nuttx/libs/libc/string/lib_bsdstpcpy.c

/****************************************************************************
 * libs/libc/string/lib_bsdstpcpy.c
 *
 * SPDX-License-Identifier: BSD
 * SPDX-FileCopyrightText: 1994-2009  Red Hat, Inc. All rights reserved
 *
 * Copyright (c) 1994-2009  Red Hat, Inc. All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the BSD License.   This program is distributed in the hope that
 * it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
 * including the implied warranties of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE.  A copy of this license is available at
 * http://www.opensource.org/licenses. Any Red Hat trademarks that are
 * incorporated in the source code or documentation are not subject to
 * the BSD License and may only be used or replicated with the express
 * permission of Red Hat, Inc.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <string.h>

#include "libc.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: stpcpy
 *
 * Description:
 *   Copies the string pointed to by 'src' (including the terminating NUL
 *   character) into the array pointed to by 'dest'.
 *
 * Returned Value:
 *   The stpcpy() function returns a pointer to the terminating NUL
 *   character copied into the 'dest' buffer
 *
 ****************************************************************************/

#ifndef CONFIG_LIBC_ARCH_STPCPY
#undef stpcpy
no_builtin("stpcpy")
nosanitize_address
FAR char *stpcpy(FAR char *dest, FAR const char *src)
{
  /* Walk a pair that agrees about where a boundary falls up to it, so that
   * the word path below is reached even when the caller aligned neither
   * pointer.  The terminator is left for the byte loop to copy.
   */

  if (!MISALIGNED(src, dest) && UNALIGNED_X(src))
    {
      while (*src != '\0')
        {
          *dest++ = *src++;
          if (!UNALIGNED_X(src))
            {
              break;
            }
        }
    }

  /* If src or dest is unaligned, then copy bytes. */

  if (!UNALIGNED(src, dest))
    {
      FAR libc_data_t *aligned_dst = (FAR libc_data_t *)dest;
      FAR const libc_data_t *aligned_src = (FAR libc_data_t *)src;

      while (!DETECTNULL(*aligned_src))
        {
          *aligned_dst++ = *aligned_src++;
        }

      dest = (FAR char *)aligned_dst;
      src = (FAR char *)aligned_src;
    }
  else if (!UNALIGNED4(src, dest))
    {
      FAR uint32_t *aligned_dst = (FAR uint32_t *)dest;
      FAR const uint32_t *aligned_src = (FAR uint32_t *)src;

      while (!DETECTNULL32(*aligned_src))
        {
          *aligned_dst++ = *aligned_src++;
        }

      dest = (FAR char *)aligned_dst;
      src = (FAR char *)aligned_src;
    }

  while ((*dest++ = *src++) != '\0');

  return --dest;
}
#endif