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1f7fe97ac3
This will be useful for CSS random functions so it should be in a reusable place. This does require us to use `AK::get_random` instead of `Crypto::get_secure_random`, but this is fine since the latter is in the process of being removed (see #6564).
66 lines
1.2 KiB
C++
66 lines
1.2 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <andreas@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Platform.h>
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#include <AK/Span.h>
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#include <AK/StdLibExtras.h>
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#include <AK/Types.h>
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#include <stdlib.h>
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#if defined(__unix__)
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# include <unistd.h>
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#endif
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namespace AK {
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void fill_with_random([[maybe_unused]] Bytes bytes);
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template<typename T>
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inline T get_random()
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{
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T t;
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fill_with_random({ &t, sizeof(T) });
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return t;
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}
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u32 get_random_uniform(u32 max_bounds);
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u64 get_random_uniform_64(u64 max_bounds);
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// http://vigna.di.unimi.it/ftp/papers/xorshiftplus.pdf
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class XorShift128PlusRNG {
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public:
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XorShift128PlusRNG();
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double get();
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private:
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u64 splitmix64(u64& state);
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u64 advance();
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u64 m_low { 0 };
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u64 m_high { 0 };
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};
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template<typename Collection>
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inline void shuffle(Collection& collection)
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{
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// Fisher-Yates shuffle
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for (size_t i = collection.size() - 1; i >= 1; --i) {
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size_t j = get_random_uniform(i + 1);
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AK::swap(collection[i], collection[j]);
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}
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}
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}
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#if USING_AK_GLOBALLY
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using AK::fill_with_random;
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using AK::get_random;
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using AK::get_random_uniform;
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using AK::shuffle;
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using AK::XorShift128PlusRNG;
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#endif
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