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#ifndef SLANG_CORE_RANDOM_GENERATOR_H
#define SLANG_CORE_RANDOM_GENERATOR_H
#include "slang-smart-pointer.h"
#include "slang.h"
#include <stdlib.h>
#include <string.h>
namespace Slang
{
class RandomGenerator : public RefObject
{
public:
/// Make a copy of the generator in the same state
virtual RandomGenerator* clone() = 0;
/// Reset with a seed
virtual void reset(int32_t seed) = 0;
/// Next int32_t random number
virtual int32_t nextInt32() = 0;
/// Next int64_t random number
virtual int64_t nextInt64();
/// Get a 0-1 range floating point
virtual float nextUnitFloat32();
/// Get the next bool
virtual bool nextBool();
/// Get multiple int32s
virtual void nextInt32s(int32_t* dst, size_t count) = 0;
/// Next uint32_t
uint32_t nextUInt32() { return uint32_t(nextInt32()); }
/// Next Int32 which can only be positive
int32_t nextPositiveInt32() { return nextInt32() & 0x7fffffff; }
/// Next Int64 which can only be positive
int64_t nextPositiveInt64() { return nextInt64() & SLANG_INT64(0x7fffffffffffffff); }
/// Returns value up to BUT NOT INCLUDING maxValue.
int32_t nextInt32UpTo(int32_t maxValue)
{
assert(maxValue > 0);
return (maxValue <= 1) ? 0 : (nextPositiveInt32() % maxValue);
}
/// Returns value from min up to BUT NOT INCLUDING max.
int32_t nextInt32InRange(int32_t min, int32_t max);
/// Returns value from min up to BUT NOT INCLUDING max
uint32_t nextUInt32InRange(uint32_t min, uint32_t max);
/// Returns value up to BUT NOT INCLUDING maxValue
int64_t nextInt64UpTo(int64_t maxValue)
{
assert(maxValue > 0);
return (maxValue <= 1) ? 0 : (nextPositiveInt64() % maxValue);
}
/// Returns value from min up to BUT NOT INCLUDING max
int64_t nextInt64InRange(int64_t min, int64_t max);
/// Fill with random data.
/// NOTE! Output is only identical bytes if generator in same state *and* size_t(dst) & 3 is the
/// same on calls.
void nextData(void* dst, size_t size);
/// Create a RandomGenerator with specified seed using default generator type
static RandomGenerator* create(int32_t seed);
};
/* Mersenne Twister random number generator
https://en.wikipedia.org/wiki/Mersenne_Twister
*/
class Mt19937RandomGenerator : public RandomGenerator
{
public:
typedef Mt19937RandomGenerator ThisType;
enum
{
kNumEntries = 624
};
Mt19937RandomGenerator* clone() SLANG_OVERRIDE { return new ThisType(*this); }
void reset(int32_t seed) SLANG_OVERRIDE;
int32_t nextInt32() SLANG_OVERRIDE;
void nextInt32s(int32_t* dst, size_t count) SLANG_OVERRIDE;
/// Ctor
Mt19937RandomGenerator();
Mt19937RandomGenerator(const ThisType& rhs);
explicit Mt19937RandomGenerator(int32_t seed);
/// Assignment
void operator=(const ThisType& rhs)
{
m_index = rhs.m_index;
::memcpy(m_mt, rhs.m_mt, sizeof(m_mt));
}
protected:
void _generate();
uint32_t m_mt[kNumEntries]; ///< The random state vector
int m_index; ///< If set to >= kMaxEntries it means reset
};
typedef Mt19937RandomGenerator DefaultRandomGenerator;
} // namespace Slang
#endif // SLANG_RANDOM_GENERATOR_H
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