fstream_win32io.cpp

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/*
 * Copyright (c) 1999
 * Silicon Graphics Computer Systems, Inc.
 *
 * Copyright (c) 1999
 * Boris Fomitchev
 *
 * This material is provided "as is", with absolutely no warranty expressed
 * or implied. Any use is at your own risk.
 *
 * Permission to use or copy this software for any purpose is hereby granted
 * without fee, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 *
 */

#include <fstream>

#if !defined (_STLP_WCE)
#  ifdef __BORLANDC__
#    include <cfcntl.h>           // For _O_RDONLY, etc
#  else
#    include <io.h>               // For _get_osfhandle
#    include <fcntl.h>            // For _O_RDONLY, etc
#  endif
#  include <sys/stat.h>         // For _fstat
#endif

#define _TEXTBUF_SIZE 0x1000

const _STLP_fd INVALID_STLP_FD = INVALID_HANDLE_VALUE;

#if !defined (INVALID_SET_FILE_POINTER)
#  define INVALID_SET_FILE_POINTER 0xffffffff
#endif

#ifndef O_ACCMODE
#  define O_ACCMODE (O_RDONLY|O_WRONLY|O_RDWR)
#endif

_STLP_BEGIN_NAMESPACE

#if !defined(__MSL__) && !defined(_STLP_WCE)
static ios_base::openmode flag_to_openmode(int mode) {
  ios_base::openmode ret = ios_base::__default_mode;

  switch (mode & O_ACCMODE) {
  case O_RDONLY:
    ret = ios_base::in; break;
  case O_WRONLY:
    ret = ios_base::out; break;
  case O_RDWR:
    ret = ios_base::in | ios_base::out; break;
  }

  if (mode & O_APPEND)
    ret |= ios_base::app;

  if (mode & O_BINARY)
    ret |= ios_base::binary;

  return ret;
}
#endif

_STLP_MOVE_TO_PRIV_NAMESPACE

// Helper functions for _Filebuf_base.

static bool __is_regular_file(_STLP_fd fd) {
  BY_HANDLE_FILE_INFORMATION info;

  // Return true if the file handle isn't a directory.
  return GetFileInformationByHandle(fd, &info) && 
         ((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) == 0);
}

// Number of characters in the file.
static streamoff __file_size(_STLP_fd fd) {
  streamoff ret = 0;

 LARGE_INTEGER li;
 li.LowPart = GetFileSize(fd, (unsigned long*) &li.HighPart);
 if (li.LowPart != INVALID_FILE_SIZE || GetLastError() == NO_ERROR)
   ret = li.QuadPart;

  return ret;
}

_STLP_MOVE_TO_STD_NAMESPACE

// Visual C++ and Intel use this, but not Metrowerks
// Also MinGW, msvcrt.dll (but not crtdll.dll) dependent version
#if (defined (_STLP_MSVC_LIB) && !defined (_STLP_WCE)) || \
    (defined (__MINGW32__) && defined (__MSVCRT__))

// fcntl(fileno, F_GETFL) for Microsoft library
// 'semi-documented' defines:
#  define IOINFO_L2E          5
#  define IOINFO_ARRAY_ELTS   (1 << IOINFO_L2E)
#  define _pioinfo(i) ( __pioinfo[(i) >> IOINFO_L2E] + \
              ((i) & (IOINFO_ARRAY_ELTS - 1)) )
#  define FAPPEND         0x20    // O_APPEND flag
#  define FTEXT           0x80    // O_TEXT flag
// end of 'semi-documented' defines

// 'semi-documented' internal structure
extern "C" {
  struct ioinfo {
    long osfhnd;    // the real os HANDLE
    char osfile;    // file handle flags
    char pipech;    // pipe buffer
#  if defined (_MT)
    // multi-threaded locking
    int lockinitflag;
    CRITICAL_SECTION lock;
#  endif
  };
#  if defined (__MINGW32__)
 __MINGW_IMPORT ioinfo * __pioinfo[];
#  else
  extern _CRTIMP ioinfo * __pioinfo[];
#  endif
} // extern "C"
// end of 'semi-documented' declarations

static ios_base::openmode _get_osfflags(int fd, HANDLE oshandle) {
  char dosflags = 0;
  if (fd >= 0)
    dosflags = _pioinfo(fd)->osfile;
  //else
    //the file will be considered as open in binary mode with no append attribute
  // end of 'semi-documented' stuff

  int mode = 0;
  if (dosflags & FAPPEND)
    mode |= O_APPEND;

  if (dosflags & FTEXT)
    mode |= O_TEXT;
  else
    mode |= O_BINARY;

  // For Read/Write access we have to guess
  DWORD dummy, dummy2;
  BOOL writeOk = WriteFile(oshandle, &dummy2, 0, &dummy, 0);
  BOOL readOk = ReadFile(oshandle, &dummy2, 0, &dummy, NULL);
  if (writeOk && readOk)
    mode |= O_RDWR;
  else if (readOk)
    mode |= O_RDONLY;
  else
    mode |= O_WRONLY;

  return flag_to_openmode(mode);
}

#elif defined (__DMC__)

