From b1ddaa81f28b8bbc62d6d50526e0935b173099eb Mon Sep 17 00:00:00 2001 From: Patryk Niedźwiedziński Date: Sat, 17 Apr 2021 10:28:11 +0200 Subject: Init --- stdio/ftello.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) create mode 100644 stdio/ftello.c (limited to 'stdio/ftello.c') diff --git a/stdio/ftello.c b/stdio/ftello.c new file mode 100644 index 0000000..7c6148a --- /dev/null +++ b/stdio/ftello.c @@ -0,0 +1,54 @@ +/*-*- 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/calls/calls.h" +#include "libc/errno.h" +#include "libc/runtime/runtime.h" +#include "libc/stdio/stdio.h" +#include "libc/sysv/consts/o.h" + +/** + * Returns current position of stream. + * + * @param stream is a non-null stream handle + * @returns current byte offset from beginning, or -1 w/ errno + */ +int64_t ftello(FILE *f) { + ssize_t rc; + int64_t pos; + uint32_t skew; + if (f->fd != -1) { + if (f->beg && !f->end && (f->iomode & O_ACCMODE) != O_RDONLY) { + if ((rc = write(f->fd, f->buf, f->beg)) == -1) { + f->state = errno; + return -1; + } + if (rc != f->beg) abort(); + f->beg = 0; + } + if ((pos = lseek(f->fd, 0, SEEK_CUR)) != -1) { + if (f->beg < f->end) pos -= f->end - f->beg; + return pos; + } else { + f->state = errno == ESPIPE ? EBADF : errno; + return -1; + } + } else { + return f->beg; + } +} -- cgit 1.4.1