libc/src/string/memccpy.cpp

   1 //===-- Implementation of memccpy ----------------------------------------===//
   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/memccpy.h"
  10
  11 #include "src/__support/common.h"
  12 #include <stddef.h> // For size_t.
  13
  14 namespace __llvm_libc {
  15
  16 LLVM_LIBC_FUNCTION(void *, memccpy,
  17                    (void *__restrict dest, const void *__restrict src, int c,
  18                     size_t count)) {
  19   unsigned char end = static_cast<unsigned char>(c);
  20   const unsigned char *uc_src = static_cast<const unsigned char *>(src);
  21   unsigned char *uc_dest = static_cast<unsigned char *>(dest);
  22   size_t i = 0;
  23   // Copy up until end is found.
  24   for (; i < count && uc_src[i] != end; ++i)
  25     uc_dest[i] = uc_src[i];
  26   // if i < count, then end must have been found, so copy end into dest and
  27   // return the byte after.
  28   if (i < count) {
  29     uc_dest[i] = uc_src[i];
  30     return uc_dest + i + 1;
  31   }
  32   return nullptr;
  33 }
  34
  35 } // namespace __llvm_libc