FileBuf.cpp

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/*******************************************************************************
* Copyright (C) 2005, Quest Software, Inc. All rights reserved.
* Copyright (C) 2006, Novell, Inc. All rights reserved.
* 
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 
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*       this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright
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*       documentation and/or other materials provided with the distribution.
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*       Quest Software, Inc., 
*       nor Novell, Inc., 
*       nor the names of its contributors or employees may be used to 
*       endorse or promote products derived from this software without 
*       specific prior written permission.
* 
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#include "blocxx/BLOCXX_config.h"
#include "blocxx/FileBuf.hpp"
#include "blocxx/IOException.hpp"

#ifdef BLOCXX_HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <fcntl.h>
#include <ios>

#ifdef BLOCXX_WIN32
#include <io.h>
#endif

namespace BLOCXX_NAMESPACE
{

FileBuf::FileBuf()
: BaseStreamBuffer(E_IN_OUT)
, m_file(0)
{
}

FileBuf::~FileBuf()
{
   close();
}

bool
FileBuf::isOpen() const
{
   return m_file != 0;
}

FileBuf*
FileBuf::open(FILE* fp)
{
   if (isOpen())
   {
      return 0;
   }

   m_file = fp;
   return this;
}

FileBuf*
FileBuf::open(AutoDescriptor fd)
{
   if (isOpen())
   {
      return 0;
   }

int d = -1;

#ifdef BLOCXX_WIN32
#pragma message(Reminder "TODO: implement it for Win!")
   //maybe it's enough just to set flags = O_RDWR
   //but it's unclear what to do with O_APPEND
   int flags = O_RDWR;

   d = _open_osfhandle(reinterpret_cast<long>(fd.get()), flags);
#else
   d = fd.get();
   int flags = ::fcntl(d, F_GETFL);
   if (flags == -1)
   {
      return 0;
   }
#endif
   
   m_file = ::fdopen(d, cppModeToCMode(posixModeToCppMode(flags)));
   if (m_file == 0)
   {
      return 0;
   }
   ::setbuf(m_file, 0);
   fd.release();
   return this;
}

#if 0
FileBuf*
FileBuf::open(const File& f)
{
   if (isOpen())
   {
      return 0;
   }
   int flags = ::fcntl(f.???, F_GETFL);
   if (flags == -1)
   {
      return 0;
   }

   m_file = ::fdopen(???, cppModeToCMode(posixModeToCppMode(flags)));
   if (m_file == 0)
   {
      return 0;
   }
   ::setbuf(m_file, 0);
   return this;
}
#endif

FileBuf*
FileBuf::open(const char* path, std::ios_base::openmode mode, mode_t permissions)
{
   if (isOpen())
   {
      return 0;
   }

   int d = ::open(path, cppModeToPOSIXMode(mode), permissions);

#ifdef BLOCXX_WIN32
   Descriptor h = reinterpret_cast<Descriptor>(_get_osfhandle(d));
   AutoDescriptor fd(h);
#else
   AutoDescriptor fd(d);
#endif

   if (fd.get() == BLOCXX_INVALID_HANDLE)
   {
      return 0;
   }

   m_file = ::fdopen(d, cppModeToCMode(mode));

   if (m_file == 0)
   {
      return 0;
   }

   ::setbuf(m_file, 0);
   fd.release();

   return this;
}

FileBuf*
FileBuf::close()
{
   if (isOpen())
   {
      ::fclose(m_file);
   }
   m_file = 0;
   return this;
}

int
FileBuf::buffer_to_device(const char* c, int n)
{
   size_t written = ::fwrite(c, 1, n, m_file);
   if (written == static_cast<size_t>(n))
   {
      return 0;
   }
   else
   {
      return -1;
   }
}

int
FileBuf::buffer_from_device(char* c, int n)
{
   if (!isOpen())
   {
      return -1;
   }
   size_t numRead = ::fread(c, 1, n, m_file);
   if (numRead != static_cast<size_t>(n))
   {
      if (ferror(m_file))
      {
         BLOCXX_THROW_ERRNO_MSG(IOException, "FileBuf::buffer_from_device: ::fread()");
      }
      else if (feof(m_file) && numRead == 0)
      {
         return -1;
      }
      else
      {
         return numRead;
      }
   }
   else
   {
      return n;
   }
}

std::ios_base::openmode
FileBuf::posixModeToCppMode(int posixMode)
{
   std::ios_base::openmode mode = posixMode & O_APPEND ? std::ios::app : std::ios_base::openmode(0);

