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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>
133 lines
4.2 KiB
C
133 lines
4.2 KiB
C
/****************************************************************************
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* libs/libc/string/lib_bsdmemccpy.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: memccpy
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*
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* Description:
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* The memccpy() function copies bytes from memory area s2 into s1,
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* stopping after the first occurrence of byte c (converted to an unsigned
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* char) is copied, or after n bytes are copied, whichever comes first. If
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* 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 memccpy() function returns a pointer to the byte after the copy of c
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* in s1, or a null pointer if c was not found in the first n bytes of s2.
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*
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****************************************************************************/
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#undef memccpy
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FAR void *memccpy(FAR void *s1, FAR const void *s2, int c, size_t n)
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{
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FAR unsigned char *pout = (FAR unsigned char *)s1;
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FAR const unsigned char *pin = (FAR const unsigned char *)s2;
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unsigned char endchar = c & 0xff;
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/* If the size is small, or either pin or pout is unaligned,
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* then punt into the byte copy loop. This should be rare.
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*/
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if (!TOO_SMALL(n) && !UNALIGNED(pin, pout))
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{
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FAR libc_data_t *paligned_out = (FAR libc_data_t *)pout;
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FAR const libc_data_t *paligned_in = (FAR libc_data_t *)pin;
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libc_data_t mask = 0;
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unsigned int i;
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for (i = 0; i < LITTLEBLOCKSIZE; i++)
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{
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mask = (mask << 8) + endchar;
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}
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while (n >= LITTLEBLOCKSIZE)
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{
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libc_data_t buffer = (libc_data_t)(*paligned_in);
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buffer ^= mask;
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if (DETECTNULL(buffer))
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{
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break;
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}
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*paligned_out++ = *paligned_in++;
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n -= LITTLEBLOCKSIZE;
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}
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pout = (FAR unsigned char *)paligned_out;
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pin = (FAR unsigned char *)paligned_in;
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}
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else if (!TOO_SMALL4(n) && !UNALIGNED4(pin, pout))
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{
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FAR uint32_t *paligned_out = (FAR uint32_t *)pout;
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FAR const uint32_t *paligned_in = (FAR uint32_t *)pin;
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uint32_t mask = 0;
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unsigned int i;
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for (i = 0; i < LITTLEBLOCKSIZE4; i++)
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{
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mask = (mask << 8) + endchar;
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}
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while (n >= LITTLEBLOCKSIZE4)
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{
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uint32_t buffer = *paligned_in;
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buffer ^= mask;
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if (DETECTNULL32(buffer))
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{
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break;
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}
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*paligned_out++ = *paligned_in++;
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n -= LITTLEBLOCKSIZE4;
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}
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pout = (FAR unsigned char *)paligned_out;
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pin = (FAR unsigned char *)paligned_in;
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}
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while (n--)
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{
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if ((*pout++ = *pin++) == endchar)
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{
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return pout;
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}
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}
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return NULL;
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}
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