1  /* Implement the strndup function.
       2     Copyright (C) 2005-2023 Free Software Foundation, Inc.
       3     Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
       4  
       5  This file is part of the libiberty library.
       6  Libiberty is free software; you can redistribute it and/or
       7  modify it under the terms of the GNU Library General Public
       8  License as published by the Free Software Foundation; either
       9  version 2 of the License, or (at your option) any later version.
      10  
      11  Libiberty is distributed in the hope that it will be useful,
      12  but WITHOUT ANY WARRANTY; without even the implied warranty of
      13  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14  Library General Public License for more details.
      15  
      16  You should have received a copy of the GNU Library General Public
      17  License along with libiberty; see the file COPYING.LIB.  If
      18  not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
      19  Boston, MA 02110-1301, USA.  */
      20  
      21  /*
      22  
      23  @deftypefn Extension char* strndup (const char *@var{s}, size_t @var{n})
      24  
      25  Returns a pointer to a copy of @var{s} with at most @var{n} characters
      26  in memory obtained from @code{malloc}, or @code{NULL} if insufficient
      27  memory was available.  The result is always NUL terminated.
      28  
      29  @end deftypefn
      30  
      31  */
      32  
      33  #include "ansidecl.h"
      34  #include <stddef.h>
      35  
      36  extern size_t	strnlen (const char *s, size_t maxlen);
      37  extern void *malloc (size_t);
      38  extern void *memcpy (void *, const void *, size_t);
      39  
      40  char *
      41  strndup (const char *s, size_t n)
      42  {
      43    char *result;
      44    size_t len = strnlen (s, n);
      45  
      46    result = (char *) malloc (len + 1);
      47    if (!result)
      48      return 0;
      49  
      50    result[len] = '\0';
      51    return (char *) memcpy (result, s, len);
      52  }