#ifdef BLOCXX_WIN32
   #define O_ACCMODE   3
#endif
   switch (posixMode & O_ACCMODE)
   {
      case O_RDONLY: mode |= (std::ios::in | std::ios::binary); break;
      case O_WRONLY: mode |= (std::ios::out | std::ios::binary); break;
      case O_RDWR:   mode |= (std::ios::in | std::ios::out | std::ios::binary); break;
   }
   return mode;
}

int
FileBuf::cppModeToPOSIXMode(std::ios_base::openmode cppMode)
{
   int mode = 0;
   if (cppMode & std::ios::app)
   {
      mode |= O_APPEND;
   }

   if (cppMode & std::ios::trunc)
   {
      mode |= O_TRUNC;
   }

   if (cppMode & (std::ios::in | std::ios::out))
   {
      mode |= O_RDWR;
   }
   else if (cppMode & std::ios::in)
   {
      mode |= O_RDONLY;
   }
   else if (cppMode & std::ios::out)
   {
      mode |= O_WRONLY;
   }
   return mode;
}

const char* FileBuf::cppModeToCMode(std::ios_base::openmode cppMode)
{
   // mask out irrelevant bits
   cppMode = cppMode & ~std::ios::ate;

   using std::ios;
   // can't use a switch here because the ios flags aren't native types.
   if( cppMode == ios::app ||
      cppMode == (ios::in|ios::app) ||
      cppMode == (ios::out|ios::app) )
   {
      return "a";
   }

   else if( cppMode == (ios::binary|ios::app) ||
      cppMode == (ios::in|ios::binary|ios::app) ||
      cppMode == (ios::out|ios::binary|ios::app) )
   {
      return "ab";
   }

   else if (cppMode == ios::in)
   {
      return "r";
   }

   else if (cppMode == (ios::in|ios::binary))
   {
      return "rb";
   }
         
   else if (cppMode == (ios::out|ios::in))
   {
      return "r+";
   }

   else if (cppMode == (ios::out|ios::in|ios::app))
   {
      return "a+";
   }

   else if (cppMode == (ios::out|ios::in|ios::binary))
   {
      return "r+b";
   }

   else if (cppMode == (ios::out|ios::in|ios::binary|ios::app))
   {
      return "a+b";
   }

   else if( (cppMode == ios::out) ||
      cppMode == (ios::trunc) ||
      cppMode == (ios::trunc|ios::app) ||
      cppMode == (ios::trunc|ios::out) ||
      cppMode == (ios::trunc|ios::out|ios::app) )
   {
      return "w";
   }

   else if( (cppMode == (ios::trunc|ios::binary)) ||
      (cppMode == (ios::trunc|ios::binary|ios::app)) ||
      (cppMode == (ios::out|ios::binary)) ||
      (cppMode == (ios::trunc|ios::out|ios::binary)) ||
      (cppMode == (ios::trunc|ios::out|ios::binary|ios::app) ))
   {
      return "wb";
   }

   else if( (cppMode == (ios::trunc|ios::out|ios::in)) ||
      (cppMode == (ios::trunc|ios::out|ios::in|ios::app)) )
   {
      return "w+";
   }

   else if( (cppMode == (ios::trunc|ios::out|ios::in|ios::binary)) ||
      (cppMode == (ios::trunc|ios::out|ios::in|ios::binary|ios::app)) )
   {
      return "w+b";
   }
   else
   {
      return "";   // bad mode
   }

}


} // end namespace BLOCXX_NAMESPACE