cosmopolitan/libc/fmt/sleb128.c

40 lines
2.2 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/fmt/leb128.h"
/**
* Encodes sleb-128 signed integer.
*/
int sleb128(const void *buf, size_t size, int128_t x) {
int c;
unsigned i;
for (i = 0; i < size; ++i) {
c = x & 0x7f;
x >>= 7;
if ((x == 0 && !(c & 0x40)) || (x == -1 && (c & 0x40))) {
break;
} else {
c |= 0x80;
}
((char *)buf)[i] = c;
}
return i;
}