cosmopolitan/libc/fmt/unhexbuf.c

37 lines
2.3 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/assert.h"
#include "libc/fmt/bing.h"
#include "libc/str/str.h"
void *unhexbuf(void *buf, size_t size, const char *hexdigs) {
size_t i;
unsigned char *p;
assert(size * 2 == strlen(hexdigs));
p = buf;
for (i = 0; i < size; ++i) {
assert(isxdigit(hexdigs[i / 2 + 0]) && isxdigit(hexdigs[i / 2 + 1]));
}
for (i = 0; i < size; ++i) {
p[i] = hextoint(hexdigs[i * 2 + 0]) * 16 + hextoint(hexdigs[i * 2 + 1]);
}
return buf;
}