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// file : butl/fdstream.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2016 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#include <butl/fdstream>
#ifndef _WIN32
# include <unistd.h> // close(), read(), write()
#else
# include <io.h> // _close(), _read(), _write()
#endif
#include <system_error>
using namespace std;
namespace butl
{
fdbuf::
~fdbuf () {close ();}
void fdbuf::
open (int fd)
{
close ();
fd_ = fd;
setg (buf_, buf_, buf_);
setp (buf_, buf_ + sizeof (buf_) - 1); // Keep space for overflow's char.
}
void fdbuf::
close ()
{
if (is_open ())
{
#ifndef _WIN32
::close (fd_);
#else
_close (fd_);
#endif
fd_ = -1;
}
}
streamsize fdbuf::
showmanyc ()
{
return is_open () ? static_cast<streamsize> (egptr () - gptr ()) : -1;
}
fdbuf::int_type fdbuf::
underflow ()
{
int_type r (traits_type::eof ());
if (is_open ())
{
if (gptr () < egptr () || load ())
r = traits_type::to_int_type (*gptr ());
}
return r;
}
bool fdbuf::
load ()
{
#ifndef _WIN32
ssize_t n (::read (fd_, buf_, sizeof (buf_)));
#else
int n (_read (fd_, buf_, sizeof (buf_)));
#endif
if (n == -1)
throw system_error (errno, system_category ());
setg (buf_, buf_, buf_ + n);
return n != 0;
}
fdbuf::int_type fdbuf::
overflow (int_type c)
{
int_type r (traits_type::eof ());
if (is_open () && c != traits_type::eof ())
{
// Store last character in the space we reserved in open(). Note
// that pbump() doesn't do any checks.
//
*pptr () = traits_type::to_char_type (c);
pbump (1);
if (save ())
r = c;
}
return r;
}
int fdbuf::
sync ()
{
return is_open () && save () ? 0 : -1;
}
bool fdbuf::
save ()
{
size_t n (pptr () - pbase ());
if (n != 0)
{
#ifndef _WIN32
ssize_t m (::write (fd_, buf_, n));
#else
int m (_write (fd_, buf_, static_cast<unsigned int> (sizeof (buf_))));
#endif
if (m == -1)
throw system_error (errno, system_category ());
if (n != static_cast<size_t> (m))
return false;
setp (buf_, buf_ + sizeof (buf_) - 1);
}
return true;
}
}
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