142 lines
3.8 KiB
C++
142 lines
3.8 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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* $LicenseInfo:firstyear=2005&license=viewergpl$
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*
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* Copyright (c) 2005-2009, Linden Research, Inc.
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*
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* Second Life Viewer Source Code
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* The source code in this file ("Source Code") is provided by Linden Lab
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* to you under the terms of the GNU General Public License, version 2.0
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* ("GPL"), unless you have obtained a separate licensing agreement
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* ("Other License"), formally executed by you and Linden Lab. Terms of
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* the GPL can be found in doc/GPL-license.txt in this distribution, or
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* online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
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*
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* There are special exceptions to the terms and conditions of the GPL as
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* it is applied to this Source Code. View the full text of the exception
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* in the file doc/FLOSS-exception.txt in this software distribution, or
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* online at
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* http://secondlifegrid.net/programs/open_source/licensing/flossexception
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*
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* By copying, modifying or distributing this software, you acknowledge
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* that you have read and understood your obligations described above,
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* and agree to abide by those obligations.
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*
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* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
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* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
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* COMPLETENESS OR PERFORMANCE.
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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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