/*! \file
 * \brief
 * 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
 */

#include "port_before.h"

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

#include <fcntl.h>

#include "port_after.h"

int
__ftruncate(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) {
                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));
        }
        return (0);
}
#endif

#ifndef OWN_FTRUNCATE
int __bindcompat_ftruncate;
#endif