8a36da99de
Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts.
118 lines
3.3 KiB
C
118 lines
3.3 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2012 Ed Schouten <ed@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/libkern.h>
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#include <sys/limits.h>
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#include <sys/param.h>
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/*
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* memcchr(): find first character in buffer not matching `c'.
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*
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* This function performs the complement of memchr(). To provide decent
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* performance, this function compares data from the buffer one word at
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* a time.
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*
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* This code is inspired by libc's strlen(), written by Xin Li.
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*/
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#if LONG_BIT != 32 && LONG_BIT != 64
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#error Unsupported word size
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#endif
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#define LONGPTR_MASK (sizeof(long) - 1)
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#define TESTBYTE \
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do { \
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if (*p != (unsigned char)c) \
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goto done; \
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p++; \
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} while (0)
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void *
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memcchr(const void *begin, int c, size_t n)
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{
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const unsigned long *lp;
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const unsigned char *p, *end;
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unsigned long word;
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/* Four or eight repetitions of `c'. */
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word = (unsigned char)c;
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word |= word << 8;
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word |= word << 16;
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#if LONG_BIT >= 64
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word |= word << 32;
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#endif
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/* Don't perform memory I/O when passing a zero-length buffer. */
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if (n == 0)
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return (NULL);
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/*
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* First determine whether there is a character unequal to `c'
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* in the first word. As this word may contain bytes before
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* `begin', we may execute this loop spuriously.
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*/
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lp = (const unsigned long *)((uintptr_t)begin & ~LONGPTR_MASK);
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end = (const unsigned char *)begin + n;
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if (*lp++ != word)
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for (p = begin; p < (const unsigned char *)lp;)
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TESTBYTE;
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/* Now compare the data one word at a time. */
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for (; (const unsigned char *)lp < end; lp++) {
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if (*lp != word) {
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p = (const unsigned char *)lp;
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TESTBYTE;
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TESTBYTE;
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TESTBYTE;
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#if LONG_BIT >= 64
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TESTBYTE;
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TESTBYTE;
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TESTBYTE;
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TESTBYTE;
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#endif
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goto done;
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}
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}
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return (NULL);
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done:
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/*
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* If the end of the buffer is not word aligned, the previous
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* loops may obtain an address that's beyond the end of the
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* buffer.
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*/
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if (p < end)
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return (__DECONST(void *, p));
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return (NULL);
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}
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