tdlight/tdutils/td/utils/Random.h

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//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2021
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/utils/common.h"
#include "td/utils/Slice.h"
#include "td/utils/Span.h"
#include <utility>
namespace td {
class Random {
public:
#if TD_HAVE_OPENSSL
static void secure_bytes(MutableSlice dest);
static void secure_bytes(unsigned char *ptr, size_t size);
static int32 secure_int32();
static int64 secure_int64();
static uint32 secure_uint32();
static uint64 secure_uint64();
// works only for current thread
static void add_seed(Slice bytes, double entropy = 0);
static void secure_cleanup();
#endif
static uint32 fast_uint32();
static uint64 fast_uint64();
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// distribution is not uniform, min_value and max_value are included
static int fast(int min_value, int max_value);
static double fast(double min_value, double max_value);
static bool fast_bool();
class Fast {
public:
uint64 operator()() {
return fast_uint64();
}
};
class Xorshift128plus {
public:
explicit Xorshift128plus(uint64 seed);
Xorshift128plus(uint64 seed_a, uint64 seed_b);
uint64 operator()();
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int fast(int min_value, int max_value);
int64 fast64(int64 min_value, int64 max_value);
void bytes(MutableSlice dest);
private:
uint64 seed_[2];
};
};
template <class T, class R>
void random_shuffle(MutableSpan<T> v, R &rnd) {
for (size_t i = 1; i < v.size(); i++) {
auto pos = static_cast<size_t>(rnd()) % (i + 1);
using std::swap;
swap(v[i], v[pos]);
}
}
} // namespace td