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Make more functions friendly to Address Sanitizer

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This commit is contained in:
Justine Tunney 2021-02-02 03:45:31 -08:00
parent 3ab76b2312
commit cbfd4ccd1e
70 changed files with 1267 additions and 291 deletions
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47
libc/str/memchr.c Normal file
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/*-*- 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 2021 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/str/str.h"
/**
* Returns pointer to first instance of character.
*
* @param m is memory to search
* @param c is search byte which is masked with 255
* @param n is byte length of p
* @return is pointer to first instance of c or NULL if not found
* @asyncsignalsafe
*/
void *memchr(const void *m, int c, size_t n) {
uint64_t v, w;
const unsigned char *p, *pe;
c &= 255;
v = 0x0101010101010101 * c;
for (p = (const unsigned char *)m, pe = p + n; p + 8 <= pe; p += 8) {
w = (uint64_t)p[7] << 070 | (uint64_t)p[6] << 060 | (uint64_t)p[5] << 050 |
(uint64_t)p[4] << 040 | (uint64_t)p[3] << 030 | (uint64_t)p[2] << 020 |
(uint64_t)p[1] << 010 | (uint64_t)p[0] << 000;
if ((w = ~(w ^ v) & ((w ^ v) - 0x0101010101010101) & 0x8080808080808080)) {
return p + ((unsigned)__builtin_ctzll(w) >> 3);
}
}
for (; p < pe; ++p) {
if (*p == c) return p;
}
return NULL;
}