just use string_length

Author: nickdesaulniers

libc/src/string/CMakeLists.txt

@@ -17,9 +17,11 @@ add_header_library(
   DEPENDS
     .memory_utils.inline_bzero
     .memory_utils.inline_memcpy
+    libc.hdr.types.size_t
     libc.include.stdlib
-    libc.src.__support.common
     libc.src.__support.CPP.bitset
+    libc.src.__support.CPP.type_traits
+    libc.src.__support.common
   ${string_config_options}
 )
 

libc/src/string/string_utils.h

@@ -14,12 +14,13 @@
 #ifndef LLVM_LIBC_SRC_STRING_STRING_UTILS_H
 #define LLVM_LIBC_SRC_STRING_STRING_UTILS_H
 
+#include "hdr/types/size_t.h"
 #include "src/__support/CPP/bitset.h"
+#include "src/__support/CPP/type_traits.h" // cpp::is_same_v
 #include "src/__support/macros/config.h"
 #include "src/__support/macros/optimization.h" // LIBC_UNLIKELY
 #include "src/string/memory_utils/inline_bzero.h"
 #include "src/string/memory_utils/inline_memcpy.h"
-#include <stddef.h> // For size_t
 
 namespace LIBC_NAMESPACE_DECL {
 namespace internal {
@@ -79,25 +80,22 @@ LIBC_INLINE size_t string_length_wide_read(const char *src) {
   return char_ptr - src;
 }
 
-template<typename T>
-LIBC_INLINE size_t string_length_trivial(const T *src) {
-  size_t length;
-  for (length = 0; *src; ++src, ++length)
-    ;
-  return length;
-}
-
 // Returns the length of a string, denoted by the first occurrence
 // of a null terminator.
-LIBC_INLINE size_t string_length(const char *src) {
+template<typename T>
+LIBC_INLINE size_t string_length(const T *src) {
 #ifdef LIBC_COPT_STRING_UNSAFE_WIDE_READ
   // Unsigned int is the default size for most processors, and on x86-64 it
   // performs better than larger sizes when the src pointer can't be assumed to
   // be aligned to a word boundary, so it's the size we use for reading the
   // string a block at a time.
-  return string_length_wide_read<unsigned int>(src);
+  if constexpr (cpp::is_same_v<T, char>)
+    return string_length_wide_read<unsigned int>(src);
 #else
-  return string_length_trivial(src);
+  size_t length;
+  for (length = 0; *src; ++src, ++length)
+    ;
+  return length;
 #endif
 }
 

libc/src/wchar/wcslen.cpp

@@ -17,7 +17,7 @@
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(size_t, wcslen, (const wchar_t *src)) {
-  return internal::string_length_trivial(src);
+  return internal::string_length(src);
 }
 
 } // namespace LIBC_NAMESPACE_DECL