Something went wrong. Try again.
OpenMW is an open implementation of the Morrowind engine
Something went wrong. Try again.
2.8 kB · 88 lines
C++
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889#include "constrainedfilestreambuf.hpp"
#include <algorithm>#include <filesystem>#include <limits>
namespace Files{ namespace File = Platform::File;
ConstrainedFileStreamBuf::ConstrainedFileStreamBuf( const std::filesystem::path& fname, std::size_t start, std::size_t length) : mOrigin(start) { mFile = File::open(fname); mSize = length != std::numeric_limits<std::size_t>::max() ? length : File::size(mFile) - start;
if (start != 0) File::seek(mFile, start);
setg(nullptr, nullptr, nullptr); }
std::streambuf::int_type ConstrainedFileStreamBuf::underflow() { if (gptr() == egptr()) { const std::size_t toRead = std::min((mOrigin + mSize) - (File::tell(mFile)), sizeof(mBuffer)); // Read in the next chunk of data, and set the read pointers on success // Failure will throw exception. const std::size_t got = File::read(mFile, mBuffer, toRead); setg(mBuffer, mBuffer, mBuffer + got); } if (gptr() == egptr()) return traits_type::eof();
return traits_type::to_int_type(*gptr()); }
std::streambuf::pos_type ConstrainedFileStreamBuf::seekoff( off_type offset, std::ios_base::seekdir whence, std::ios_base::openmode mode) { if ((mode & std::ios_base::out) || !(mode & std::ios_base::in)) return traits_type::eof();
// new file position, relative to mOrigin size_t newPos; switch (whence) { case std::ios_base::beg: newPos = offset; break; case std::ios_base::cur: newPos = (File::tell(mFile) - mOrigin - (egptr() - gptr())) + offset; break; case std::ios_base::end: newPos = mSize + offset; break; default: return traits_type::eof(); }
if (newPos > mSize) return traits_type::eof();
File::seek(mFile, mOrigin + newPos);
// Clear read pointers so underflow() gets called on the next read attempt. setg(nullptr, nullptr, nullptr);
return newPos; }
std::streambuf::pos_type ConstrainedFileStreamBuf::seekpos(pos_type pos, std::ios_base::openmode mode) { if ((mode & std::ios_base::out) || !(mode & std::ios_base::in)) return traits_type::eof();
if (static_cast<std::size_t>(pos) > mSize) return traits_type::eof();
File::seek(mFile, mOrigin + pos);
// Clear read pointers so underflow() gets called on the next read attempt. setg(nullptr, nullptr, nullptr); return pos; }}