/* ftruncate - set file size, BSD Style
 *
 * shortens or enlarges the file as neeeded
 * uses some undocumented locking call. It is known to work on SCO unix,
 * other vendors should try.
 * The #error directive prevents unsupported OSes
 */

#ifndef LINT
static char rcsid[] = "$Id: ftruncate.c,v 8.2 1996/08/08 22:49:37 vixie Exp $";
#endif

#if defined(M_UNIX) && !defined(_SCO_DS)
#define OWN_FTRUNCATE
#include <stdio.h>
#ifdef _XOPEN_SOURCE
#undef _XOPEN_SOURCE
#endif
#ifdef _POSIX_SOURCE
#undef _POSIX_SOURCE
#endif
#include <fcntl.h>

int
__ftruncate(fd, wantsize)
	int fd;
	long wantsize;
{
	long cursize;

	/* determine current file size */
	if ((cursize = lseek(fd, 0L, 2)) == -1) {
		return (-1);
	}

	/* maybe lengthen... */
	if (cursize < wantsize) {
		if (lseek(fd, wantsize - 1, 0) == -1 ||
		    write(fd, "", 1) == -1) {
			return (-1);
		}
		return (0);
	}
	/* maybe shorten... */
	if (wantsize < cursize) {
#ifndef WINNT
		struct flock fl;

		fl.l_whence = 0;
		fl.l_len = 0;
		fl.l_start = wantsize;
		fl.l_type = F_WRLCK;
		return (fcntl(fd, F_FREESP, &fl));
#else
		return (lseek(fd, wantsize, 0) && SetEndOfFile((HANDLE)fd));
#endif
	}
	return (0);
}
#endif

#ifndef OWN_FTRUNCATE
int __bindcompat_ftruncate;
#endif
