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vcmi/lib/filesystem/CBinaryReader.cpp
2013-04-07 10:48:07 +00:00

109 lines
2.2 KiB
C++

#include "StdInc.h"
#include "CBinaryReader.h"
#include <SDL_endian.h>
#include "CInputStream.h"
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
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)
{
return stream->read(data, size);
}
template <typename CData>
CData CBinaryReader::readInteger()
{
CData val;
si64 b = stream->read(reinterpret_cast<unsigned char *>(&val), sizeof(val));
if(b < sizeof(val))
{
throw std::runtime_error(getEndOfStreamExceptionMsg(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::readString()
{
int len = readUInt32();
assert(len >= 0 && len <= 500000); //not too long
std::string ret;
ret.reserve(len);
for(int gg = 0; gg < len; ++gg)
{
ret += readInt8();
}
return ret;
}
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();
}