[libc] [llvm] [libc] Cleaned up wcsspn and wcscspn (PR #147408)

[Michael Jones via llvm-commits]

================
@@ -0,0 +1,46 @@
+//===-- wchar utils ---------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_WCHAR_WCHAR_UTILS_H
+#define LLVM_LIBC_SRC_WCHAR_WCHAR_UTILS_H
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/attributes.h" // LIBC_INLINE
+
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
+
+// returns true if the character exists in the string
+LIBC_INLINE bool internal_wcschr(wchar_t c, const wchar_t *str) {
+  for (int n = 0; str[n]; ++n) {
+    if (str[n] == c)
+      return true;
+  }
+  return false;
+}
+
+// To avoid duplicated code, call this with true for wcscspn and call with false
+// for wcsspn
+LIBC_INLINE size_t inline_wcsspn(const wchar_t *s1, const wchar_t *s2,
+                                 bool invert) {
+  size_t i = 0;
+  for (; s1[i]; ++i) {
+    bool check = internal_wcschr(s1[i], s2);
+    check = invert ? !check : check;
+    if (!check)
+      return i;
----------------
michaelrj-google wrote:

```suggestion
LIBC_INLINE size_t inline_wcsspn(const wchar_t *s1, const wchar_t *s2,
                                 bool match_set) {
  size_t i = 0;
  for (; s1[i]; ++i) {
    bool in_set = internal_wcschr(s1[i], s2);
    if (in_set == match_set)
      return i;
```

https://github.com/llvm/llvm-project/pull/147408