mirror of https://github.com/sudo-project/sudo.git
82 lines
2.1 KiB
C
82 lines
2.1 KiB
C
/*
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* SPDX-License-Identifier: ISC
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*
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* Copyright (c) 2019-2020 Todd C. Miller <Todd.Miller@sudo.ws>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* This is an open source non-commercial project. Dear PVS-Studio, please check it.
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* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
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*/
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#include <config.h>
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#include <sudo_compat.h>
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#include <sudo_debug.h>
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#include <sudo_util.h>
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/*
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* Round 32-bit unsigned length to the next highest power of two.
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* Always returns at least 64.
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*/
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unsigned int
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sudo_pow2_roundup_v1(unsigned int len)
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{
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if (len < 64)
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return 64;
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#ifdef HAVE___BUILTIN_CLZ
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return 1U << (32 - __builtin_clz(len - 1));
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#else
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len--;
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len |= len >> 1;
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len |= len >> 2;
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len |= len >> 4;
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len |= len >> 8;
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len |= len >> 16;
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len++;
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return len;
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#endif
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}
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/*
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* Round a size_t length to the next highest power of two.
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* Always returns at least 64.
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*/
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size_t
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sudo_pow2_roundup_v2(size_t len)
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{
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if (len < 64)
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return 64;
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#if defined(__LP64__) && defined(HAVE___BUILTIN_CLZL)
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return 1UL << (64 - __builtin_clzl(len - 1));
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#elif !defined(__LP64__) && defined(HAVE___BUILTIN_CLZ)
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return 1U << (32 - __builtin_clz(len - 1));
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#else
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len--;
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len |= len >> 1;
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len |= len >> 2;
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len |= len >> 4;
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len |= len >> 8;
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len |= len >> 16;
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# ifdef __LP64__
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len |= len >> 32;
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# endif
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len++;
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return len;
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#endif
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}
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