libc/src/string/strncpy.cpp

   1 //===-- Implementation of strncpy -----------------------------------------===//
   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/strncpy.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(char *, strncpy,
  17                    (char *__restrict dest, const char *__restrict src,
  18                     size_t n)) {
  19   size_t i = 0;
  20   // Copy up until \0 is found.
  21   for (; i < n && src[i] != '\0'; ++i)
  22     dest[i] = src[i];
  23   // When n>strlen(src), n-strlen(src) \0 are appended.
  24   for (; i < n; ++i)
  25     dest[i] = '\0';
  26   return dest;
  27 }
  28
  29 } // namespace __llvm_libc