mirror of https://gitee.com/bigwinds/arangodb
100 lines
2.9 KiB
C++
100 lines
2.9 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Dr. Frank Celler
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGODB_RANDOM_RANDOM_GENERATOR_H
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#define ARANGODB_RANDOM_RANDOM_GENERATOR_H 1
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#include <cstdint>
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#include <memory>
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namespace arangodb {
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// -----------------------------------------------------------------------------
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// RandomDevice
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// -----------------------------------------------------------------------------
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class RandomDevice {
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RandomDevice(RandomDevice const&) = delete;
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RandomDevice& operator=(RandomDevice const&) = delete;
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public:
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RandomDevice() {}
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virtual ~RandomDevice() {}
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public:
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virtual uint32_t random() = 0;
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public:
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int32_t interval(int32_t left, int32_t right);
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uint32_t interval(uint32_t left, uint32_t right);
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public:
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static unsigned long seed();
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private:
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int32_t random(int32_t left, int32_t right);
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int32_t power2(int32_t left, uint32_t right);
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int32_t other(int32_t left, uint32_t right);
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};
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// -----------------------------------------------------------------------------
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// RandomGenerator
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// -----------------------------------------------------------------------------
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class RandomGenerator {
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RandomGenerator(RandomGenerator const&) = delete;
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RandomGenerator& operator=(RandomGenerator const&) = delete;
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public:
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enum class RandomType {
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MERSENNE = 1,
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RANDOM = 2,
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URANDOM = 3,
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COMBINED = 4,
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WINDOWS_CRYPT = 5 // uses the built in cryptographic services offered and
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// recommended by microsoft (e.g. CryptGenKey(...) )
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};
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public:
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static void initialize(RandomType);
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static void shutdown();
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static void ensureDeviceIsInitialized();
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static void seed(uint64_t);
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static int16_t interval(int16_t, int16_t);
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static int32_t interval(int32_t, int32_t);
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static int64_t interval(int64_t, int64_t);
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static uint16_t interval(uint16_t);
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static uint32_t interval(uint32_t);
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static uint64_t interval(uint64_t);
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private:
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static RandomType _type;
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static thread_local std::unique_ptr<RandomDevice> _device;
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};
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} // namespace arangodb
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#endif
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