AuroraRuntime/Source/RNG/AuRandomDevice.cpp

337 lines
8.4 KiB
C++

/***
Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.
File: AuRandomDevice.cpp
Date: 2021-9-3
Author: Reece
***/
#include <AuroraRuntime.hpp>
#include "AuRandomDevice.hpp"
namespace Aurora::RNG
{
static const double kDblEpsilon = 2.2204460492503131e-16;
RandomDevice::RandomDevice()
{
}
RandomDevice::RandomDevice(const RandomDef &def)
{
this->Init(def);
}
void RandomDevice::Init(const RandomDef &def)
{
this->def_ = def;
// Gross...
if (!def.bSecure)
{
if (def.seed)
{
this->fast_ = AuMove(WELL_SeedRand(def.seed.value()));
}
else if (def.seed64)
{
this->fast_ = AuMove(WELL_SeedRand64(def.seed64.value()));
}
else if (def.seedMassive)
{
this->fast_ = AuMove(WELL_SeedRandBig64(def.seedMassive.value()));
}
else
{
RNG::RngFillArray<false>(this->fast_.state);
}
}
// secure rng requires no init -> we just passthrough to the global ReadSecureRNG function
}
void RandomDevice::Read(Memory::MemoryViewWrite view)
{
if (!view)
{
SysPushErrorArg();
return;
}
if (this->def_.bSecure)
{
ReadSecureRNG(view);
}
else
{
WELL_NextBytes(&this->fast_, view.ptr, AuUInt32(view.length));
}
}
AuString RandomDevice::NextString(AuUInt32 uLength, ERngStringCharacters type)
{
AuString ret(uLength, '\00');
NextString(ret.data(), AuUInt32(ret.size()), type);
return ret;
}
static AuUInt64 RngConvertBounds(AuUInt32 i)
{
AuUInt8 ret;
AuBitScanReverse(ret, i);
return 1ull << (ret + 1);
}
void RandomDevice::NextString(char *pString, AuUInt32 uLength, ERngStringCharacters type)
{
static AuPair<const char *, int> rngSequence[static_cast<int>(ERngStringCharacters::eEnumCount)] =
{
{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", 52},
{"abcdefghijklmnopqrstuvwxyz", 26},
{"ABCDEFGHIJKLMNOPQRSTUVWXYZ", 26},
{"1234567890", 10},
{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890", 62},
{"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890=-+!$%^*.[];:", 75}
};
if (!pString)
{
SysPushErrorArg();
return;
}
Read(AuMemoryViewWrite { pString, uLength });
if (!ERngStringCharactersIsValid(type))
{
SysPushErrorArg("NextString was called with an invalid ERngStringCharacters {}", (AuUInt)type);
type = ERngStringCharacters::eAlphaNumericCharacters; // guess we cant just return false
}
const auto &pair = rngSequence[static_cast<int>(type)];
for (auto i = 0u; i < uLength; i++)
{
auto uUpperBound = RngConvertBounds(pair.second);
AuUInt8 uNext {};
auto uWord = reinterpret_cast<const AuUInt8 *>(pString)[i];
while ((uNext = (uWord & (uUpperBound - 1))) >= pair.second)
{
uWord = AuFnv1a32Runtime(&uWord, sizeof(uWord));
}
pString[i] = pair.first[uNext];
}
}
AuUInt8 RandomDevice::NextByte()
{
if (this->def_.bSecure)
{
AuUInt8 uRet {};
ReadSecureRNG({ &uRet, 1 });
return uRet;
}
else
{
return AuUInt8(WELL_NextLong(&this->fast_) & 0xFF);
}
}
bool RandomDevice::NextBoolean()
{
if (this->def_.bSecure)
{
AuUInt8 uRet {};
ReadSecureRNG({ &uRet, 1 });
return bool(uRet & 0x1);
}
else
{
return bool(WELL_NextLong(&this->fast_) & 0x1);
}
}
AuUInt32 RandomDevice::NextU32()
{
if (this->def_.bSecure)
{
AuUInt32 uRet {};
