cosmopolitan/libc/stdio/fread_unlocked.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

103 lines
3.6 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=8 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/calls/struct/iovec.h"
#include "libc/errno.h"
#include "libc/macros.internal.h"
#include "libc/stdckdint.h"
#include "libc/stdio/internal.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/o.h"
/**
* Reads data from stream.
*
* @param stride specifies the size of individual items
* @param count is the number of strides to fetch
* @return count on success, [0,count) on eof, or 0 on error or count==0
*/
size_t fread_unlocked(void *buf, size_t stride, size_t count, FILE *f) {
char *p;
ssize_t rc;
size_t n, m;
struct iovec iov[2];
if (!stride) {
return 0;
}
if ((f->iomode & O_ACCMODE) == O_WRONLY) {
f->state = errno = EBADF;
return 0;
}
if (f->beg > f->end) {
f->state = errno = EINVAL;
return 0;
}
if (ckd_mul(&n, stride, count)) {
f->state = errno = EOVERFLOW;
return 0;
}
p = buf;
m = f->end - f->beg;
if (MIN(n, m)) {
memcpy(p, f->buf + f->beg, MIN(n, m));
}
if (n < m) {
f->beg += n;
return count;
}
if (n == m) {
f->beg = f->end = 0;
return count;
}
if (f->fd == -1) {
f->beg = 0;
f->end = 0;
f->state = -1;
return m / stride;
}
iov[0].iov_base = p + m;
iov[0].iov_len = n - m;
if (f->bufmode != _IONBF && n < f->size) {
iov[1].iov_base = f->buf;
if (f->size > PUSHBACK) {
iov[1].iov_len = f->size - PUSHBACK;
} else {
iov[1].iov_len = f->size;
}
} else {
iov[1].iov_base = NULL;
iov[1].iov_len = 0;
}
if ((rc = readv(f->fd, iov, 2)) == -1) {
f->state = errno;
return 0;
}
n = rc;
f->beg = 0;
f->end = 0;
if (n > iov[0].iov_len) {
f->end += n - iov[0].iov_len;
return count;
} else {
n = (m + n) / stride;
if (n < count) f->state = -1;
return n;
}
}