/* @(#)device.c	17.1.1.1 (ES0-DMD) 01/25/02 17:47:36 */
/*===========================================================================
  Copyright (C) 1995 European Southern Observatory (ESO)
 
  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 Massachusetss Ave, Cambridge, 
  MA 02139, USA.
 
  Corresponding concerning ESO-MIDAS should be addressed as follows:
	Internet e-mail: midas@eso.org
	Postal address: European Southern Observatory
			Data Management Division 
			Karl-Schwarzschild-Strasse 2
			D 85748 Garching bei Muenchen 
			GERMANY
===========================================================================*/

/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.TYPE		Module
.NAME		device.c
.LANGUAGE	C
.AUTHOR		Francois Ochsenbein [ESO]
.CATEGORY	Interface to i/o on devices like tapes / OD / etc
.ENVIRONMENT	
.COMMENTS	
	The functions of this module are just an interface on top of
	osu routines. They directly call the osu routines and log
	error messages if any.
.VERSION	1.0	02-May-1990: Creation
-----------------------------------------------------------------------------*/

#define PM_LEVEL LEVEL_FI  	/* The Monitoring level for this file */

#include <device.h>		/* Function prototypes & Structures	*/
#include <filedef.h>		/* Symbols READ WRITE etc...		*/
#include <osdev.h>		/* os-level definitions			*/
#include <macrogen.h>		/* standard macros	*/
#include <trace.h>	
#include <levels.h>
#include <error.h>
#include <ok.h>

char *osmsg(), *osuname();

static int dev_error (f)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Just report error
.RETURNS NOK
----------------------------------------------------------------------*/
	int	f;	/* IN: File number */
{
	char	*p, *ers;
	char	*ltoa();

    ers = osmsg();		/* MUST BE DONE BEFORE osuname call   */
    if_not(p = osuname(f))	p = ltoa(f);
    ERR_ED_STRING(ers, p);

    return(NOK);
}

int dev_stat(f, stat)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Retrieve status of an opened unit 
.RETURNS OK / NOK
----------------------------------------------------------------------*/
	int f;			/* IN: The unit number	*/
	struct devstat *stat;	/* OUT: Status of the unit */
{ 
	int 	s;

  ENTER("dev_stat");
  s = osustat(f);
  if (s < 0)	s = dev_error(f);
  else		s = OK;
  EXIT(s);
}

char *dev_name(f)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Retrieve name of an opened unit 
.RETURNS Name / NULL pointer if failed
----------------------------------------------------------------------*/
	int f;		/* IN: The unit number	*/
{ 
	char	*p;

  ENTER("*dev_name");
  if_not(p = osuname(f))	dev_error(f);
  EXITp(p);
}

long dev_feet(f)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Retrieve length of used tape
.RETURNS Length in feet/1000
----------------------------------------------------------------------*/
	int f;		/* IN: The unit number	*/
{ 
	long feet, osufeet();

  ENTER(".dev_feet");
  feet = osufeet(f);
  EXITl(feet);
}

int dev_bsize(f)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Get the block size of the unit.
.RETURNS The size of blocks for block devices (1 for tapes)
----------------------------------------------------------------------*/
	int f;		/* IN: The unit number	*/
{ 
	int	s;

  ENTER("dev_bsize");
  s = osubsize(f);	
  if (s < 0)		dev_error(f);
  EXIT (s);
}

int dev_open (device, mode, den)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Assign (mount) a tape with a specified density
.RETURNS The device number / NOK on error
.REMARKS The default device class is "mt".
	 The mount is performed here.
	 If density is not specified or is zero, use DEFAULT_DENSITY 
	 for write-only; get the density otherwise.
----------------------------------------------------------------------*/
	char *device;	/* IN: The unit name, NULL or blank for NUL device */
	int  mode;	/* IN: open mode: READ, WRITE, READ_WRITE, APPEND */
	int  den;	/* IN: The density/blocksize; 0 if default */
{
	int 	f;
	char	*name;

  ENTER("dev_open");

  if_not(name = device)	name = "";
  if_not(*name)		/* NULL device */
  	name = NULL_DEV;

  f = osuopen(name, mode, den);
  if (f <= 0)	f = NOK, ERR_ED_STRING(osmsg(), name);

