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

created internal wcsspn to avoid duplicated code

---------

Co-authored-by: Sriya Pratipati <sriyap@google.com>

libc/src/wchar/CMakeLists.txt

@@ -1,3 +1,13 @@
+add_header_library(
+  wchar_utils
+  HDRS
+    wchar_utils.h
+  DEPENDS
+    libc.hdr.types.size_t
+    libc.hdr.types.wchar_t
+    libc.src.__support.common
+)
+
 add_entrypoint_object(
   wcslen
   SRCS
@@ -255,6 +265,8 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.wchar_macros
     libc.hdr.types.size_t
+    libc.src.wchar.wchar_utils
+    libc.src.__support.macros.null_check
 )
 
 add_entrypoint_object(
@@ -266,6 +278,8 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.wchar_macros
     libc.hdr.types.size_t
+    libc.src.wchar.wchar_utils
+    libc.src.__support.macros.null_check
 )
 
 add_entrypoint_object(

libc/src/wchar/wchar_utils.h

@@ -0,0 +1,45 @@
+//===-- 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 static bool wcschr(wchar_t c, const wchar_t *str) {
+  for (int n = 0; str[n]; ++n) {
+    if (str[n] == c)
+      return true;
+  }
+  return false;
+}
+
+// bool should be true for wcscspn for complimentary span
+// should be false for wcsspn since we want it to span
+LIBC_INLINE static size_t wcsspn(const wchar_t *s1, const wchar_t *s2,
+                                 bool not_match_set) {
+  size_t i = 0;
+  for (; s1[i]; ++i) {
+    bool in_set = wcschr(s1[i], s2);
+    if (in_set == not_match_set)
+      return i;
+  }
+  return i;
+}
+
+} // namespace internal
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif //  LLVM_LIBC_SRC_WCHAR_WCHAR_UTILS_H

libc/src/wchar/wcscspn.cpp

@@ -12,23 +12,15 @@
 #include "hdr/types/wchar_t.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
+#include "src/__support/macros/null_check.h"
+#include "wchar_utils.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
-bool check(wchar_t c, const wchar_t *s2) {
-  for (int n = 0; s2[n]; ++n) {
-    if (s2[n] == c)
-      return false;
-  }
-  return true;
-}
 LLVM_LIBC_FUNCTION(size_t, wcscspn, (const wchar_t *s1, const wchar_t *s2)) {
-  size_t i = 0;
-  for (; s1[i]; ++i) {
-    if (!check(s1[i], s2))
-      return i;
-  }
-  return i;
+  LIBC_CRASH_ON_NULLPTR(s1);
+  LIBC_CRASH_ON_NULLPTR(s2);
+  return internal::wcsspn(s1, s2, /*not_match_set=*/true);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

libc/src/wchar/wcsspn.cpp

@@ -12,23 +12,15 @@
 #include "hdr/types/wchar_t.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
+#include "src/__support/macros/null_check.h"
+#include "wchar_utils.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
-bool check(wchar_t c, const wchar_t *s2) {
-  for (int n = 0; s2[n]; ++n) {
-    if (s2[n] == c)
-      return true;
-  }
-  return false;
-}
 LLVM_LIBC_FUNCTION(size_t, wcsspn, (const wchar_t *s1, const wchar_t *s2)) {
-  size_t i = 0;
-  for (; s1[i]; ++i) {
-    if (!check(s1[i], s2))
-      return i;
-  }
-  return i;
+  LIBC_CRASH_ON_NULLPTR(s1);
+  LIBC_CRASH_ON_NULLPTR(s2);
+  return internal::wcsspn(s1, s2, /*not_match_set=*/false);
 }
 
 } // namespace LIBC_NAMESPACE_DECL

utils/bazel/llvm-project-overlay/libc/BUILD.bazel

@@ -6083,6 +6083,17 @@ libc_function(
 
 ############################## wchar targets ###############################
 
+libc_support_library(
+    name = "wchar_utils",
+    hdrs = ["src/wchar/wchar_utils.h"],
+    deps = [
+        ":__support_common",
+        ":__support_macros_attributes",
+        ":types_size_t",
+        ":types_wchar_t",
+    ],
+)
+
 libc_function(
     name = "btowc",
     srcs = ["src/wchar/btowc.cpp"],
@@ -6180,6 +6191,7 @@ libc_function(
         ":__support_macros_config",
         ":types_size_t",
         ":types_wchar_t",
+        ":wchar_utils",
     ],
 )
 
@@ -6291,6 +6303,7 @@ libc_function(
         ":__support_macros_config",
         ":types_size_t",
         ":types_wchar_t",
+        ":wchar_utils",
     ],
 )