// 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_INTERNAL_SEQUENCE_URBG_H_ #define ABSL_RANDOM_INTERNAL_SEQUENCE_URBG_H_ #include <cstdint> #include <cstring> #include <limits> #include <type_traits> #include <vector> #include "absl/base/config.h" namespace absl { ABSL_NAMESPACE_BEGIN namespace random_internal { // `sequence_urbg` is a simple random number generator which meets the // requirements of [rand.req.urbg], and is solely for testing absl // distributions. class sequence_urbg { public: using result_type = uint64_t; static constexpr result_type(min)() { return (std::numeric_limits<result_type>::min)(); } static constexpr result_type(max)() { return (std::numeric_limits<result_type>::max)(); } sequence_urbg(std::initializer_list<result_type> data) : i_(0), data_(data) {} void reset() { i_ = 0; } result_type operator()() { return data_[i_++ % data_.size()]; } size_t invocations() const { return i_; } private: size_t i_; std::vector<result_type> data_; }; } // namespace random_internal ABSL_NAMESPACE_END } // namespace absl #endif // ABSL_RANDOM_INTERNAL_SEQUENCE_URBG_H_