  EXIT(f);
}

int dev_close (f, opt)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Close (dismount) a tape / optical disk
.RETURNS OK / NOK
----------------------------------------------------------------------*/
	int f;		/* IN: The unit to dismount	*/
	int opt;	/* IN: Option 1 to Dismount	*/
{
	int	s;
  
  ENTER("dev_close");
  s = osuclose(f, opt);
  if (s < 0) 	s = dev_error(f);
  else		s = OK;
  EXIT(s);
}

int dev_read (f, buffer, length)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Read a block from magnetic tape / optical disk.
.RETURNS Bytes read (>length if buffer too small) / EOF for error or EOF; 
.REMARKS The length MUST be a multiple of a sector size for
	 optical disks.
	 The returned length may be zero for virgin sectors.
.REMARKS Reading consecutive file marks, it is posible to go further 
	 than two file marks.
----------------------------------------------------------------------*/
	int 	f;		/* IN: The file control block	*/
	char	*buffer;	/* OUT: The buffer			*/
	int	length;		/* IN: The length of the buffer	*/
{ 
	int	s;
  
  ENTER("dev_read");
  s = osuread(f, buffer, length);
  if (s < 0)	dev_error(f);
  if (s == 0)	s = EOF;
  EXIT(s);
}

int dev_write (f, buffer, length)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Write a block on magnetic tape / optical disk.
.RETURNS Length written / EOF (error)
.REMARKS 
----------------------------------------------------------------------*/
	int 	f;		/* IN: The file control block	*/
	char	*buffer;	/* IN: The buffer		*/
	int	length;		/* IN: The length of the buffer	*/
{ 
	int	s;
  
  ENTER("dev_write");
  s = osuwrite(f, buffer, length);
  if (s < 0)	dev_error(f);
  EXIT(s);
}

int dev_mark(f)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Close a File (Write a Tape-Mark on the tape)
.RETURNS OK / NOK
.REMARKS Tape mouvements are optimized.
	 Does nothing if file opened for read-only (returns
	 wihout error)
----------------------------------------------------------------------*/
	int f;		/* IN: The file control block	*/
{
	int s;
	
  ENTER("dev_mark");
  s = osufclose(f);
  if (s < 0)	s = dev_error(f);
  else		s = OK;
  EXIT(s);
}

long dev_fseek (f, offset, mode)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE File seek (Move the tape, i.e. find tape-marks).
	 Identical to osubseek for disks.
.RETURNS New file number
.REMARKS On return, the tape is always positioned at a
	 file beginning. The tape move is always stopped
	 when two consecutive tape-marks are encountered.
----------------------------------------------------------------------*/
	int	f;		/* IN: Unit Number	*/
	long offset;		/* IN : Offset for displacement	*/
	int  mode;		/* IN : mode of addressing */
{
	long	s, osufseek();
	
  ENTER(".dev_fseek");
  s = osufseek(f, offset, mode);
  if (s < 0)		dev_error(f);
  EXITl(s);
}

long dev_ftell (f)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE	Compute current file number
.RETURNS	Current file number
.REMARKS	For disks, identical to osubtell.
----------------------------------------------------------------------*/
	int	f;		/* IN: Unit Number	*/
{
	long	s, osuftell();
	
  ENTER(".dev_ftell");
  s = osuftell(f);
  if (s < 0)		dev_error(f);
  EXITl(s);
}

long dev_bseek (f, offset, mode)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Block seek: Skip blocks on tape, skip sectors on
	 optical disks.
.RETURNS New block number / -1 if error or unknown block number.
.REMARKS Seek is stopped by a tape-mark, BUT the tape-mark is skipped.
		Disk: Simply set the position.
----------------------------------------------------------------------*/
	int	f;		/* IN: Unit Number	*/
	long offset;		/* IN : Offset for displacement	*/
	int  mode;		/* IN : mode of addressing */
{
	long	s, osubseek();
	
  ENTER(".dev_bseek");
  s = osubseek(f, offset, mode);
  if (s < 0)		dev_error(f);
  EXITl(s);
}

long dev_btell (f)
/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
.PURPOSE Compute current block / sector number
.RETURNS Current block number (in current file)
.REMARKS
----------------------------------------------------------------------*/
	int	f;		/* IN: Unit Number	*/
{
	long	s, osubtell();
	
  ENTER(".dev_btell");
  s = osubtell(f);
  if (s < 0)		dev_error(f);
  EXITl(s);
}