1 // Copyright 2017 The Abseil Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef ABSL_RANDOM_INTERNAL_SEQUENCE_URBG_H_ 16 #define ABSL_RANDOM_INTERNAL_SEQUENCE_URBG_H_ 17 18 #include <cstdint> 19 #include <cstring> 20 #include <limits> 21 #include <type_traits> 22 #include <vector> 23 24 #include "absl/base/config.h" 25 26 namespace absl { 27 ABSL_NAMESPACE_BEGIN 28 namespace random_internal { 29 30 // `sequence_urbg` is a simple random number generator which meets the 31 // requirements of [rand.req.urbg], and is solely for testing absl 32 // distributions. 33 class sequence_urbg { 34 public: 35 using result_type = uint64_t; 36 result_type(min)37 static constexpr result_type(min)() { 38 return (std::numeric_limits<result_type>::min)(); 39 } result_type(max)40 static constexpr result_type(max)() { 41 return (std::numeric_limits<result_type>::max)(); 42 } 43 sequence_urbg(std::initializer_list<result_type> data)44 sequence_urbg(std::initializer_list<result_type> data) : i_(0), data_(data) {} reset()45 void reset() { i_ = 0; } 46 operator()47 result_type operator()() { return data_[i_++ % data_.size()]; } 48 invocations()49 size_t invocations() const { return i_; } 50 51 private: 52 size_t i_; 53 std::vector<result_type> data_; 54 }; 55 56 } // namespace random_internal 57 ABSL_NAMESPACE_END 58 } // namespace absl 59 60 #endif // ABSL_RANDOM_INTERNAL_SEQUENCE_URBG_H_ 61