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vcmi/lib/filesystem/CBinaryReader.cpp

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/*
* CBinaryReader.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 "CBinaryReader.h"
#include "CInputStream.h"
#include "../TextOperations.h"
VCMI_LIB_NAMESPACE_BEGIN
#ifdef VCMI_ENDIAN_BIG
template <typename CData>
CData readLE(CData data)
{
auto dataPtr = (char*)&data;
std::reverse(dataPtr, dataPtr + sizeof(data));
return data;
}
#else
template <typename CData>
CData readLE(CData data)
{
return data;
}
#endif
CBinaryReader::CBinaryReader() : stream(nullptr)
{
}
CBinaryReader::CBinaryReader(CInputStream * stream) : stream(stream)
{
}
CInputStream * CBinaryReader::getStream()
{
return stream;
}
void CBinaryReader::setStream(CInputStream * stream)
{
this->stream = stream;
}
si64 CBinaryReader::read(ui8 * data, si64 size)
{
si64 bytesRead = stream->read(data, size);
if(bytesRead != size)
{
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throw std::runtime_error(getEndOfStreamExceptionMsg(static_cast<long>(size)));
}
return bytesRead;
}
template <typename CData>
CData CBinaryReader::readInteger()
{
CData val;
stream->read(reinterpret_cast<unsigned char *>(&val), sizeof(val));
return readLE(val);
}
//FIXME: any way to do this without macro?
#define INSTANTIATE(datatype, methodname) \
datatype CBinaryReader::methodname() \
{ return readInteger<datatype>(); }
// While it is certanly possible to leave only template method
// but typing template parameter every time can be annoying
// and templates parameters can't be resolved by return type
INSTANTIATE(ui8, readUInt8)
INSTANTIATE(si8, readInt8)
INSTANTIATE(ui16, readUInt16)
INSTANTIATE(si16, readInt16)
INSTANTIATE(ui32, readUInt32)
INSTANTIATE(si32, readInt32)
INSTANTIATE(ui64, readUInt64)
INSTANTIATE(si64, readInt64)
#undef INSTANTIATE
std::string CBinaryReader::readBaseString()
{
unsigned int len = readUInt32();
assert(len <= 500000); //not too long
if (len > 0)
{
std::string ret;
ret.resize(len);
read(reinterpret_cast<ui8*>(&ret[0]), len);
return ret;
}
return "";
}
void CBinaryReader::skip(int count)
{
stream->skip(count);
}
std::string CBinaryReader::getEndOfStreamExceptionMsg(long bytesToRead) const
{
std::stringstream ss;
ss << "The end of the stream was reached unexpectedly. The stream has a length of " << stream->getSize() << " and the current reading position is "
<< stream->tell() << ". The client wanted to read " << bytesToRead << " bytes.";
return ss.str();
}
VCMI_LIB_NAMESPACE_END