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/* $Id$ */
/** @file
* IPRT - ASMMemZeroPage - generic C implementation.
*/
/*
* Copyright (C) 2006-2022 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include <iprt/asm.h>
#include "internal/iprt.h"
RTDECL(void RT_FAR *) ASMMemFirstNonZero(void const RT_FAR *pv, size_t cb) RT_NOTHROW_DEF
{
uint8_t const *pb = (uint8_t const RT_FAR *)pv;
/*
* If we've got a large buffer to search, do it in larger units.
*/
if (cb >= sizeof(size_t) * 2)
{
/* Align the pointer: */
while ((uintptr_t)pb & (sizeof(size_t) - 1))
{
if (RT_LIKELY(*pb == 0))
{ /* likely */ }
else
return (void RT_FAR *)pb;
cb--;
pb++;
}
/* Scan in size_t sized words: */
while ( cb >= sizeof(size_t)
&& *(size_t *)pb == 0)
{
pb += sizeof(size_t);
cb -= sizeof(size_t);
}
}
/*
* Search byte by byte.
*/
for (; cb; cb--, pb++)
if (RT_LIKELY(*pb == 0))
{ /* likely */ }
else
return (void RT_FAR *)pb;
return NULL;
}
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