geode-client-native/src/tests/fwklib/GsRandom.cpp

/*=========================================================================
 * Copyright (c) 2002-2014 Pivotal Software, Inc. All Rights Reserved.  
 * This product is protected by U.S. and international copyright
 * and intellectual property laws. Pivotal products are covered by
 * more patents listed at http://www.pivotal.io/patents.
 *=========================================================================
 */

#include "GsRandom.hpp"

using namespace gemfire;
using namespace gemfire::testframework;

GsRandom * GsRandom::singleton = 0;
MTRand GsRandom::gen;
int32_t GsRandom::seedUsed = -101;
SpinLock GsRandom::lck;
  
  /** 
    * Creates a new random number generator using a single 
    * <code>int32_t</code> seed. 
    *
    * @param   seed   the initial seed.
    * @see     java.util.Random#Random(int32_t)
    */
GsRandom * GsRandom::getInstance(int32_t seed) {
  if ( singleton == 0 )
    setInstance(seed);
  else
  {
    SpinLockGuard guard( lck );
    setSeed(seed);
  }
  return singleton;
}
  
void GsRandom::setInstance(int32_t seed) {
  SpinLockGuard guard( lck );
  if ( singleton == 0 ) {
    singleton = new GsRandom();
    if (seed != -1)
      singleton->gen.seed(seed);
    else
      singleton->gen.seed();
    seedUsed = seed;
  }
}

void GsRandom::setSeed(int32_t seed) {
  if (seed != seedUsed)
  {
    if (seed != -1)
      singleton->gen.seed(seed);
    else
      singleton->gen.seed();
    seedUsed = seed;
  }
}

/**
* @param max the maximum length of the random string to generate.
* @param min the minimum length of the random string to generate, default is 0.
* @return a bounded random string with a length between min and
* max length inclusive.
*/
char * GsRandom::randomString(int32_t max, int32_t min) {
  int32_t len = (max == min) ? max : nextInt(min, max);
  char * buf = (char *)malloc(len + 1);
  for (int32_t i = 0; i < len; i++)
    buf[i] = nextByte();
  buf[len] = 0;
  return buf;
}

/**
* Like randomString(), but returns only readable characters.
*
* @param max the maximum length of the random string to generate.
* @param min the minimum length of the random string to generate, default is 0.
* @return a bounded random string with a length between min and
* max length inclusive.
*/
char * GsRandom::randomReadableString(int32_t max, int32_t min) {
  int32_t len = (max == min) ? max : nextInt(min, max);
  char * buf = (char *)malloc(len + 1);
  for (int32_t i = 0; i < len; i++)
    buf[i] = nextByte(32, 126);
  buf[len] = 0;
  return buf;
}

const char choseFrom[] = "0123456789 abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const int32_t choseSize = static_cast<int32_t> (strlen(choseFrom)) - 1;
/**
* Like randomString(), but returns only only alphanumeric, underscore, or space characters.
*
* @param max the maximum length of the random string to generate.
* @param min the minimum length of the random string to generate, default is 0.
* @return a bounded random string with a length between min and
* max length inclusive.
*/
char * GsRandom::randomAlphanumericString(int32_t max, int32_t min, const char * prefix) {
  int32_t len = (max == min) ? max : nextInt(min, max);
  char * buf = (char *)malloc(len + 1);
  for (int32_t i = 0; i < len; i++)
    buf[i] = choseFrom[nextByte(0, choseSize)];
  buf[len] = 0;
  return buf;
}