mirror of https://github.com/minetest/irrlicht.git
128 lines
2.4 KiB
C++
128 lines
2.4 KiB
C++
// Copyright (C) 2002-2012 Nikolaus Gebhardt
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// This file is part of the "Irrlicht Engine".
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// For conditions of distribution and use, see copyright notice in irrlicht.h
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#include "CLimitReadFile.h"
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#include "irrString.h"
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namespace irr
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{
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namespace io
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{
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CLimitReadFile::CLimitReadFile(IReadFile* alreadyOpenedFile, long pos,
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long areaSize, const io::path& name)
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: Filename(name), AreaStart(0), AreaEnd(0), Pos(0),
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File(alreadyOpenedFile)
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{
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#ifdef _DEBUG
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setDebugName("CLimitReadFile");
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#endif
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if (File)
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{
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File->grab();
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AreaStart = pos;
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AreaEnd = AreaStart + areaSize;
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}
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}
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CLimitReadFile::~CLimitReadFile()
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{
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if (File)
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File->drop();
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}
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//! returns how much was read
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size_t CLimitReadFile::read(void* buffer, size_t sizeToRead)
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{
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if (0 == File)
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return 0;
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#if 1
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long r = AreaStart + Pos;
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long toRead = core::min_(AreaEnd, r + (long)sizeToRead) - core::max_(AreaStart, r);
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if (toRead < 0)
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return 0;
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File->seek(r);
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r = (long)File->read(buffer, toRead);
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Pos += r;
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return r;
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#else
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const long pos = File->getPos();
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if (pos >= AreaEnd)
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return 0;
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if (pos + (long)sizeToRead >= AreaEnd)
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sizeToRead = AreaEnd - pos;
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return File->read(buffer, sizeToRead);
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#endif
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}
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//! changes position in file, returns true if successful
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bool CLimitReadFile::seek(long finalPos, bool relativeMovement)
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{
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#if 1
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Pos = core::s32_clamp(finalPos + (relativeMovement ? Pos : 0 ), 0, AreaEnd - AreaStart);
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return true;
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#else
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const long pos = File->getPos();
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if (relativeMovement)
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{
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if (pos + finalPos > AreaEnd)
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finalPos = AreaEnd - pos;
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}
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else
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{
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finalPos += AreaStart;
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if (finalPos > AreaEnd)
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return false;
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}
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return File->seek(finalPos, relativeMovement);
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#endif
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}
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//! returns size of file
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long CLimitReadFile::getSize() const
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{
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return AreaEnd - AreaStart;
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}
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//! returns where in the file we are.
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long CLimitReadFile::getPos() const
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{
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#if 1
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return Pos;
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#else
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return File->getPos() - AreaStart;
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#endif
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}
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//! returns name of file
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const io::path& CLimitReadFile::getFileName() const
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{
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return Filename;
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}
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IReadFile* createLimitReadFile(const io::path& fileName, IReadFile* alreadyOpenedFile, long pos, long areaSize)
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{
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return new CLimitReadFile(alreadyOpenedFile, pos, areaSize, fileName);
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}
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} // end namespace io
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} // end namespace irr
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