chromium/third_party/abseil-cpp/absl/random/log_uniform_int_distribution.h

// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef ABSL_RANDOM_LOG_UNIFORM_INT_DISTRIBUTION_H_
#define ABSL_RANDOM_LOG_UNIFORM_INT_DISTRIBUTION_H_

#include <algorithm>
#include <cassert>
#include <cmath>
#include <istream>
#include <limits>
#include <ostream>
#include <type_traits>

#include "absl/numeric/bits.h"
#include "absl/random/internal/fastmath.h"
#include "absl/random/internal/generate_real.h"
#include "absl/random/internal/iostream_state_saver.h"
#include "absl/random/internal/traits.h"
#include "absl/random/uniform_int_distribution.h"

namespace absl {
ABSL_NAMESPACE_BEGIN

// log_uniform_int_distribution:
//
// Returns a random variate R in range [min, max] such that
// floor(log(R-min, base)) is uniformly distributed.
// We ensure uniformity by discretization using the
// boundary sets [0, 1, base, base * base, ... min(base*n, max)]
//
template <typename IntType = int>
class log_uniform_int_distribution { … };

template <typename IntType>
template <typename URBG>
typename log_uniform_int_distribution<IntType>::unsigned_type
log_uniform_int_distribution<IntType>::Generate(
    URBG& g,  // NOLINT(runtime/references)
    const param_type& p) { … }

template <typename CharT, typename Traits, typename IntType>
std::basic_ostream<CharT, Traits>& operator<<(
    std::basic_ostream<CharT, Traits>& os,  // NOLINT(runtime/references)
    const log_uniform_int_distribution<IntType>& x) { … }

template <typename CharT, typename Traits, typename IntType>
std::basic_istream<CharT, Traits>& operator>>(
    std::basic_istream<CharT, Traits>& is,       // NOLINT(runtime/references)
    log_uniform_int_distribution<IntType>& x) { … }

ABSL_NAMESPACE_END
}  // namespace absl

#endif  // ABSL_RANDOM_LOG_UNIFORM_INT_DISTRIBUTION_H_