/* -*-C-*-

$Id: ntfile.c,v 1.13 1999/01/02 06:11:34 cph Exp $

Copyright (c) 1992-1999 Massachusetts Institute of Technology

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at
your option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "nt.h"
#include "osfile.h"
#include "ntio.h"

#define DEFUN_OPEN_FILE(name, args)					\
Tchannel								\
name (const char * filename)						\
{									\
  HANDLE hFile;								\
  STD_HANDLE_API_CALL (hFile, CreateFile, args);			\
  return (NT_open_handle (hFile));					\
}

// In the following we specify FILE_SHARE_READ | FILE_SHARE_WRITE
// so that we can edit and save out a file while we are still in a
// error REPL from a buggy source file.

DEFUN_OPEN_FILE (OS_open_input_file,
  (filename, GENERIC_READ, (FILE_SHARE_READ | FILE_SHARE_WRITE), 0,
   OPEN_EXISTING, (FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN), 0));

DEFUN_OPEN_FILE (OS_open_output_file,
  (filename, GENERIC_WRITE, FILE_SHARE_READ, 0,
   CREATE_ALWAYS, (FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN), 0));

DEFUN_OPEN_FILE (OS_open_io_file,
  (filename, (GENERIC_READ | GENERIC_WRITE),
   (FILE_SHARE_READ | FILE_SHARE_WRITE), 0,
   OPEN_ALWAYS, (FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS), 0));

Tchannel
OS_open_append_file (const char * filename)
{
  HANDLE hFile;
  STD_HANDLE_API_CALL
    (hFile,
     CreateFile, (filename,
	          GENERIC_WRITE,
		  FILE_SHARE_READ	/*sharing*/,
		  0,			/*security*/
		  OPEN_ALWAYS,
		  FILE_ATTRIBUTE_NORMAL /*attributes&flags*/,
		  0			/*Template*/
		  ));
  if ((SetFilePointer (hFile, 0, 0, FILE_END)) == 0xFFFFFFFF)
    NT_error_api_call ((GetLastError ()), apicall_SetFilePointer);
  return (NT_open_handle (hFile));
}

static Tchannel
make_load_channel (HANDLE handle)
{
  channel_class_t * class = (NT_handle_channel_class (handle));
  return
    ((((CHANNEL_CLASS_TYPE (class)) == channel_type_terminal)
      || ((CHANNEL_CLASS_TYPE (class)) == channel_type_directory))
     ? NO_CHANNEL
     : (NT_make_channel (handle, class)));
}

Tchannel
OS_open_load_file (const char * filename)
{
  HANDLE handle
    = (CreateFile (filename, GENERIC_READ, FILE_SHARE_READ, 0,
		   OPEN_EXISTING, 0, 0));
  return
    ((handle != INVALID_HANDLE_VALUE)
     ? (make_load_channel (handle))
     : NO_CHANNEL);
}

Tchannel
OS_open_dump_file (const char * filename)
{
  HANDLE handle
    = (CreateFile (filename, GENERIC_WRITE, FILE_SHARE_READ, 0,
		   CREATE_ALWAYS, 0, 0));
  return
    ((handle != INVALID_HANDLE_VALUE)
     ? (make_load_channel (handle))
     : NO_CHANNEL);
}

off_t
OS_file_length (Tchannel channel)
{
  DWORD result = (GetFileSize ((CHANNEL_HANDLE (channel)), 0));
  if (result == 0xFFFFFFFF)
    NT_error_api_call ((GetLastError ()), apicall_GetFileSize);
  return (result);
}

off_t
OS_file_position (Tchannel channel)
{
  DWORD position
    = (SetFilePointer ((CHANNEL_HANDLE (channel)), 0, 0, FILE_CURRENT));
  if (position == 0xFFFFFFFF)
    NT_error_api_call ((GetLastError ()), apicall_SetFilePointer);
  return (position);
}

void
OS_file_set_position (Tchannel channel, off_t position)
{
  DWORD old_position
    = (SetFilePointer ((CHANNEL_HANDLE (channel)), position, 0, FILE_BEGIN));
  if (old_position == 0xFFFFFFFF)
    NT_error_api_call ((GetLastError ()), apicall_SetFilePointer);
  if (old_position != ((DWORD) position))
    error_external_return ();
}