/*-*- 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/dce.h" #include "libc/intrin/asan.internal.h" #include "libc/nexgen32e/x86feature.h" #include "libc/str/str.h" typedef wchar_t xmm_t __attribute__((__vector_size__(16), __aligned__(4))); static inline const wchar_t *wmemrchr_pure(const wchar_t *s, wchar_t c, size_t n) { size_t i; for (i = n; i--;) { if (s[i] == c) { return s + i; } } return 0; } noasan static inline const wchar_t *wmemrchr_sse(const wchar_t *s, wchar_t c, size_t n) { size_t i; unsigned k, m; xmm_t v, t = {c, c, c, c}; for (i = n; i >= 4;) { v = *(const xmm_t *)(s + (i -= 4)); m = __builtin_ia32_pmovmskb128(v == t); if (m) { m = __builtin_clzl(m) ^ (sizeof(long) * CHAR_BIT - 1); return s + i + m / 4; } } while (i--) { if (s[i] == c) { return s + i; } } return 0; } /** * Returns pointer to first instance of character. * * @param s is memory to search * @param c is search word * @param n is number of wchar_t elements in `s` * @return is pointer to first instance of c or NULL if not found * @asyncsignalsafe */ void *wmemrchr(const wchar_t *s, wchar_t c, size_t n) { size_t bytes; const void *r; if (!IsTiny() && X86_HAVE(SSE)) { if (IsAsan()) { if (__builtin_mul_overflow(n, sizeof(wchar_t), &bytes)) bytes = -1; __asan_verify(s, bytes); } r = wmemrchr_sse(s, c, n); } else { r = wmemrchr_pure(s, c, n); } return (void *)r; }