/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/weaken.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/dce.h"
#include "libc/log/backtrace.internal.h"
#include "libc/zipos/zipos.internal.h"

/**
 * Changes current position of file descriptor/handle.
 *
 * @param fd is a number returned by open()
 * @param offset is the relative byte count
 * @param whence can be SEEK_SET, SEEK_CUR, or SEEK_END
 * @return new position relative to beginning, or -1 on error
 * @asyncsignalsafe
 */
int64_t lseek(int fd, int64_t offset, unsigned whence) {
  if (fd < g_fds.n && g_fds.p[fd].kind == kFdZip) {
    return weaken(__zipos_lseek)(
        (struct ZiposHandle *)(intptr_t)g_fds.p[fd].handle, offset, whence);
  } else if (!IsWindows() && !IsOpenbsd() && !IsNetbsd()) {
    return sys_lseek(fd, offset, whence, 0);
  } else if (IsOpenbsd() || IsNetbsd()) {
    return sys_lseek(fd, offset, offset, whence);
  } else {
    return sys_lseek_nt(fd, offset, whence);
  }
}