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d1dc791d11
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>
117 lines
3.8 KiB
C
117 lines
3.8 KiB
C
/****************************************************************************
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* libs/libc/string/lib_bsdstrncpy.c
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*
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* SPDX-License-Identifier: BSD
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* SPDX-FileCopyrightText: 1994-2009 Red Hat, Inc. All rights reserved
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*
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* Copyright (c) 1994-2009 Red Hat, Inc. All rights reserved.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the BSD License. This program is distributed in the hope that
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* it will be useful, but WITHOUT ANY WARRANTY expressed or implied,
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* including the implied warranties of MERCHANTABILITY or FITNESS FOR
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* A PARTICULAR PURPOSE. A copy of this license is available at
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* http://www.opensource.org/licenses. Any Red Hat trademarks that are
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* incorporated in the source code or documentation are not subject to
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* the BSD License and may only be used or replicated with the express
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* permission of Red Hat, Inc.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <string.h>
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#include "libc.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: strncpy
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*
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* Description:
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* Copies the string pointed to by 'src' (including the terminating NUL
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* character) into the array pointed to by 'dest'. strncpy() will not
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* copy more than 'n' bytes from 'src' to 'dest' array (including the
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* NUL terminator).
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*
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* If the array pointed to by 'src' is a string that is shorter than 'n'
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* bytes, NUL characters will be appended to the copy in the array
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* pointed to by 'dest', until 'n' bytes in all are written.
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*
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* If copying takes place between objects that overlap, the behavior is
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* undefined.
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*
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* Returned Value:
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* The strncpy() function returns the pointer to 'dest'
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*
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****************************************************************************/
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#if !defined(CONFIG_LIBC_ARCH_STRNCPY) && defined(LIBC_BUILD_STRNCPY)
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#undef strncpy
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nosanitize_address
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no_builtin("strncpy")
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FAR char *strncpy(FAR char *dest, FAR const char *src, size_t n)
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{
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FAR char *dst0 = dest;
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FAR const char *src0 = src;
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/* If src and dest is aligned and n large enough, then copy words. */
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if (!UNALIGNED(src0, dst0) && !TOO_SMALL(n))
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{
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FAR libc_data_t *aligned_dst = (FAR libc_data_t *)dst0;
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FAR const libc_data_t *aligned_src = (FAR libc_data_t *)src0;
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while (n >= LITTLEBLOCKSIZE && !DETECTNULL(*aligned_src))
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{
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n -= LITTLEBLOCKSIZE;
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*aligned_dst++ = *aligned_src++;
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}
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dst0 = (FAR char *)aligned_dst;
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src0 = (FAR char *)aligned_src;
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}
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else if (!UNALIGNED4(src0, dst0) && !TOO_SMALL4(n))
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{
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FAR uint32_t *aligned_dst = (FAR uint32_t *)dst0;
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FAR const uint32_t *aligned_src = (FAR uint32_t *)src0;
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while (n >= LITTLEBLOCKSIZE4 && !DETECTNULL32(*aligned_src))
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{
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n -= LITTLEBLOCKSIZE4;
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*aligned_dst++ = *aligned_src++;
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}
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dst0 = (FAR char *)aligned_dst;
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src0 = (FAR char *)aligned_src;
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}
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while (n > 0)
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{
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--n;
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if ((*dst0++ = *src0++) == '\0')
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{
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break;
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}
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}
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while (n-- > 0)
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{
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*dst0++ = '\0';
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}
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return dest;
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}
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#endif
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