#  define FHND_APPEND 0x04
#  define FHND_DEVICE 0x08
#  define FHND_TEXT   0x10

extern "C" unsigned char __fhnd_info[_NFILE];

static ios_base::openmode _get_osfflags(int fd, HANDLE oshandle) {
  int mode = 0;

  if (__fhnd_info[fd] & FHND_APPEND)
    mode |= O_APPEND;

  if (__fhnd_info[fd] & FHND_TEXT == 0)
    mode |= O_BINARY;

  for (FILE *fp = &_iob[0]; fp < &_iob[_NFILE]; fp++) {
    if ((fileno(fp) == fd) && (fp->_flag & (_IOREAD | _IOWRT | _IORW))) {
      const int osflags = fp->_flag;

      if ((osflags & _IOREAD) && !(osflags & _IOWRT) && !(osflags & _IORW))
        mode |= O_RDONLY;
      else if ((osflags & _IOWRT) && !(osflags & _IOREAD) && !(osflags & _IORW))
        mode |= O_WRONLY;
      else
        mode |= O_RDWR;
      break;
    }
  }

  return flag_to_openmode(mode);
}
#endif

size_t _Filebuf_base::_M_page_size = 4096;

_Filebuf_base::_Filebuf_base()
  : _M_file_id(INVALID_STLP_FD),
    _M_openmode(0),
    _M_is_open(false),
    _M_should_close(false),
    _M_view_id(0)
{}

void _Filebuf_base::_S_initialize() {
  SYSTEM_INFO SystemInfo;
  GetSystemInfo(&SystemInfo);
  _M_page_size = SystemInfo.dwPageSize;
  // might be .dwAllocationGranularity
}

// Return the size of the file.  This is a wrapper for stat.
// Returns zero if the size cannot be determined or is ill-defined.
streamoff _Filebuf_base::_M_file_size() {
  return _STLP_PRIV __file_size(_M_file_id);
}

bool _Filebuf_base::_M_open(const char* name, ios_base::openmode openmode,
                            long permission) {
  _STLP_fd file_no;

  if (_M_is_open)
    return false;

  DWORD dwDesiredAccess, dwCreationDisposition;
  bool doTruncate = false;

  switch (openmode & (~ios_base::ate & ~ios_base::binary)) {
  case ios_base::out:
  case ios_base::out | ios_base::trunc:
    dwDesiredAccess = GENERIC_WRITE;
    dwCreationDisposition = OPEN_ALWAYS;
    // boris : even though it is very non-intuitive, standard
    // requires them both to behave same.
    doTruncate = true;
    break;
  case ios_base::out | ios_base::app:
    dwDesiredAccess = GENERIC_WRITE;
    dwCreationDisposition = OPEN_ALWAYS;
    break;
  case ios_base::in:
    dwDesiredAccess = GENERIC_READ;
    dwCreationDisposition = OPEN_EXISTING;
    permission = 0;             // Irrelevant unless we're writing.
    break;
  case ios_base::in | ios_base::out:
    dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
    dwCreationDisposition = OPEN_EXISTING;
    break;
  case ios_base::in | ios_base::out | ios_base::trunc:
    dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
    dwCreationDisposition = OPEN_ALWAYS;
    doTruncate = true;
    break;
  default:                      // The above are the only combinations of
    return false;               // flags allowed by the C++ standard.
  }

  DWORD dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;

#if defined(_STLP_USE_WIDE_INTERFACE)
    file_no = CreateFile (_STLP_PRIV __ASCIIToWide(name).c_str(),
#else
    file_no = CreateFileA(name,
#endif
                          dwDesiredAccess, dwShareMode, 0,
                          dwCreationDisposition, permission, 0);

  if (file_no == INVALID_STLP_FD)
    return false;

  if (
#if !defined (_STLP_WCE)
      GetFileType(file_no) == FILE_TYPE_DISK &&
#endif
      ((doTruncate && SetEndOfFile(file_no) == 0) ||
       (((openmode & ios_base::ate) != 0) &&
        (SetFilePointer(file_no, 0, NULL, FILE_END) == INVALID_SET_FILE_POINTER)))) {
    CloseHandle(file_no);
    return false;
  }

  _M_is_open = true;
  _M_file_id = file_no;
  _M_should_close = _M_is_open;
  _M_openmode = openmode;

  if (_M_is_open)
    _M_regular_file = _STLP_PRIV __is_regular_file(_M_file_id);

  return (_M_is_open != 0);
}

bool _Filebuf_base::_M_open(const char* name, ios_base::openmode openmode) {
  // This doesn't really grant everyone in the world read/write
  // access.  On Unix, file-creation system calls always clear
  // bits that are set in the umask from the permissions flag.
  return this->_M_open(name, openmode, FILE_ATTRIBUTE_NORMAL);
}

bool _Filebuf_base::_M_open(_STLP_fd __id, ios_base::openmode init_mode) {
#if (defined (_STLP_MSVC_LIB) && !defined (_STLP_WCE)) || \
    (defined (__MINGW32__) && defined (__MSVCRT__)) || defined (__DMC__)

  if (_M_is_open || __id == INVALID_STLP_FD)
    return false;

  if (init_mode != ios_base::__default_mode)
    _M_openmode = init_mode;
  else
    _M_openmode = _get_osfflags(-1, __id);

  _M_is_open = true;
  _M_file_id = __id;
  _M_should_close = false;