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70 lines
1.5 KiB
C++
70 lines
1.5 KiB
C++
/*
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* CFileInputStream.cpp, part of VCMI engine
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*
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* Authors: listed in file AUTHORS in main folder
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*
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* License: GNU General Public License v2.0 or later
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* Full text of license available in license.txt file, in main folder
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*
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*/
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#include "StdInc.h"
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#include "CFileInputStream.h"
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#include "../ExceptionsCommon.h"
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VCMI_LIB_NAMESPACE_BEGIN
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CFileInputStream::CFileInputStream(const boost::filesystem::path & file, si64 start, si64 size)
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: dataStart{start},
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dataSize{size},
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fileStream{file.c_str(), std::ios::in | std::ios::binary}
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{
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if (fileStream.fail())
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throw DataLoadingException("Failed to open file '" + file.string() + "'. Reason: " + strerror(errno) );
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if (dataSize == 0)
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{
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fileStream.seekg(0, std::ios::end);
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dataSize = tell();
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}
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fileStream.seekg(dataStart, std::ios::beg);
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}
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si64 CFileInputStream::read(ui8 * data, si64 size)
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{
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si64 origin = tell();
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si64 toRead = std::min(dataSize - origin, size);
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fileStream.read(reinterpret_cast<char *>(data), toRead);
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return fileStream.gcount();
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}
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si64 CFileInputStream::seek(si64 position)
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{
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fileStream.seekg(dataStart + std::min(position, dataSize));
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return tell();
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}
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si64 CFileInputStream::tell()
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{
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return static_cast<si64>(fileStream.tellg()) - dataStart;
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}
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si64 CFileInputStream::skip(si64 delta)
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{
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si64 origin = tell();
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//ensure that we're not seeking past the end of real data
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si64 toSeek = std::min(dataSize - origin, delta);
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fileStream.seekg(toSeek, std::ios::cur);
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return tell() - origin;
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}
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si64 CFileInputStream::getSize()
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{
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return dataSize;
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}
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VCMI_LIB_NAMESPACE_END
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