mirror of
https://github.com/SerenityOS/serenity
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471db7ce0a
Add count_trailing_zeroes_32() which is implemented with builtins if available, otherwise there's a generic fallback.
100 lines
3.3 KiB
C++
100 lines
3.3 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.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 are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND 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 ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER 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 OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#ifdef __i386__
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# define AK_ARCH_I386 1
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#endif
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#ifdef __x86_64__
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# define AK_ARCH_X86_64 1
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#endif
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#define ARCH(arch) (defined(AK_ARCH_##arch) && AK_ARCH_##arch)
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#ifdef __clang__
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# define CONSUMABLE(initial_state) __attribute__((consumable(initial_state)))
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# define CALLABLE_WHEN(...) __attribute__((callable_when(__VA_ARGS__)))
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# define SET_TYPESTATE(state) __attribute__((set_typestate(state)))
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# define RETURN_TYPESTATE(state) __attribute__((return_typestate(state)))
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#else
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# define CONSUMABLE(initial_state)
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# define CALLABLE_WHEN(...)
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# define SET_TYPESTATE(state)
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# define RETURN_TYPESTATE(state)
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#endif
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#ifndef __serenity__
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# define PAGE_SIZE sysconf(_SC_PAGESIZE)
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# include <errno.h>
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# include <fcntl.h>
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# include <stdlib.h>
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# include <string.h>
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inline int open_with_path_length(const char* path, size_t path_length, int options, mode_t mode)
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{
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auto* tmp = (char*)malloc(path_length + 1);
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memcpy(tmp, path, path_length);
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tmp[path_length] = '\0';
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int fd = open(tmp, options, mode);
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int saved_errno = errno;
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free(tmp);
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errno = saved_errno;
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return fd;
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}
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#endif
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template<typename T>
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[[gnu::always_inline]] inline T convert_between_host_and_network(T value)
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{
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#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
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if constexpr (sizeof(T) == 8)
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return __builtin_bswap64(value);
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if constexpr (sizeof(T) == 4)
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return __builtin_bswap32(value);
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if constexpr (sizeof(T) == 2)
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return __builtin_bswap16(value);
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if constexpr (sizeof(T) == 1)
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return value;
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#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
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return value;
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#endif
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}
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[[gnu::always_inline]] inline int count_trailing_zeroes_32(unsigned int val)
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{
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#if defined(__GNUC__) || defined(__clang__)
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return __builtin_ctz(val);
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#else
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for (u8 i = 0; i < 32; ++i) {
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if ((val >> i) & 1) {
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return i;
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}
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}
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return 0;
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#endif
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} |