text: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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
   *
   *     http://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.
   */
  
  #include "Random.h"
  
  #include <decaf/lang/System.h>
  
  #include <decaf/lang/exceptions/NullPointerException.h>
  #include <decaf/lang/exceptions/IllegalArgumentException.h>
  
  using namespace decaf;
  using namespace decaf::util;
  using namespace decaf::lang;
  using namespace decaf::lang::exceptions;
  
  unsigned long long Random::multiplier = 0x5deece66dLL;
  
  ////////////////////////////////////////////////////////////////////////////////
  Random::Random() : haveNextNextGaussian(false), seed(0), nextNextGaussian(0) {
      setSeed( System::currentTimeMillis() );
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  Random::Random( unsigned long long seed ) : haveNextNextGaussian(false), seed(0), nextNextGaussian(0) {
      setSeed( seed );
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  Random::~Random() {
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  bool Random::nextBoolean() {
      return next( 1 ) != 0;
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  void Random::nextBytes( std::vector<unsigned char>& buf ) {
  
      try{
  
          if( buf.empty() ) {
              return;
          }
  
          this->nextBytes( &buf[0], (int)buf.size() );
      }
      DECAF_CATCH_RETHROW( NullPointerException )
      DECAF_CATCH_RETHROW( IllegalArgumentException )
      DECAF_CATCHALL_THROW( Exception )
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  void Random::nextBytes( unsigned char* buf, int size ) {
  
      if( buf == NULL ) {
          throw NullPointerException( __FILE__, __LINE__, "Buffer passed cannot be NULL." );
      }
  
      if( size < 0 ) {
          throw IllegalArgumentException( __FILE__, __LINE__, "Specified buffer size was negative." );
      }
  
      int rand = 0;
      int count = 0, loop = 0;
      while( count < size ) {
          if( loop == 0 ) {
              rand = nextInt();
              loop = 3;
          } else {
              loop--;
          }
          buf[count++] = (unsigned char)rand;
          rand >>= 8;
      }
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  double Random::nextDouble() {
      long long divisor = 1LL;
      divisor <<= 31;
      divisor <<= 22;
      return ( (double)( ( (long long) next(26) << 27) + next(27)) / (double) divisor);
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  float Random::nextFloat() {
      return ( next(24) / 16777216.0f );
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  double Random::nextGaussian() {
  
      if( haveNextNextGaussian ) {
          // if X1 has been returned, return the second Gaussian
          haveNextNextGaussian = false;
          return nextNextGaussian;
      }
  
      double v1, v2, s;
      do {
          // Generates two independent random variables U1, U2
          v1 = 2 * nextDouble() - 1;
          v2 = 2 * nextDouble() - 1;
          s = v1 * v1 + v2 * v2;
      } while( s >= 1 );
      double norm = std::sqrt( -2 * std::log(s) / s );
      // should that not be norm instead of multiplier ?
      nextNextGaussian = v2 * norm;
      haveNextNextGaussian = true;
      // should that not be norm instead of multiplier ?
      return v1 * norm;
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  int Random::nextInt() {
      return next( 32 );
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  int Random::nextInt( int n ) {
  
      if( n > 0 ) {
  
          if( ( n & -n ) == n ) {
              return (int)( ( n * (long long)next( 31 ) ) >> 31 );
          }
  
          int bits, val;
  
          do {
              bits = next( 31 );
              val = bits % n;
          } while( bits - val + ( n - 1 ) < 0 );
  
          return val;
      }
  
      throw exceptions::IllegalArgumentException(
          __FILE__, __LINE__,
          "Value passed cannot be less than or equal to zero." );
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  long long Random::nextLong() {
      return ( (long long) next(32) << 32 ) + next(32);
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  void Random::setSeed( unsigned long long seed ) {
      unsigned long long mask = 1ULL;
      mask <<= 31;
      mask <<= 17;
      this->seed = ( seed ^ multiplier ) & ( mask - 1 );
      haveNextNextGaussian = false;
  }
  
  ////////////////////////////////////////////////////////////////////////////////
  int Random::next( int bits ) {
      long long mask = 1L;
      mask <<= 31;
      mask <<= 17;
      seed = ( seed * multiplier + 0xbL ) & ( mask - 1 );
      // was: return (int) (seed >>> (48 - bits));
      return (int)( seed >> (48 - bits) );
  }
  