#include "config.h"
#include "f2c.h"
#include "fio.h"

#include <sys/types.h>
#include <unistd.h>

#undef abs
#undef min
#undef max
#include <stdlib.h>
#include <string.h>

extern char *f__r_mode[], *f__w_mode[];

integer
f_end (alist * a)
{
  unit *b;
  FILE *tf;

  if (f__init & 2)
    f__fatal (131, "I/O recursion");
  if (a->aunit >= MXUNIT || a->aunit < 0)
    err (a->aerr, 101, "endfile");
  b = &f__units[a->aunit];
  if (b->ufd == NULL)
    {
      char nbuf[10];
      sprintf (nbuf, "fort.%ld", (long) a->aunit);
      if ((tf = fopen (nbuf, f__w_mode[0])))
	fclose (tf);
      return (0);
    }
  b->uend = 1;
  return (b->useek ? t_runc (a) : 0);
}

#ifndef HAVE_FTRUNCATE
static int
copy (FILE * from, register long len, FILE * to)
{
  int len1;
  char buf[BUFSIZ];

  while (fread (buf, len1 = len > BUFSIZ ? BUFSIZ : (int) len, 1, from))
    {
      if (!fwrite (buf, len1, 1, to))
	return 1;
      if ((len -= len1) <= 0)
	break;
    }
  return 0;
}
#endif /* !defined(HAVE_FTRUNCATE) */

int
t_runc (alist * a)
{
  off_t loc, len;
  unit *b;
  int rc;
  FILE *bf;
#ifndef HAVE_FTRUNCATE
  FILE *tf;
#endif /* !defined(HAVE_FTRUNCATE) */

  b = &f__units[a->aunit];
  if (b->url)
    return (0);			/*don't truncate direct files */
  loc = FTELL (bf = b->ufd);
  FSEEK (bf, 0, SEEK_END);
  len = FTELL (bf);
  if (loc >= len || b->useek == 0 || b->ufnm == NULL)
    return (0);
#ifndef HAVE_FTRUNCATE
  rc = 0;
  fclose (b->ufd);
  if (!loc)
    {
      if (!(bf = fopen (b->ufnm, f__w_mode[b->ufmt])))
	rc = 1;
      if (b->uwrt)
	b->uwrt = 1;
      goto done;
    }
  if (!(bf = fopen (b->ufnm, f__r_mode[0])) || !(tf = tmpfile ()))
    {
#ifdef NON_UNIX_STDIO
    bad:
#endif
      rc = 1;
      goto done;
    }
  if (copy (bf, loc, tf))
    {
    bad1:
      rc = 1;
      goto done1;
    }
  if (!(bf = freopen (b->ufnm, f__w_mode[0], bf)))
    goto bad1;
  FSEEK (tf, 0, SEEK_SET);
  if (copy (tf, loc, bf))
    goto bad1;
  b->uwrt = 1;
  b->urw = 2;
#ifdef NON_UNIX_STDIO
  if (b->ufmt)
    {
      fclose (bf);
      if (!(bf = fopen (b->ufnm, f__w_mode[3])))
	goto bad;
      FSEEK (bf, 0, SEEK_END);
      b->urw = 3;
    }
#endif
done1:
  fclose (tf);
done:
  f__cf = b->ufd = bf;
#else /* !defined(HAVE_FTRUNCATE) */
  fflush (b->ufd);
  rc = ftruncate (fileno (b->ufd), loc);
  FSEEK (bf, loc, SEEK_SET);
#endif /* !defined(HAVE_FTRUNCATE) */
  if (rc)
    err (a->aerr, 111, "endfile");
  return 0;
}