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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>
107 lines
3 KiB
C
107 lines
3 KiB
C
/****************************************************************************
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* libs/libc/string/lib_bsdmemcmp.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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#if !defined(CONFIG_LIBC_ARCH_MEMCMP) && defined(LIBC_BUILD_MEMCMP)
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#undef memcmp
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no_builtin("memcmp")
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int memcmp(FAR const void *s1, FAR const void *s2, size_t n)
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{
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FAR unsigned char *p1 = (FAR unsigned char *)s1;
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FAR unsigned char *p2 = (FAR unsigned char *)s2;
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/* If the size is too small, or either pointer is unaligned,
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* then we punt to the byte compare loop. Hopefully this will
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* not turn up in inner loops.
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*/
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if (!TOO_SMALL(n) && !UNALIGNED(p1, p2))
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{
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FAR libc_data_t *a1 = (FAR libc_data_t *)p1;
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FAR libc_data_t *a2 = (FAR libc_data_t *)p2;
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while (n >= LITTLEBLOCKSIZE)
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{
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if (*a1 != *a2)
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{
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break;
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}
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a1++;
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a2++;
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n -= LITTLEBLOCKSIZE;
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}
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p1 = (FAR unsigned char *)a1;
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p2 = (FAR unsigned char *)a2;
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}
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else if (!TOO_SMALL4(n) && !UNALIGNED4(p1, p2))
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{
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FAR uint32_t *a1 = (FAR uint32_t *)p1;
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FAR uint32_t *a2 = (FAR uint32_t *)p2;
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while (n >= LITTLEBLOCKSIZE4)
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{
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if (*a1 != *a2)
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{
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break;
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}
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a1++;
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a2++;
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n -= LITTLEBLOCKSIZE4;
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}
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p1 = (FAR unsigned char *)a1;
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p2 = (FAR unsigned char *)a2;
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}
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while (n--)
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{
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if (*p1 != *p2)
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{
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return *p1 - *p2;
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}
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p1++;
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p2++;
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}
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return 0;
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}
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#endif
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