pcg.h

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#pragma once
 
 
#include <cx/cx.h>
#include <cx/debug/assert.h>
 
CX_C_BEGIN
 
 
typedef struct PcgState {
    uint64 state;   
    uint64 inc;     
} PcgState;
 
 
void pcgSeed(_Out_ PcgState* rng, uint64 initstate, uint64 initseq);
 
void pcgAutoSeed(_Out_ PcgState* rng);
 
 
 
uint32 pcgRandom(_Inout_ PcgState* rng);
 
uint32 pcgBounded(_Inout_ PcgState* rng, uint32 bound);
 
bool pcgFlip(_Inout_ PcgState* rng);
 
_meta_inline int32 pcgSBounded(_Inout_ PcgState* rng, int32 bound)
{
    devAssert(bound >= 0);
    return (int32)pcgBounded(rng, bound);
}
 
_meta_inline uint32 pcgRange(_Inout_ PcgState* rng, uint32 lower, uint32 upper)
{
    if (lower >= upper)
        return lower;
 
    return lower + pcgBounded(rng, upper - lower + 1);
}
 
_meta_inline int32 pcgSRange(_Inout_ PcgState* rng, int32 lower, int32 upper)
{
    if (lower >= upper)
        return lower;
 
    return (int32)(lower + pcgBounded(rng, (uint32)(upper - lower + 1)));
}
 
uint64 pcgRandom64(_Inout_ PcgState* rng);
 
uint64 pcgBounded64(_Inout_ PcgState* rng, uint64 bound);
 
_meta_inline uint64 pcgRange64(_Inout_ PcgState* rng, uint64 lower, uint64 upper)
{
    if (lower >= upper)
        return lower;
 
    return lower + pcgBounded64(rng, upper - lower + 1);
}
 
_meta_inline int64 pcgSRange64(_Inout_ PcgState* rng, int64 lower, int64 upper)
{
    if (lower >= upper)
        return lower;
 
    return (int64)(lower + pcgBounded64(rng, (uint64)(upper - lower + 1)));
}
 
float32 pcgFRange(_Inout_ PcgState* rng, float32 lower, float32 upper);
 
float64 pcgFRange64(_Inout_ PcgState* rng, float64 lower, float64 upper);
 
 
 
void pcgAdvance(_Inout_ PcgState* rng, uint64 delta);
 
 
 
CX_C_END