//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 3 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, see <http://www.gnu.org/licenses/>
/* tempfile.c */
/* Copyright 1995 Willis E. Howard, III */
/* Willis E. Howard, III  email: WEHoward@aol.com  mail: POB 1473 Elkhart, IN  46515 */

/* Find a temporary file than can be opened for write,
   that does not exist, and that differs from the
   argument only by the file extension.  A pointer to
   the name will be returned.  Return NULL on failure.
   Running this from a read-only medium will always fail.

   Only 12 different file extensions are tried.  If you
   fail to erase the temporary file after using it, the
   routine will fail after the finite number of files
   are created with the same base name in the same
   subdirectory.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "tempfile.h"

static char found_name[81];

char *
tempfile (char *name)
{
    char **ePointer;
    char *extensions[] =                         /* trial extensions for temp file */
    {
     "TMP",
     "T01",
     "X78",
     "ZXY",
     "H4D",
     "V9Y",
     "001",
     "040",
     "963",
     "826",
     "543",
     "195",
     NULL
    };
    char t_name[81];
    FILE * fPointer;

    if (strlen (name) > 76)                      /* too long */
        return NULL;
    strcpy (t_name, name);                       /* get local copy of name */
    if (strrchr (t_name, '.') != NULL)           /* delete extension */
        *strrchr (t_name, '.') = '\0';
    strcat (t_name, ".");                        /* t_name now has no extension */

    for (ePointer = extensions; *ePointer != NULL; ePointer++)
    {
        strcpy (found_name, t_name);
        strcat (found_name, *ePointer);
        if ((fPointer = fopen (found_name, "r")) == NULL)
            break;
        else
            fclose (fPointer);
    }

    if (*ePointer == NULL)               /* end of list, failure */
        return NULL;

    if ((fPointer = fopen (found_name, "w")) == NULL)
        return NULL;
    fclose(fPointer);

    remove (found_name);

    return found_name;
}