ReadSecureRNG({ &uRet, 4 });
return uRet;
}
else
{
return WELL_NextLong(&this->fast_);
}
}
AuUInt64 RandomDevice::NextU64()
{
if (this->def_.bSecure)
{
AuUInt64 uRet {};
ReadSecureRNG({ &uRet, 8 });
return uRet;
}
else
{
return NextFillTmpl<AuUInt64>();
}
}
AuInt32 RandomDevice::NextInt(AuInt32 uMin, AuInt32 uMax)
{
auto uRange = uMax - uMin;
auto uMassiveWord = NextU32();
auto uUpperBound = RngConvertBounds(uRange + 1);
AuUInt32 uNext {};
while ((uNext = (uMassiveWord & (uUpperBound - 1))) > uRange)
{
uMassiveWord = AuFnv1a32Runtime(&uMassiveWord, sizeof(uMassiveWord));
}
return uMin + uNext;
}
AuUInt32 RandomDevice::NextU32(AuUInt32 uMin, AuUInt32 uMax)
{
auto uRange = uMax - uMin;
auto uMassiveWord = NextU32();
auto uUpperBound = RngConvertBounds(uRange + 1);
AuUInt32 uNext {};
while ((uNext = (uMassiveWord & (uUpperBound - 1))) > uRange)
{
uMassiveWord = AuFnv1a32Runtime(&uMassiveWord, sizeof(uMassiveWord));
}
return uMin + uNext;
}
// Source: https://stackoverflow.com/a/5016867
bool RandomDevice::DecGeometric(int x)
{
if (x <= 0)
{
return true;
}
while (true)
{
auto r = this->NextByte();
if (x < 8)
{
return (r & ((1 << x) - 1)) == 0;
}
else if (r != 0)
{
return false;
}
x -= 8;
}
}
// Source: https://stackoverflow.com/a/5016867
double RandomDevice::UniformFloatInRange(double udMin, double udMax)
{
#if defined(AURNG_USE_GARBAGE_DECIMALS)
return (double(this->NextU32()) * (double(1.0) / double(AuNumericLimits<AuUInt32>::max()))) * udMax;
#else
union
{
double f;
AuUInt64 u;
} convert;
convert.f = udMin;
auto uABits = convert.u;
convert.f = udMax;
auto uBBits = convert.u;
auto uMask = uBBits - uABits;
uMask |= uMask >> 1;
uMask |= uMask >> 2;
uMask |= uMask >> 4;
uMask |= uMask >> 8;
uMask |= uMask >> 16;
uMask |= uMask >> 32;
int bExp {};
frexp(udMax, &bExp);
while (true)
{
int iXExp {};
double x;
auto uXBits = this->NextU64();
uXBits &= uMask;
uXBits += uABits;
if (uXBits >= uBBits)
{
continue;
}
convert.u = uXBits;
x = convert.f;
frexp(x, &iXExp);
if (DecGeometric(bExp - iXExp))
{
return x;
}
}
#endif
}
double RandomDevice::NextDecimal()
{
return this->UniformFloatInRange(kDblEpsilon, 1.0);
}
AuUInt32 RandomDevice::NextIndex(AuUInt32 uCount /* = max + 1*/)
{
auto uMassiveWord = NextU32();
auto uUpperBound = RngConvertBounds(uCount);
AuUInt32 uNext {};
while ((uNext = (uMassiveWord & (uUpperBound - 1))) >= uCount)
{
uMassiveWord = AuFnv1a32Runtime(&uMassiveWord, sizeof(uMassiveWord));
}
return uNext;
}
double RandomDevice::NextNumber(double dMin, double dMax)
{
auto dRange = dMax - dMin;
return this->UniformFloatInRange(kDblEpsilon, dRange + kDblEpsilon) + dMin - kDblEpsilon;
}
AuMemoryViewRead RandomDevice::ToSeed()
{
if (this->def_.bSecure)
{
return {};
}
return this->fast_.state;
}
AUKN_SYM IRandomDevice *RandomNew(const Aurora::RNG::RandomDef &def)
{
auto pDevice = _new RandomDevice();
if (!pDevice)
{
return nullptr;
}
pDevice->Init(def);
return pDevice;
}
AUKN_SYM void RandomRelease(IRandomDevice *pDevice)
{
AuSafeDelete<RandomDevice *>(pDevice);
}
AUROXTL_INTERFACE_SOO_SRC(Random, RandomDevice, (const RandomDef &, def))
}