[libc] add wmemchr

Author: RossComputerGuy

libc/config/gpu/entrypoints.txt

@@ -261,6 +261,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.time.nanosleep
 
     # wchar.h entrypoints
+    libc.src.wchar.wmemchr
     libc.src.wchar.wctob
 
     # locale.h entrypoints

libc/config/linux/aarch64/entrypoints.txt

@@ -349,6 +349,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.unistd.write
 
     # wchar.h entrypoints
+    libc.src.wchar.wmemchr
     libc.src.wchar.wctob
 )
 

libc/config/linux/riscv/entrypoints.txt

@@ -346,6 +346,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.unistd.write
 
     # wchar.h entrypoints
+    libc.src.wchar.wmemchr
     libc.src.wchar.wctob
 )
 

libc/config/linux/x86_64/entrypoints.txt

@@ -348,6 +348,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.unistd.write
 
     # wchar.h entrypoints
+    libc.src.wchar.wmemchr
     libc.src.wchar.wctob
     libc.src.wchar.btowc
 )

libc/hdrgen/yaml/wchar.yaml

@@ -14,3 +14,11 @@ functions:
     return_type: int
     arguments:
       - type: wint_t
+  - name: wmemchr
+    standards:
+      - stdc
+    return_type: const wchar_t *
+    arguments:
+      - type: const wchar_t *
+      - type: wchar_t
+      - type: size_t

libc/src/wchar/CMakeLists.txt

@@ -22,3 +22,15 @@ add_entrypoint_object(
     libc.hdr.wchar_macros
     libc.src.__support.wctype_utils
 )
+
+add_entrypoint_object(
+  wmemchr
+  SRCS
+    wmemchr.cpp
+  HDRS
+    wmemchr.h
+  DEPENDS
+    libc.hdr.types.size_t
+    libc.hdr.types.wchar_t
+    libc.src.__support.wctype_utils
+)

libc/src/wchar/wmemchr.cpp

@@ -0,0 +1,26 @@
+//===-- Implementation of wmemchr -----------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/wchar/wmemchr.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(const wchar_t *, wmemchr,
+                   (const wchar_t *s, wchar_t c, size_t n)) {
+  for (size_t i = 0; i < n; i++) {
+    if (s[i] == c) {
+      return &s[i];
+    }
+  }
+
+  return nullptr;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/wchar/wmemchr.h

@@ -0,0 +1,22 @@
+//===-- Implementation header for wmemchr -----------------------*- 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_WMEMCHR_H
+#define LLVM_LIBC_SRC_WCHAR_WMEMCHR_H
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+const wchar_t *wmemchr(const wchar_t *s, wchar_t c, size_t n);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_WCHAR_WMEMCHR_H