X:/dropbox/visualizationlibrary/src/vlCore/Random.cpp

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/**************************************************************************************/
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/*  Visualization Library                                                             */
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/*  Copyright (c) 2005-2010, Michele Bosi                                             */
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#include <vlCore/Random.hpp>
#include <vlCore/Time.hpp>
#include <vlCore/Log.hpp>
#include <vlCore/MersenneTwister.hpp>
#include <cstdlib>

#if defined(VL_PLATFORM_WINDOWS)
  #include <wincrypt.h>
#endif

using namespace vl;

//-----------------------------------------------------------------------------
Random::Random()
{
  VL_DEBUG_SET_OBJECT_NAME()
#if defined(_MSC_VER) || defined(__MINGW32__)
  hCryptProv = NULL;
  if( !CryptAcquireContext( (HCRYPTPROV*)&hCryptProv, NULL, NULL, PROV_RSA_FULL, 0) )
    hCryptProv = NULL;
#elif defined(__GNUG__) && !defined(__MINGW32__)
  mDefURandom = fopen("/dev/urandom", "rb");
#endif
}
//-----------------------------------------------------------------------------
Random::~Random()
{
#if defined(_MSC_VER) || defined(__MINGW32__)
  if( hCryptProv  )
  {
    CryptReleaseContext( (HCRYPTPROV)hCryptProv, 0 );
    hCryptProv = NULL;
  }
#elif defined(__GNUG__) && !defined(__MINGW32__)
  if (mDefURandom)
  {
    fclose(mDefURandom);
    mDefURandom = NULL;
  }
#endif
}
//-----------------------------------------------------------------------------
bool Random::fillRandom(void* ptr, size_t bytes) const
{
#if defined(_MSC_VER) || defined(__MINGW32__)
  if( !(hCryptProv && CryptGenRandom( (HCRYPTPROV)hCryptProv, bytes, (BYTE*)ptr)) )
  {
    fillRandomMersenneTwister(ptr, bytes);
    return false;
  }
  else
    return true;
#elif defined(__GNUG__) && !defined(__MINGW32__)
  if ( mDefURandom && fread(ptr, 1, bytes, mDefURandom) == bytes )
    return true;
  else
  {
    fillRandomMersenneTwister(ptr, bytes);
    return false;
  }
#else
  fillRandomMersenneTwister(ptr, bytes);
  return false;
#endif
}
//-----------------------------------------------------------------------------
void Random::fillRandomMersenneTwister(void* ptr, size_t bytes) const
{
  unsigned int rnd = 0;

  unsigned char* cptr = (unsigned char*)ptr;
  memset(cptr, 0, bytes);
  for (size_t i=0; i<bytes; ++i)
  {
    defMersenneTwister()->randInt( rnd );
    cptr[i] ^= (rnd>>0)  & 0xFF;
    cptr[i] ^= (rnd>>8)  & 0xFF;
    cptr[i] ^= (rnd>>16) & 0xFF;
    cptr[i] ^= (rnd>>12) & 0xFF;
  }
}
//-----------------------------------------------------------------------------