mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-05-28 00:02:28 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Make major improvements to stdio

Browse source 
Buffering now has optimal performance, bugs have been fixed, and some
missing apis have been introduced. This implementation is also now more
production worthy since it's less brittle now in terms of system errors.
That's going to help redbean since lua i/o is all based on stdio.

See #97
This commit is contained in:
Justine Tunney 2021-03-26 22:31:41 -07:00
parent 09bcfa23d5
commit da36e7e256
69 changed files with 1595 additions and 735 deletions
Download patch file Download diff file Expand all files Collapse all files

83
libc/stdio/fseeko.c Normal file
View file

@ -0,0 +1,83 @@
/*-*- 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 2021 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/stdio/stdio.h"
#include "libc/sysv/consts/o.h"
/**
* Repositions open file stream.
*
* This function flushes the buffer (unless it's currently in the EOF
* state) and then calls lseek() on the underlying file. If the stream
* is in the EOF state, this function can be used to restore it without
* needing to reopen the file.
*
* @param f is a non-null stream handle
* @param offset is the byte delta
* @param whence can be SEET_SET, SEEK_CUR, or SEEK_END
* @returns 0 on success or -1 on error
*/
int fseeko(FILE *f, int64_t offset, int whence) {
ssize_t rc;
int64_t pos;
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 (whence == SEEK_CUR && f->beg < f->end) {
offset -= f->end - f->beg;
}
if (lseek(f->fd, offset, whence) != -1) {
f->beg = 0;
f->end = 0;
return 0;
} else {
f->state = errno == ESPIPE ? EBADF : errno;
return -1;
}
} else {
switch (whence) {
case SEEK_SET:
pos = offset;
break;
case SEEK_CUR:
pos = f->beg + offset;
break;
case SEEK_END:
pos = f->end + offset;
break;
default:
pos = -1;
break;
}
if (0 <= pos && pos <= f->end) {
f->beg = pos;
return 0;
} else {
f->state = errno = EINVAL;
return -1;
}
}
}