Do some string library work

libc/str/strcpy16.c

@@ -21,12 +21,13 @@
 /**
  * Copies NUL-terminated UCS-2 or UTF-16 string.
  *
- * DEST and SRC must not overlap unless DEST ≤ SRC.
+ * 𝑑 and 𝑠 must not overlap unless 𝑑 ≤ 𝑠.
  *
- * @param dest is destination memory
- * @param src is a NUL-terminated 16-bit string
- * @return original dest
+ * @param d is dination memory
+ * @param s is a NUL-terminated 16-bit string
+ * @return original d
+ * @asyncsignalsafe
  */
-char16_t *strcpy16(char16_t *dest, const char16_t *src) {
-  return memcpy(dest, src, (strlen16(src) + 1) * sizeof(char16_t));
+char16_t *strcpy16(char16_t *d, const char16_t *s) {
+  return memcpy(d, s, (strlen16(s) + 1) * sizeof(char16_t));
 }

libc/str/strlen16.c

@@ -31,7 +31,7 @@ typedef char16_t xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
  */
 noasan size_t strlen16(const char16_t *s) {
   size_t n;
-  xmm_t v, z = {0};
+  xmm_t z = {0};
   unsigned m, k = (uintptr_t)s & 15;
   const xmm_t *p = (const xmm_t *)((uintptr_t)s & -16);
   if (IsAsan()) __asan_verify(s, 2);

libc/str/tprecode16to8.c

@@ -50,7 +50,7 @@ static noasan axdx_t tprecode16to8_sse2(char *dst, size_t dstsize,
  * Transcodes UTF-16 to UTF-8.
  *
  * This is a low-level function intended for the core runtime. Use
- * utf16toutf8() for a much better API that uses malloc().
+ * utf16to8() for a much better API that uses malloc().
  *
  * @param dst is output buffer
  * @param dstsize is bytes in dst

libc/str/tprecode8to16.c

@@ -47,7 +47,7 @@ static inline noasan axdx_t tprecode8to16_sse2(char16_t *dst, size_t dstsize,
  * Transcodes UTF-8 to UTF-16.
  *
  * This is a low-level function intended for the core runtime. Use
- * utf8toutf16() for a much better API that uses malloc().
+ * utf8to16() for a much better API that uses malloc().
  *
  * @param dst is output buffer
  * @param dstsize is shorts in dst

libc/str/wcscpy.c

@@ -23,12 +23,11 @@
  *
  * 𝑑 and 𝑠 must not overlap unless 𝑑 ≤ 𝑠.
  *
- * @param 𝑑 is destination memory
- * @param 𝑠 is a NUL-terminated string
- * @return original dest
+ * @param d is destination memory
+ * @param s is a NUL-terminated string
+ * @return original d
  * @asyncsignalsafe
  */
 wchar_t *wcscpy(wchar_t *d, const wchar_t *s) {
-  memcpy(d, s, (wcslen(s) + 1) * sizeof(wchar_t));
-  return d;
+  return memcpy(d, s, (wcslen(s) + 1) * sizeof(wchar_t));
 }

libc/str/wcslen.c

@@ -1,7 +1,7 @@
 /*-*- 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                              │
+│ 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         │
@@ -16,27 +16,28 @@
 │ 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/str/str.h"
 
+typedef wchar_t xmm_t __attribute__((__vector_size__(16), __aligned__(16)));
+
 /**
- * Searches for substring.
+ * Returns length of NUL-terminated wide string.
  *
- * @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
+ * @param s is non-null NUL-terminated wide string pointer
+ * @return number of wide characters (excluding NUL)
  * @asyncsignalsafe
- * @see memmem()
  */
-wchar_t *wcsstr(const wchar_t *haystack, const wchar_t *needle) {
-  size_t i;
-  for (;;) {
-    for (i = 0;;) {
-      if (!needle[i]) return (/*unconst*/ wchar_t *)haystack;
-      if (!haystack[i]) break;
-      if (needle[i] != haystack[i]) break;
-      ++i;
-    }
-    if (!*haystack++) break;
-  }
-  return NULL;
+noasan size_t wcslen(const wchar_t *s) {
+  size_t n;
+  xmm_t z = {0};
+  unsigned m, k = (uintptr_t)s & 15;
+  const xmm_t *p = (const xmm_t *)((uintptr_t)s & -16);
+  if (IsAsan()) __asan_verify(s, 4);
+  m = __builtin_ia32_pmovmskb128(*p == z) >> k << k;
+  while (!m) m = __builtin_ia32_pmovmskb128(*++p == z);
+  n = (const wchar_t *)p + (__builtin_ctzl(m) >> 2) - s;
+  if (IsAsan()) __asan_verify(s, n);
+  return n;
 }

libc/str/wcsncasecmp.c

@@ -30,6 +30,6 @@ int wcsncasecmp(const wchar_t *a, const wchar_t *b, size_t n) {
   size_t i = 0;
   unsigned x, y;
   if (!n-- || a == b) return 0;
-  while ((x = tolower(a[i])) == (y = tolower(b[i])) && b[i] && i < n) ++i;
+  while ((x = towlower(a[i])) == (y = towlower(b[i])) && b[i] && i < n) ++i;
   return x - y;
 }

libc/str/wcsstr.c

@@ -0,0 +1,42 @@
+/*-*- 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/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()
+ */
+wchar_t *wcsstr(const wchar_t *haystack, const wchar_t *needle) {
+  size_t i;
+  for (;;) {
+    for (i = 0;;) {
+      if (!needle[i]) return (/*unconst*/ wchar_t *)haystack;
+      if (!haystack[i]) break;
+      if (needle[i] != haystack[i]) break;
+      ++i;
+    }
+    if (!*haystack++) break;
+  }
+  return NULL;
+}