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