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