gcc/libiberty/strndup.c

/* Implement the strndup function.
   Copyright (C) 2005-2017 Free Software Foundation, Inc.
   Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.

This file is part of the libiberty library.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

Libiberty is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA.  */

/*

@deftypefn Extension char* strndup (const char *@var{s}, size_t @var{n})

Returns a pointer to a copy of @var{s} with at most @var{n} characters
in memory obtained from @code{malloc}, or @code{NULL} if insufficient
memory was available.  The result is always NUL terminated.

@end deftypefn

*/

#include "ansidecl.h"
#include <stddef.h>

extern size_t	strnlen (const char *s, size_t maxlen);
extern PTR	malloc (size_t);
extern PTR	memcpy (PTR, const PTR, size_t);

char *
strndup (const char *s, size_t n)
{
  char *result;
  size_t len = strnlen (s, n);

  result = (char *) malloc (len + 1);
  if (!result)
    return 0;

  result[len] = '\0';
  return (char *) memcpy (result, s, len);
}