[libc] Stop duplicating wcschr().

[enh-google]

Three implementations of wcschr() is two too many.

[llvmbot]

@llvm/pr-subscribers-libc

Author: None (enh-google)

Changes

Three implementations of wcschr() is two too many.

---

Full diff: https://github.com/llvm/llvm-project/pull/150661.diff

4 Files Affected:

• (modified) libc/src/wchar/wchar_utils.h (+4-7)
• (modified) libc/src/wchar/wcschr.cpp (+2-5)
• (modified) libc/src/wchar/wcspbrk.cpp (+1-9)
• (modified) libc/src/wchar/wcstok.cpp (+3-10)

diff --git a/libc/src/wchar/wchar_utils.h b/libc/src/wchar/wchar_utils.h
index e0218c7d89b1f..d69638fa71912 100644
--- a/libc/src/wchar/wchar_utils.h
+++ b/libc/src/wchar/wchar_utils.h
@@ -17,13 +17,10 @@
 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;
+LIBC_INLINE static wchar_t *wcschr(const wchar_t *s, wchar_t c) {
+  for (; *s && *s != c; ++s)
+    ;
+  return (*s == c) ? s : nullptr;
 }
 
 // bool should be true for wcscspn for complimentary span
diff --git a/libc/src/wchar/wcschr.cpp b/libc/src/wchar/wcschr.cpp
index defc2ce3c3b72..e53ec9a4c95ba 100644
--- a/libc/src/wchar/wcschr.cpp
+++ b/libc/src/wchar/wcschr.cpp
@@ -11,15 +11,12 @@
 #include "hdr/types/wchar_t.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
+#include "wchar_utils.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(const wchar_t *, wcschr, (const wchar_t *s, wchar_t c)) {
-  for (; *s && *s != c; ++s)
-    ;
-  if (*s == c)
-    return s;
-  return nullptr;
+  return internal::wcschr(s, c);
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/wchar/wcspbrk.cpp b/libc/src/wchar/wcspbrk.cpp
index a00ba9979a489..9faa34fe5fd1a 100644
--- a/libc/src/wchar/wcspbrk.cpp
+++ b/libc/src/wchar/wcspbrk.cpp
@@ -14,14 +14,6 @@
 
 namespace LIBC_NAMESPACE_DECL {
 
-bool contains_char(const wchar_t *str, wchar_t target) {
-  for (; *str != L'\0'; str++)
-    if (*str == target)
-      return true;
-
-  return false;
-}
-
 LLVM_LIBC_FUNCTION(const wchar_t *, wcspbrk,
                    (const wchar_t *src, const wchar_t *breakset)) {
   LIBC_CRASH_ON_NULLPTR(src);
@@ -29,7 +21,7 @@ LLVM_LIBC_FUNCTION(const wchar_t *, wcspbrk,
 
   // currently O(n * m), can be further optimized to O(n + m) with a hash set
   for (int src_idx = 0; src[src_idx] != 0; src_idx++)
-    if (contains_char(breakset, src[src_idx]))
+    if (internal::wcschr(breakset, src[src_idx]))
       return src + src_idx;
 
   return nullptr;
diff --git a/libc/src/wchar/wcstok.cpp b/libc/src/wchar/wcstok.cpp
index 291efc15e158a..32a500bf302c7 100644
--- a/libc/src/wchar/wcstok.cpp
+++ b/libc/src/wchar/wcstok.cpp
@@ -13,15 +13,8 @@
 
 namespace LIBC_NAMESPACE_DECL {
 
-bool isADelimeter(wchar_t wc, const wchar_t *delimiters) {
-  for (const wchar_t *delim_ptr = delimiters; *delim_ptr != L'\0'; ++delim_ptr)
-    if (wc == *delim_ptr)
-      return true;
-  return false;
-}
-
 LLVM_LIBC_FUNCTION(wchar_t *, wcstok,
-                   (wchar_t *__restrict str, const wchar_t *__restrict delim,
+                   (wchar_t *__restrict str, const wchar_t *__restrict delims,
                     wchar_t **__restrict context)) {
   if (str == nullptr) {
     if (*context == nullptr)
@@ -31,11 +24,11 @@ LLVM_LIBC_FUNCTION(wchar_t *, wcstok,
   }
 
   wchar_t *tok_start, *tok_end;
-  for (tok_start = str; *tok_start != L'\0' && isADelimeter(*tok_start, delim);
+  for (tok_start = str; *tok_start != L'\0' && wcschr(delims, *tok_start);
        ++tok_start)
     ;
 
-  for (tok_end = tok_start; *tok_end != L'\0' && !isADelimeter(*tok_end, delim);
+  for (tok_end = tok_start; *tok_end != L'\0' && !wcschr(delims, *tok_end);
        ++tok_end)
     ;
 

[lntue]

errors from the pre-commit:

In file included from /home/runner/work/llvm-project/llvm-project/libc/src/wchar/wcstok.cpp:13:
/home/runner/work/llvm-project/llvm-project/libc/src/wchar/wchar_utils.h:23:10: error: cannot initialize return object of type 'wchar_t *' with an rvalue of type 'const wchar_t *'
   23 |   return (*s == c) ? s : nullptr;
      |          ^~~~~~~~~~~~~~~~~~~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/wchar/wchar_utils.h:32:19: error: no matching function for call to 'wcschr'
   32 |     bool in_set = wcschr(s1[i], s2);
      |                   ^~~~~~
/home/runner/work/llvm-project/llvm-project/libc/src/wchar/wchar_utils.h:20:29: note: candidate function not viable: no known conversion from 'const wchar_t' to 'const wchar_t *' for 1st argument; take the address of the argument with &
   20 | LIBC_INLINE static wchar_t *wcschr(const wchar_t *s, wchar_t c) {
      |                             ^      ~~~~~~~~~~~~~~~~
   21 |   for (; *s && *s != c; ++s)
   22 |     ;
   23 |   return (*s == c) ? s : nullptr;
   24 | }

[uzairnawaz]

Thanks for the fixes, I didn't realize how often we were rewriting the same code 😅

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[frobtech]

lgtm. We need a clang-tidy checker to reject static used in headers.