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Diffstat (limited to 'lib/common/BufferedStream.cpp')
| -rw-r--r-- | lib/common/BufferedStream.cpp | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/lib/common/BufferedStream.cpp b/lib/common/BufferedStream.cpp new file mode 100644 index 00000000..edf7122c --- /dev/null +++ b/lib/common/BufferedStream.cpp @@ -0,0 +1,245 @@ +// distribution boxbackup-0.11rc1 (svn version: 2023_2024) +// +// Copyright (c) 2003 - 2006 +// Ben Summers and contributors. All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions +// are met: +// 1. Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// 2. Redistributions in binary form must reproduce the above copyright +// notice, this list of conditions and the following disclaimer in the +// documentation and/or other materials provided with the distribution. +// 3. All use of this software and associated advertising materials must +// display the following acknowledgment: +// This product includes software developed by Ben Summers. +// 4. The names of the Authors may not be used to endorse or promote +// products derived from this software without specific prior written +// permission. +// +// [Where legally impermissible the Authors do not disclaim liability for +// direct physical injury or death caused solely by defects in the software +// unless it is modified by a third party.] +// +// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR +// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +// DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, +// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +// ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +// POSSIBILITY OF SUCH DAMAGE. +// +// +// +// -------------------------------------------------------------------------- +// +// File +// Name: BufferedStream.cpp +// Purpose: Buffering wrapper around IOStreams +// Created: 2007/01/16 +// +// -------------------------------------------------------------------------- + +#include "Box.h" +#include "BufferedStream.h" +#include "CommonException.h" + +#include <string.h> + +#include "MemLeakFindOn.h" + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::BufferedStream(const char *, int, int) +// Purpose: Constructor, set up buffer +// Created: 2007/01/16 +// +// -------------------------------------------------------------------------- +BufferedStream::BufferedStream(IOStream& rSource) +: mrSource(rSource), mBufferSize(0), mBufferPosition(0) +{ } + + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::Read(void *, int) +// Purpose: Reads bytes from the file +// Created: 2007/01/16 +// +// -------------------------------------------------------------------------- +int BufferedStream::Read(void *pBuffer, int NBytes, int Timeout) +{ + if (mBufferSize == mBufferPosition) + { + // buffer is empty, fill it. + + int numBytesRead = mrSource.Read(mBuffer, sizeof(mBuffer), + Timeout); + + if (numBytesRead < 0) + { + return numBytesRead; + } + + mBufferSize = numBytesRead; + } + + int sizeToReturn = mBufferSize - mBufferPosition; + + if (sizeToReturn > NBytes) + { + sizeToReturn = NBytes; + } + + memcpy(pBuffer, mBuffer + mBufferPosition, sizeToReturn); + mBufferPosition += sizeToReturn; + + if (mBufferPosition == mBufferSize) + { + // clear out the buffer + mBufferSize = 0; + mBufferPosition = 0; + } + + return sizeToReturn; +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::BytesLeftToRead() +// Purpose: Returns number of bytes to read (may not be most efficient function ever) +// Created: 2007/01/16 +// +// -------------------------------------------------------------------------- +IOStream::pos_type BufferedStream::BytesLeftToRead() +{ + return mrSource.BytesLeftToRead() + mBufferSize - mBufferPosition; +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::Write(void *, int) +// Purpose: Writes bytes to the underlying stream (not supported) +// Created: 2003/07/31 +// +// -------------------------------------------------------------------------- +void BufferedStream::Write(const void *pBuffer, int NBytes) +{ + THROW_EXCEPTION(CommonException, NotSupported); +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::GetPosition() +// Purpose: Get position in stream +// Created: 2003/08/21 +// +// -------------------------------------------------------------------------- +IOStream::pos_type BufferedStream::GetPosition() const +{ + return mrSource.GetPosition() - mBufferSize + mBufferPosition; +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::Seek(pos_type, int) +// Purpose: Seeks within file, as lseek, invalidate buffer +// Created: 2003/07/31 +// +// -------------------------------------------------------------------------- +void BufferedStream::Seek(IOStream::pos_type Offset, int SeekType) +{ + switch (SeekType) + { + case SeekType_Absolute: + { + // just go there + mrSource.Seek(Offset, SeekType); + } + break; + + case SeekType_Relative: + { + // Actual underlying file position is + // (mBufferSize - mBufferPosition) ahead of us. + // Need to subtract that amount from the seek + // to seek forward that much less, putting the + // real pointer in the right place. + mrSource.Seek(Offset - mBufferSize + mBufferPosition, + SeekType); + } + break; + + case SeekType_End: + { + // Actual underlying file position is + // (mBufferSize - mBufferPosition) ahead of us. + // Need to add that amount to the seek + // to seek backwards that much more, putting the + // real pointer in the right place. + mrSource.Seek(Offset + mBufferSize - mBufferPosition, + SeekType); + } + } + + // always clear the buffer for now (may be slightly wasteful) + mBufferSize = 0; + mBufferPosition = 0; +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::Close() +// Purpose: Closes the underlying stream (not needed) +// Created: 2003/07/31 +// +// -------------------------------------------------------------------------- +void BufferedStream::Close() +{ + THROW_EXCEPTION(CommonException, NotSupported); +} + + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::StreamDataLeft() +// Purpose: Any data left to write? +// Created: 2003/08/02 +// +// -------------------------------------------------------------------------- +bool BufferedStream::StreamDataLeft() +{ + return mrSource.StreamDataLeft(); +} + +// -------------------------------------------------------------------------- +// +// Function +// Name: BufferedStream::StreamClosed() +// Purpose: Is the stream closed? +// Created: 2003/08/02 +// +// -------------------------------------------------------------------------- +bool BufferedStream::StreamClosed() +{ + return mrSource.StreamClosed(); +} + |