libc/src/string/strncat.cpp

   1 //===-- Implementation of strncat -----------------------------------------===//
   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/strncat.h"
  10 #include "src/string/string_utils.h"
  11 #include "src/string/strncpy.h"
  12
  13 #include "src/__support/common.h"
  14
  15 namespace LIBC_NAMESPACE {
  16
  17 LLVM_LIBC_FUNCTION(char *, strncat,
  18                    (char *__restrict dest, const char *__restrict src,
  19                     size_t count)) {
  20   size_t src_length = internal::string_length(src);
  21   size_t copy_amount = src_length > count ? count : src_length;
  22   size_t dest_length = internal::string_length(dest);
  23   LIBC_NAMESPACE::strncpy(dest + dest_length, src, copy_amount);
  24   dest[dest_length + copy_amount] = '\0';
  25   return dest;
  26 }
  27
  28 } // namespace LIBC_NAMESPACE