cosmopolitan/libc/str/strcasecmp.c
Justine Tunney 2ab9e9f7fd
Make improvements
- Introduce portable sched_getcpu() api
- Support GCC's __target_clones__ feature
- Make fma() go faster on x86 in default mode
- Remove some asan checks from core libraries
- WinMain() now ensures $HOME and $USER are defined
2024-02-12 10:23:00 -08:00

59 lines
2.9 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 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/dce.h"
#include "libc/str/str.h"
#include "libc/str/tab.internal.h"
/**
* Compares NUL-terminated strings ascii case-insensitively.
*
* @param a is first non-null nul-terminated string pointer
* @param b is second non-null nul-terminated string pointer
* @return is <0, 0, or >0 based on tolower(uint8_t) comparison
* @asyncsignalsafe
*/
int strcasecmp(const char *a, const char *b) {
int x, y;
size_t i = 0;
uint64_t v, w;
if (a == b) return 0;
if (((uintptr_t)a & 7) == ((uintptr_t)b & 7)) {
for (; (uintptr_t)(a + i) & 7; ++i) {
CheckEm:
if ((x = kToLower[a[i] & 255]) != (y = kToLower[b[i] & 255]) || !y) {
return x - y;
}
}
for (;; i += 8) {
v = *(uint64_t *)(a + i);
w = *(uint64_t *)(b + i);
w = (v ^ w) | (~v & (v - 0x0101010101010101) & 0x8080808080808080);
if (w) {
i += (unsigned)__builtin_ctzll(w) >> 3;
goto CheckEm;
}
}
} else {
while ((x = kToLower[a[i] & 255]) == (y = kToLower[b[i] & 255]) && y) ++i;
return x - y;
}
}
__weak_reference(strcasecmp, strcasecmp_l);