache)
{
currentByteCachePosition = _byteCachePosition; // atomic read
if (currentByteCachePosition > (BYTE_CACHE_SIZE - count) || currentByteCachePosition <= 0)
{
status = BCrypt.BCryptGenRandom(_byteCache, BYTE_CACHE_SIZE);
if (status == BCrypt.NTSTATUS.STATUS_SUCCESS)
{
_byteCachePosition = count; // atomic write
Utils.BlockCopy(_byteCache, 0, buffer, 0, count);
return;
}
// defensive logic to prevent _byteCachePosition from wrapping into valid range due to BCryptGenRandom failures
if (currentByteCachePosition > BYTE_CACHE_SIZE || currentByteCachePosition < 0) _byteCachePosition = BYTE_CACHE_SIZE;
throw new CryptographicException((int)status);
}// if outside the valid range
}// lock
}// while(true)
}//NextBytes()
