cosmopolitan/libc/calls/lseek.c
Justine Tunney 51904e2687 Improve Python and Linenoise
This change reinvents all the GNU Readline features I discovered that I
couldn't live without, e.g. UTF-8, CTRL-R search and CTRL-Y yanking. It
now feels just as good in terms of user interface from the subconscious
workflow perspective. It's real nice to finally have an embeddable line
reader that's actually good with a 30 kb footprint and a bsd-2 license.

This change adds a directory to the examples folder, explaining how the
new Python compiler may be used.  Some of the bugs with Python binaries
have been addressed but overall it's still a work in progress.
2021-09-11 22:30:37 -07:00

46 lines
2.7 KiB
C

/*-*- 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);
}
}