mirror of
https://github.com/OpenMW/openmw.git
synced 2025-01-22 00:53:52 +00:00
5c7f1bd497
moved the ConstrainedDataStream into its own source file and changed BSAFile to use it though the exposed factory function. This is in preperation foreimplementing it based on feedback from profiling that (at least on windows) the C++ iostreams library is quite slow.
112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
/*
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OpenMW - The completely unofficial reimplementation of Morrowind
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Copyright (C) 2008-2010 Nicolay Korslund
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Email: < korslund@gmail.com >
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WWW: http://openmw.sourceforge.net/
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This file (bsa_file.cpp) is part of the OpenMW package.
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OpenMW is distributed as free software: you can redistribute it
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and/or modify it under the terms of the GNU General Public License
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version 3, as published by the Free Software Foundation.
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This program is distributed in the hope that it will be useful, but
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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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General Public License for more details.
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You should have received a copy of the GNU General Public License
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version 3 along with this program. If not, see
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http://www.gnu.org/licenses/ .
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*/
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#include "constrainedfiledatastream.hpp"
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#include <stdexcept>
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class ConstrainedDataStream : public Ogre::DataStream {
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std::ifstream mStream;
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const size_t mStart;
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size_t mPos;
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bool mIsEOF;
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public:
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ConstrainedDataStream(const Ogre::String &fname, size_t start, size_t length)
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: mStream(fname.c_str(), std::ios_base::binary), mStart(start), mPos(0), mIsEOF(false)
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{
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mSize = length;
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if(!mStream.seekg(mStart, std::ios_base::beg))
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throw std::runtime_error("Error seeking to start of BSA entry");
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}
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ConstrainedDataStream(const Ogre::String &name, const Ogre::String &fname,
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size_t start, size_t length)
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: Ogre::DataStream(name), mStream(fname.c_str(), std::ios_base::binary),
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mStart(start), mPos(0), mIsEOF(false)
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{
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mSize = length;
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if(!mStream.seekg(mStart, std::ios_base::beg))
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throw std::runtime_error("Error seeking to start of BSA entry");
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}
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virtual size_t read(void *buf, size_t count)
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{
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mStream.clear();
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if(count > mSize-mPos)
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{
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count = mSize-mPos;
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mIsEOF = true;
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}
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mStream.read(reinterpret_cast<char*>(buf), count);
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count = mStream.gcount();
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mPos += count;
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return count;
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}
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virtual void skip(long count)
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{
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if((count >= 0 && (size_t)count <= mSize-mPos) ||
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(count < 0 && (size_t)-count <= mPos))
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{
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mStream.clear();
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if(mStream.seekg(count, std::ios_base::cur))
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{
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mPos += count;
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mIsEOF = false;
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}
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}
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}
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virtual void seek(size_t pos)
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{
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if(pos < mSize)
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{
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mStream.clear();
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if(mStream.seekg(pos+mStart, std::ios_base::beg))
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{
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mPos = pos;
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mIsEOF = false;
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}
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}
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}
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virtual size_t tell() const
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{ return mPos; }
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virtual bool eof() const
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{ return mIsEOF; }
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virtual void close()
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{ mStream.close(); }
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};
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Ogre::DataStreamPtr openConstrainedFileDataStream (char const * filename, size_t offset, size_t length)
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{
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assert (length != 0xFFFFFFFF); // reserved for future use...
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return Ogre::DataStreamPtr(new ConstrainedDataStream(filename, offset, length));
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}
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