libc/src/string/memrchr.cpp

   1 //===-- Implementation of memrchr -----------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/string/memrchr.h"
  10 #include "src/__support/common.h"
  11 #include "src/__support/macros/config.h"
  12 #include <stddef.h>
  13
  14 namespace LIBC_NAMESPACE_DECL {
  15
  16 LLVM_LIBC_FUNCTION(void *, memrchr, (const void *src, int c, size_t n)) {
  17   const unsigned char *str = reinterpret_cast<const unsigned char *>(src);
  18   const unsigned char ch = static_cast<unsigned char>(c);
  19   for (; n != 0; --n) {
  20     const unsigned char *s = str + n - 1;
  21     if (*s == ch)
  22       return const_cast<unsigned char *>(s);
  23   }
  24   return nullptr;
  25 }
  26
  27 } // namespace LIBC_NAMESPACE_DECL