cosmopolitan/libc/fmt/vsscanf.c

52 lines
2.6 KiB
C

/*-*- 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 │
│ │
│ 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/dce.h"
#include "libc/fmt/fmt.h"
struct StringScannerState {
const unsigned char *s;
size_t i;
};
static int vsscanfcb(void *arg) {
int res;
struct StringScannerState *state;
state = arg;
if ((res = state->s[state->i])) {
state->i++;
} else {
res = -1;
}
return res;
}
/**
* Decodes string.
*
* @see libc/fmt/vcscanf.h (for docs and implementation)
* @note to offer the best performance, we assume small codebases
* needing vsscanf() won't need sscanf() too; and as such, there's
* a small code size penalty to using both
*/
int(vsscanf)(const char *str, const char *fmt, va_list va) {
struct StringScannerState state = {(const unsigned char *)str, 0};
return vcscanf(vsscanfcb, &state, fmt, va);
}