/*	$NetBSD: dosfile.c,v 1.1.1.1 1997/03/14 02:40:32 perry Exp $	*/

/*
 * Copyright (c) 1996
 *	Matthias Drochner.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed for the NetBSD Project
 *	by Matthias Drochner.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* DOS filesystem for libsa
 standalone - uses no device, works only with
 DOS running
 needs lowlevel parts from dos_file.S
 */

#include <lib/libsa/stand.h>

#include "diskbuf.h"

extern int dosopen __P((char*));
extern void dosclose __P((int));
extern int dosread __P((int, char*, int));
extern int dosseek __P((int, int, int));

struct dosfile{
  int doshandle, off;
};

extern int doserrno; /* in dos_file.S */

int dos_open(path, f)
char *path;
struct open_file *f;
{
  struct dosfile *df;

  df = (struct dosfile*)alloc(sizeof(*df));
  if(!df) return(-1);

  df->off = 0;
  df->doshandle = dosopen(path);
  if(df->doshandle < 0){
    printf("DOS error %d\n", doserrno);
    free(df, sizeof(*df));
    return(-1);
  }
  f->f_fsdata = (void*)df;
  return(0);
}

int dos_read(f, addr, size, resid)
struct open_file *f;
char *addr;
u_int size;
u_int *resid;	/* out */
{
  struct dosfile *df;
  int got;
  static int tc = 0;

  df = (struct dosfile*)f->f_fsdata;

  if(!(tc++ % 4)) twiddle();

  if((unsigned long)addr >= 0x10000) {
    u_int lsize = size;

    while(lsize > 0) {
      u_int tsize;
      int tgot;

      tsize = lsize;

      if(tsize > DISKBUFSIZE)
	tsize = DISKBUFSIZE;

      diskbuf_user = dos_read;

      tgot = dosread(df->doshandle, diskbuf, tsize);

      if(tgot < 0) {
	printf("DOS error %d\n", doserrno);
	return(-1);
      }

      bcopy(diskbuf, addr, tgot);

      addr += tgot;
      lsize -= tgot;

      if(tgot != tsize)
	break;	/* EOF */
    }
    got = size - lsize;
  } else {
    got = dosread(df->doshandle, addr, size);

    if(got < 0){
      printf("DOS error %d\n", doserrno);
      return(-1);
    }
  }

  df->off += got;
  size -= got;

  if(resid)
    *resid = size;
  return(0);
}

int dos_close(f)
struct open_file *f;
{
  struct dosfile *df;
  df = (struct dosfile*)f->f_fsdata;

  dosclose(df->doshandle);

  if(df) free(df, sizeof(*df));
  return(0);
}

int dos_write(f, start, size, resid)
struct open_file *f;
char *start;
u_int size;
u_int *resid;	/* out */
{
  errno = EROFS;
  return(-1);
}

int dos_stat(f, sb)
struct open_file *f;
struct stat *sb;
{
  struct dosfile *df;
  df = (struct dosfile*)f->f_fsdata;

  sb->st_mode = 0444;
  sb->st_nlink = 1;
  sb->st_uid = 0;
  sb->st_gid = 0;
  sb->st_size = -1;
  return(0);
}

off_t dos_seek(f, offset, where)
struct open_file *f;
off_t offset;
int where;
{
  struct dosfile *df;
  int doswhence, res;
#ifdef DOS_CHECK
  int checkoffs;
#endif
  df = (struct dosfile*)f->f_fsdata;

  switch(where){
    case SEEK_SET:
      doswhence = 0;
#ifdef DOS_CHECK
      checkoffs = offset; /* don't trust DOS */
#endif
      break;
    case SEEK_CUR:
      doswhence = 1;
#ifdef DOS_CHECK
      checkoffs = df->off + offset;
#endif
      break;
    case SEEK_END:
      doswhence = 2;
#ifdef DOS_CHECK
      checkoffs = -1; /* we dont know len */
#endif
      break;
    default: errno=EOFFSET; return(-1);
  }
  res = dosseek(df->doshandle, offset, doswhence);
  if(res == -1){
    errno = EIO;
    return(-1);
  }
#ifdef DOS_CHECK
  if((checkoffs !=- 1) && (res != checkoffs)){
    printf("dosfile: unexpected seek result (%d+%d(%d)=%d)\n",
	   df->off, offset, where, res);
    errno = EOFFSET;
    return(-1);
  }
#endif
  df->off = res;
  return(res);
}