/*

 * Copyright (c) 2017-2024 Free Software Foundation, Inc.

 *

 * This file is part of libwget.

 *

 * Libwget is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * Libwget 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 Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with libwget.  If not, see <https://www.gnu.org/licenses/>.

 *

 */

#include <config.h>

#include <stddef.h>

#include <string.h>

#include <wget.h>

/**

 * \ingroup libwget-utils

 * \param[out] dst Output string buffer

 * \param[in] src Input string

 * \param[in] size Size of \p dst

 * \return Number of copied bytes (excluding trailing 0) or -1 when \p src doesn't fit into \p dst

 *

 * Copy string \p src into \p dst with overflow checking.

 *

 * If either \p dst is %NULL or \p size is 0, the return value is -1 and nothing is written.

 * If \p src is %NULL and size is 0, the return value is -1.

 * If \p src is %NULL and size is >0, the return value is 0 and \p dst is an empty string.

 *

 * Else the return value is the number of bytes copied to \p dst excluding the terminating 0.

 */

ssize_t wget_strscpy(char *dst, const char *src, size_t size)

{

  if (unlikely(!dst))

    return -1;

  if (unlikely(!src)) {

    if (size) {

      *dst = 0;

      return 0;

    } else

      return -1;

  }

  const char *old = src;

  // Copy as many bytes as will fit

  if (likely(size)) {

    while (--size) {

      if (!(*dst++ = *src++))

        return src - old - 1;

    }

    *dst = 0;

    return src - old;

  }

  return -1;

}