60 lines
2.8 KiB
C
60 lines
2.8 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 │
|
|
│ │
|
|
│ 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/alg/alg.h"
|
|
#include "libc/nexgen32e/x86feature.h"
|
|
#include "libc/str/internal.h"
|
|
#include "libc/str/str.h"
|
|
|
|
/**
|
|
* Searches for substring.
|
|
*
|
|
* @param haystack is the search area, as a NUL-terminated string
|
|
* @param needle is the desired substring, also NUL-terminated
|
|
* @return pointer to first substring within haystack, or NULL
|
|
* @asyncsignalsafe
|
|
* @see memmem()
|
|
*/
|
|
char *strstr(const char *haystack, const char *needle) {
|
|
size_t i;
|
|
if (needle[0]) {
|
|
if (needle[1]) {
|
|
for (;;) {
|
|
#if 0 /* todo: fix me */
|
|
if (!((uintptr_t)haystack & 15) && X86_HAVE(SSE4_2) &&
|
|
(((uintptr_t)needle + strlen(needle)) & 0xfff) <= 0xff0) {
|
|
return strstr$sse42(haystack, needle);
|
|
}
|
|
#endif
|
|
for (i = 0;;) {
|
|
if (!needle[i]) return haystack;
|
|
if (!haystack[i]) break;
|
|
if (needle[i] != haystack[i]) break;
|
|
++i;
|
|
}
|
|
if (!*haystack++) break;
|
|
}
|
|
return NULL;
|
|
} else {
|
|
return strchr(haystack, needle[0]);
|
|
}
|
|
} else {
|
|
return haystack;
|
|
}
|
|
}
|