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Do some string library work
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42 changed files with 1381 additions and 136 deletions
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@ -1,7 +1,7 @@
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ Copyright 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/str/str.h"
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typedef wchar_t xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
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/**
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* Searches for substring.
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* Returns length of NUL-terminated wide string.
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*
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* @param haystack is the search area, as a NUL-terminated string
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* @param needle is the desired substring, also NUL-terminated
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* @return pointer to first substring within haystack, or NULL
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* @param s is non-null NUL-terminated wide string pointer
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* @return number of wide characters (excluding NUL)
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* @asyncsignalsafe
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* @see memmem()
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*/
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wchar_t *wcsstr(const wchar_t *haystack, const wchar_t *needle) {
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size_t i;
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for (;;) {
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for (i = 0;;) {
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if (!needle[i]) return (/*unconst*/ wchar_t *)haystack;
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if (!haystack[i]) break;
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if (needle[i] != haystack[i]) break;
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++i;
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}
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if (!*haystack++) break;
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}
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return NULL;
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noasan size_t wcslen(const wchar_t *s) {
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size_t n;
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xmm_t z = {0};
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unsigned m, k = (uintptr_t)s & 15;
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const xmm_t *p = (const xmm_t *)((uintptr_t)s & -16);
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if (IsAsan()) __asan_verify(s, 4);
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m = __builtin_ia32_pmovmskb128(*p == z) >> k << k;
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while (!m) m = __builtin_ia32_pmovmskb128(*++p == z);
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n = (const wchar_t *)p + (__builtin_ctzl(m) >> 2) - s;
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if (IsAsan()) __asan_verify(s, n);
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return n;
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}
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