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/**
* @file lliobuffer.h
* @author Phoenix
* @date 2005-05-04
* @brief Declaration of buffers for use in IO Pipes.
*
* $LicenseInfo:firstyear=2005&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#ifndef LL_LLIOBUFFER_H
#define LL_LLIOBUFFER_H
#include "lliopipe.h"
/**
* @class LLIOBuffer
* @brief This class is an io class that represents an automtically
* resizing io buffer.
* @see LLIOPipe
*
* This class is currently impelemented quick and dirty, but should be
* correct. This class should be extended to have a more flexible
* (and capped) memory allocation and usage scheme. Eventually, I
* would like to have the ability to share this buffer between
* different objects.
*/
class LLIOBuffer : public LLIOPipe
{
public:
LLIOBuffer();
virtual ~LLIOBuffer();
/**
* @brief Return a raw pointer to the current data set.
*
* The pointer returned can be used for reading or even adjustment
* if you are a bit crazy up to size() bytes into memory.
* @return A potentially NULL pointer to the raw buffer data
*/
U8* data() const;
/**
* @brief Return the size of the buffer
*/
S64 size() const;
/**
* @brief Return a raw pointer to the current read position in the data.
*
* The pointer returned can be used for reading or even adjustment
* if you are a bit crazy up to bytesLeft() bytes into memory.
* @return A potentially NULL pointer to the buffer data starting
* at the read point
*/
U8* current() const;
/**
* @brief Return the number of unprocessed bytes in buffer.
*/
S64 bytesLeft() const;
/**
* @brief Move the buffer offsets back to the beginning.
*
* This method effectively clears what has been stored here,
* without mucking around with memory allocation.
*/
void clear();
/**
* @brief Enumeration passed into the seek function
*
* The READ head is used for where to start processing data for
* the next link in the chain, while the WRITE head specifies
* where new data processed from the previous link in the chain
* will be written.
*/
enum EHead
{
READ,
WRITE
};
/**
* @brief Seek to a place in the buffer
*
* @param head The READ or WRITE head.
* @param delta The offset from the current position to seek.
* @return The status of the operation. status >= if head moved.
*/
EStatus seek(EHead head, S64 delta);
public:
/* @name LLIOPipe virtual implementations
*/
//@{
protected:
/**
* @brief Process the data in buffer
*/
virtual EStatus process_impl(
const LLChannelDescriptors& channels,
buffer_ptr_t& buffer,
bool& eos,
LLSD& context,
LLPumpIO* pump);
//@}
protected:
U8* mBuffer;
S64 mBufferSize;
U8* mReadHead;
U8* mWriteHead;
};
#endif // LL_LLIOBUFFER_H
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