uSTL_2.3/src/ofstream.cc

169 lines
4.0 KiB
C++

// This file is part of the uSTL library, an STL implementation.
//
// Copyright (c) 2005 by Mike Sharov <msharov@users.sourceforge.net>
// This file is free software, distributed under the MIT License.
#include "ofstream.h"
#include "ustring.h"
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdarg.h>
namespace ustl {
//----------------------------------------------------------------------
ifstream cin (STDIN_FILENO);
ofstream cout (STDOUT_FILENO);
ofstream cerr (STDERR_FILENO);
//----------------------------------------------------------------------
/// Default constructor.
ofstream::ofstream (void)
: ostringstream (),
m_File ()
{
reserve (255);
}
/// Constructs a stream for writing to \p Fd.
ofstream::ofstream (int Fd)
: ostringstream (),
m_File (Fd)
{
clear (m_File.rdstate());
reserve (255);
}
/// Constructs a stream for writing to \p filename.
ofstream::ofstream (const char* filename, openmode mode)
: ostringstream (),
m_File (filename, mode)
{
clear (m_File.rdstate());
}
/// Default destructor.
ofstream::~ofstream (void) noexcept
{
flush();
if (m_File.fd() <= STDERR_FILENO) // Do not close cin,cout,cerr
m_File.detach();
}
/// Flushes the buffer and closes the file.
void ofstream::close (void)
{
clear (m_File.rdstate());
flush();
m_File.close();
}
/// Flushes the buffer to the file.
ofstream& ofstream::flush (void)
{
clear();
while (good() && pos() && overflow (remaining())) ;
clear (m_File.rdstate());
return (*this);
}
/// Seeks to \p p based on \p d.
ofstream& ofstream::seekp (off_t p, seekdir d)
{
flush();
m_File.seekp (p, d);
clear (m_File.rdstate());
return (*this);
}
/// Called when more buffer space (\p n bytes) is needed.
ofstream::size_type ofstream::overflow (size_type n)
{
if (eof() || (n > remaining() && n < capacity() - pos()))
return (ostringstream::overflow (n));
size_type bw = m_File.write (cdata(), pos());
clear (m_File.rdstate());
erase (begin(), bw);
if (remaining() < n)
ostringstream::overflow (n);
return (remaining());
}
//----------------------------------------------------------------------
/// Constructs a stream to read from \p Fd.
ifstream::ifstream (int Fd)
: istringstream (),
m_Buffer (255,'\0'),
m_File (Fd)
{
link (m_Buffer.data(), streamsize(0));
}
/// Constructs a stream to read from \p filename.
ifstream::ifstream (const char* filename, openmode mode)
: istringstream (),
m_Buffer (255,'\0'),
m_File (filename, mode)
{
clear (m_File.rdstate());
link (m_Buffer.data(), streamsize(0));
}
/// Reads at least \p n more bytes and returns available bytes.
ifstream::size_type ifstream::underflow (size_type n)
{
if (eof())
return (istringstream::underflow (n));
const ssize_t freeSpace = m_Buffer.size() - pos();
const ssize_t neededFreeSpace = max (n, m_Buffer.size() / 2);
const size_t oughtToErase = Align (max (0, neededFreeSpace - freeSpace));
const size_type nToErase = min (pos(), oughtToErase);
m_Buffer.memlink::erase (m_Buffer.begin(), nToErase);
const uoff_t oldPos (pos() - nToErase);
size_type br = oldPos;
if (m_Buffer.size() - br < n) {
m_Buffer.resize (br + neededFreeSpace);
link (m_Buffer.data(), streamsize(0));
}
cout.flush();
size_type brn = 1;
for (; br < oldPos + n && brn && m_File.good(); br += brn)
brn = m_File.readsome (m_Buffer.begin() + br, m_Buffer.size() - br);
clear (m_File.rdstate());
m_Buffer[br] = 0;
link (m_Buffer.data(), br);
seek (oldPos);
return (remaining());
}
/// Flushes the input.
int ifstream::sync (void)
{
istringstream::sync();
underflow (0U);
clear (m_File.rdstate());
return (-good());
}
/// Seeks to \p p based on \p d.
ifstream& ifstream::seekg (off_t p, seekdir d)
{
m_Buffer.clear();
link (m_Buffer);
m_File.seekg (p, d);
clear (m_File.rdstate());
return (*this);
}
//----------------------------------------------------------------------
} // namespace ustl