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#include "fast.h"
#include <util/stream/input.h>
static inline ui32 FixSeq(ui32 seq1, ui32 seq2) noexcept {
const ui32 mask = (~(ui32)(0)) >> 1;
if ((seq1 & mask) == (seq2 & mask)) {
return ~seq2;
}
return seq2;
}
TFastRng64::TFastRng64(ui64 seed1, ui32 seq1, ui64 seed2, ui32 seq2) noexcept
: R1_(seed1, seq1)
, R2_(seed2, FixSeq(seq1, seq2))
{
}
TFastRng64::TArgs::TArgs(ui64 seed) noexcept {
TReallyFastRng32 rng(seed);
Seed1 = rng.GenRand64();
Seq1 = rng.GenRand();
Seed2 = rng.GenRand64();
Seq2 = rng.GenRand();
}
TFastRng64::TArgs::TArgs(IInputStream& entropy) {
static_assert(sizeof(*this) == 3 * sizeof(ui64), "please, fix me");
entropy.LoadOrFail(this, sizeof(*this));
}
template <class T>
static inline T Read(IInputStream& in) noexcept {
T t = T();
in.LoadOrFail(&t, sizeof(t));
return t;
}
TFastRng32::TFastRng32(IInputStream& entropy)
: TFastRng32(Read<ui64>(entropy), Read<ui32>(entropy))
{
}
TReallyFastRng32::TReallyFastRng32(IInputStream& entropy)
: TReallyFastRng32(Read<ui64>(entropy))
{
}
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