cosmopolitan/libc/calls/vdprintf.c

66 lines
3.0 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 │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/internal.h"
#include "libc/dce.h"
#include "libc/fmt/fmt.h"
#include "libc/limits.h"
#include "libc/nt/files.h"
#include "libc/sysv/errfuns.h"
#define DBUFSIZ 1460 /* tcp ethernet frame < -Wframe-larger-than=4096 */
struct dfile {
int fd;
unsigned idx;
unsigned toto;
unsigned char buf[DBUFSIZ];
};
static int vdprintf_flush(struct dfile *df) {
ssize_t wrote;
do {
wrote = write(df->fd, &df->buf[0], df->idx);
if (wrote == -1) return -1;
df->toto += (unsigned)wrote;
df->idx -= (unsigned)wrote;
if (df->toto > INT_MAX) return eoverflow();
} while (df->idx);
return 0;
}
static int vdprintfputchar(unsigned char c, struct dfile *df) {
df->buf[df->idx++] = c;
if (df->idx == DBUFSIZ && vdprintf_flush(df) == -1) return -1;
return 0;
}
/**
* Formats string directly to system i/o device.
*/
int(vdprintf)(int fd, const char *fmt, va_list va) {
struct dfile df;
df.fd = fd;
df.idx = 0;
df.toto = 0;
if (palandprintf(vdprintfputchar, &df, fmt, va) == -1) return -1;
if (df.idx && vdprintf_flush(&df) == -1) return -1;
return df.toto;
}