cosmopolitan/libc/stdio/fwrite_unlocked.c
Justine Tunney 8ff48201ca
Rewrite .zip.o file linker
This change takes an entirely new approach to the incremental linking of
pkzip executables. The assets created by zipobj.com are now treated like
debug data. After a .com.dbg is compiled, fixupobj.com should be run, so
it can apply fixups to the offsets and move the zip directory to the end
of the file. Since debug data doesn't get objcopy'd, a new tool has been
introduced called zipcopy.com which should be run after objcopy whenever
a .com file is created. This is all automated by the `cosmocc` toolchain
which is rapidly becoming the new recommended approach.

This change also introduces the new C23 checked arithmetic macros.
2023-06-10 09:29:44 -07:00

118 lines
4.4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net 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/assert.h"
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/struct/iovec.h"
#include "libc/calls/struct/iovec.internal.h"
#include "libc/errno.h"
#include "libc/fmt/conv.h"
#include "libc/macros.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/sock/sock.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"
/**
* Writes data to stream.
*
* @param stride specifies the size of individual items
* @param count is the number of strides to write
* @return count on success, [0,count) on EOF, 0 on error or count==0
*/
size_t fwrite_unlocked(const void *data, size_t stride, size_t count, FILE *f) {
ldiv_t d;
ssize_t rc;
size_t n, m;
const char *p;
struct iovec iov[2];
if (f->state) {
return 0;
}
if ((f->iomode & O_ACCMODE) == O_RDONLY) {
f->state = errno = EBADF;
return 0;
}
if (ckd_mul(&n, stride, count)) {
f->state = errno = EOVERFLOW;
return 0;
}
m = f->size - f->beg;
if (n <= m && f->bufmode != _IONBF) {
// this isn't a fully buffered stream, and
// there's enough room in the buffer for the request
memcpy(f->buf + f->beg, data, n);
f->beg += n;
if (f->fd != -1 && f->bufmode == _IOLBF &&
(p = memrchr(f->buf, '\n', f->beg))) {
// write out as many lines as possible
n = p + 1 - f->buf;
if ((rc = write(f->fd, f->buf, n)) == -1) {
// the write() system call failed
if (errno == EINTR || errno == EAGAIN) {
return count;
} else {
f->state = errno;
return 0;
}
}
// copy backwards last line fragment or uncompleted data
n = rc;
if (f->beg - n) {
memmove(f->buf, f->buf + n, f->beg - n);
}
f->beg -= n;
}
return count;
}
// what's happening is either
// (1) a fully buffered stream, or
// (2) no room in buffer to hold full request
if (f->fd == -1) {
// this is an in-memory stream
// store as much of request as we can hold
n = MIN(n, m);
d = ldiv(n, stride);
n -= d.rem;
if (n) {
memcpy(f->buf + f->beg, data, n);
f->beg += n;
}
// trigger eof condition
f->state = EOF;
return d.quot;
}
// perform a fragmented write
// (1) we avoid needless copies in fully buffered mode
// (2) we avoid need for malloc() when it's out of room
iov[0].iov_base = f->buf;
iov[0].iov_len = f->beg;
iov[1].iov_base = data;
iov[1].iov_len = n;
n += f->beg;
if (WritevUninterruptible(f->fd, iov, 2) == -1) {
f->state = errno;
return 0;
}
f->beg = 0;
return count;
}