nuttx/libs/libc/string/lib_bsdstrcpy.c
Xiang Xiao d1dc791d11 libs/libc/string: Add 4-byte alignment middle path for BSD functions.
libc_data_t is 8 bytes wide, so a buffer which is 4-byte but not
8-byte aligned falls back to the byte at a time loop.  Add a 32-bit
middle path so such buffers still handle four bytes per iteration.

* Add DETECTNULL32/DETECTCHAR32, UNALIGNED4/UNALIGNED4_X,
  LITTLEBLOCKSIZE4/BIGBLOCKSIZE4 and TOO_SMALL4 to libs/libc/libc.h.
* Take the new path in memccpy, memcmp, memcpy, memset, stpcpy,
  stpncpy, strcmp, strcpy, strncmp and strncpy when both pointers are
  4-byte aligned but the 8-byte path can't be used.

Assisted-by: Claude:claude-opus-5
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
2026-08-17 10:47:33 +02:00

94 lines
3 KiB
C

/****************************************************************************
* libs/libc/string/lib_bsdstrcpy.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: strcpy
*
* Description:
* Copies the string pointed to by 'src' (including the terminating NUL
* character) into the array pointed to by 'des'.
*
* Returned Value:
* The strcpy() function returns the 'dest' pointer
*
****************************************************************************/
#if !defined(CONFIG_LIBC_ARCH_STRCPY) && defined(LIBC_BUILD_STRCPY)
#undef strcpy
nosanitize_address
no_builtin("strcpy")
FAR char *strcpy(FAR char *dest, FAR const char *src)
{
FAR char *dst0 = dest;
FAR const char *src0 = src;
/* If SRC or DEST is unaligned, then copy bytes. */
if (!UNALIGNED(src0, dst0))
{
FAR libc_data_t *aligned_dst = (FAR libc_data_t *)dst0;
FAR const libc_data_t *aligned_src = (FAR libc_data_t *)src0;
while (!DETECTNULL(*aligned_src))
{
*aligned_dst++ = *aligned_src++;
}
dst0 = (FAR char *)aligned_dst;
src0 = (FAR char *)aligned_src;
}
else if (!UNALIGNED4(src0, dst0))
{
FAR uint32_t *aligned_dst = (FAR uint32_t *)dst0;
FAR const uint32_t *aligned_src = (FAR uint32_t *)src0;
while (!DETECTNULL32(*aligned_src))
{
*aligned_dst++ = *aligned_src++;
}
dst0 = (FAR char *)aligned_dst;
src0 = (FAR char *)aligned_src;
}
while ((*dst0++ = *src0++) != '\0');
return dest;
}
#endif