kc3-lang/angle/util/random_utils.h

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• Author : Lingfeng Yang
  Date : 2018-06-07 11:33:25
  Hash : 45b5a875
  Message : GLES1: Texture environment API BUG=angleproject:2306 Change-Id: Ibb168d5c9f7aa96a48c96ffbe96ecead2276975e Reviewed-on: https://chromium-review.googlesource.com/1092101 Commit-Queue: Lingfeng Yang <lfy@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>

• util/random_utils.h

• //
  // Copyright (c) 2014 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // random_utils:
  //   Helper functions for random number generation.
  //
  
  #ifndef UTIL_RANDOM_UTILS_H
  #define UTIL_RANDOM_UTILS_H
  
  // TODO(jmadill): Rework this if Chromium decides to ban <random>
  #include <random>
  #include <vector>
  
  #include <export.h>
  
  namespace angle
  {
  
  class ANGLE_EXPORT RNG
  {
    public:
      // Seed from clock
      RNG();
      // Seed from fixed number.
      RNG(unsigned int seed);
      ~RNG();
  
      void reseed(unsigned int newSeed);
  
      bool randomBool(float probTrue = 0.5f);
      int randomInt();
      int randomIntBetween(int min, int max);
      unsigned int randomUInt();
      float randomFloat();
      float randomFloatBetween(float min, float max);
      float randomFloatNonnegative();
      float randomNegativeOneToOne();
  
      template <class T>
      T &randomSelect(std::vector<T> &elements)
      {
          return elements[randomIntBetween(0, elements.size() - 1)];
      }
  
      template <class T>
      const T &randomSelect(const std::vector<T> &elements)
      {
          return elements.at(randomIntBetween(0, elements.size() - 1));
      }
  
    private:
      std::default_random_engine mGenerator;
  };
  
  // Implemented inline to avoid cross-module allocation issues.
  inline void FillVectorWithRandomUBytes(RNG *rng, std::vector<uint8_t> *data)
  {
      for (size_t i = 0; i < data->size(); ++i)
      {
          (*data)[i] = static_cast<uint8_t>(rng->randomIntBetween(0, 255));
      }
  }
  
  inline void FillVectorWithRandomUBytes(std::vector<uint8_t> *data)
  {
      RNG rng;
      FillVectorWithRandomUBytes(&rng, data);
  }
  
  }  // namespace angle
  
  #endif  // UTIL_RANDOM_UTILS_H