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 "src/__support/macros/config.h"
  13 #include <stddef.h> // For size_t.
  14
  15 namespace LIBC_NAMESPACE_DECL {
  16
  17 LLVM_LIBC_FUNCTION(char *, strncpy,
  18                    (char *__restrict dest, const char *__restrict src,
  19                     size_t n)) {
  20   size_t i = 0;
  21   // Copy up until \0 is found.
  22   for (; i < n && src[i] != '\0'; ++i)
  23     dest[i] = src[i];
  24   // When n>strlen(src), n-strlen(src) \0 are appended.
  25   for (; i < n; ++i)
  26     dest[i] = '\0';
  27   return dest;
  28 }
  29
  30 } // namespace LIBC_NAMESPACE_DECL