mirror of
https://github.com/matrix-construct/construct
synced 2024-11-05 05:18:54 +01:00
131 lines
2.6 KiB
C++
131 lines
2.6 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or 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 is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_RAND_H
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/// Some character set dictionaries
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namespace ircd::rand::dict
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{
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extern const std::string alnum;
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extern const std::string alpha;
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extern const std::string upper;
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extern const std::string lower;
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extern const std::string numeric;
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}
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/// Tools for randomization
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namespace ircd::rand
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{
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struct xoshiro256p;
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// Interface state.
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extern std::random_device device;
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extern std::mt19937_64 mt;
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// Random integer
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uint64_t integer() noexcept;
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uint64_t integer(const uint64_t &min, const uint64_t &max) noexcept; // inclusive
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uint64_t integer(xoshiro256p &) noexcept;
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// Random vector
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template<class T> T vector() noexcept = delete;
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template<> u128x1 vector() noexcept;
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template<> u256x1 vector() noexcept;
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template<> u512x1 vector() noexcept;
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// Random fill of buffer
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const_buffer fill(const mutable_buffer &out) noexcept;
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// Random fill of array
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template<class T,
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size_t S>
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decltype(auto) fill(T (&buf)[S]) noexcept;
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// Random character from dictionary
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char character(const std::string &dict = dict::alnum) noexcept;
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// Random string from dictionary, fills buffer
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string_view string(const mutable_buffer &out, const std::string &dict) noexcept;
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}
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struct ircd::rand::xoshiro256p
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{
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uint64_t s[4];
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xoshiro256p() noexcept;
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};
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template<class T,
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size_t S>
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inline decltype(auto)
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ircd::rand::fill(T (&buf)[S])
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noexcept
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{
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static_assert
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(
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sizeof(buf) == sizeof(T) * S
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);
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const mutable_buffer mb
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{
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reinterpret_cast<char *>(buf), sizeof(buf)
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};
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fill(mb);
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return buf;
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}
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/// Random character from dictionary
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inline char
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ircd::rand::character(const std::string &dict)
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noexcept
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{
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assert(!dict.empty());
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const auto pos
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{
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integer(0, dict.size() - 1)
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};
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assert(pos < dict.size());
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return dict[pos];
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}
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inline
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ircd::rand::xoshiro256p::xoshiro256p()
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noexcept
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{
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fill(s);
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}
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inline uint64_t
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ircd::rand::integer(xoshiro256p &state)
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noexcept
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{
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auto &s(state.s);
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const u64
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ret(s[0] + s[3]),
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t(s[1] << 17);
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s[2] ^= s[0];
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s[3] ^= s[1];
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s[1] ^= s[2];
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s[0] ^= s[3];
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s[2] ^= t;
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#if __has_builtin(__builtin_rotateleft64)
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s[3] = __builtin_rotateleft64(s[3], 45);
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#else
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s[3] = (s[3] << 45) | (s[3] >> (64 - 45));
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#endif
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return ret;
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}
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