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

/* Compile this with -DNO_TRUNCATE if unistd.h does not exist or */
/* if it does not define int truncate(const char *name, off_t). */

#ifdef MSDOS
#undef NO_TRUNCATE
#define NO_TRUNCATE
#endif

#ifndef NO_TRUNCATE
#include "unistd.h"
#endif

#ifdef KR_headers
extern char *strcpy();
extern FILE *tmpfile();
#else
#undef abs
#undef min
#undef max
#include "stdlib.h"
#include "string.h"
#ifdef __cplusplus
extern "C" {
#endif
#endif

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

#ifdef KR_headers
integer f_end(a) alist *a;
#else
integer f_end(alist *a)
#endif
{
  unit *b;
  FILE *tf;

  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);
}

#ifdef NO_TRUNCATE
 static int
#ifdef KR_headers
copy(from, len, to) FILE *from, *to; register long len;
#else
copy(FILE *from, register long len, FILE *to)
#endif
{
  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 /* NO_TRUNCATE */

 int
#ifdef KR_headers
t_runc(a) alist *a;
#else
t_runc(alist *a)
#endif
{
  OFF_T loc, len;
  unit *b;
  int rc;
  FILE *bf;
#ifdef NO_TRUNCATE
  FILE *tf;
#endif

  b = &f__units[a->aunit];
  if(b->url)
         return(0);       /*don't truncate direct files*/
  loc=FTELL(bf = b->ufd);
  FSEEK(bf,(OFF_T)0,SEEK_END);
  len=FTELL(bf);
  if(loc >= len || b->useek == 0)
         return(0);
#ifdef NO_TRUNCATE
  if(b->ufnm == NULL)
         return 0;
  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, (long)loc, tf)) {
 bad1:
         rc = 1;
         goto done1;
         }
  if(!(bf = FREOPEN(b->ufnm, f__w_mode[0], bf)))
         goto bad1;
  rewind(tf);
  if(copy(tf, (long)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,(OFF_T)0,SEEK_END);
         b->urw = 3;
         }
#endif
done1:
  fclose(tf);
done:
  f__cf = b->ufd = bf;
#else /* NO_TRUNCATE */
  if(b->urw & 2)
         fflush(b->ufd); /* necessary on some Linux systems */
#ifndef FTRUNCATE
#define FTRUNCATE ftruncate
#endif
  rc = FTRUNCATE(fileno(b->ufd), loc);
  /* The following FSEEK is unnecessary on some systems, */
  /* but should be harmless. */
  FSEEK(b->ufd, (OFF_T)0, SEEK_END);
#endif /* NO_TRUNCATE */
  if(rc)
         err(a->aerr,111,"endfile");
  return 0;
  }
#ifdef __cplusplus
}
#endif
