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#ifndef OPENMW_COMPONENTS_FILES_MEMORYSTREAM_H
#define OPENMW_COMPONENTS_FILES_MEMORYSTREAM_H
#include <istream>
namespace Files
{
struct MemBuf : std::streambuf
{
MemBuf(char const* buffer, size_t size)
// a streambuf isn't specific to istreams, so we need a non-const pointer :/
: bufferStart(const_cast<char*>(buffer))
, bufferEnd(bufferStart + size)
{
this->setg(bufferStart, bufferStart, bufferEnd);
}
pos_type seekoff(off_type off, std::ios_base::seekdir dir, std::ios_base::openmode which) override
{
if (dir == std::ios_base::cur)
gbump(off);
else
setg(bufferStart, (dir == std::ios_base::beg ? bufferStart : bufferEnd) + off, bufferEnd);
return gptr() - bufferStart;
}
pos_type seekpos(pos_type pos, std::ios_base::openmode which) override
{
return seekoff(pos, std::ios_base::beg, which);
}
protected:
char* bufferStart;
char* bufferEnd;
};
/// @brief A variant of std::istream that reads from a constant in-memory buffer.
struct IMemStream : virtual MemBuf, std::istream
{
IMemStream(char const* buffer, size_t size)
: MemBuf(buffer, size)
, std::istream(static_cast<std::streambuf*>(this))
{
}
};
}
#endif
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