Make improvements

- wcsstr() is now linearly complex
- strstr16() is now linearly complex
- strstr() is now vectorized on aarch64 (10x)
- strstr() now uses KMP on pathological cases
- memmem() is now vectorized on aarch64 (10x)
- memmem() now uses KMP on pathological cases
- Disable shared_ptr::owner_before until fixed
- Make iswlower(), iswupper() consistent with glibc
- Remove figure space from iswspace() implementation
- Include line and paragraph separator in iswcntrl()
- Use Musl wcwidth(), iswalpha(), iswpunct(), towlower(), towupper()

libc/str/kmp.c

@@ -0,0 +1,74 @@
+/*-*- 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 2024 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/kmp.h"
+#include "libc/mem/alloca.h"
+#include "libc/runtime/stack.h"
+
+static void computeLPS(const char *pattern, long M, long *lps) {
+  long len = 0;
+  lps[0] = 0;
+  long i = 1;
+  while (i < M) {
+    if (pattern[i] == pattern[len]) {
+      len++;
+      lps[i] = len;
+      i++;
+    } else {
+      if (len != 0) {
+        len = lps[len - 1];
+      } else {
+        lps[i] = 0;
+        i++;
+      }
+    }
+  }
+}
+
+char *__memmem_kmp(const char *s, size_t n, const char *ss, size_t m) {
+  if (!m)
+    return (char *)s;
+  if (n < m)
+    return NULL;
+#pragma GCC push_options
+#pragma GCC diagnostic ignored "-Walloca-larger-than="
+#pragma GCC diagnostic ignored "-Wanalyzer-out-of-bounds"
+  long need = sizeof(long) * m;
+  long *lps = (long *)alloca(need);
+  CheckLargeStackAllocation(lps, need);
+#pragma GCC pop_options
+  computeLPS(ss, m, lps);
+  long i = 0;
+  long j = 0;
+  while (i < n) {
+    if (ss[j] == s[i]) {
+      i++;
+      j++;
+    }
+    if (j == m) {
+      return (char *)(s + i - j);
+    } else if (i < n && ss[j] != s[i]) {
+      if (j != 0) {
+        j = lps[j - 1];
+      } else {
+        i++;
+      }
+    }
+  }
+  return NULL;
+}